From 71f92bb8123a1307bb52af63b13637d774c744eb Mon Sep 17 00:00:00 2001
From: Chris Simpkins <git.simpkins@gmail.com>
Date: Sat, 29 Feb 2020 23:54:13 -0500
Subject: [PATCH 01/40] [tidy] update documentation from `make check` to `x.py
 test`

---
 src/tools/tidy/src/main.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/tools/tidy/src/main.rs b/src/tools/tidy/src/main.rs
index ec8b14c288a2f..0b43396505138 100644
--- a/src/tools/tidy/src/main.rs
+++ b/src/tools/tidy/src/main.rs
@@ -1,8 +1,8 @@
 //! Tidy checks source code in this repository.
 //!
 //! This program runs all of the various tidy checks for style, cleanliness,
-//! etc. This is run by default on `make check` and as part of the auto
-//! builders.
+//! etc. This is run by default on `./x.py test` and as part of the auto
+//! builders. The tidy checks can be executed with `./x.py test src/tools/tidy`.
 
 #![deny(warnings)]
 

From 8858d71d28d68a0063f3ccab1fbf378d69afc78b Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <guillaume1.gomez@gmail.com>
Date: Sat, 16 Nov 2019 16:12:09 +0100
Subject: [PATCH 02/40] Put back output-format option for show-coverage

---
 src/librustdoc/config.rs            | 59 +++++++++++++++++++++++++----
 src/librustdoc/core.rs              |  2 +
 src/librustdoc/html/render.rs       |  3 +-
 src/librustdoc/html/render/cache.rs |  1 +
 4 files changed, 56 insertions(+), 9 deletions(-)

diff --git a/src/librustdoc/config.rs b/src/librustdoc/config.rs
index 33b3e800374e3..99a55f3c68282 100644
--- a/src/librustdoc/config.rs
+++ b/src/librustdoc/config.rs
@@ -1,5 +1,6 @@
 use std::collections::BTreeMap;
 use std::ffi::OsStr;
+use std::convert::TryFrom;
 use std::fmt;
 use std::path::PathBuf;
 
@@ -24,6 +25,33 @@ use crate::opts;
 use crate::passes::{self, Condition, DefaultPassOption};
 use crate::theme;
 
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+pub enum OutputFormat {
+    Json,
+    HTML,
+}
+
+impl OutputFormat {
+    pub fn is_json(&self) -> bool {
+        match *self {
+            OutputFormat::Json => true,
+            _ => false,
+        }
+    }
+}
+
+impl TryFrom<&str> for OutputFormat {
+    type Error = String;
+
+    fn try_from(value: &str) -> Result<Self, Self::Error> {
+        match value {
+            "json" => Ok(OutputFormat::Json),
+            "html" => Ok(OutputFormat::HTML),
+            _ => Err(format!("unknown output format `{}`", value)),
+        }
+    }
+}
+
 /// Configuration options for rustdoc.
 #[derive(Clone)]
 pub struct Options {
@@ -115,6 +143,8 @@ pub struct Options {
     pub crate_version: Option<String>,
     /// Collected options specific to outputting final pages.
     pub render_options: RenderOptions,
+    /// Output format rendering (used only for "show-coverage" option for the moment)
+    pub output_format: Option<OutputFormat>,
 }
 
 impl fmt::Debug for Options {
@@ -425,14 +455,6 @@ impl Options {
             }
         }
 
-        match matches.opt_str("w").as_ref().map(|s| &**s) {
-            Some("html") | None => {}
-            Some(s) => {
-                diag.struct_err(&format!("unknown output format: {}", s)).emit();
-                return Err(1);
-            }
-        }
-
         let index_page = matches.opt_str("index-page").map(|s| PathBuf::from(&s));
         if let Some(ref index_page) = index_page {
             if !index_page.is_file() {
@@ -469,6 +491,23 @@ impl Options {
             }
         };
 
+        let output_format = match matches.opt_str("output-format") {
+            Some(s) => match OutputFormat::try_from(s.as_str()) {
+                Ok(o) => {
+                    if o.is_json() && !show_coverage {
+                        diag.struct_err("json output format isn't supported for doc generation")
+                            .emit();
+                        return Err(1);
+                    }
+                    Some(o)
+                }
+                Err(e) => {
+                    diag.struct_err(&e).emit();
+                    return Err(1);
+                }
+            }
+            None => None,
+        };
         let crate_name = matches.opt_str("crate-name");
         let proc_macro_crate = crate_types.contains(&CrateType::ProcMacro);
         let playground_url = matches.opt_str("playground-url");
@@ -553,6 +592,7 @@ impl Options {
                 generate_search_filter,
                 generate_redirect_pages,
             },
+            output_format,
         })
     }
 
@@ -568,6 +608,9 @@ fn check_deprecated_options(matches: &getopts::Matches, diag: &rustc_errors::Han
 
     for flag in deprecated_flags.iter() {
         if matches.opt_present(flag) {
+            if *flag == "output-format" && matches.opt_present("show-coverage") {
+                continue;
+            }
             let mut err =
                 diag.struct_warn(&format!("the '{}' flag is considered deprecated", flag));
             err.warn(
diff --git a/src/librustdoc/core.rs b/src/librustdoc/core.rs
index 8bc34e949f175..b9ae3d53afc04 100644
--- a/src/librustdoc/core.rs
+++ b/src/librustdoc/core.rs
@@ -228,6 +228,7 @@ pub fn run_core(options: RustdocOptions) -> (clean::Crate, RenderInfo, RenderOpt
         mut manual_passes,
         display_warnings,
         render_options,
+        output_format,
         ..
     } = options;
 
@@ -385,6 +386,7 @@ pub fn run_core(options: RustdocOptions) -> (clean::Crate, RenderInfo, RenderOpt
 
                 let mut renderinfo = RenderInfo::default();
                 renderinfo.access_levels = access_levels;
+                renderinfo.output_format = output_format;
 
                 let mut ctxt = DocContext {
                     tcx,
diff --git a/src/librustdoc/html/render.rs b/src/librustdoc/html/render.rs
index 4dd2a6562a4cd..016054c688ddc 100644
--- a/src/librustdoc/html/render.rs
+++ b/src/librustdoc/html/render.rs
@@ -60,7 +60,7 @@ use serde::ser::SerializeSeq;
 use serde::{Serialize, Serializer};
 
 use crate::clean::{self, AttributesExt, Deprecation, GetDefId, SelfTy};
-use crate::config::RenderOptions;
+use crate::config::{OutputFormat, RenderOptions};
 use crate::docfs::{DocFS, ErrorStorage, PathError};
 use crate::doctree;
 use crate::html::escape::Escape;
@@ -270,6 +270,7 @@ pub struct RenderInfo {
     pub deref_trait_did: Option<DefId>,
     pub deref_mut_trait_did: Option<DefId>,
     pub owned_box_did: Option<DefId>,
+    pub output_format: Option<OutputFormat>,
 }
 
 // Helper structs for rendering items/sidebars and carrying along contextual
diff --git a/src/librustdoc/html/render/cache.rs b/src/librustdoc/html/render/cache.rs
index a0a35e4ce4b85..4198369eca8f5 100644
--- a/src/librustdoc/html/render/cache.rs
+++ b/src/librustdoc/html/render/cache.rs
@@ -139,6 +139,7 @@ impl Cache {
             deref_trait_did,
             deref_mut_trait_did,
             owned_box_did,
+            ..
         } = renderinfo;
 
         let external_paths =

From 10492c392af127074d13593ae0dd5067286e8e15 Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <guillaume1.gomez@gmail.com>
Date: Sat, 16 Nov 2019 16:12:29 +0100
Subject: [PATCH 03/40] Add support for json output in show-coverage option

---
 .../passes/calculate_doc_coverage.rs          | 67 ++++++++++++++++++-
 1 file changed, 64 insertions(+), 3 deletions(-)

diff --git a/src/librustdoc/passes/calculate_doc_coverage.rs b/src/librustdoc/passes/calculate_doc_coverage.rs
index d4a7f3313a49b..0ca5a956bdb69 100644
--- a/src/librustdoc/passes/calculate_doc_coverage.rs
+++ b/src/librustdoc/passes/calculate_doc_coverage.rs
@@ -1,4 +1,5 @@
 use crate::clean;
+use crate::config::OutputFormat;
 use crate::core::DocContext;
 use crate::fold::{self, DocFolder};
 use crate::passes::Pass;
@@ -6,6 +7,7 @@ use crate::passes::Pass;
 use rustc_ast::attr;
 use rustc_span::symbol::sym;
 use rustc_span::FileName;
+use serialize::json::{ToJson, Json};
 
 use std::collections::BTreeMap;
 use std::ops;
@@ -16,8 +18,8 @@ pub const CALCULATE_DOC_COVERAGE: Pass = Pass {
     description: "counts the number of items with and without documentation",
 };
 
-fn calculate_doc_coverage(krate: clean::Crate, _: &DocContext<'_>) -> clean::Crate {
-    let mut calc = CoverageCalculator::default();
+fn calculate_doc_coverage( krate: clean::Crate, ctx: &DocContext<'_>) -> clean::Crate {
+    let mut calc = CoverageCalculator::new(ctx.renderinfo.borrow().output_format);
     let krate = calc.fold_crate(krate);
 
     calc.print_results();
@@ -64,13 +66,72 @@ impl ops::AddAssign for ItemCount {
     }
 }
 
-#[derive(Default)]
 struct CoverageCalculator {
     items: BTreeMap<FileName, ItemCount>,
+    output_format: Option<OutputFormat>,
+}
+
+fn limit_filename_len(filename: String) -> String {
+    // if a filename is too long, shorten it so we don't blow out the table
+    // FIXME(misdreavus): this needs to count graphemes, and probably also track
+    // double-wide characters...
+    if filename.len() > 35 {
+        "...".to_string() + &filename[filename.len() - 32..]
+    } else {
+        filename
+    }
+}
+
+impl ToJson for CoverageCalculator {
+    fn to_json(&self) -> Json {
+        let mut total = ItemCount::default();
+        let mut entries = BTreeMap::default();
+
+        entries.insert("files".to_owned(), Json::Array(self.items
+            .iter()
+            .filter_map(|(file, &count)| {
+                count.percentage().map(|percent| {
+                    (limit_filename_len(file.to_string()), count, percent)
+                })
+            })
+            .map(|(name, count, percentage)| {
+                let mut fields = BTreeMap::default();
+
+                fields.insert("documented".to_owned(), Json::U64(count.with_docs));
+                fields.insert("total".to_owned(), Json::U64(count.total));
+                fields.insert("percentage".to_owned(), Json::F64(percentage));
+
+                total += count;
+
+                let mut obj = BTreeMap::default();
+                obj.insert(name, Json::Object(fields));
+
+                Json::Object(obj)
+            })
+            .collect::<Vec<_>>()));
+        let mut fields = BTreeMap::default();
+        fields.insert("documented".to_owned(), Json::U64(total.with_docs));
+        fields.insert("total".to_owned(), Json::U64(total.total));
+        fields.insert("percentage".to_owned(), Json::F64(total.percentage().unwrap_or(0.0)));
+
+        entries.insert("total".to_owned(), Json::Object(fields));
+        Json::Object(entries)
+    }
 }
 
 impl CoverageCalculator {
+    fn new(output_format: Option<OutputFormat>) -> CoverageCalculator {
+        CoverageCalculator {
+            items: Default::default(),
+            output_format,
+        }
+    }
+
     fn print_results(&self) {
+        if self.output_format.map(|o| o.is_json()).unwrap_or_else(|| false) {
+            println!("{}", self.to_json().pretty());
+            return;
+        }
         let mut total = ItemCount::default();
 
         fn print_table_line() {

From 15babed8b7936e03ed4cd57afd5c91c44dc4f0be Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <guillaume1.gomez@gmail.com>
Date: Sat, 16 Nov 2019 16:23:27 +0100
Subject: [PATCH 04/40] add tests for rustdoc output-format json

---
 src/test/rustdoc-ui/coverage/json.rs         | 27 ++++++++++++++++++++
 src/test/rustdoc-ui/coverage/json.stdout     |  7 +++++
 src/test/rustdoc/output-format-fail-check.rs |  5 ++++
 3 files changed, 39 insertions(+)
 create mode 100644 src/test/rustdoc-ui/coverage/json.rs
 create mode 100644 src/test/rustdoc-ui/coverage/json.stdout
 create mode 100644 src/test/rustdoc/output-format-fail-check.rs

diff --git a/src/test/rustdoc-ui/coverage/json.rs b/src/test/rustdoc-ui/coverage/json.rs
new file mode 100644
index 0000000000000..8b80244f825c4
--- /dev/null
+++ b/src/test/rustdoc-ui/coverage/json.rs
@@ -0,0 +1,27 @@
+// build-pass
+// compile-flags:-Z unstable-options --show-coverage
+
+pub mod foo {
+    /// Hello!
+    pub struct Foo;
+    /// Bar
+    pub enum Bar { A }
+}
+
+/// X
+pub struct X;
+
+/// Bar
+pub mod bar {
+    /// bar
+    pub struct Bar;
+    /// X
+    pub enum X { Y }
+}
+
+/// yolo
+pub enum Yolo { X }
+
+pub struct Xo<T: Clone> {
+    x: T,
+}
diff --git a/src/test/rustdoc-ui/coverage/json.stdout b/src/test/rustdoc-ui/coverage/json.stdout
new file mode 100644
index 0000000000000..be56a8c0ffafa
--- /dev/null
+++ b/src/test/rustdoc-ui/coverage/json.stdout
@@ -0,0 +1,7 @@
++-------------------------------------+------------+------------+------------+
+| File                                | Documented |      Total | Percentage |
++-------------------------------------+------------+------------+------------+
+| ...test/rustdoc-ui/coverage/json.rs |          7 |         13 |      53.8% |
++-------------------------------------+------------+------------+------------+
+| Total                               |          7 |         13 |      53.8% |
++-------------------------------------+------------+------------+------------+
diff --git a/src/test/rustdoc/output-format-fail-check.rs b/src/test/rustdoc/output-format-fail-check.rs
new file mode 100644
index 0000000000000..a78811078be29
--- /dev/null
+++ b/src/test/rustdoc/output-format-fail-check.rs
@@ -0,0 +1,5 @@
+// compile-flags:-Z unstable-options --output-format
+// should-fail
+
+/// toudoum!
+pub struct SomeStruct;

From f1070b152546827e599cdee1f64c55faaf8bf082 Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <guillaume1.gomez@gmail.com>
Date: Mon, 17 Feb 2020 13:53:27 +0100
Subject: [PATCH 05/40] Replace ToJson with serde

---
 src/librustdoc/config.rs                      | 16 ++--
 .../passes/calculate_doc_coverage.rs          | 90 ++++++-------------
 src/test/rustdoc-ui/coverage/html.rs          |  4 +
 src/test/rustdoc-ui/coverage/html.stderr      |  2 +
 src/test/rustdoc-ui/coverage/json.rs          |  2 +-
 src/test/rustdoc-ui/coverage/json.stdout      |  8 +-
 .../coverage}/output-format-fail-check.rs     |  1 -
 .../coverage/output-format-fail-check.stderr  |  6 ++
 8 files changed, 51 insertions(+), 78 deletions(-)
 create mode 100644 src/test/rustdoc-ui/coverage/html.rs
 create mode 100644 src/test/rustdoc-ui/coverage/html.stderr
 rename src/test/{rustdoc => rustdoc-ui/coverage}/output-format-fail-check.rs (85%)
 create mode 100644 src/test/rustdoc-ui/coverage/output-format-fail-check.stderr

diff --git a/src/librustdoc/config.rs b/src/librustdoc/config.rs
index 99a55f3c68282..58c8a7d82bfb5 100644
--- a/src/librustdoc/config.rs
+++ b/src/librustdoc/config.rs
@@ -1,6 +1,6 @@
 use std::collections::BTreeMap;
-use std::ffi::OsStr;
 use std::convert::TryFrom;
+use std::ffi::OsStr;
 use std::fmt;
 use std::path::PathBuf;
 
@@ -28,12 +28,12 @@ use crate::theme;
 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
 pub enum OutputFormat {
     Json,
-    HTML,
+    Html,
 }
 
 impl OutputFormat {
     pub fn is_json(&self) -> bool {
-        match *self {
+        match self {
             OutputFormat::Json => true,
             _ => false,
         }
@@ -46,7 +46,7 @@ impl TryFrom<&str> for OutputFormat {
     fn try_from(value: &str) -> Result<Self, Self::Error> {
         match value {
             "json" => Ok(OutputFormat::Json),
-            "html" => Ok(OutputFormat::HTML),
+            "html" => Ok(OutputFormat::Html),
             _ => Err(format!("unknown output format `{}`", value)),
         }
     }
@@ -498,6 +498,12 @@ impl Options {
                         diag.struct_err("json output format isn't supported for doc generation")
                             .emit();
                         return Err(1);
+                    } else if !o.is_json() && show_coverage {
+                        diag.struct_err(
+                            "html output format isn't supported for the --show-coverage option",
+                        )
+                        .emit();
+                        return Err(1);
                     }
                     Some(o)
                 }
@@ -505,7 +511,7 @@ impl Options {
                     diag.struct_err(&e).emit();
                     return Err(1);
                 }
-            }
+            },
             None => None,
         };
         let crate_name = matches.opt_str("crate-name");
diff --git a/src/librustdoc/passes/calculate_doc_coverage.rs b/src/librustdoc/passes/calculate_doc_coverage.rs
index 0ca5a956bdb69..f48224512ba4f 100644
--- a/src/librustdoc/passes/calculate_doc_coverage.rs
+++ b/src/librustdoc/passes/calculate_doc_coverage.rs
@@ -7,7 +7,8 @@ use crate::passes::Pass;
 use rustc_ast::attr;
 use rustc_span::symbol::sym;
 use rustc_span::FileName;
-use serialize::json::{ToJson, Json};
+use serde::Serialize;
+use serde_json;
 
 use std::collections::BTreeMap;
 use std::ops;
@@ -18,16 +19,16 @@ pub const CALCULATE_DOC_COVERAGE: Pass = Pass {
     description: "counts the number of items with and without documentation",
 };
 
-fn calculate_doc_coverage( krate: clean::Crate, ctx: &DocContext<'_>) -> clean::Crate {
-    let mut calc = CoverageCalculator::new(ctx.renderinfo.borrow().output_format);
+fn calculate_doc_coverage(krate: clean::Crate, ctx: &DocContext<'_>) -> clean::Crate {
+    let mut calc = CoverageCalculator::new();
     let krate = calc.fold_crate(krate);
 
-    calc.print_results();
+    calc.print_results(ctx.renderinfo.borrow().output_format);
 
     krate
 }
 
-#[derive(Default, Copy, Clone)]
+#[derive(Default, Copy, Clone, Serialize)]
 struct ItemCount {
     total: u64,
     with_docs: u64,
@@ -68,68 +69,37 @@ impl ops::AddAssign for ItemCount {
 
 struct CoverageCalculator {
     items: BTreeMap<FileName, ItemCount>,
-    output_format: Option<OutputFormat>,
 }
 
 fn limit_filename_len(filename: String) -> String {
-    // if a filename is too long, shorten it so we don't blow out the table
-    // FIXME(misdreavus): this needs to count graphemes, and probably also track
-    // double-wide characters...
-    if filename.len() > 35 {
-        "...".to_string() + &filename[filename.len() - 32..]
+    let nb_chars = filename.chars().count();
+    if nb_chars > 35 {
+        "...".to_string()
+            + &filename[filename.char_indices().nth(nb_chars - 32).map(|x| x.0).unwrap_or(0)..]
     } else {
         filename
     }
 }
 
-impl ToJson for CoverageCalculator {
-    fn to_json(&self) -> Json {
-        let mut total = ItemCount::default();
-        let mut entries = BTreeMap::default();
-
-        entries.insert("files".to_owned(), Json::Array(self.items
-            .iter()
-            .filter_map(|(file, &count)| {
-                count.percentage().map(|percent| {
-                    (limit_filename_len(file.to_string()), count, percent)
-                })
-            })
-            .map(|(name, count, percentage)| {
-                let mut fields = BTreeMap::default();
-
-                fields.insert("documented".to_owned(), Json::U64(count.with_docs));
-                fields.insert("total".to_owned(), Json::U64(count.total));
-                fields.insert("percentage".to_owned(), Json::F64(percentage));
-
-                total += count;
-
-                let mut obj = BTreeMap::default();
-                obj.insert(name, Json::Object(fields));
-
-                Json::Object(obj)
-            })
-            .collect::<Vec<_>>()));
-        let mut fields = BTreeMap::default();
-        fields.insert("documented".to_owned(), Json::U64(total.with_docs));
-        fields.insert("total".to_owned(), Json::U64(total.total));
-        fields.insert("percentage".to_owned(), Json::F64(total.percentage().unwrap_or(0.0)));
-
-        entries.insert("total".to_owned(), Json::Object(fields));
-        Json::Object(entries)
+impl CoverageCalculator {
+    fn new() -> CoverageCalculator {
+        CoverageCalculator { items: Default::default() }
     }
-}
 
-impl CoverageCalculator {
-    fn new(output_format: Option<OutputFormat>) -> CoverageCalculator {
-        CoverageCalculator {
-            items: Default::default(),
-            output_format,
-        }
+    fn to_json(&self) -> String {
+        serde_json::to_string(
+            &self
+                .items
+                .iter()
+                .map(|(k, v)| (k.to_string(), v))
+                .collect::<BTreeMap<String, &ItemCount>>(),
+        )
+        .expect("failed to convert JSON data to string")
     }
 
-    fn print_results(&self) {
-        if self.output_format.map(|o| o.is_json()).unwrap_or_else(|| false) {
-            println!("{}", self.to_json().pretty());
+    fn print_results(&self, output_format: Option<OutputFormat>) {
+        if output_format.map(|o| o.is_json()).unwrap_or_else(|| false) {
+            println!("{}", self.to_json());
             return;
         }
         let mut total = ItemCount::default();
@@ -154,15 +124,7 @@ impl CoverageCalculator {
 
         for (file, &count) in &self.items {
             if let Some(percentage) = count.percentage() {
-                let mut name = file.to_string();
-                // if a filename is too long, shorten it so we don't blow out the table
-                // FIXME(misdreavus): this needs to count graphemes, and probably also track
-                // double-wide characters...
-                if name.len() > 35 {
-                    name = "...".to_string() + &name[name.len() - 32..];
-                }
-
-                print_table_record(&name, count, percentage);
+                print_table_record(&limit_filename_len(file.to_string()), count, percentage);
 
                 total += count;
             }
diff --git a/src/test/rustdoc-ui/coverage/html.rs b/src/test/rustdoc-ui/coverage/html.rs
new file mode 100644
index 0000000000000..181cb4c5061a7
--- /dev/null
+++ b/src/test/rustdoc-ui/coverage/html.rs
@@ -0,0 +1,4 @@
+// compile-flags:-Z unstable-options --output-format html --show-coverage
+
+/// Foo
+pub struct Xo;
diff --git a/src/test/rustdoc-ui/coverage/html.stderr b/src/test/rustdoc-ui/coverage/html.stderr
new file mode 100644
index 0000000000000..adca375d4bce5
--- /dev/null
+++ b/src/test/rustdoc-ui/coverage/html.stderr
@@ -0,0 +1,2 @@
+error: html output format isn't supported for the --show-coverage option
+
diff --git a/src/test/rustdoc-ui/coverage/json.rs b/src/test/rustdoc-ui/coverage/json.rs
index 8b80244f825c4..b1220b32e9194 100644
--- a/src/test/rustdoc-ui/coverage/json.rs
+++ b/src/test/rustdoc-ui/coverage/json.rs
@@ -1,5 +1,5 @@
 // build-pass
-// compile-flags:-Z unstable-options --show-coverage
+// compile-flags:-Z unstable-options --output-format json --show-coverage
 
 pub mod foo {
     /// Hello!
diff --git a/src/test/rustdoc-ui/coverage/json.stdout b/src/test/rustdoc-ui/coverage/json.stdout
index be56a8c0ffafa..63b22a7d94b00 100644
--- a/src/test/rustdoc-ui/coverage/json.stdout
+++ b/src/test/rustdoc-ui/coverage/json.stdout
@@ -1,7 +1 @@
-+-------------------------------------+------------+------------+------------+
-| File                                | Documented |      Total | Percentage |
-+-------------------------------------+------------+------------+------------+
-| ...test/rustdoc-ui/coverage/json.rs |          7 |         13 |      53.8% |
-+-------------------------------------+------------+------------+------------+
-| Total                               |          7 |         13 |      53.8% |
-+-------------------------------------+------------+------------+------------+
+{"$DIR/json.rs":{"total":13,"with_docs":7}}
diff --git a/src/test/rustdoc/output-format-fail-check.rs b/src/test/rustdoc-ui/coverage/output-format-fail-check.rs
similarity index 85%
rename from src/test/rustdoc/output-format-fail-check.rs
rename to src/test/rustdoc-ui/coverage/output-format-fail-check.rs
index a78811078be29..30b525df76359 100644
--- a/src/test/rustdoc/output-format-fail-check.rs
+++ b/src/test/rustdoc-ui/coverage/output-format-fail-check.rs
@@ -1,5 +1,4 @@
 // compile-flags:-Z unstable-options --output-format
-// should-fail
 
 /// toudoum!
 pub struct SomeStruct;
diff --git a/src/test/rustdoc-ui/coverage/output-format-fail-check.stderr b/src/test/rustdoc-ui/coverage/output-format-fail-check.stderr
new file mode 100644
index 0000000000000..9e9aa0e050163
--- /dev/null
+++ b/src/test/rustdoc-ui/coverage/output-format-fail-check.stderr
@@ -0,0 +1,6 @@
+warning: the 'output-format' flag is considered deprecated
+   |
+   = warning: see issue #44136 <https://github.com/rust-lang/rust/issues/44136> for more information
+
+error: too many file operands
+

From 1c01646e6f1ed540fa1be66f3389181ad5644778 Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <guillaume1.gomez@gmail.com>
Date: Thu, 27 Feb 2020 17:20:32 +0100
Subject: [PATCH 06/40] Extend json detection in runtest

---
 src/tools/compiletest/src/runtest.rs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/tools/compiletest/src/runtest.rs b/src/tools/compiletest/src/runtest.rs
index ac808b1f14e13..86621e8812b4c 100644
--- a/src/tools/compiletest/src/runtest.rs
+++ b/src/tools/compiletest/src/runtest.rs
@@ -3204,7 +3204,9 @@ impl<'test> TestCx<'test> {
         let json = cflags.contains("--error-format json")
             || cflags.contains("--error-format pretty-json")
             || cflags.contains("--error-format=json")
-            || cflags.contains("--error-format=pretty-json");
+            || cflags.contains("--error-format=pretty-json")
+            || cflags.contains("--output-format json")
+            || cflags.contains("--output-format=json");
 
         let mut normalized = output.to_string();
 

From b6466273ba3d019433a8665fb337bfedeaf209ef Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <guillaume1.gomez@gmail.com>
Date: Mon, 2 Mar 2020 13:20:32 +0100
Subject: [PATCH 07/40] remove output-format test

---
 src/test/rustdoc-ui/coverage/output-format-fail-check.rs    | 4 ----
 .../rustdoc-ui/coverage/output-format-fail-check.stderr     | 6 ------
 2 files changed, 10 deletions(-)
 delete mode 100644 src/test/rustdoc-ui/coverage/output-format-fail-check.rs
 delete mode 100644 src/test/rustdoc-ui/coverage/output-format-fail-check.stderr

diff --git a/src/test/rustdoc-ui/coverage/output-format-fail-check.rs b/src/test/rustdoc-ui/coverage/output-format-fail-check.rs
deleted file mode 100644
index 30b525df76359..0000000000000
--- a/src/test/rustdoc-ui/coverage/output-format-fail-check.rs
+++ /dev/null
@@ -1,4 +0,0 @@
-// compile-flags:-Z unstable-options --output-format
-
-/// toudoum!
-pub struct SomeStruct;
diff --git a/src/test/rustdoc-ui/coverage/output-format-fail-check.stderr b/src/test/rustdoc-ui/coverage/output-format-fail-check.stderr
deleted file mode 100644
index 9e9aa0e050163..0000000000000
--- a/src/test/rustdoc-ui/coverage/output-format-fail-check.stderr
+++ /dev/null
@@ -1,6 +0,0 @@
-warning: the 'output-format' flag is considered deprecated
-   |
-   = warning: see issue #44136 <https://github.com/rust-lang/rust/issues/44136> for more information
-
-error: too many file operands
-

From 528cbc4879ceab332d509e4959fcea8baa7e8b92 Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Sun, 8 Mar 2020 16:43:03 +0100
Subject: [PATCH 08/40] fix memory leak when vec::IntoIter panics during drop

---
 src/liballoc/vec.rs | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/liballoc/vec.rs b/src/liballoc/vec.rs
index 61416f2b906d3..913e261ef12a5 100644
--- a/src/liballoc/vec.rs
+++ b/src/liballoc/vec.rs
@@ -2626,13 +2626,21 @@ impl<T: Clone> Clone for IntoIter<T> {
 #[stable(feature = "rust1", since = "1.0.0")]
 unsafe impl<#[may_dangle] T> Drop for IntoIter<T> {
     fn drop(&mut self) {
+        struct DropGuard<'a, T>(&'a mut IntoIter<T>);
+
+        impl<T> Drop for DropGuard<'_, T> {
+            fn drop(&mut self) {
+                // RawVec handles deallocation
+                let _ = unsafe { RawVec::from_raw_parts(self.0.buf.as_ptr(), self.0.cap) };
+            }
+        }
+
+        let guard = DropGuard(self);
         // destroy the remaining elements
         unsafe {
-            ptr::drop_in_place(self.as_mut_slice());
+            ptr::drop_in_place(guard.0.as_mut_slice());
         }
-
-        // RawVec handles deallocation
-        let _ = unsafe { RawVec::from_raw_parts(self.buf.as_ptr(), self.cap) };
+        // now `guard` will be dropped and do the rest
     }
 }
 

From 1a9fc18e830dc57731e2976edb5c5f0fabc5019c Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Mon, 9 Mar 2020 11:16:23 +0100
Subject: [PATCH 09/40] panic_bounds_check: use caller_location, like
 PanicFnLangItem

---
 src/libcore/panicking.rs              | 18 ++++++++++++++++++
 src/librustc_codegen_ssa/mir/block.rs |  6 +++++-
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/src/libcore/panicking.rs b/src/libcore/panicking.rs
index 61b764f2d6206..d58a7cfec951b 100644
--- a/src/libcore/panicking.rs
+++ b/src/libcore/panicking.rs
@@ -52,6 +52,24 @@ pub fn panic(expr: &str) -> ! {
     panic_fmt(fmt::Arguments::new_v1(&[expr], &[]), Location::caller())
 }
 
+#[cfg(not(bootstrap))]
+#[cold]
+#[cfg_attr(not(feature = "panic_immediate_abort"), inline(never))]
+#[track_caller]
+#[lang = "panic_bounds_check"] // needed by codegen for panic on OOB array/slice access
+fn panic_bounds_check(index: usize, len: usize) -> ! {
+    if cfg!(feature = "panic_immediate_abort") {
+        unsafe { super::intrinsics::abort() }
+    }
+
+    panic_fmt(
+        format_args!("index out of bounds: the len is {} but the index is {}", len, index),
+        Location::caller(),
+    )
+}
+
+// For bootstrap, we need a variant with the old argument order.
+#[cfg(bootstrap)]
 #[cold]
 #[cfg_attr(not(feature = "panic_immediate_abort"), inline(never))]
 #[lang = "panic_bounds_check"] // needed by codegen for panic on OOB array/slice access
diff --git a/src/librustc_codegen_ssa/mir/block.rs b/src/librustc_codegen_ssa/mir/block.rs
index a1b54607b809e..f22c0216a78d1 100644
--- a/src/librustc_codegen_ssa/mir/block.rs
+++ b/src/librustc_codegen_ssa/mir/block.rs
@@ -415,11 +415,15 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             AssertKind::BoundsCheck { ref len, ref index } => {
                 let len = self.codegen_operand(&mut bx, len).immediate();
                 let index = self.codegen_operand(&mut bx, index).immediate();
-                (lang_items::PanicBoundsCheckFnLangItem, vec![location, index, len])
+                // It's `fn panic_bounds_check(index: usize, len: usize)`, and
+                // `#[track_caller]` adds an implicit third argument.
+                (lang_items::PanicBoundsCheckFnLangItem, vec![index, len, location])
             }
             _ => {
                 let msg_str = Symbol::intern(msg.description());
                 let msg = bx.const_str(msg_str);
+                // It's `pub fn panic(expr: &str)`, with the wide reference being passed
+                // as two arguments, and `#[track_caller]` adds an implicit third argument.
                 (lang_items::PanicFnLangItem, vec![msg.0, msg.1, location])
             }
         };

From 51b60b75e79e39dcbb1fa96d72f4cbb82df7f2ae Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Mon, 9 Mar 2020 16:56:45 +0100
Subject: [PATCH 10/40] Improve readability

---
 src/librustc_codegen_ssa/mir/block.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/librustc_codegen_ssa/mir/block.rs b/src/librustc_codegen_ssa/mir/block.rs
index f22c0216a78d1..6963f1d811a9b 100644
--- a/src/librustc_codegen_ssa/mir/block.rs
+++ b/src/librustc_codegen_ssa/mir/block.rs
@@ -415,8 +415,8 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             AssertKind::BoundsCheck { ref len, ref index } => {
                 let len = self.codegen_operand(&mut bx, len).immediate();
                 let index = self.codegen_operand(&mut bx, index).immediate();
-                // It's `fn panic_bounds_check(index: usize, len: usize)`, and
-                // `#[track_caller]` adds an implicit third argument.
+                // It's `fn panic_bounds_check(index: usize, len: usize)`,
+                // and `#[track_caller]` adds an implicit third argument.
                 (lang_items::PanicBoundsCheckFnLangItem, vec![index, len, location])
             }
             _ => {

From f34e0664a1fa63f89f2257dba7d0d13445f58c02 Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Mon, 9 Mar 2020 19:58:58 +0100
Subject: [PATCH 11/40] remove no-longer needed span from Miri Machine hook

---
 src/librustc_mir/const_eval/machine.rs   | 1 -
 src/librustc_mir/interpret/machine.rs    | 1 -
 src/librustc_mir/interpret/terminator.rs | 2 +-
 src/librustc_mir/transform/const_prop.rs | 1 -
 4 files changed, 1 insertion(+), 4 deletions(-)

diff --git a/src/librustc_mir/const_eval/machine.rs b/src/librustc_mir/const_eval/machine.rs
index ed8029834680c..bb661d3d2a30a 100644
--- a/src/librustc_mir/const_eval/machine.rs
+++ b/src/librustc_mir/const_eval/machine.rs
@@ -280,7 +280,6 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter<'mir,
 
     fn assert_panic(
         ecx: &mut InterpCx<'mir, 'tcx, Self>,
-        _span: Span,
         msg: &AssertMessage<'tcx>,
         _unwind: Option<mir::BasicBlock>,
     ) -> InterpResult<'tcx> {
diff --git a/src/librustc_mir/interpret/machine.rs b/src/librustc_mir/interpret/machine.rs
index 6615cc608fb54..087517ff4e31d 100644
--- a/src/librustc_mir/interpret/machine.rs
+++ b/src/librustc_mir/interpret/machine.rs
@@ -165,7 +165,6 @@ pub trait Machine<'mir, 'tcx>: Sized {
     /// Called to evaluate `Assert` MIR terminators that trigger a panic.
     fn assert_panic(
         ecx: &mut InterpCx<'mir, 'tcx, Self>,
-        span: Span,
         msg: &mir::AssertMessage<'tcx>,
         unwind: Option<mir::BasicBlock>,
     ) -> InterpResult<'tcx>;
diff --git a/src/librustc_mir/interpret/terminator.rs b/src/librustc_mir/interpret/terminator.rs
index ea8378574a3e0..b5c34daf8a318 100644
--- a/src/librustc_mir/interpret/terminator.rs
+++ b/src/librustc_mir/interpret/terminator.rs
@@ -95,7 +95,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 if expected == cond_val {
                     self.go_to_block(target);
                 } else {
-                    M::assert_panic(self, terminator.source_info.span, msg, cleanup)?;
+                    M::assert_panic(self, msg, cleanup)?;
                 }
             }
 
diff --git a/src/librustc_mir/transform/const_prop.rs b/src/librustc_mir/transform/const_prop.rs
index 0560f77f5c99f..4c353d1ae22e7 100644
--- a/src/librustc_mir/transform/const_prop.rs
+++ b/src/librustc_mir/transform/const_prop.rs
@@ -197,7 +197,6 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for ConstPropMachine {
 
     fn assert_panic(
         _ecx: &mut InterpCx<'mir, 'tcx, Self>,
-        _span: Span,
         _msg: &rustc::mir::AssertMessage<'tcx>,
         _unwind: Option<rustc::mir::BasicBlock>,
     ) -> InterpResult<'tcx> {

From 0982c58edc5b9fe4cfc8b22bc3edaa95e4f5c638 Mon Sep 17 00:00:00 2001
From: Chris Simpkins <git.simpkins@gmail.com>
Date: Mon, 9 Mar 2020 21:40:00 -0400
Subject: [PATCH 12/40] update tidy documentation to recommend ./x.py test tidy

---
 src/tools/tidy/src/main.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/tools/tidy/src/main.rs b/src/tools/tidy/src/main.rs
index 0b43396505138..909529d730784 100644
--- a/src/tools/tidy/src/main.rs
+++ b/src/tools/tidy/src/main.rs
@@ -2,7 +2,7 @@
 //!
 //! This program runs all of the various tidy checks for style, cleanliness,
 //! etc. This is run by default on `./x.py test` and as part of the auto
-//! builders. The tidy checks can be executed with `./x.py test src/tools/tidy`.
+//! builders. The tidy checks can be executed with `./x.py test tidy`.
 
 #![deny(warnings)]
 

From 259b06e33f533096f0b46beca8719fd4afceb78b Mon Sep 17 00:00:00 2001
From: Chris Simpkins <git.simpkins@gmail.com>
Date: Mon, 9 Mar 2020 21:55:56 -0400
Subject: [PATCH 13/40] add documentation of x.py tool testing

---
 src/bootstrap/README.md | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/bootstrap/README.md b/src/bootstrap/README.md
index c501378bff549..87da7327fe619 100644
--- a/src/bootstrap/README.md
+++ b/src/bootstrap/README.md
@@ -55,6 +55,9 @@ The script accepts commands, flags, and arguments to determine what to do:
   # run all unit tests
   ./x.py test
 
+  # execute tool tests
+  ./x.py test tidy
+
   # execute the UI test suite
   ./x.py test src/test/ui
 

From 9f734c978c4c32eea552d45fef582804c1d2b9bf Mon Sep 17 00:00:00 2001
From: Chris Simpkins <git.simpkins@gmail.com>
Date: Mon, 9 Mar 2020 22:04:59 -0400
Subject: [PATCH 14/40] Add documentation of tool testing with x.py script

---
 src/bootstrap/flags.rs | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/bootstrap/flags.rs b/src/bootstrap/flags.rs
index 516be6a30c235..a8b76c44f79d3 100644
--- a/src/bootstrap/flags.rs
+++ b/src/bootstrap/flags.rs
@@ -359,7 +359,7 @@ Arguments:
                 subcommand_help.push_str(
                     "\n
 Arguments:
-    This subcommand accepts a number of paths to directories to tests that
+    This subcommand accepts a number of paths to test directories that
     should be compiled and run. For example:
 
         ./x.py test src/test/ui
@@ -367,11 +367,15 @@ Arguments:
         ./x.py test src/libstd --stage 0 --no-doc
         ./x.py test src/test/ui --bless
         ./x.py test src/test/ui --compare-mode nll
-
+    
     Note that `test src/test/* --stage N` does NOT depend on `build src/rustc --stage N`;
     just like `build src/libstd --stage N` it tests the compiler produced by the previous
     stage.
 
+    Execute tool tests with a tool name argument:
+
+        ./x.py test tidy
+
     If no arguments are passed then the complete artifacts for that stage are
     compiled and tested.
 

From 4922b683de170c70260b73426ccf16172fa63b7f Mon Sep 17 00:00:00 2001
From: Chris Simpkins <git.simpkins@gmail.com>
Date: Mon, 9 Mar 2020 22:15:41 -0400
Subject: [PATCH 15/40] remove trailing whitespace (tidy)

---
 src/bootstrap/flags.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/bootstrap/flags.rs b/src/bootstrap/flags.rs
index a8b76c44f79d3..4b04ee84c31db 100644
--- a/src/bootstrap/flags.rs
+++ b/src/bootstrap/flags.rs
@@ -367,7 +367,7 @@ Arguments:
         ./x.py test src/libstd --stage 0 --no-doc
         ./x.py test src/test/ui --bless
         ./x.py test src/test/ui --compare-mode nll
-    
+
     Note that `test src/test/* --stage N` does NOT depend on `build src/rustc --stage N`;
     just like `build src/libstd --stage N` it tests the compiler produced by the previous
     stage.

From c60d581eb15d6fbe17a657da7c1de4dc82b70b68 Mon Sep 17 00:00:00 2001
From: Chris Simpkins <git.simpkins@gmail.com>
Date: Mon, 9 Mar 2020 23:00:41 -0400
Subject: [PATCH 16/40] update x.py tidy testing command

---
 CONTRIBUTING.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index d6840b20c89ac..a58d4f2a7c6a4 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -142,7 +142,7 @@ the issue in question.
 Please make sure your pull request is in compliance with Rust's style
 guidelines by running
 
-    $ python x.py test src/tools/tidy
+    $ python x.py test tidy
 
 Make this check before every pull request (and every new commit in a pull
 request); you can add [git hooks](https://git-scm.com/book/en/v2/Customizing-Git-Git-Hooks)

From 6f2c01bcfbdcaa9686ceb37cce29564a2d662828 Mon Sep 17 00:00:00 2001
From: Ayush Kumar Mishra <ayush.k.mishra@xcelenergy.com>
Date: Tue, 10 Mar 2020 08:33:14 +0530
Subject: [PATCH 17/40] Add long error explanation for E0739

---
 src/librustc_error_codes/error_codes.rs             |  2 +-
 src/librustc_error_codes/error_codes/E0739.md       | 13 +++++++++++++
 .../ui/rfc-2091-track-caller/only-for-fns.stderr    |  1 +
 3 files changed, 15 insertions(+), 1 deletion(-)
 create mode 100644 src/librustc_error_codes/error_codes/E0739.md

diff --git a/src/librustc_error_codes/error_codes.rs b/src/librustc_error_codes/error_codes.rs
index 11d1209923fb2..0e14e2196caf0 100644
--- a/src/librustc_error_codes/error_codes.rs
+++ b/src/librustc_error_codes/error_codes.rs
@@ -411,6 +411,7 @@ E0735: include_str!("./error_codes/E0735.md"),
 E0736: include_str!("./error_codes/E0736.md"),
 E0737: include_str!("./error_codes/E0737.md"),
 E0738: include_str!("./error_codes/E0738.md"),
+E0739: include_str!("./error_codes/E0739.md"),
 E0740: include_str!("./error_codes/E0740.md"),
 E0741: include_str!("./error_codes/E0741.md"),
 E0742: include_str!("./error_codes/E0742.md"),
@@ -610,5 +611,4 @@ E0748: include_str!("./error_codes/E0748.md"),
     E0722, // Malformed `#[optimize]` attribute
     E0724, // `#[ffi_returns_twice]` is only allowed in foreign functions
     E0726, // non-explicit (not `'_`) elided lifetime in unsupported position
-    E0739, // invalid track_caller application/syntax
 }
diff --git a/src/librustc_error_codes/error_codes/E0739.md b/src/librustc_error_codes/error_codes/E0739.md
new file mode 100644
index 0000000000000..d3016f53a94b0
--- /dev/null
+++ b/src/librustc_error_codes/error_codes/E0739.md
@@ -0,0 +1,13 @@
+`#[track_caller]` can not be applied on struct. 
+
+Erroneous code example:
+
+```compile_fail,E0739
+#![feature(track_caller)]
+#[track_caller]
+struct Bar {
+    a: u8,
+}
+```
+
+[RFC 2091]: https://github.com/rust-lang/rfcs/blob/master/text/2091-inline-semantic.md
diff --git a/src/test/ui/rfc-2091-track-caller/only-for-fns.stderr b/src/test/ui/rfc-2091-track-caller/only-for-fns.stderr
index 7becb9c5b60af..c2fb8fa1eb6ca 100644
--- a/src/test/ui/rfc-2091-track-caller/only-for-fns.stderr
+++ b/src/test/ui/rfc-2091-track-caller/only-for-fns.stderr
@@ -8,3 +8,4 @@ LL | struct S;
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0739`.

From 761c8c1eefa8cecb1a55628674690c53cc8c473b Mon Sep 17 00:00:00 2001
From: Ayush Kumar Mishra <ayush.k.mishra@xcelenergy.com>
Date: Tue, 10 Mar 2020 09:07:29 +0530
Subject: [PATCH 18/40] Removed trailing whitespace

---
 src/librustc_error_codes/error_codes/E0739.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/librustc_error_codes/error_codes/E0739.md b/src/librustc_error_codes/error_codes/E0739.md
index d3016f53a94b0..707751066edbc 100644
--- a/src/librustc_error_codes/error_codes/E0739.md
+++ b/src/librustc_error_codes/error_codes/E0739.md
@@ -1,4 +1,4 @@
-`#[track_caller]` can not be applied on struct. 
+`#[track_caller]` can not be applied on struct.
 
 Erroneous code example:
 

From 9596dc2a47861d73996a550cba7caf55b2737c17 Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Thu, 5 Mar 2020 01:47:15 +0100
Subject: [PATCH 19/40] parse_labeled_expr: simplify

---
 src/librustc_parse/parser/expr.rs | 28 +++++++++++++---------------
 1 file changed, 13 insertions(+), 15 deletions(-)

diff --git a/src/librustc_parse/parser/expr.rs b/src/librustc_parse/parser/expr.rs
index 16ea2773b2009..e0e6fd5eed6b7 100644
--- a/src/librustc_parse/parser/expr.rs
+++ b/src/librustc_parse/parser/expr.rs
@@ -1069,24 +1069,22 @@ impl<'a> Parser<'a> {
 
     fn parse_labeled_expr(&mut self, label: Label, attrs: AttrVec) -> PResult<'a, P<Expr>> {
         let lo = label.ident.span;
+        let label = Some(label);
         self.expect(&token::Colon)?;
         if self.eat_keyword(kw::While) {
-            return self.parse_while_expr(Some(label), lo, attrs);
-        }
-        if self.eat_keyword(kw::For) {
-            return self.parse_for_expr(Some(label), lo, attrs);
-        }
-        if self.eat_keyword(kw::Loop) {
-            return self.parse_loop_expr(Some(label), lo, attrs);
-        }
-        if self.token == token::OpenDelim(token::Brace) {
-            return self.parse_block_expr(Some(label), lo, BlockCheckMode::Default, attrs);
+            self.parse_while_expr(label, lo, attrs)
+        } else if self.eat_keyword(kw::For) {
+            self.parse_for_expr(label, lo, attrs)
+        } else if self.eat_keyword(kw::Loop) {
+            self.parse_loop_expr(label, lo, attrs)
+        } else if self.check(&token::OpenDelim(token::Brace)) {
+            self.parse_block_expr(label, lo, BlockCheckMode::Default, attrs)
+        } else {
+            let msg = "expected `while`, `for`, `loop` or `{` after a label";
+            self.struct_span_err(self.token.span, msg).span_label(self.token.span, msg).emit();
+            // Continue as an expression in an effort to recover on `'label: non_block_expr`.
+            self.parse_expr()
         }
-
-        let msg = "expected `while`, `for`, `loop` or `{` after a label";
-        self.struct_span_err(self.token.span, msg).span_label(self.token.span, msg).emit();
-        // Continue as an expression in an effort to recover on `'label: non_block_expr`.
-        self.parse_expr()
     }
 
     /// Recover on the syntax `do catch { ... }` suggesting `try { ... }` instead.

From c303c4463cd3530c634dac8614feac7723ab0c58 Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Thu, 5 Mar 2020 02:46:13 +0100
Subject: [PATCH 20/40] use error_block_no_opening_brace more

---
 src/librustc_parse/parser/stmt.rs             |  6 ++-
 src/test/ui/parser/block-no-opening-brace.rs  | 30 +++++++++++
 .../ui/parser/block-no-opening-brace.stderr   | 53 +++++++++++++++++++
 3 files changed, 88 insertions(+), 1 deletion(-)
 create mode 100644 src/test/ui/parser/block-no-opening-brace.rs
 create mode 100644 src/test/ui/parser/block-no-opening-brace.stderr

diff --git a/src/librustc_parse/parser/stmt.rs b/src/librustc_parse/parser/stmt.rs
index 3864ec3aaa163..511d4bfccd2cf 100644
--- a/src/librustc_parse/parser/stmt.rs
+++ b/src/librustc_parse/parser/stmt.rs
@@ -304,7 +304,11 @@ impl<'a> Parser<'a> {
         maybe_whole!(self, NtBlock, |x| (Vec::new(), x));
 
         let lo = self.token.span;
-        self.expect(&token::OpenDelim(token::Brace))?;
+
+        if !self.eat(&token::OpenDelim(token::Brace)) {
+            return self.error_block_no_opening_brace();
+        }
+
         Ok((self.parse_inner_attributes()?, self.parse_block_tail(lo, BlockCheckMode::Default)?))
     }
 
diff --git a/src/test/ui/parser/block-no-opening-brace.rs b/src/test/ui/parser/block-no-opening-brace.rs
new file mode 100644
index 0000000000000..169625bf8973b
--- /dev/null
+++ b/src/test/ui/parser/block-no-opening-brace.rs
@@ -0,0 +1,30 @@
+// edition:2018
+
+#![feature(try_blocks)]
+
+fn main() {}
+
+fn f1() {
+   loop
+     let x = 0; //~ ERROR expected `{`, found keyword `let`
+   }
+
+fn f2() {
+   while true
+     let x = 0; //~ ERROR expected `{`, found keyword `let`
+   }
+
+fn f3() {
+   for x in 0..1
+     let x = 0; //~ ERROR expected `{`, found keyword `let`
+   }
+
+fn f4() {
+   try //~ ERROR expected expression, found reserved keyword `try`
+     let x = 0;
+   }
+
+fn f5() {
+   async //~ ERROR async closures are unstable
+     let x = 0; //~ ERROR expected one of `move`, `|`, or `||`, found keyword `let`
+   }
diff --git a/src/test/ui/parser/block-no-opening-brace.stderr b/src/test/ui/parser/block-no-opening-brace.stderr
new file mode 100644
index 0000000000000..56db1147360de
--- /dev/null
+++ b/src/test/ui/parser/block-no-opening-brace.stderr
@@ -0,0 +1,53 @@
+error: expected `{`, found keyword `let`
+  --> $DIR/block-no-opening-brace.rs:9:6
+   |
+LL |      let x = 0;
+   |      ^^^-------
+   |      |
+   |      expected `{`
+   |      help: try placing this code inside a block: `{ let x = 0; }`
+
+error: expected `{`, found keyword `let`
+  --> $DIR/block-no-opening-brace.rs:14:6
+   |
+LL |      let x = 0;
+   |      ^^^-------
+   |      |
+   |      expected `{`
+   |      help: try placing this code inside a block: `{ let x = 0; }`
+
+error: expected `{`, found keyword `let`
+  --> $DIR/block-no-opening-brace.rs:19:6
+   |
+LL |      let x = 0;
+   |      ^^^-------
+   |      |
+   |      expected `{`
+   |      help: try placing this code inside a block: `{ let x = 0; }`
+
+error: expected expression, found reserved keyword `try`
+  --> $DIR/block-no-opening-brace.rs:23:4
+   |
+LL |    try
+   |    ^^^ expected expression
+
+error: expected one of `move`, `|`, or `||`, found keyword `let`
+  --> $DIR/block-no-opening-brace.rs:29:6
+   |
+LL |    async
+   |         - expected one of `move`, `|`, or `||`
+LL |      let x = 0;
+   |      ^^^ unexpected token
+
+error[E0658]: async closures are unstable
+  --> $DIR/block-no-opening-brace.rs:28:4
+   |
+LL |    async
+   |    ^^^^^
+   |
+   = note: see issue #62290 <https://github.com/rust-lang/rust/issues/62290> for more information
+   = help: add `#![feature(async_closure)]` to the crate attributes to enable
+
+error: aborting due to 6 previous errors
+
+For more information about this error, try `rustc --explain E0658`.

From 883e90dd81b207cc5d9e85c02f628432b7f8d65d Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Thu, 5 Mar 2020 03:24:58 +0100
Subject: [PATCH 21/40] simplify parse_inner_attributes

---
 src/librustc_parse/parser/attr.rs | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/src/librustc_parse/parser/attr.rs b/src/librustc_parse/parser/attr.rs
index bdd78e671a8b3..1e7f5b662f3d2 100644
--- a/src/librustc_parse/parser/attr.rs
+++ b/src/librustc_parse/parser/attr.rs
@@ -201,12 +201,8 @@ impl<'a> Parser<'a> {
         let mut attrs: Vec<ast::Attribute> = vec![];
         loop {
             match self.token.kind {
-                token::Pound => {
-                    // Don't even try to parse if it's not an inner attribute.
-                    if !self.look_ahead(1, |t| t == &token::Not) {
-                        break;
-                    }
-
+                // Only try to parse if it is an inner attribute (has `!`).
+                token::Pound if self.look_ahead(1, |t| t == &token::Not) => {
                     let attr = self.parse_attribute(true)?;
                     assert_eq!(attr.style, ast::AttrStyle::Inner);
                     attrs.push(attr);

From 8ee220c447911c519ebbd118e1415d961317b18d Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Thu, 5 Mar 2020 05:49:30 +0100
Subject: [PATCH 22/40] more reuse in block parsing & improve diagnostics.

---
 src/librustc_ast/token.rs                     | 10 +++++
 src/librustc_parse/parser/expr.rs             | 16 ++++----
 src/librustc_parse/parser/stmt.rs             | 17 +++++---
 .../label_break_value_illegal_uses.stderr     |  5 ++-
 src/test/ui/parser/bad-interpolated-block.rs  | 15 +++++++
 .../ui/parser/bad-interpolated-block.stderr   | 39 +++++++++++++++++++
 src/test/ui/parser/closure-return-syntax.rs   |  2 +-
 .../ui/parser/closure-return-syntax.stderr    |  7 +++-
 .../unsafe/unsafe-block-without-braces.stderr |  7 ++--
 9 files changed, 98 insertions(+), 20 deletions(-)
 create mode 100644 src/test/ui/parser/bad-interpolated-block.rs
 create mode 100644 src/test/ui/parser/bad-interpolated-block.stderr

diff --git a/src/librustc_ast/token.rs b/src/librustc_ast/token.rs
index b67b7d346f756..3fc6444168e24 100644
--- a/src/librustc_ast/token.rs
+++ b/src/librustc_ast/token.rs
@@ -535,6 +535,16 @@ impl Token {
         false
     }
 
+    // Is the token an interpolated block (`$b:block`)?
+    pub fn is_whole_block(&self) -> bool {
+        if let Interpolated(ref nt) = self.kind {
+            if let NtBlock(..) = **nt {
+                return true;
+            }
+        }
+        false
+    }
+
     /// Returns `true` if the token is either the `mut` or `const` keyword.
     pub fn is_mutability(&self) -> bool {
         self.is_keyword(kw::Mut) || self.is_keyword(kw::Const)
diff --git a/src/librustc_parse/parser/expr.rs b/src/librustc_parse/parser/expr.rs
index e0e6fd5eed6b7..b1c5eaf8973ab 100644
--- a/src/librustc_parse/parser/expr.rs
+++ b/src/librustc_parse/parser/expr.rs
@@ -1077,7 +1077,7 @@ impl<'a> Parser<'a> {
             self.parse_for_expr(label, lo, attrs)
         } else if self.eat_keyword(kw::Loop) {
             self.parse_loop_expr(label, lo, attrs)
-        } else if self.check(&token::OpenDelim(token::Brace)) {
+        } else if self.check(&token::OpenDelim(token::Brace)) || self.token.is_whole_block() {
             self.parse_block_expr(label, lo, BlockCheckMode::Default, attrs)
         } else {
             let msg = "expected `while`, `for`, `loop` or `{` after a label";
@@ -1361,18 +1361,20 @@ impl<'a> Parser<'a> {
         opt_label: Option<Label>,
         lo: Span,
         blk_mode: BlockCheckMode,
-        outer_attrs: AttrVec,
+        mut attrs: AttrVec,
     ) -> PResult<'a, P<Expr>> {
         if let Some(label) = opt_label {
             self.sess.gated_spans.gate(sym::label_break_value, label.ident.span);
         }
 
-        self.expect(&token::OpenDelim(token::Brace))?;
-
-        let mut attrs = outer_attrs;
-        attrs.extend(self.parse_inner_attributes()?);
+        if self.token.is_whole_block() {
+            self.struct_span_err(self.token.span, "cannot use a `block` macro fragment here")
+                .span_label(lo.to(self.token.span), "the `block` fragment is within this context")
+                .emit();
+        }
 
-        let blk = self.parse_block_tail(lo, blk_mode)?;
+        let (inner_attrs, blk) = self.parse_block_common(lo, blk_mode)?;
+        attrs.extend(inner_attrs);
         Ok(self.mk_expr(blk.span, ExprKind::Block(blk, opt_label), attrs))
     }
 
diff --git a/src/librustc_parse/parser/stmt.rs b/src/librustc_parse/parser/stmt.rs
index 511d4bfccd2cf..f05b08c5b55e0 100644
--- a/src/librustc_parse/parser/stmt.rs
+++ b/src/librustc_parse/parser/stmt.rs
@@ -240,13 +240,11 @@ impl<'a> Parser<'a> {
     pub fn parse_block(&mut self) -> PResult<'a, P<Block>> {
         maybe_whole!(self, NtBlock, |x| x);
 
-        let lo = self.token.span;
-
         if !self.eat(&token::OpenDelim(token::Brace)) {
             return self.error_block_no_opening_brace();
         }
 
-        self.parse_block_tail(lo, BlockCheckMode::Default)
+        self.parse_block_tail(self.prev_token.span, BlockCheckMode::Default)
     }
 
     fn error_block_no_opening_brace<T>(&mut self) -> PResult<'a, T> {
@@ -301,15 +299,22 @@ impl<'a> Parser<'a> {
     pub(super) fn parse_inner_attrs_and_block(
         &mut self,
     ) -> PResult<'a, (Vec<Attribute>, P<Block>)> {
-        maybe_whole!(self, NtBlock, |x| (Vec::new(), x));
+        self.parse_block_common(self.token.span, BlockCheckMode::Default)
+    }
 
-        let lo = self.token.span;
+    /// Parses a block. Inner attributes are allowed.
+    pub(super) fn parse_block_common(
+        &mut self,
+        lo: Span,
+        blk_mode: BlockCheckMode,
+    ) -> PResult<'a, (Vec<Attribute>, P<Block>)> {
+        maybe_whole!(self, NtBlock, |x| (Vec::new(), x));
 
         if !self.eat(&token::OpenDelim(token::Brace)) {
             return self.error_block_no_opening_brace();
         }
 
-        Ok((self.parse_inner_attributes()?, self.parse_block_tail(lo, BlockCheckMode::Default)?))
+        Ok((self.parse_inner_attributes()?, self.parse_block_tail(lo, blk_mode)?))
     }
 
     /// Parses the rest of a block expression or function body.
diff --git a/src/test/ui/label/label_break_value_illegal_uses.stderr b/src/test/ui/label/label_break_value_illegal_uses.stderr
index fd8850dd8dab2..a2c75882be0ca 100644
--- a/src/test/ui/label/label_break_value_illegal_uses.stderr
+++ b/src/test/ui/label/label_break_value_illegal_uses.stderr
@@ -2,7 +2,10 @@ error: expected `{`, found `'b`
   --> $DIR/label_break_value_illegal_uses.rs:6:12
    |
 LL |     unsafe 'b: {}
-   |            ^^ expected `{`
+   |            ^^----
+   |            |
+   |            expected `{`
+   |            help: try placing this code inside a block: `{ 'b: {} }`
 
 error: expected `{`, found `'b`
   --> $DIR/label_break_value_illegal_uses.rs:10:13
diff --git a/src/test/ui/parser/bad-interpolated-block.rs b/src/test/ui/parser/bad-interpolated-block.rs
new file mode 100644
index 0000000000000..38d53a14bc0bc
--- /dev/null
+++ b/src/test/ui/parser/bad-interpolated-block.rs
@@ -0,0 +1,15 @@
+#![feature(label_break_value)]
+
+fn main() {}
+
+macro_rules! m {
+    ($b:block) => {
+        'lab: $b; //~ ERROR cannot use a `block` macro fragment here
+        unsafe $b; //~ ERROR cannot use a `block` macro fragment here
+        |x: u8| -> () $b; //~ ERROR cannot use a `block` macro fragment here
+    }
+}
+
+fn foo() {
+    m!({});
+}
diff --git a/src/test/ui/parser/bad-interpolated-block.stderr b/src/test/ui/parser/bad-interpolated-block.stderr
new file mode 100644
index 0000000000000..2cbb6a13e74b9
--- /dev/null
+++ b/src/test/ui/parser/bad-interpolated-block.stderr
@@ -0,0 +1,39 @@
+error: cannot use a `block` macro fragment here
+  --> $DIR/bad-interpolated-block.rs:7:15
+   |
+LL |         'lab: $b;
+   |         ------^^
+   |         |
+   |         the `block` fragment is within this context
+...
+LL |     m!({});
+   |     ------- in this macro invocation
+   |
+   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: cannot use a `block` macro fragment here
+  --> $DIR/bad-interpolated-block.rs:8:16
+   |
+LL |         unsafe $b;
+   |         -------^^
+   |         |
+   |         the `block` fragment is within this context
+...
+LL |     m!({});
+   |     ------- in this macro invocation
+   |
+   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: cannot use a `block` macro fragment here
+  --> $DIR/bad-interpolated-block.rs:9:23
+   |
+LL |         |x: u8| -> () $b;
+   |                       ^^ the `block` fragment is within this context
+...
+LL |     m!({});
+   |     ------- in this macro invocation
+   |
+   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to 3 previous errors
+
diff --git a/src/test/ui/parser/closure-return-syntax.rs b/src/test/ui/parser/closure-return-syntax.rs
index 54eb791d2bce4..c6a08abeff4ba 100644
--- a/src/test/ui/parser/closure-return-syntax.rs
+++ b/src/test/ui/parser/closure-return-syntax.rs
@@ -3,5 +3,5 @@
 
 fn main() {
     let x = || -> i32 22;
-    //~^ ERROR expected one of `!`, `(`, `+`, `::`, `<`, or `{`, found `22`
+    //~^ ERROR expected `{`, found `22`
 }
diff --git a/src/test/ui/parser/closure-return-syntax.stderr b/src/test/ui/parser/closure-return-syntax.stderr
index bfb7f98c5f527..7bf6202a72a2d 100644
--- a/src/test/ui/parser/closure-return-syntax.stderr
+++ b/src/test/ui/parser/closure-return-syntax.stderr
@@ -1,8 +1,11 @@
-error: expected one of `!`, `(`, `+`, `::`, `<`, or `{`, found `22`
+error: expected `{`, found `22`
   --> $DIR/closure-return-syntax.rs:5:23
    |
 LL |     let x = || -> i32 22;
-   |                       ^^ expected one of `!`, `(`, `+`, `::`, `<`, or `{`
+   |                       ^^-
+   |                       |
+   |                       expected `{`
+   |                       help: try placing this code inside a block: `{ 22; }`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/unsafe/unsafe-block-without-braces.stderr b/src/test/ui/unsafe/unsafe-block-without-braces.stderr
index 13e0c3681fa00..895f33638f95a 100644
--- a/src/test/ui/unsafe/unsafe-block-without-braces.stderr
+++ b/src/test/ui/unsafe/unsafe-block-without-braces.stderr
@@ -1,10 +1,11 @@
 error: expected `{`, found `std`
   --> $DIR/unsafe-block-without-braces.rs:3:9
    |
-LL |     unsafe //{
-   |           - expected `{`
 LL |         std::mem::transmute::<f32, u32>(1.0);
-   |         ^^^ unexpected token
+   |         ^^^----------------------------------
+   |         |
+   |         expected `{`
+   |         help: try placing this code inside a block: `{ std::mem::transmute::<f32, u32>(1.0); }`
 
 error: aborting due to previous error
 

From 055733f3b3dc5d0841b9284da0c628f9d362461d Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Thu, 5 Mar 2020 07:54:22 +0100
Subject: [PATCH 23/40] parse: recover on `&'lt $expr` / `'lt $expr`.

---
 src/librustc_parse/parser/expr.rs             | 35 ++++++++--
 src/test/ui/parser/labeled-no-colon-expr.rs   | 17 +++++
 .../ui/parser/labeled-no-colon-expr.stderr    | 70 +++++++++++++++++++
 .../ui/parser/regions-out-of-scope-slice.rs   |  2 +-
 .../parser/regions-out-of-scope-slice.stderr  |  9 ++-
 .../ui/parser/trait-object-lifetime-parens.rs |  3 +-
 .../trait-object-lifetime-parens.stderr       | 12 +++-
 7 files changed, 136 insertions(+), 12 deletions(-)
 create mode 100644 src/test/ui/parser/labeled-no-colon-expr.rs
 create mode 100644 src/test/ui/parser/labeled-no-colon-expr.stderr

diff --git a/src/librustc_parse/parser/expr.rs b/src/librustc_parse/parser/expr.rs
index b1c5eaf8973ab..5b39701001fdd 100644
--- a/src/librustc_parse/parser/expr.rs
+++ b/src/librustc_parse/parser/expr.rs
@@ -673,10 +673,28 @@ impl<'a> Parser<'a> {
     /// Parse `& mut? <expr>` or `& raw [ const | mut ] <expr>`.
     fn parse_borrow_expr(&mut self, lo: Span) -> PResult<'a, (Span, ExprKind)> {
         self.expect_and()?;
+        let has_lifetime = self.token.is_lifetime() && self.look_ahead(1, |t| t != &token::Colon);
+        let lifetime = has_lifetime.then(|| self.expect_lifetime()); // For recovery, see below.
         let (borrow_kind, mutbl) = self.parse_borrow_modifiers(lo);
         let expr = self.parse_prefix_expr(None);
-        let (span, expr) = self.interpolated_or_expr_span(expr)?;
-        Ok((lo.to(span), ExprKind::AddrOf(borrow_kind, mutbl, expr)))
+        let (hi, expr) = self.interpolated_or_expr_span(expr)?;
+        let span = lo.to(hi);
+        if let Some(lt) = lifetime {
+            self.error_remove_borrow_lifetime(span, lt.ident.span);
+        }
+        Ok((span, ExprKind::AddrOf(borrow_kind, mutbl, expr)))
+    }
+
+    fn error_remove_borrow_lifetime(&self, span: Span, lt_span: Span) {
+        self.struct_span_err(span, "borrow expressions cannot be annotated with lifetimes")
+            .span_label(lt_span, "annotated with lifetime here")
+            .span_suggestion(
+                lt_span,
+                "remove the lifetime annotation",
+                String::new(),
+                Applicability::MachineApplicable,
+            )
+            .emit();
     }
 
     /// Parse `mut?` or `raw [ const | mut ]`.
@@ -1067,11 +1085,12 @@ impl<'a> Parser<'a> {
         self.maybe_recover_from_bad_qpath(expr, true)
     }
 
+    /// Parse `'label: $expr`. The label is already parsed.
     fn parse_labeled_expr(&mut self, label: Label, attrs: AttrVec) -> PResult<'a, P<Expr>> {
         let lo = label.ident.span;
         let label = Some(label);
-        self.expect(&token::Colon)?;
-        if self.eat_keyword(kw::While) {
+        let ate_colon = self.eat(&token::Colon);
+        let expr = if self.eat_keyword(kw::While) {
             self.parse_while_expr(label, lo, attrs)
         } else if self.eat_keyword(kw::For) {
             self.parse_for_expr(label, lo, attrs)
@@ -1084,7 +1103,15 @@ impl<'a> Parser<'a> {
             self.struct_span_err(self.token.span, msg).span_label(self.token.span, msg).emit();
             // Continue as an expression in an effort to recover on `'label: non_block_expr`.
             self.parse_expr()
+        }?;
+
+        if !ate_colon {
+            self.struct_span_err(expr.span, "labeled expression must be followed by `:`")
+                .span_label(lo, "the label")
+                .emit();
         }
+
+        Ok(expr)
     }
 
     /// Recover on the syntax `do catch { ... }` suggesting `try { ... }` instead.
diff --git a/src/test/ui/parser/labeled-no-colon-expr.rs b/src/test/ui/parser/labeled-no-colon-expr.rs
new file mode 100644
index 0000000000000..db9ef52c1aeec
--- /dev/null
+++ b/src/test/ui/parser/labeled-no-colon-expr.rs
@@ -0,0 +1,17 @@
+#![feature(label_break_value)]
+
+fn main() {
+    'l0 while false {} //~ ERROR labeled expression must be followed by `:`
+    'l1 for _ in 0..1 {} //~ ERROR labeled expression must be followed by `:`
+    'l2 loop {} //~ ERROR labeled expression must be followed by `:`
+    'l3 {} //~ ERROR labeled expression must be followed by `:`
+    'l4 0; //~ ERROR labeled expression must be followed by `:`
+    //~^ ERROR expected `while`, `for`, `loop` or `{`
+
+    macro_rules! m {
+        ($b:block) => {
+            'l5 $b; //~ ERROR cannot use a `block` macro fragment here
+        }
+    }
+    m!({}); //~ ERROR labeled expression must be followed by `:`
+}
diff --git a/src/test/ui/parser/labeled-no-colon-expr.stderr b/src/test/ui/parser/labeled-no-colon-expr.stderr
new file mode 100644
index 0000000000000..8a9e2b324004e
--- /dev/null
+++ b/src/test/ui/parser/labeled-no-colon-expr.stderr
@@ -0,0 +1,70 @@
+error: labeled expression must be followed by `:`
+  --> $DIR/labeled-no-colon-expr.rs:4:5
+   |
+LL |     'l0 while false {}
+   |     ---^^^^^^^^^^^^^^^
+   |     |
+   |     the label
+
+error: labeled expression must be followed by `:`
+  --> $DIR/labeled-no-colon-expr.rs:5:5
+   |
+LL |     'l1 for _ in 0..1 {}
+   |     ---^^^^^^^^^^^^^^^^^
+   |     |
+   |     the label
+
+error: labeled expression must be followed by `:`
+  --> $DIR/labeled-no-colon-expr.rs:6:5
+   |
+LL |     'l2 loop {}
+   |     ---^^^^^^^^
+   |     |
+   |     the label
+
+error: labeled expression must be followed by `:`
+  --> $DIR/labeled-no-colon-expr.rs:7:5
+   |
+LL |     'l3 {}
+   |     ---^^^
+   |     |
+   |     the label
+
+error: expected `while`, `for`, `loop` or `{` after a label
+  --> $DIR/labeled-no-colon-expr.rs:8:9
+   |
+LL |     'l4 0;
+   |         ^ expected `while`, `for`, `loop` or `{` after a label
+
+error: labeled expression must be followed by `:`
+  --> $DIR/labeled-no-colon-expr.rs:8:9
+   |
+LL |     'l4 0;
+   |     --- ^
+   |     |
+   |     the label
+
+error: cannot use a `block` macro fragment here
+  --> $DIR/labeled-no-colon-expr.rs:13:17
+   |
+LL |             'l5 $b;
+   |             ----^^
+   |             |
+   |             the `block` fragment is within this context
+...
+LL |     m!({});
+   |     ------- in this macro invocation
+   |
+   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: labeled expression must be followed by `:`
+  --> $DIR/labeled-no-colon-expr.rs:16:8
+   |
+LL |             'l5 $b;
+   |             --- the label
+...
+LL |     m!({});
+   |        ^^
+
+error: aborting due to 8 previous errors
+
diff --git a/src/test/ui/parser/regions-out-of-scope-slice.rs b/src/test/ui/parser/regions-out-of-scope-slice.rs
index 21369d0be61b1..d223619e1de9e 100644
--- a/src/test/ui/parser/regions-out-of-scope-slice.rs
+++ b/src/test/ui/parser/regions-out-of-scope-slice.rs
@@ -4,7 +4,7 @@ fn foo(cond: bool) {
     let mut x;
 
     if cond {
-        x = &'blk [1,2,3]; //~ ERROR expected `:`, found `[`
+        x = &'blk [1,2,3]; //~ ERROR borrow expressions cannot be annotated with lifetimes
     }
 }
 
diff --git a/src/test/ui/parser/regions-out-of-scope-slice.stderr b/src/test/ui/parser/regions-out-of-scope-slice.stderr
index 8d9bf0b7a0445..bbc657ffd614c 100644
--- a/src/test/ui/parser/regions-out-of-scope-slice.stderr
+++ b/src/test/ui/parser/regions-out-of-scope-slice.stderr
@@ -1,8 +1,11 @@
-error: expected `:`, found `[`
-  --> $DIR/regions-out-of-scope-slice.rs:7:19
+error: borrow expressions cannot be annotated with lifetimes
+  --> $DIR/regions-out-of-scope-slice.rs:7:13
    |
 LL |         x = &'blk [1,2,3];
-   |                   ^ expected `:`
+   |             ^----^^^^^^^^
+   |              |
+   |              annotated with lifetime here
+   |              help: remove the lifetime annotation
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/trait-object-lifetime-parens.rs b/src/test/ui/parser/trait-object-lifetime-parens.rs
index c8b0eb684f33d..dbed17f634ae7 100644
--- a/src/test/ui/parser/trait-object-lifetime-parens.rs
+++ b/src/test/ui/parser/trait-object-lifetime-parens.rs
@@ -8,7 +8,8 @@ fn check<'a>() {
     let _: Box<Trait + ('a)>; //~ ERROR parenthesized lifetime bounds are not supported
     let _: Box<('a) + Trait>;
     //~^ ERROR expected type, found `'a`
-    //~| ERROR expected `:`, found `)`
+    //~| ERROR expected `while`, `for`, `loop` or `{` after a label
+    //~| ERROR expected expression, found `)`
 }
 
 fn main() {}
diff --git a/src/test/ui/parser/trait-object-lifetime-parens.stderr b/src/test/ui/parser/trait-object-lifetime-parens.stderr
index 319a308c0137c..367fcc2855580 100644
--- a/src/test/ui/parser/trait-object-lifetime-parens.stderr
+++ b/src/test/ui/parser/trait-object-lifetime-parens.stderr
@@ -10,11 +10,17 @@ error: parenthesized lifetime bounds are not supported
 LL |     let _: Box<Trait + ('a)>;
    |                        ^^^^ help: remove the parentheses
 
-error: expected `:`, found `)`
+error: expected `while`, `for`, `loop` or `{` after a label
   --> $DIR/trait-object-lifetime-parens.rs:9:19
    |
 LL |     let _: Box<('a) + Trait>;
-   |                   ^ expected `:`
+   |                   ^ expected `while`, `for`, `loop` or `{` after a label
+
+error: expected expression, found `)`
+  --> $DIR/trait-object-lifetime-parens.rs:9:19
+   |
+LL |     let _: Box<('a) + Trait>;
+   |                   ^ expected expression
 
 error: expected type, found `'a`
   --> $DIR/trait-object-lifetime-parens.rs:9:17
@@ -24,5 +30,5 @@ LL |     let _: Box<('a) + Trait>;
    |         |
    |         while parsing the type for `_`
 
-error: aborting due to 4 previous errors
+error: aborting due to 5 previous errors
 

From 379f3181def3021818b7d8c3d69a512c290d9dc9 Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Thu, 5 Mar 2020 08:08:07 +0100
Subject: [PATCH 24/40] parse: simplify parse_fn_body

---
 src/librustc_parse/parser/item.rs | 24 +++++++-----------------
 1 file changed, 7 insertions(+), 17 deletions(-)

diff --git a/src/librustc_parse/parser/item.rs b/src/librustc_parse/parser/item.rs
index 126686c8defbf..428c01a834441 100644
--- a/src/librustc_parse/parser/item.rs
+++ b/src/librustc_parse/parser/item.rs
@@ -1411,23 +1411,13 @@ impl<'a> Parser<'a> {
     /// This can either be `;` when there's no body,
     /// or e.g. a block when the function is a provided one.
     fn parse_fn_body(&mut self, attrs: &mut Vec<Attribute>) -> PResult<'a, Option<P<Block>>> {
-        let (inner_attrs, body) = match self.token.kind {
-            token::Semi => {
-                self.bump();
-                (Vec::new(), None)
-            }
-            token::OpenDelim(token::Brace) => {
-                let (attrs, body) = self.parse_inner_attrs_and_block()?;
-                (attrs, Some(body))
-            }
-            token::Interpolated(ref nt) => match **nt {
-                token::NtBlock(..) => {
-                    let (attrs, body) = self.parse_inner_attrs_and_block()?;
-                    (attrs, Some(body))
-                }
-                _ => return self.expected_semi_or_open_brace(),
-            },
-            _ => return self.expected_semi_or_open_brace(),
+        let (inner_attrs, body) = if self.check(&token::Semi) {
+            self.bump();
+            (Vec::new(), None)
+        } else if self.check(&token::OpenDelim(token::Brace)) || self.token.is_whole_block() {
+            self.parse_inner_attrs_and_block().map(|(attrs, body)| (attrs, Some(body)))?
+        } else {
+            return self.expected_semi_or_open_brace();
         };
         attrs.extend(inner_attrs);
         Ok(body)

From be86b2d37be1631798688afbd45aa0d517135ad1 Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Thu, 5 Mar 2020 09:08:09 +0100
Subject: [PATCH 25/40] parse: recover on `fn foo() = expr;`

---
 src/librustc_parse/parser/item.rs             |  17 ++-
 src/test/ui/parser/fn-body-eq-expr-semi.rs    |  23 ++++
 .../ui/parser/fn-body-eq-expr-semi.stderr     | 117 ++++++++++++++++++
 3 files changed, 156 insertions(+), 1 deletion(-)
 create mode 100644 src/test/ui/parser/fn-body-eq-expr-semi.rs
 create mode 100644 src/test/ui/parser/fn-body-eq-expr-semi.stderr

diff --git a/src/librustc_parse/parser/item.rs b/src/librustc_parse/parser/item.rs
index 428c01a834441..8263bd879ad86 100644
--- a/src/librustc_parse/parser/item.rs
+++ b/src/librustc_parse/parser/item.rs
@@ -1412,10 +1412,25 @@ impl<'a> Parser<'a> {
     /// or e.g. a block when the function is a provided one.
     fn parse_fn_body(&mut self, attrs: &mut Vec<Attribute>) -> PResult<'a, Option<P<Block>>> {
         let (inner_attrs, body) = if self.check(&token::Semi) {
-            self.bump();
+            self.bump(); // `;`
             (Vec::new(), None)
         } else if self.check(&token::OpenDelim(token::Brace)) || self.token.is_whole_block() {
             self.parse_inner_attrs_and_block().map(|(attrs, body)| (attrs, Some(body)))?
+        } else if self.token.kind == token::Eq {
+            // Recover `fn foo() = $expr;`.
+            self.bump(); // `=`
+            let eq_sp = self.prev_token.span;
+            let _ = self.parse_expr()?;
+            self.expect_semi()?; // `;`
+            let span = eq_sp.to(self.prev_token.span);
+            self.struct_span_err(span, "function body cannot be `= expression;`")
+                .multipart_suggestion(
+                    "surround the expression with `{` and `}` instead of `=` and `;`",
+                    vec![(eq_sp, "{".to_string()), (self.prev_token.span, " }".to_string())],
+                    Applicability::MachineApplicable,
+                )
+                .emit();
+            (Vec::new(), Some(self.mk_block_err(span)))
         } else {
             return self.expected_semi_or_open_brace();
         };
diff --git a/src/test/ui/parser/fn-body-eq-expr-semi.rs b/src/test/ui/parser/fn-body-eq-expr-semi.rs
new file mode 100644
index 0000000000000..09444079365bf
--- /dev/null
+++ b/src/test/ui/parser/fn-body-eq-expr-semi.rs
@@ -0,0 +1,23 @@
+fn main() {}
+
+fn syntax() {
+    fn foo() = 42; //~ ERROR function body cannot be `= expression;`
+    fn bar() -> u8 = 42; //~ ERROR function body cannot be `= expression;`
+}
+
+extern {
+    fn foo() = 42; //~ ERROR function body cannot be `= expression;`
+    //~^ ERROR incorrect function inside `extern` block
+    fn bar() -> u8 = 42; //~ ERROR function body cannot be `= expression;`
+    //~^ ERROR incorrect function inside `extern` block
+}
+
+trait Foo {
+    fn foo() = 42; //~ ERROR function body cannot be `= expression;`
+    fn bar() -> u8 = 42; //~ ERROR function body cannot be `= expression;`
+}
+
+impl Foo for () {
+    fn foo() = 42; //~ ERROR function body cannot be `= expression;`
+    fn bar() -> u8 = 42; //~ ERROR function body cannot be `= expression;`
+}
diff --git a/src/test/ui/parser/fn-body-eq-expr-semi.stderr b/src/test/ui/parser/fn-body-eq-expr-semi.stderr
new file mode 100644
index 0000000000000..739133e0b408b
--- /dev/null
+++ b/src/test/ui/parser/fn-body-eq-expr-semi.stderr
@@ -0,0 +1,117 @@
+error: function body cannot be `= expression;`
+  --> $DIR/fn-body-eq-expr-semi.rs:4:14
+   |
+LL |     fn foo() = 42;
+   |              ^^^^^
+   |
+help: surround the expression with `{` and `}` instead of `=` and `;`
+   |
+LL |     fn foo() { 42 }
+   |              ^    ^
+
+error: function body cannot be `= expression;`
+  --> $DIR/fn-body-eq-expr-semi.rs:5:20
+   |
+LL |     fn bar() -> u8 = 42;
+   |                    ^^^^^
+   |
+help: surround the expression with `{` and `}` instead of `=` and `;`
+   |
+LL |     fn bar() -> u8 { 42 }
+   |                    ^    ^
+
+error: function body cannot be `= expression;`
+  --> $DIR/fn-body-eq-expr-semi.rs:9:14
+   |
+LL |     fn foo() = 42;
+   |              ^^^^^
+   |
+help: surround the expression with `{` and `}` instead of `=` and `;`
+   |
+LL |     fn foo() { 42 }
+   |              ^    ^
+
+error: function body cannot be `= expression;`
+  --> $DIR/fn-body-eq-expr-semi.rs:11:20
+   |
+LL |     fn bar() -> u8 = 42;
+   |                    ^^^^^
+   |
+help: surround the expression with `{` and `}` instead of `=` and `;`
+   |
+LL |     fn bar() -> u8 { 42 }
+   |                    ^    ^
+
+error: function body cannot be `= expression;`
+  --> $DIR/fn-body-eq-expr-semi.rs:16:14
+   |
+LL |     fn foo() = 42;
+   |              ^^^^^
+   |
+help: surround the expression with `{` and `}` instead of `=` and `;`
+   |
+LL |     fn foo() { 42 }
+   |              ^    ^
+
+error: function body cannot be `= expression;`
+  --> $DIR/fn-body-eq-expr-semi.rs:17:20
+   |
+LL |     fn bar() -> u8 = 42;
+   |                    ^^^^^
+   |
+help: surround the expression with `{` and `}` instead of `=` and `;`
+   |
+LL |     fn bar() -> u8 { 42 }
+   |                    ^    ^
+
+error: function body cannot be `= expression;`
+  --> $DIR/fn-body-eq-expr-semi.rs:21:14
+   |
+LL |     fn foo() = 42;
+   |              ^^^^^
+   |
+help: surround the expression with `{` and `}` instead of `=` and `;`
+   |
+LL |     fn foo() { 42 }
+   |              ^    ^
+
+error: function body cannot be `= expression;`
+  --> $DIR/fn-body-eq-expr-semi.rs:22:20
+   |
+LL |     fn bar() -> u8 = 42;
+   |                    ^^^^^
+   |
+help: surround the expression with `{` and `}` instead of `=` and `;`
+   |
+LL |     fn bar() -> u8 { 42 }
+   |                    ^    ^
+
+error: incorrect function inside `extern` block
+  --> $DIR/fn-body-eq-expr-semi.rs:9:8
+   |
+LL | extern {
+   | ------ `extern` blocks define existing foreign functions and functions inside of them cannot have a body
+LL |     fn foo() = 42;
+   |        ^^^   ----- help: remove the invalid body: `;`
+   |        |
+   |        cannot have a body
+   |
+   = help: you might have meant to write a function accessible through FFI, which can be done by writing `extern fn` outside of the `extern` block
+   = note: for more information, visit https://doc.rust-lang.org/std/keyword.extern.html
+
+error: incorrect function inside `extern` block
+  --> $DIR/fn-body-eq-expr-semi.rs:11:8
+   |
+LL | extern {
+   | ------ `extern` blocks define existing foreign functions and functions inside of them cannot have a body
+...
+LL |     fn bar() -> u8 = 42;
+   |        ^^^         ----- help: remove the invalid body: `;`
+   |        |
+   |        cannot have a body
+   |
+   = help: you might have meant to write a function accessible through FFI, which can be done by writing `extern fn` outside of the `extern` block
+   = note: for more information, visit https://doc.rust-lang.org/std/keyword.extern.html
+
+error: aborting due to 10 previous errors
+

From addbc5b9df3fca76e7c271a78a0568144b9634f9 Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Thu, 5 Mar 2020 11:42:56 +0100
Subject: [PATCH 26/40] unify/improve/simplify attribute parsing

---
 src/librustc_parse/parser/attr.rs             | 223 ++++++++----------
 src/librustc_parse/parser/stmt.rs             |  11 +-
 src/test/ui/did_you_mean/issue-40006.stderr   |   4 +-
 .../empty_generics.rs                         |   2 +-
 .../empty_generics.stderr                     |   4 +-
 src/test/ui/issues/issue-20616-8.rs           |   2 +-
 src/test/ui/issues/issue-20616-8.stderr       |   4 +-
 src/test/ui/issues/issue-20616-9.rs           |   2 +-
 src/test/ui/issues/issue-20616-9.stderr       |   4 +-
 src/test/ui/issues/issue-66473.rs             | Bin 113 -> 127 bytes
 src/test/ui/issues/issue-66473.stderr         | Bin 2632 -> 2660 bytes
 src/test/ui/parser/bounds-lifetime.rs         |   2 +-
 src/test/ui/parser/bounds-lifetime.stderr     |   4 +-
 src/test/ui/parser/column-offset-1-based.rs   |   2 +-
 .../ui/parser/column-offset-1-based.stderr    |   4 +-
 .../ui/parser/doc-comment-in-if-statement.rs  |   1 +
 .../parser/doc-comment-in-if-statement.stderr |  15 +-
 src/test/ui/parser/issue-1655.rs              |   3 +-
 src/test/ui/parser/issue-1655.stderr          |   6 +-
 src/test/ui/parser/issue-63135.rs             |   2 +-
 src/test/ui/parser/issue-63135.stderr         |  18 +-
 src/test/ui/parser/issue-68730.rs             | Bin 170 -> 175 bytes
 src/test/ui/parser/issue-68730.stderr         | Bin 956 -> 966 bytes
 23 files changed, 140 insertions(+), 173 deletions(-)

diff --git a/src/librustc_parse/parser/attr.rs b/src/librustc_parse/parser/attr.rs
index 1e7f5b662f3d2..b5af124fd4298 100644
--- a/src/librustc_parse/parser/attr.rs
+++ b/src/librustc_parse/parser/attr.rs
@@ -1,4 +1,4 @@
-use super::{Parser, PathStyle, TokenType};
+use super::{Parser, PathStyle};
 use rustc_ast::ast;
 use rustc_ast::attr;
 use rustc_ast::token::{self, Nonterminal};
@@ -10,14 +10,20 @@ use rustc_span::{Span, Symbol};
 use log::debug;
 
 #[derive(Debug)]
-enum InnerAttributeParsePolicy<'a> {
+pub(super) enum InnerAttrPolicy<'a> {
     Permitted,
-    NotPermitted { reason: &'a str, saw_doc_comment: bool, prev_attr_sp: Option<Span> },
+    Forbidden { reason: &'a str, saw_doc_comment: bool, prev_attr_sp: Option<Span> },
 }
 
 const DEFAULT_UNEXPECTED_INNER_ATTR_ERR_MSG: &str = "an inner attribute is not \
                                                      permitted in this context";
 
+pub(super) const DEFAULT_INNER_ATTR_FORBIDDEN: InnerAttrPolicy<'_> = InnerAttrPolicy::Forbidden {
+    reason: DEFAULT_UNEXPECTED_INNER_ATTR_ERR_MSG,
+    saw_doc_comment: false,
+    prev_attr_sp: None,
+};
+
 impl<'a> Parser<'a> {
     /// Parses attributes that appear before an item.
     pub(super) fn parse_outer_attributes(&mut self) -> PResult<'a, Vec<ast::Attribute>> {
@@ -25,48 +31,44 @@ impl<'a> Parser<'a> {
         let mut just_parsed_doc_comment = false;
         loop {
             debug!("parse_outer_attributes: self.token={:?}", self.token);
-            match self.token.kind {
-                token::Pound => {
-                    let inner_error_reason = if just_parsed_doc_comment {
-                        "an inner attribute is not permitted following an outer doc comment"
-                    } else if !attrs.is_empty() {
-                        "an inner attribute is not permitted following an outer attribute"
-                    } else {
-                        DEFAULT_UNEXPECTED_INNER_ATTR_ERR_MSG
-                    };
-                    let inner_parse_policy = InnerAttributeParsePolicy::NotPermitted {
-                        reason: inner_error_reason,
-                        saw_doc_comment: just_parsed_doc_comment,
-                        prev_attr_sp: attrs.last().map(|a| a.span),
-                    };
-                    let attr = self.parse_attribute_with_inner_parse_policy(inner_parse_policy)?;
-                    attrs.push(attr);
-                    just_parsed_doc_comment = false;
-                }
-                token::DocComment(s) => {
-                    let attr = self.mk_doc_comment(s);
-                    if attr.style != ast::AttrStyle::Outer {
-                        let span = self.token.span;
-                        let mut err = self.struct_span_err(span, "expected outer doc comment");
-                        err.note(
+            if self.check(&token::Pound) {
+                let inner_error_reason = if just_parsed_doc_comment {
+                    "an inner attribute is not permitted following an outer doc comment"
+                } else if !attrs.is_empty() {
+                    "an inner attribute is not permitted following an outer attribute"
+                } else {
+                    DEFAULT_UNEXPECTED_INNER_ATTR_ERR_MSG
+                };
+                let inner_parse_policy = InnerAttrPolicy::Forbidden {
+                    reason: inner_error_reason,
+                    saw_doc_comment: just_parsed_doc_comment,
+                    prev_attr_sp: attrs.last().map(|a| a.span),
+                };
+                let attr = self.parse_attribute_with_inner_parse_policy(inner_parse_policy)?;
+                attrs.push(attr);
+                just_parsed_doc_comment = false;
+            } else if let token::DocComment(s) = self.token.kind {
+                let attr = self.mk_doc_comment(s);
+                if attr.style != ast::AttrStyle::Outer {
+                    self.struct_span_err(self.token.span, "expected outer doc comment")
+                        .note(
                             "inner doc comments like this (starting with \
-                                  `//!` or `/*!`) can only appear before items",
-                        );
-                        return Err(err);
-                    }
-                    attrs.push(attr);
-                    self.bump();
-                    just_parsed_doc_comment = true;
+                              `//!` or `/*!`) can only appear before items",
+                        )
+                        .emit();
                 }
-                _ => break,
+                attrs.push(attr);
+                self.bump();
+                just_parsed_doc_comment = true;
+            } else {
+                break;
             }
         }
         Ok(attrs)
     }
 
     fn mk_doc_comment(&self, s: Symbol) -> ast::Attribute {
-        let style = comments::doc_comment_style(&s.as_str());
-        attr::mk_doc_comment(style, s, self.token.span)
+        attr::mk_doc_comment(comments::doc_comment_style(&s.as_str()), s, self.token.span)
     }
 
     /// Matches `attribute = # ! [ meta_item ]`.
@@ -75,96 +77,68 @@ impl<'a> Parser<'a> {
     /// attribute.
     pub fn parse_attribute(&mut self, permit_inner: bool) -> PResult<'a, ast::Attribute> {
         debug!("parse_attribute: permit_inner={:?} self.token={:?}", permit_inner, self.token);
-        let inner_parse_policy = if permit_inner {
-            InnerAttributeParsePolicy::Permitted
-        } else {
-            InnerAttributeParsePolicy::NotPermitted {
-                reason: DEFAULT_UNEXPECTED_INNER_ATTR_ERR_MSG,
-                saw_doc_comment: false,
-                prev_attr_sp: None,
-            }
-        };
+        let inner_parse_policy =
+            if permit_inner { InnerAttrPolicy::Permitted } else { DEFAULT_INNER_ATTR_FORBIDDEN };
         self.parse_attribute_with_inner_parse_policy(inner_parse_policy)
     }
 
-    /// The same as `parse_attribute`, except it takes in an `InnerAttributeParsePolicy`
+    /// The same as `parse_attribute`, except it takes in an `InnerAttrPolicy`
     /// that prescribes how to handle inner attributes.
     fn parse_attribute_with_inner_parse_policy(
         &mut self,
-        inner_parse_policy: InnerAttributeParsePolicy<'_>,
+        inner_parse_policy: InnerAttrPolicy<'_>,
     ) -> PResult<'a, ast::Attribute> {
         debug!(
             "parse_attribute_with_inner_parse_policy: inner_parse_policy={:?} self.token={:?}",
             inner_parse_policy, self.token
         );
-        let (span, item, style) = match self.token.kind {
-            token::Pound => {
-                let lo = self.token.span;
-                self.bump();
-
-                if let InnerAttributeParsePolicy::Permitted = inner_parse_policy {
-                    self.expected_tokens.push(TokenType::Token(token::Not));
-                }
-
-                let style = if self.token == token::Not {
-                    self.bump();
-                    ast::AttrStyle::Inner
-                } else {
-                    ast::AttrStyle::Outer
-                };
+        let lo = self.token.span;
+        let (span, item, style) = if self.eat(&token::Pound) {
+            let style =
+                if self.eat(&token::Not) { ast::AttrStyle::Inner } else { ast::AttrStyle::Outer };
 
-                self.expect(&token::OpenDelim(token::Bracket))?;
-                let item = self.parse_attr_item()?;
-                self.expect(&token::CloseDelim(token::Bracket))?;
-                let hi = self.prev_token.span;
-
-                let attr_sp = lo.to(hi);
-
-                // Emit error if inner attribute is encountered and not permitted
-                if style == ast::AttrStyle::Inner {
-                    if let InnerAttributeParsePolicy::NotPermitted {
-                        reason,
-                        saw_doc_comment,
-                        prev_attr_sp,
-                    } = inner_parse_policy
-                    {
-                        let prev_attr_note = if saw_doc_comment {
-                            "previous doc comment"
-                        } else {
-                            "previous outer attribute"
-                        };
-
-                        let mut diagnostic = self.struct_span_err(attr_sp, reason);
-
-                        if let Some(prev_attr_sp) = prev_attr_sp {
-                            diagnostic
-                                .span_label(attr_sp, "not permitted following an outer attribute")
-                                .span_label(prev_attr_sp, prev_attr_note);
-                        }
-
-                        diagnostic
-                            .note(
-                                "inner attributes, like `#![no_std]`, annotate the item \
-                                   enclosing them, and are usually found at the beginning of \
-                                   source files. Outer attributes, like `#[test]`, annotate the \
-                                   item following them.",
-                            )
-                            .emit();
-                    }
-                }
+            self.expect(&token::OpenDelim(token::Bracket))?;
+            let item = self.parse_attr_item()?;
+            self.expect(&token::CloseDelim(token::Bracket))?;
+            let attr_sp = lo.to(self.prev_token.span);
 
-                (attr_sp, item, style)
-            }
-            _ => {
-                let token_str = pprust::token_to_string(&self.token);
-                let msg = &format!("expected `#`, found `{}`", token_str);
-                return Err(self.struct_span_err(self.token.span, msg));
+            // Emit error if inner attribute is encountered and forbidden.
+            if style == ast::AttrStyle::Inner {
+                self.error_on_forbidden_inner_attr(attr_sp, inner_parse_policy);
             }
+
+            (attr_sp, item, style)
+        } else {
+            let token_str = pprust::token_to_string(&self.token);
+            let msg = &format!("expected `#`, found `{}`", token_str);
+            return Err(self.struct_span_err(self.token.span, msg));
         };
 
         Ok(attr::mk_attr_from_item(style, item, span))
     }
 
+    pub(super) fn error_on_forbidden_inner_attr(&self, attr_sp: Span, policy: InnerAttrPolicy<'_>) {
+        if let InnerAttrPolicy::Forbidden { reason, saw_doc_comment, prev_attr_sp } = policy {
+            let prev_attr_note =
+                if saw_doc_comment { "previous doc comment" } else { "previous outer attribute" };
+
+            let mut diag = self.struct_span_err(attr_sp, reason);
+
+            if let Some(prev_attr_sp) = prev_attr_sp {
+                diag.span_label(attr_sp, "not permitted following an outer attribute")
+                    .span_label(prev_attr_sp, prev_attr_note);
+            }
+
+            diag.note(
+                "inner attributes, like `#![no_std]`, annotate the item \
+                       enclosing them, and are usually found at the beginning of \
+                       source files. Outer attributes, like `#[test]`, annotate the \
+                       item following them.",
+            )
+            .emit();
+        }
+    }
+
     /// Parses an inner part of an attribute (the path and following tokens).
     /// The tokens must be either a delimited token stream, or empty token stream,
     /// or the "legacy" key-value form.
@@ -200,24 +174,22 @@ impl<'a> Parser<'a> {
     crate fn parse_inner_attributes(&mut self) -> PResult<'a, Vec<ast::Attribute>> {
         let mut attrs: Vec<ast::Attribute> = vec![];
         loop {
-            match self.token.kind {
-                // Only try to parse if it is an inner attribute (has `!`).
-                token::Pound if self.look_ahead(1, |t| t == &token::Not) => {
-                    let attr = self.parse_attribute(true)?;
-                    assert_eq!(attr.style, ast::AttrStyle::Inner);
+            // Only try to parse if it is an inner attribute (has `!`).
+            if self.check(&token::Pound) && self.look_ahead(1, |t| t == &token::Not) {
+                let attr = self.parse_attribute(true)?;
+                assert_eq!(attr.style, ast::AttrStyle::Inner);
+                attrs.push(attr);
+            } else if let token::DocComment(s) = self.token.kind {
+                // We need to get the position of this token before we bump.
+                let attr = self.mk_doc_comment(s);
+                if attr.style == ast::AttrStyle::Inner {
                     attrs.push(attr);
+                    self.bump();
+                } else {
+                    break;
                 }
-                token::DocComment(s) => {
-                    // We need to get the position of this token before we bump.
-                    let attr = self.mk_doc_comment(s);
-                    if attr.style == ast::AttrStyle::Inner {
-                        attrs.push(attr);
-                        self.bump();
-                    } else {
-                        break;
-                    }
-                }
-                _ => break,
+            } else {
+                break;
             }
         }
         Ok(attrs)
@@ -228,8 +200,7 @@ impl<'a> Parser<'a> {
         debug!("checking if {:?} is unusuffixed", lit);
 
         if !lit.kind.is_unsuffixed() {
-            let msg = "suffixed literals are not allowed in attributes";
-            self.struct_span_err(lit.span, msg)
+            self.struct_span_err(lit.span, "suffixed literals are not allowed in attributes")
                 .help(
                     "instead of using a suffixed literal \
                                     (`1u8`, `1.0f32`, etc.), use an unsuffixed version \
diff --git a/src/librustc_parse/parser/stmt.rs b/src/librustc_parse/parser/stmt.rs
index f05b08c5b55e0..036e8a5d25859 100644
--- a/src/librustc_parse/parser/stmt.rs
+++ b/src/librustc_parse/parser/stmt.rs
@@ -1,3 +1,4 @@
+use super::attr::DEFAULT_INNER_ATTR_FORBIDDEN;
 use super::diagnostics::Error;
 use super::expr::LhsExpr;
 use super::pat::GateOr;
@@ -238,13 +239,11 @@ impl<'a> Parser<'a> {
 
     /// Parses a block. No inner attributes are allowed.
     pub fn parse_block(&mut self) -> PResult<'a, P<Block>> {
-        maybe_whole!(self, NtBlock, |x| x);
-
-        if !self.eat(&token::OpenDelim(token::Brace)) {
-            return self.error_block_no_opening_brace();
+        let (attrs, block) = self.parse_inner_attrs_and_block()?;
+        if let [.., last] = &*attrs {
+            self.error_on_forbidden_inner_attr(last.span, DEFAULT_INNER_ATTR_FORBIDDEN);
         }
-
-        self.parse_block_tail(self.prev_token.span, BlockCheckMode::Default)
+        Ok(block)
     }
 
     fn error_block_no_opening_brace<T>(&mut self) -> PResult<'a, T> {
diff --git a/src/test/ui/did_you_mean/issue-40006.stderr b/src/test/ui/did_you_mean/issue-40006.stderr
index 613d7eee59480..76e87a3749c33 100644
--- a/src/test/ui/did_you_mean/issue-40006.stderr
+++ b/src/test/ui/did_you_mean/issue-40006.stderr
@@ -32,11 +32,11 @@ LL |     X() {}
 LL | }
    | - the item list ends here
 
-error: expected `[`, found `#`
+error: expected one of `!` or `[`, found `#`
   --> $DIR/issue-40006.rs:19:17
    |
 LL |     fn xxx() { ### }
-   |                 ^ expected `[`
+   |                 ^ expected one of `!` or `[`
 
 error: expected one of `!` or `::`, found `=`
   --> $DIR/issue-40006.rs:22:7
diff --git a/src/test/ui/generic-associated-types/empty_generics.rs b/src/test/ui/generic-associated-types/empty_generics.rs
index 522e23ca43d78..6eb25a92f3413 100644
--- a/src/test/ui/generic-associated-types/empty_generics.rs
+++ b/src/test/ui/generic-associated-types/empty_generics.rs
@@ -3,7 +3,7 @@
 
 trait Foo {
     type Bar<,>;
-    //~^ ERROR expected one of `>`, `const`, identifier, or lifetime, found `,`
+    //~^ ERROR expected one of `#`, `>`, `const`, identifier, or lifetime, found `,`
 }
 
 fn main() {}
diff --git a/src/test/ui/generic-associated-types/empty_generics.stderr b/src/test/ui/generic-associated-types/empty_generics.stderr
index bd5708d814037..1599d683ad6dd 100644
--- a/src/test/ui/generic-associated-types/empty_generics.stderr
+++ b/src/test/ui/generic-associated-types/empty_generics.stderr
@@ -1,10 +1,10 @@
-error: expected one of `>`, `const`, identifier, or lifetime, found `,`
+error: expected one of `#`, `>`, `const`, identifier, or lifetime, found `,`
   --> $DIR/empty_generics.rs:5:14
    |
 LL | trait Foo {
    |           - while parsing this item list starting here
 LL |     type Bar<,>;
-   |              ^ expected one of `>`, `const`, identifier, or lifetime
+   |              ^ expected one of `#`, `>`, `const`, identifier, or lifetime
 LL |
 LL | }
    | - the item list ends here
diff --git a/src/test/ui/issues/issue-20616-8.rs b/src/test/ui/issues/issue-20616-8.rs
index c9e8b61e50b52..3ceb58d1252d3 100644
--- a/src/test/ui/issues/issue-20616-8.rs
+++ b/src/test/ui/issues/issue-20616-8.rs
@@ -29,7 +29,7 @@ type Type_5_<'a> = Type_1_<'a, ()>;
 
 
 type Type_8<'a,,> = &'a ();
-//~^ error: expected one of `>`, `const`, identifier, or lifetime, found `,`
+//~^ error: expected one of `#`, `>`, `const`, identifier, or lifetime, found `,`
 
 
 //type Type_9<T,,> = Box<T>; // error: expected identifier, found `,`
diff --git a/src/test/ui/issues/issue-20616-8.stderr b/src/test/ui/issues/issue-20616-8.stderr
index 479469634c523..e9f37e50fffec 100644
--- a/src/test/ui/issues/issue-20616-8.stderr
+++ b/src/test/ui/issues/issue-20616-8.stderr
@@ -1,8 +1,8 @@
-error: expected one of `>`, `const`, identifier, or lifetime, found `,`
+error: expected one of `#`, `>`, `const`, identifier, or lifetime, found `,`
   --> $DIR/issue-20616-8.rs:31:16
    |
 LL | type Type_8<'a,,> = &'a ();
-   |                ^ expected one of `>`, `const`, identifier, or lifetime
+   |                ^ expected one of `#`, `>`, `const`, identifier, or lifetime
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-20616-9.rs b/src/test/ui/issues/issue-20616-9.rs
index 1c509f26fd63a..7f84284481e2f 100644
--- a/src/test/ui/issues/issue-20616-9.rs
+++ b/src/test/ui/issues/issue-20616-9.rs
@@ -32,4 +32,4 @@ type Type_5_<'a> = Type_1_<'a, ()>;
 
 
 type Type_9<T,,> = Box<T>;
-//~^ error: expected one of `>`, `const`, identifier, or lifetime, found `,`
+//~^ error: expected one of `#`, `>`, `const`, identifier, or lifetime, found `,`
diff --git a/src/test/ui/issues/issue-20616-9.stderr b/src/test/ui/issues/issue-20616-9.stderr
index b7e3322b7aa92..dc309d1bce158 100644
--- a/src/test/ui/issues/issue-20616-9.stderr
+++ b/src/test/ui/issues/issue-20616-9.stderr
@@ -1,8 +1,8 @@
-error: expected one of `>`, `const`, identifier, or lifetime, found `,`
+error: expected one of `#`, `>`, `const`, identifier, or lifetime, found `,`
   --> $DIR/issue-20616-9.rs:34:15
    |
 LL | type Type_9<T,,> = Box<T>;
-   |               ^ expected one of `>`, `const`, identifier, or lifetime
+   |               ^ expected one of `#`, `>`, `const`, identifier, or lifetime
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-66473.rs b/src/test/ui/issues/issue-66473.rs
index cc298a28b97e5bc6e683fe5faee36d95d64720bf..9db4521bb423926b5dba771279e0e245581d51be 100644
GIT binary patch
delta 21
ccmXS{pWwoqpO>nTpQezYn4pkfG|^cP08twU4FCWD

delta 7
Ocmb;~oZvDsNEZMMiUQRD

diff --git a/src/test/ui/issues/issue-66473.stderr b/src/test/ui/issues/issue-66473.stderr
index dbeef44bad0ec68b68ce3c3c06768df43587855c..b370b125cfefda4f82cbb4866fec528b1465a2ef 100644
GIT binary patch
delta 43
mcmX>h@<e3AG)~_9yi|q!G=&7k1cm&f$x}Jw(L_FTh5`Ums}Cdq

delta 15
XcmaDNazbRoG|tIOIO8S@aD@N>HCzS5

diff --git a/src/test/ui/parser/bounds-lifetime.rs b/src/test/ui/parser/bounds-lifetime.rs
index 9225cfce94eb8..c9251ac532185 100644
--- a/src/test/ui/parser/bounds-lifetime.rs
+++ b/src/test/ui/parser/bounds-lifetime.rs
@@ -6,6 +6,6 @@ type A = for<'a: 'b + 'c> fn(); // OK (rejected later by ast_validation)
 type A = for<'a: 'b,> fn(); // OK(rejected later by ast_validation)
 type A = for<'a: 'b +> fn(); // OK (rejected later by ast_validation)
 type A = for<'a, T> fn(); // OK (rejected later by ast_validation)
-type A = for<,> fn(); //~ ERROR expected one of `>`, `const`, identifier, or lifetime, found `,`
+type A = for<,> fn(); //~ ERROR expected one of `#`, `>`, `const`, identifier, or lifetime
 
 fn main() {}
diff --git a/src/test/ui/parser/bounds-lifetime.stderr b/src/test/ui/parser/bounds-lifetime.stderr
index 12b9b61ebd174..e47a21d892b2f 100644
--- a/src/test/ui/parser/bounds-lifetime.stderr
+++ b/src/test/ui/parser/bounds-lifetime.stderr
@@ -1,8 +1,8 @@
-error: expected one of `>`, `const`, identifier, or lifetime, found `,`
+error: expected one of `#`, `>`, `const`, identifier, or lifetime, found `,`
   --> $DIR/bounds-lifetime.rs:9:14
    |
 LL | type A = for<,> fn();
-   |              ^ expected one of `>`, `const`, identifier, or lifetime
+   |              ^ expected one of `#`, `>`, `const`, identifier, or lifetime
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/column-offset-1-based.rs b/src/test/ui/parser/column-offset-1-based.rs
index e158e5247db18..0c24478c25c8b 100644
--- a/src/test/ui/parser/column-offset-1-based.rs
+++ b/src/test/ui/parser/column-offset-1-based.rs
@@ -1 +1 @@
-# //~ ERROR expected `[`, found `<eof>`
+# //~ ERROR expected one of `!` or `[`, found `<eof>`
diff --git a/src/test/ui/parser/column-offset-1-based.stderr b/src/test/ui/parser/column-offset-1-based.stderr
index 5cbf3d3e95965..766d72a0a5a93 100644
--- a/src/test/ui/parser/column-offset-1-based.stderr
+++ b/src/test/ui/parser/column-offset-1-based.stderr
@@ -1,8 +1,8 @@
-error: expected `[`, found `<eof>`
+error: expected one of `!` or `[`, found `<eof>`
   --> $DIR/column-offset-1-based.rs:1:1
    |
 LL | #
-   | ^ expected `[`
+   | ^ expected one of `!` or `[`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/doc-comment-in-if-statement.rs b/src/test/ui/parser/doc-comment-in-if-statement.rs
index c85fe25a7d0d1..69b174b4cb3c7 100644
--- a/src/test/ui/parser/doc-comment-in-if-statement.rs
+++ b/src/test/ui/parser/doc-comment-in-if-statement.rs
@@ -1,4 +1,5 @@
 fn main() {
     if true /*!*/ {}
     //~^ ERROR expected `{`, found doc comment `/*!*/`
+    //~| ERROR expected outer doc comment
 }
diff --git a/src/test/ui/parser/doc-comment-in-if-statement.stderr b/src/test/ui/parser/doc-comment-in-if-statement.stderr
index a720dd68bd037..1fe3735daf09b 100644
--- a/src/test/ui/parser/doc-comment-in-if-statement.stderr
+++ b/src/test/ui/parser/doc-comment-in-if-statement.stderr
@@ -1,10 +1,19 @@
+error: expected outer doc comment
+  --> $DIR/doc-comment-in-if-statement.rs:2:13
+   |
+LL |     if true /*!*/ {}
+   |             ^^^^^
+   |
+   = note: inner doc comments like this (starting with `//!` or `/*!`) can only appear before items
+
 error: expected `{`, found doc comment `/*!*/`
   --> $DIR/doc-comment-in-if-statement.rs:2:13
    |
 LL |     if true /*!*/ {}
-   |     --      ^^^^^ expected `{`
-   |     |
+   |     --      ^^^^^ -- help: try placing this code inside a block: `{ {} }`
+   |     |       |
+   |     |       expected `{`
    |     this `if` expression has a condition, but no block
 
-error: aborting due to previous error
+error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/parser/issue-1655.rs b/src/test/ui/parser/issue-1655.rs
index 3d0bf3c1c7b9f..e9fc6f15346f2 100644
--- a/src/test/ui/parser/issue-1655.rs
+++ b/src/test/ui/parser/issue-1655.rs
@@ -1,6 +1,5 @@
-// error-pattern:expected `[`, found `vec`
 mod blade_runner {
-    #vec[doc(
+    #vec[doc( //~ ERROR expected one of `!` or `[`, found `vec`
         brief = "Blade Runner is probably the best movie ever",
         desc = "I like that in the world of Blade Runner it is always
                 raining, and that it's always night time. And Aliens
diff --git a/src/test/ui/parser/issue-1655.stderr b/src/test/ui/parser/issue-1655.stderr
index 3f656b63cdb84..0c390a0ec563c 100644
--- a/src/test/ui/parser/issue-1655.stderr
+++ b/src/test/ui/parser/issue-1655.stderr
@@ -1,8 +1,8 @@
-error: expected `[`, found `vec`
-  --> $DIR/issue-1655.rs:3:6
+error: expected one of `!` or `[`, found `vec`
+  --> $DIR/issue-1655.rs:2:6
    |
 LL |     #vec[doc(
-   |      ^^^ expected `[`
+   |      ^^^ expected one of `!` or `[`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/issue-63135.rs b/src/test/ui/parser/issue-63135.rs
index 7d46b8904f033..a5a8de85466bb 100644
--- a/src/test/ui/parser/issue-63135.rs
+++ b/src/test/ui/parser/issue-63135.rs
@@ -1,3 +1,3 @@
-// error-pattern: aborting due to 7 previous errors
+// error-pattern: aborting due to 5 previous errors
 
 fn i(n{...,f #
diff --git a/src/test/ui/parser/issue-63135.stderr b/src/test/ui/parser/issue-63135.stderr
index 04afae93be0e5..396aec8335dbf 100644
--- a/src/test/ui/parser/issue-63135.stderr
+++ b/src/test/ui/parser/issue-63135.stderr
@@ -31,23 +31,11 @@ LL | fn i(n{...,f #
    |        |  expected `}`
    |        `..` must be at the end and cannot have a trailing comma
 
-error: expected `[`, found `}`
+error: expected one of `!` or `[`, found `}`
   --> $DIR/issue-63135.rs:3:16
    |
 LL | fn i(n{...,f #
-   |                ^ expected `[`
+   |                ^ expected one of `!` or `[`
 
-error: expected one of `:` or `|`, found `)`
-  --> $DIR/issue-63135.rs:3:16
-   |
-LL | fn i(n{...,f #
-   |                ^ expected one of `:` or `|`
-
-error: expected `;` or `{`, found `<eof>`
-  --> $DIR/issue-63135.rs:3:16
-   |
-LL | fn i(n{...,f #
-   |                ^ expected `;` or `{`
-
-error: aborting due to 7 previous errors
+error: aborting due to 5 previous errors
 
diff --git a/src/test/ui/parser/issue-68730.rs b/src/test/ui/parser/issue-68730.rs
index b570e9417751b01f67db9a2e4edfa7631400b8d9..20e18b4bcbb323d50ecfe254f9800cd5aa0a4a40 100644
GIT binary patch
delta 13
UcmZ3*xSnxBF0*oi&ctkc03QJaMgRZ+

delta 9
QcmZ3_xQcN??!+Qn01`X{nE(I)

diff --git a/src/test/ui/parser/issue-68730.stderr b/src/test/ui/parser/issue-68730.stderr
index 090b41d839f82b68c11fe38111b9fda254aa39b0..9f8833e17fe25afc9f10b08683294ecd7e9efe32 100644
GIT binary patch
delta 27
dcmdnPevEy?b0%ix1f9uQ%xaUlnG>PxAOL-32nYZG

delta 19
ZcmX@czK4CobEe5}m|B5YW%4X$9ROJz2r&Qv


From fe848b44feb5078f4f5c81bca0b61a29f71b6ef2 Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Fri, 6 Mar 2020 00:32:05 +0100
Subject: [PATCH 27/40] parse_block_tail: reduce visibility

---
 src/librustc_parse/parser/stmt.rs | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/src/librustc_parse/parser/stmt.rs b/src/librustc_parse/parser/stmt.rs
index 036e8a5d25859..8afc86c704d35 100644
--- a/src/librustc_parse/parser/stmt.rs
+++ b/src/librustc_parse/parser/stmt.rs
@@ -318,11 +318,7 @@ impl<'a> Parser<'a> {
 
     /// Parses the rest of a block expression or function body.
     /// Precondition: already parsed the '{'.
-    pub(super) fn parse_block_tail(
-        &mut self,
-        lo: Span,
-        s: BlockCheckMode,
-    ) -> PResult<'a, P<Block>> {
+    fn parse_block_tail(&mut self, lo: Span, s: BlockCheckMode) -> PResult<'a, P<Block>> {
         let mut stmts = vec![];
         while !self.eat(&token::CloseDelim(token::Brace)) {
             if self.token == token::Eof {

From e72df7edadcc2ff3fba93b1a0a2e321dc45f8d65 Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Fri, 6 Mar 2020 03:43:59 +0100
Subject: [PATCH 28/40] parse_labeled_expr: add a suggestion on missing colon.

---
 src/librustc_parse/parser/expr.rs             | 16 ++++++++--
 .../ui/parser/labeled-no-colon-expr.stderr    | 29 ++++++++++++-------
 2 files changed, 31 insertions(+), 14 deletions(-)

diff --git a/src/librustc_parse/parser/expr.rs b/src/librustc_parse/parser/expr.rs
index 5b39701001fdd..bab6a58296d89 100644
--- a/src/librustc_parse/parser/expr.rs
+++ b/src/librustc_parse/parser/expr.rs
@@ -1106,14 +1106,24 @@ impl<'a> Parser<'a> {
         }?;
 
         if !ate_colon {
-            self.struct_span_err(expr.span, "labeled expression must be followed by `:`")
-                .span_label(lo, "the label")
-                .emit();
+            self.error_labeled_expr_must_be_followed_by_colon(lo, expr.span);
         }
 
         Ok(expr)
     }
 
+    fn error_labeled_expr_must_be_followed_by_colon(&self, lo: Span, span: Span) {
+        self.struct_span_err(span, "labeled expression must be followed by `:`")
+            .span_label(lo, "the label")
+            .span_suggestion_short(
+                lo.shrink_to_hi(),
+                "add `:` after the label",
+                ": ".to_string(),
+                Applicability::MachineApplicable,
+            )
+            .emit();
+    }
+
     /// Recover on the syntax `do catch { ... }` suggesting `try { ... }` instead.
     fn recover_do_catch(&mut self, attrs: AttrVec) -> PResult<'a, P<Expr>> {
         let lo = self.token.span;
diff --git a/src/test/ui/parser/labeled-no-colon-expr.stderr b/src/test/ui/parser/labeled-no-colon-expr.stderr
index 8a9e2b324004e..a69532555d49e 100644
--- a/src/test/ui/parser/labeled-no-colon-expr.stderr
+++ b/src/test/ui/parser/labeled-no-colon-expr.stderr
@@ -2,32 +2,36 @@ error: labeled expression must be followed by `:`
   --> $DIR/labeled-no-colon-expr.rs:4:5
    |
 LL |     'l0 while false {}
-   |     ---^^^^^^^^^^^^^^^
-   |     |
+   |     ----^^^^^^^^^^^^^^
+   |     |  |
+   |     |  help: add `:` after the label
    |     the label
 
 error: labeled expression must be followed by `:`
   --> $DIR/labeled-no-colon-expr.rs:5:5
    |
 LL |     'l1 for _ in 0..1 {}
-   |     ---^^^^^^^^^^^^^^^^^
-   |     |
+   |     ----^^^^^^^^^^^^^^^^
+   |     |  |
+   |     |  help: add `:` after the label
    |     the label
 
 error: labeled expression must be followed by `:`
   --> $DIR/labeled-no-colon-expr.rs:6:5
    |
 LL |     'l2 loop {}
-   |     ---^^^^^^^^
-   |     |
+   |     ----^^^^^^^
+   |     |  |
+   |     |  help: add `:` after the label
    |     the label
 
 error: labeled expression must be followed by `:`
   --> $DIR/labeled-no-colon-expr.rs:7:5
    |
 LL |     'l3 {}
-   |     ---^^^
-   |     |
+   |     ----^^
+   |     |  |
+   |     |  help: add `:` after the label
    |     the label
 
 error: expected `while`, `for`, `loop` or `{` after a label
@@ -40,8 +44,9 @@ error: labeled expression must be followed by `:`
   --> $DIR/labeled-no-colon-expr.rs:8:9
    |
 LL |     'l4 0;
-   |     --- ^
-   |     |
+   |     ----^
+   |     |  |
+   |     |  help: add `:` after the label
    |     the label
 
 error: cannot use a `block` macro fragment here
@@ -61,7 +66,9 @@ error: labeled expression must be followed by `:`
   --> $DIR/labeled-no-colon-expr.rs:16:8
    |
 LL |             'l5 $b;
-   |             --- the label
+   |             ---- help: add `:` after the label
+   |             |
+   |             the label
 ...
 LL |     m!({});
    |        ^^

From 83be689b947d391360a965660cba0f3baf1c062e Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Sat, 7 Mar 2020 09:31:00 +0100
Subject: [PATCH 29/40] parser/attr: adjust indentation.

---
 src/librustc_parse/parser/attr.rs | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/src/librustc_parse/parser/attr.rs b/src/librustc_parse/parser/attr.rs
index b5af124fd4298..b56dd30739dae 100644
--- a/src/librustc_parse/parser/attr.rs
+++ b/src/librustc_parse/parser/attr.rs
@@ -130,10 +130,9 @@ impl<'a> Parser<'a> {
             }
 
             diag.note(
-                "inner attributes, like `#![no_std]`, annotate the item \
-                       enclosing them, and are usually found at the beginning of \
-                       source files. Outer attributes, like `#[test]`, annotate the \
-                       item following them.",
+                "inner attributes, like `#![no_std]`, annotate the item enclosing them, \
+                and are usually found at the beginning of source files. \
+                Outer attributes, like `#[test]`, annotate the item following them.",
             )
             .emit();
         }
@@ -202,9 +201,8 @@ impl<'a> Parser<'a> {
         if !lit.kind.is_unsuffixed() {
             self.struct_span_err(lit.span, "suffixed literals are not allowed in attributes")
                 .help(
-                    "instead of using a suffixed literal \
-                                    (`1u8`, `1.0f32`, etc.), use an unsuffixed version \
-                                    (`1`, `1.0`, etc.)",
+                    "instead of using a suffixed literal (`1u8`, `1.0f32`, etc.), \
+                    use an unsuffixed version (`1`, `1.0`, etc.)",
                 )
                 .emit();
         }

From 65b7ba5129bf1f32be78379255c921c08126c97f Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Sat, 7 Mar 2020 09:41:12 +0100
Subject: [PATCH 30/40] parser: add note for `'label expr`.

---
 src/librustc_parse/parser/expr.rs               |  1 +
 src/test/ui/parser/labeled-no-colon-expr.stderr | 12 ++++++++++++
 2 files changed, 13 insertions(+)

diff --git a/src/librustc_parse/parser/expr.rs b/src/librustc_parse/parser/expr.rs
index bab6a58296d89..826213ba450b9 100644
--- a/src/librustc_parse/parser/expr.rs
+++ b/src/librustc_parse/parser/expr.rs
@@ -1121,6 +1121,7 @@ impl<'a> Parser<'a> {
                 ": ".to_string(),
                 Applicability::MachineApplicable,
             )
+            .note("labels are used before loops and blocks, allowing e.g., `break 'label` to them")
             .emit();
     }
 
diff --git a/src/test/ui/parser/labeled-no-colon-expr.stderr b/src/test/ui/parser/labeled-no-colon-expr.stderr
index a69532555d49e..4f5e8f78aa0cd 100644
--- a/src/test/ui/parser/labeled-no-colon-expr.stderr
+++ b/src/test/ui/parser/labeled-no-colon-expr.stderr
@@ -6,6 +6,8 @@ LL |     'l0 while false {}
    |     |  |
    |     |  help: add `:` after the label
    |     the label
+   |
+   = note: labels are used before loops and blocks, allowing e.g., `break 'label` to them
 
 error: labeled expression must be followed by `:`
   --> $DIR/labeled-no-colon-expr.rs:5:5
@@ -15,6 +17,8 @@ LL |     'l1 for _ in 0..1 {}
    |     |  |
    |     |  help: add `:` after the label
    |     the label
+   |
+   = note: labels are used before loops and blocks, allowing e.g., `break 'label` to them
 
 error: labeled expression must be followed by `:`
   --> $DIR/labeled-no-colon-expr.rs:6:5
@@ -24,6 +28,8 @@ LL |     'l2 loop {}
    |     |  |
    |     |  help: add `:` after the label
    |     the label
+   |
+   = note: labels are used before loops and blocks, allowing e.g., `break 'label` to them
 
 error: labeled expression must be followed by `:`
   --> $DIR/labeled-no-colon-expr.rs:7:5
@@ -33,6 +39,8 @@ LL |     'l3 {}
    |     |  |
    |     |  help: add `:` after the label
    |     the label
+   |
+   = note: labels are used before loops and blocks, allowing e.g., `break 'label` to them
 
 error: expected `while`, `for`, `loop` or `{` after a label
   --> $DIR/labeled-no-colon-expr.rs:8:9
@@ -48,6 +56,8 @@ LL |     'l4 0;
    |     |  |
    |     |  help: add `:` after the label
    |     the label
+   |
+   = note: labels are used before loops and blocks, allowing e.g., `break 'label` to them
 
 error: cannot use a `block` macro fragment here
   --> $DIR/labeled-no-colon-expr.rs:13:17
@@ -72,6 +82,8 @@ LL |             'l5 $b;
 ...
 LL |     m!({});
    |        ^^
+   |
+   = note: labels are used before loops and blocks, allowing e.g., `break 'label` to them
 
 error: aborting due to 8 previous errors
 

From c01b3e6996a803d7794546cbcbba867eff8fb6e2 Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Sat, 7 Mar 2020 09:49:46 +0100
Subject: [PATCH 31/40] block-no-opening-brace: add another statement

---
 src/test/ui/parser/block-no-opening-brace.rs  | 31 +++++-----
 .../ui/parser/block-no-opening-brace.stderr   | 58 +++++++++----------
 2 files changed, 45 insertions(+), 44 deletions(-)

diff --git a/src/test/ui/parser/block-no-opening-brace.rs b/src/test/ui/parser/block-no-opening-brace.rs
index 169625bf8973b..e4bb39f6836b4 100644
--- a/src/test/ui/parser/block-no-opening-brace.rs
+++ b/src/test/ui/parser/block-no-opening-brace.rs
@@ -5,26 +5,27 @@
 fn main() {}
 
 fn f1() {
-   loop
-     let x = 0; //~ ERROR expected `{`, found keyword `let`
-   }
+    loop
+        let x = 0; //~ ERROR expected `{`, found keyword `let`
+        drop(0);
+    }
 
 fn f2() {
-   while true
-     let x = 0; //~ ERROR expected `{`, found keyword `let`
-   }
+    while true
+        let x = 0; //~ ERROR expected `{`, found keyword `let`
+    }
 
 fn f3() {
-   for x in 0..1
-     let x = 0; //~ ERROR expected `{`, found keyword `let`
-   }
+    for x in 0..1
+        let x = 0; //~ ERROR expected `{`, found keyword `let`
+    }
 
 fn f4() {
-   try //~ ERROR expected expression, found reserved keyword `try`
-     let x = 0;
-   }
+    try //~ ERROR expected expression, found reserved keyword `try`
+        let x = 0;
+    }
 
 fn f5() {
-   async //~ ERROR async closures are unstable
-     let x = 0; //~ ERROR expected one of `move`, `|`, or `||`, found keyword `let`
-   }
+    async //~ ERROR async closures are unstable
+        let x = 0; //~ ERROR expected one of `move`, `|`, or `||`, found keyword `let`
+    }
diff --git a/src/test/ui/parser/block-no-opening-brace.stderr b/src/test/ui/parser/block-no-opening-brace.stderr
index 56db1147360de..a88e4ac44cfda 100644
--- a/src/test/ui/parser/block-no-opening-brace.stderr
+++ b/src/test/ui/parser/block-no-opening-brace.stderr
@@ -1,49 +1,49 @@
 error: expected `{`, found keyword `let`
-  --> $DIR/block-no-opening-brace.rs:9:6
+  --> $DIR/block-no-opening-brace.rs:9:9
    |
-LL |      let x = 0;
-   |      ^^^-------
-   |      |
-   |      expected `{`
-   |      help: try placing this code inside a block: `{ let x = 0; }`
+LL |         let x = 0;
+   |         ^^^-------
+   |         |
+   |         expected `{`
+   |         help: try placing this code inside a block: `{ let x = 0; }`
 
 error: expected `{`, found keyword `let`
-  --> $DIR/block-no-opening-brace.rs:14:6
+  --> $DIR/block-no-opening-brace.rs:15:9
    |
-LL |      let x = 0;
-   |      ^^^-------
-   |      |
-   |      expected `{`
-   |      help: try placing this code inside a block: `{ let x = 0; }`
+LL |         let x = 0;
+   |         ^^^-------
+   |         |
+   |         expected `{`
+   |         help: try placing this code inside a block: `{ let x = 0; }`
 
 error: expected `{`, found keyword `let`
-  --> $DIR/block-no-opening-brace.rs:19:6
+  --> $DIR/block-no-opening-brace.rs:20:9
    |
-LL |      let x = 0;
-   |      ^^^-------
-   |      |
-   |      expected `{`
-   |      help: try placing this code inside a block: `{ let x = 0; }`
+LL |         let x = 0;
+   |         ^^^-------
+   |         |
+   |         expected `{`
+   |         help: try placing this code inside a block: `{ let x = 0; }`
 
 error: expected expression, found reserved keyword `try`
-  --> $DIR/block-no-opening-brace.rs:23:4
+  --> $DIR/block-no-opening-brace.rs:24:5
    |
-LL |    try
-   |    ^^^ expected expression
+LL |     try
+   |     ^^^ expected expression
 
 error: expected one of `move`, `|`, or `||`, found keyword `let`
-  --> $DIR/block-no-opening-brace.rs:29:6
+  --> $DIR/block-no-opening-brace.rs:30:9
    |
-LL |    async
-   |         - expected one of `move`, `|`, or `||`
-LL |      let x = 0;
-   |      ^^^ unexpected token
+LL |     async
+   |          - expected one of `move`, `|`, or `||`
+LL |         let x = 0;
+   |         ^^^ unexpected token
 
 error[E0658]: async closures are unstable
-  --> $DIR/block-no-opening-brace.rs:28:4
+  --> $DIR/block-no-opening-brace.rs:29:5
    |
-LL |    async
-   |    ^^^^^
+LL |     async
+   |     ^^^^^
    |
    = note: see issue #62290 <https://github.com/rust-lang/rust/issues/62290> for more information
    = help: add `#![feature(async_closure)]` to the crate attributes to enable

From 09997e72272157a88c40cd2b1b1b7a14f808c0e0 Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Sat, 7 Mar 2020 11:00:40 +0100
Subject: [PATCH 32/40] error_block_no_opening_brace: handle closures better

---
 src/librustc_parse/parser/stmt.rs                | 16 +++++++---------
 src/librustc_span/source_map.rs                  |  7 +++++++
 .../ui/parser/attr-stmt-expr-attr-bad.stderr     | 16 ++++++++--------
 src/test/ui/parser/closure-return-syntax.stderr  |  4 ++--
 4 files changed, 24 insertions(+), 19 deletions(-)

diff --git a/src/librustc_parse/parser/stmt.rs b/src/librustc_parse/parser/stmt.rs
index 8afc86c704d35..fb85f54b136a7 100644
--- a/src/librustc_parse/parser/stmt.rs
+++ b/src/librustc_parse/parser/stmt.rs
@@ -259,16 +259,14 @@ impl<'a> Parser<'a> {
         //
         // which is valid in other languages, but not Rust.
         match self.parse_stmt_without_recovery() {
-            Ok(Some(stmt)) => {
+            // If the next token is an open brace (e.g., `if a b {`), the place-
+            // inside-a-block suggestion would be more likely wrong than right.
+            Ok(Some(_))
                 if self.look_ahead(1, |t| t == &token::OpenDelim(token::Brace))
-                    || do_not_suggest_help
-                {
-                    // If the next token is an open brace (e.g., `if a b {`), the place-
-                    // inside-a-block suggestion would be more likely wrong than right.
-                    e.span_label(sp, "expected `{`");
-                    return Err(e);
-                }
-                let stmt_span = if self.eat(&token::Semi) {
+                    || do_not_suggest_help => {}
+            Ok(Some(stmt)) => {
+                let stmt_own_line = self.sess.source_map().is_line_before_span_empty(sp);
+                let stmt_span = if stmt_own_line && self.eat(&token::Semi) {
                     // Expand the span to include the semicolon.
                     stmt.span.with_hi(self.prev_token.span.hi())
                 } else {
diff --git a/src/librustc_span/source_map.rs b/src/librustc_span/source_map.rs
index cd2d2c4c3d768..5170f69e05985 100644
--- a/src/librustc_span/source_map.rs
+++ b/src/librustc_span/source_map.rs
@@ -517,6 +517,13 @@ impl SourceMap {
         Ok((lo, hi))
     }
 
+    pub fn is_line_before_span_empty(&self, sp: Span) -> bool {
+        match self.span_to_prev_source(sp) {
+            Ok(s) => s.split('\n').last().map(|l| l.trim_start().is_empty()).unwrap_or(false),
+            Err(_) => false,
+        }
+    }
+
     pub fn span_to_lines(&self, sp: Span) -> FileLinesResult {
         debug!("span_to_lines(sp={:?})", sp);
         let (lo, hi) = self.is_valid_span(sp)?;
diff --git a/src/test/ui/parser/attr-stmt-expr-attr-bad.stderr b/src/test/ui/parser/attr-stmt-expr-attr-bad.stderr
index 4dcba27cb68db..af4901509135a 100644
--- a/src/test/ui/parser/attr-stmt-expr-attr-bad.stderr
+++ b/src/test/ui/parser/attr-stmt-expr-attr-bad.stderr
@@ -140,7 +140,7 @@ error: expected `{`, found `#`
   --> $DIR/attr-stmt-expr-attr-bad.rs:41:37
    |
 LL | #[cfg(FALSE)] fn e() { let _ = if 0 #[attr] {}; }
-   |                                --   ^       --- help: try placing this code inside a block: `{ {}; }`
+   |                                --   ^       -- help: try placing this code inside a block: `{ {} }`
    |                                |    |
    |                                |    expected `{`
    |                                this `if` expression has a condition, but no block
@@ -163,7 +163,7 @@ error: expected `{`, found `#`
   --> $DIR/attr-stmt-expr-attr-bad.rs:47:45
    |
 LL | #[cfg(FALSE)] fn e() { let _ = if 0 {} else #[attr] {}; }
-   |                                             ^       --- help: try placing this code inside a block: `{ {}; }`
+   |                                             ^       -- help: try placing this code inside a block: `{ {} }`
    |                                             |
    |                                             expected `{`
 
@@ -179,7 +179,7 @@ error: expected `{`, found `#`
   --> $DIR/attr-stmt-expr-attr-bad.rs:51:45
    |
 LL | #[cfg(FALSE)] fn e() { let _ = if 0 {} else #[attr] if 0 {}; }
-   |                                             ^       -------- help: try placing this code inside a block: `{ if 0 {}; }`
+   |                                             ^       ------- help: try placing this code inside a block: `{ if 0 {} }`
    |                                             |
    |                                             expected `{`
 
@@ -187,7 +187,7 @@ error: expected `{`, found `#`
   --> $DIR/attr-stmt-expr-attr-bad.rs:53:50
    |
 LL | #[cfg(FALSE)] fn e() { let _ = if 0 {} else if 0 #[attr] {}; }
-   |                                             --   ^       --- help: try placing this code inside a block: `{ {}; }`
+   |                                             --   ^       -- help: try placing this code inside a block: `{ {} }`
    |                                             |    |
    |                                             |    expected `{`
    |                                             this `if` expression has a condition, but no block
@@ -204,7 +204,7 @@ error: expected `{`, found `#`
   --> $DIR/attr-stmt-expr-attr-bad.rs:57:45
    |
 LL | #[cfg(FALSE)] fn e() { let _ = if let _ = 0 #[attr] {}; }
-   |                                --           ^       --- help: try placing this code inside a block: `{ {}; }`
+   |                                --           ^       -- help: try placing this code inside a block: `{ {} }`
    |                                |            |
    |                                |            expected `{`
    |                                this `if` expression has a condition, but no block
@@ -227,7 +227,7 @@ error: expected `{`, found `#`
   --> $DIR/attr-stmt-expr-attr-bad.rs:63:53
    |
 LL | #[cfg(FALSE)] fn e() { let _ = if let _ = 0 {} else #[attr] {}; }
-   |                                                     ^       --- help: try placing this code inside a block: `{ {}; }`
+   |                                                     ^       -- help: try placing this code inside a block: `{ {} }`
    |                                                     |
    |                                                     expected `{`
 
@@ -243,7 +243,7 @@ error: expected `{`, found `#`
   --> $DIR/attr-stmt-expr-attr-bad.rs:67:53
    |
 LL | #[cfg(FALSE)] fn e() { let _ = if let _ = 0 {} else #[attr] if let _ = 0 {}; }
-   |                                                     ^       ---------------- help: try placing this code inside a block: `{ if let _ = 0 {}; }`
+   |                                                     ^       --------------- help: try placing this code inside a block: `{ if let _ = 0 {} }`
    |                                                     |
    |                                                     expected `{`
 
@@ -251,7 +251,7 @@ error: expected `{`, found `#`
   --> $DIR/attr-stmt-expr-attr-bad.rs:69:66
    |
 LL | #[cfg(FALSE)] fn e() { let _ = if let _ = 0 {} else if let _ = 0 #[attr] {}; }
-   |                                                     --           ^       --- help: try placing this code inside a block: `{ {}; }`
+   |                                                     --           ^       -- help: try placing this code inside a block: `{ {} }`
    |                                                     |            |
    |                                                     |            expected `{`
    |                                                     this `if` expression has a condition, but no block
diff --git a/src/test/ui/parser/closure-return-syntax.stderr b/src/test/ui/parser/closure-return-syntax.stderr
index 7bf6202a72a2d..1ccdd97730555 100644
--- a/src/test/ui/parser/closure-return-syntax.stderr
+++ b/src/test/ui/parser/closure-return-syntax.stderr
@@ -2,10 +2,10 @@ error: expected `{`, found `22`
   --> $DIR/closure-return-syntax.rs:5:23
    |
 LL |     let x = || -> i32 22;
-   |                       ^^-
+   |                       ^^
    |                       |
    |                       expected `{`
-   |                       help: try placing this code inside a block: `{ 22; }`
+   |                       help: try placing this code inside a block: `{ 22 }`
 
 error: aborting due to previous error
 

From 25cd01b863ce783e5f3300deecc12b22ae4e5336 Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Sat, 7 Mar 2020 12:14:39 +0100
Subject: [PATCH 33/40] issue 68890: add more minimal repro

---
 src/test/ui/parser/issue-68890-2.rs     |  3 +++
 src/test/ui/parser/issue-68890-2.stderr | 14 ++++++++++++++
 2 files changed, 17 insertions(+)
 create mode 100644 src/test/ui/parser/issue-68890-2.rs
 create mode 100644 src/test/ui/parser/issue-68890-2.stderr

diff --git a/src/test/ui/parser/issue-68890-2.rs b/src/test/ui/parser/issue-68890-2.rs
new file mode 100644
index 0000000000000..4bf56f0b0c2ac
--- /dev/null
+++ b/src/test/ui/parser/issue-68890-2.rs
@@ -0,0 +1,3 @@
+type X = (?'a) +;
+//~^ ERROR `?` may only modify trait bounds, not lifetime bounds
+//~| ERROR expected trait bound, not lifetime bound
diff --git a/src/test/ui/parser/issue-68890-2.stderr b/src/test/ui/parser/issue-68890-2.stderr
new file mode 100644
index 0000000000000..d6196eb1506a3
--- /dev/null
+++ b/src/test/ui/parser/issue-68890-2.stderr
@@ -0,0 +1,14 @@
+error: `?` may only modify trait bounds, not lifetime bounds
+  --> $DIR/issue-68890-2.rs:1:11
+   |
+LL | type X = (?'a) +;
+   |           ^
+
+error: expected trait bound, not lifetime bound
+  --> $DIR/issue-68890-2.rs:1:11
+   |
+LL | type X = (?'a) +;
+   |           ^^^
+
+error: aborting due to 2 previous errors
+

From c0b073bc625d2178255876bc10834f46837ba773 Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Sat, 7 Mar 2020 12:54:31 +0100
Subject: [PATCH 34/40] simplify & improve parse_ty_tuple_or_parens

---
 src/librustc_parse/parser/ty.rs               | 37 +++++----
 src/test/ui/parser/issue-68890-2.rs           |  7 +-
 src/test/ui/parser/issue-68890-2.stderr       | 22 ++++--
 src/test/ui/parser/issue-68890.rs             |  2 +-
 src/test/ui/parser/issue-68890.stderr         |  6 +-
 .../ui/parser/trait-object-trait-parens.rs    | 17 ++--
 .../parser/trait-object-trait-parens.stderr   | 78 +++++++++++++------
 7 files changed, 107 insertions(+), 62 deletions(-)

diff --git a/src/librustc_parse/parser/ty.rs b/src/librustc_parse/parser/ty.rs
index 16adf5c05a4ee..08168cf7df988 100644
--- a/src/librustc_parse/parser/ty.rs
+++ b/src/librustc_parse/parser/ty.rs
@@ -142,7 +142,7 @@ impl<'a> Parser<'a> {
             } else {
                 let path = self.parse_path(PathStyle::Type)?;
                 let parse_plus = allow_plus == AllowPlus::Yes && self.check_plus();
-                self.parse_remaining_bounds(lifetime_defs, path, lo, parse_plus)?
+                self.parse_remaining_bounds_path(lifetime_defs, path, lo, parse_plus)?
             }
         } else if self.eat_keyword(kw::Impl) {
             self.parse_impl_ty(&mut impl_dyn_multi)?
@@ -203,21 +203,12 @@ impl<'a> Parser<'a> {
             match ty.kind {
                 // `(TY_BOUND_NOPAREN) + BOUND + ...`.
                 TyKind::Path(None, path) if maybe_bounds => {
-                    self.parse_remaining_bounds(Vec::new(), path, lo, true)
+                    self.parse_remaining_bounds_path(Vec::new(), path, lo, true)
                 }
-                TyKind::TraitObject(mut bounds, TraitObjectSyntax::None)
+                TyKind::TraitObject(bounds, TraitObjectSyntax::None)
                     if maybe_bounds && bounds.len() == 1 && !trailing_plus =>
                 {
-                    let path = match bounds.remove(0) {
-                        GenericBound::Trait(pt, ..) => pt.trait_ref.path,
-                        GenericBound::Outlives(..) => {
-                            return Err(self.struct_span_err(
-                                ty.span,
-                                "expected trait bound, not lifetime bound",
-                            ));
-                        }
-                    };
-                    self.parse_remaining_bounds(Vec::new(), path, lo, true)
+                    self.parse_remaining_bounds(bounds, true)
                 }
                 // `(TYPE)`
                 _ => Ok(TyKind::Paren(P(ty))),
@@ -227,18 +218,26 @@ impl<'a> Parser<'a> {
         }
     }
 
-    fn parse_remaining_bounds(
+    fn parse_remaining_bounds_path(
         &mut self,
         generic_params: Vec<GenericParam>,
         path: ast::Path,
         lo: Span,
         parse_plus: bool,
     ) -> PResult<'a, TyKind> {
-        assert_ne!(self.token, token::Question);
-
         let poly_trait_ref = PolyTraitRef::new(generic_params, path, lo.to(self.prev_token.span));
-        let mut bounds = vec![GenericBound::Trait(poly_trait_ref, TraitBoundModifier::None)];
-        if parse_plus {
+        let bounds = vec![GenericBound::Trait(poly_trait_ref, TraitBoundModifier::None)];
+        self.parse_remaining_bounds(bounds, parse_plus)
+    }
+
+    /// Parse the remainder of a bare trait object type given an already parsed list.
+    fn parse_remaining_bounds(
+        &mut self,
+        mut bounds: GenericBounds,
+        plus: bool,
+    ) -> PResult<'a, TyKind> {
+        assert_ne!(self.token, token::Question);
+        if plus {
             self.eat_plus(); // `+`, or `+=` gets split and `+` is discarded
             bounds.append(&mut self.parse_generic_bounds(Some(self.prev_token.span))?);
         }
@@ -358,7 +357,7 @@ impl<'a> Parser<'a> {
             }))
         } else if allow_plus == AllowPlus::Yes && self.check_plus() {
             // `Trait1 + Trait2 + 'a`
-            self.parse_remaining_bounds(Vec::new(), path, lo, true)
+            self.parse_remaining_bounds_path(Vec::new(), path, lo, true)
         } else {
             // Just a type path.
             Ok(TyKind::Path(None, path))
diff --git a/src/test/ui/parser/issue-68890-2.rs b/src/test/ui/parser/issue-68890-2.rs
index 4bf56f0b0c2ac..ae02246046880 100644
--- a/src/test/ui/parser/issue-68890-2.rs
+++ b/src/test/ui/parser/issue-68890-2.rs
@@ -1,3 +1,6 @@
-type X = (?'a) +;
+fn main() {}
+
+type X<'a> = (?'a) +;
 //~^ ERROR `?` may only modify trait bounds, not lifetime bounds
-//~| ERROR expected trait bound, not lifetime bound
+//~| ERROR at least one trait is required for an object type
+//~| WARN trait objects without an explicit `dyn` are deprecated
diff --git a/src/test/ui/parser/issue-68890-2.stderr b/src/test/ui/parser/issue-68890-2.stderr
index d6196eb1506a3..d475c79cb27b4 100644
--- a/src/test/ui/parser/issue-68890-2.stderr
+++ b/src/test/ui/parser/issue-68890-2.stderr
@@ -1,14 +1,22 @@
 error: `?` may only modify trait bounds, not lifetime bounds
-  --> $DIR/issue-68890-2.rs:1:11
+  --> $DIR/issue-68890-2.rs:3:15
    |
-LL | type X = (?'a) +;
-   |           ^
+LL | type X<'a> = (?'a) +;
+   |               ^
 
-error: expected trait bound, not lifetime bound
-  --> $DIR/issue-68890-2.rs:1:11
+warning: trait objects without an explicit `dyn` are deprecated
+  --> $DIR/issue-68890-2.rs:3:14
    |
-LL | type X = (?'a) +;
-   |           ^^^
+LL | type X<'a> = (?'a) +;
+   |              ^^^^^^^ help: use `dyn`: `dyn (?'a) +`
+   |
+   = note: `#[warn(bare_trait_objects)]` on by default
+
+error[E0224]: at least one trait is required for an object type
+  --> $DIR/issue-68890-2.rs:3:14
+   |
+LL | type X<'a> = (?'a) +;
+   |              ^^^^^^^
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/parser/issue-68890.rs b/src/test/ui/parser/issue-68890.rs
index a7c5a5e13008a..bab4ed7f800c5 100644
--- a/src/test/ui/parser/issue-68890.rs
+++ b/src/test/ui/parser/issue-68890.rs
@@ -1,4 +1,4 @@
 enum e{A((?'a a+?+l))}
 //~^ ERROR `?` may only modify trait bounds, not lifetime bounds
 //~| ERROR expected one of `)`, `+`, or `,`
-//~| ERROR expected trait bound, not lifetime bound
+//~| ERROR expected item, found `)`
diff --git a/src/test/ui/parser/issue-68890.stderr b/src/test/ui/parser/issue-68890.stderr
index 9bb8761b67b5f..2a3bf6b41f02e 100644
--- a/src/test/ui/parser/issue-68890.stderr
+++ b/src/test/ui/parser/issue-68890.stderr
@@ -10,11 +10,11 @@ error: expected one of `)`, `+`, or `,`, found `a`
 LL | enum e{A((?'a a+?+l))}
    |               ^ expected one of `)`, `+`, or `,`
 
-error: expected trait bound, not lifetime bound
-  --> $DIR/issue-68890.rs:1:11
+error: expected item, found `)`
+  --> $DIR/issue-68890.rs:1:21
    |
 LL | enum e{A((?'a a+?+l))}
-   |           ^^^
+   |                     ^ expected item
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/parser/trait-object-trait-parens.rs b/src/test/ui/parser/trait-object-trait-parens.rs
index a113de14b6fbc..9fbc938c4dce8 100644
--- a/src/test/ui/parser/trait-object-trait-parens.rs
+++ b/src/test/ui/parser/trait-object-trait-parens.rs
@@ -1,15 +1,20 @@
 trait Trait<'a> {}
 
+trait Obj {}
+
 fn f<T: (Copy) + (?Sized) + (for<'a> Trait<'a>)>() {}
 
 fn main() {
-    let _: Box<(Copy) + (?Sized) + (for<'a> Trait<'a>)>;
+    let _: Box<(Obj) + (?Sized) + (for<'a> Trait<'a>)>;
+    //~^ ERROR `?Trait` is not permitted in trait object types
+    //~| ERROR only auto traits can be used as additional traits
+    //~| WARN trait objects without an explicit `dyn` are deprecated
+    let _: Box<(?Sized) + (for<'a> Trait<'a>) + (Obj)>;
     //~^ ERROR `?Trait` is not permitted in trait object types
+    //~| ERROR only auto traits can be used as additional traits
     //~| WARN trait objects without an explicit `dyn` are deprecated
-    let _: Box<(?Sized) + (for<'a> Trait<'a>) + (Copy)>;
-    //~^ WARN trait objects without an explicit `dyn` are deprecated
-    let _: Box<(for<'a> Trait<'a>) + (Copy) + (?Sized)>;
-    //~^ ERROR use of undeclared lifetime name `'a`
-    //~| ERROR `?Trait` is not permitted in trait object types
+    let _: Box<(for<'a> Trait<'a>) + (Obj) + (?Sized)>;
+    //~^ ERROR `?Trait` is not permitted in trait object types
+    //~| ERROR only auto traits can be used as additional traits
     //~| WARN trait objects without an explicit `dyn` are deprecated
 }
diff --git a/src/test/ui/parser/trait-object-trait-parens.stderr b/src/test/ui/parser/trait-object-trait-parens.stderr
index 4b9f49423cbf4..7022a66ca1a17 100644
--- a/src/test/ui/parser/trait-object-trait-parens.stderr
+++ b/src/test/ui/parser/trait-object-trait-parens.stderr
@@ -1,44 +1,74 @@
 error: `?Trait` is not permitted in trait object types
-  --> $DIR/trait-object-trait-parens.rs:6:25
+  --> $DIR/trait-object-trait-parens.rs:8:24
    |
-LL |     let _: Box<(Copy) + (?Sized) + (for<'a> Trait<'a>)>;
-   |                         ^^^^^^^^
+LL |     let _: Box<(Obj) + (?Sized) + (for<'a> Trait<'a>)>;
+   |                        ^^^^^^^^
 
 error: `?Trait` is not permitted in trait object types
-  --> $DIR/trait-object-trait-parens.rs:11:47
+  --> $DIR/trait-object-trait-parens.rs:12:17
    |
-LL |     let _: Box<(for<'a> Trait<'a>) + (Copy) + (?Sized)>;
-   |                                               ^^^^^^^^
+LL |     let _: Box<(?Sized) + (for<'a> Trait<'a>) + (Obj)>;
+   |                 ^^^^^^
+
+error: `?Trait` is not permitted in trait object types
+  --> $DIR/trait-object-trait-parens.rs:16:46
+   |
+LL |     let _: Box<(for<'a> Trait<'a>) + (Obj) + (?Sized)>;
+   |                                              ^^^^^^^^
 
 warning: trait objects without an explicit `dyn` are deprecated
-  --> $DIR/trait-object-trait-parens.rs:6:16
+  --> $DIR/trait-object-trait-parens.rs:8:16
    |
-LL |     let _: Box<(Copy) + (?Sized) + (for<'a> Trait<'a>)>;
-   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn (Copy) + (?Sized) + (for<'a> Trait<'a>)`
+LL |     let _: Box<(Obj) + (?Sized) + (for<'a> Trait<'a>)>;
+   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn (Obj) + (?Sized) + (for<'a> Trait<'a>)`
    |
    = note: `#[warn(bare_trait_objects)]` on by default
 
 warning: trait objects without an explicit `dyn` are deprecated
-  --> $DIR/trait-object-trait-parens.rs:9:16
+  --> $DIR/trait-object-trait-parens.rs:12:16
    |
-LL |     let _: Box<(?Sized) + (for<'a> Trait<'a>) + (Copy)>;
-   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn (?Sized) + (for<'a> Trait<'a>) + (Copy)`
+LL |     let _: Box<(?Sized) + (for<'a> Trait<'a>) + (Obj)>;
+   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn (?Sized) + (for<'a> Trait<'a>) + (Obj)`
 
 warning: trait objects without an explicit `dyn` are deprecated
-  --> $DIR/trait-object-trait-parens.rs:11:16
+  --> $DIR/trait-object-trait-parens.rs:16:16
+   |
+LL |     let _: Box<(for<'a> Trait<'a>) + (Obj) + (?Sized)>;
+   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn (for<'a> Trait<'a>) + (Obj) + (?Sized)`
+
+error[E0225]: only auto traits can be used as additional traits in a trait object
+  --> $DIR/trait-object-trait-parens.rs:8:35
+   |
+LL |     let _: Box<(Obj) + (?Sized) + (for<'a> Trait<'a>)>;
+   |                -----              ^^^^^^^^^^^^^^^^^^^
+   |                |                  |
+   |                |                  additional non-auto trait
+   |                |                  trait alias used in trait object type (additional use)
+   |                first non-auto trait
+   |                trait alias used in trait object type (first use)
+
+error[E0225]: only auto traits can be used as additional traits in a trait object
+  --> $DIR/trait-object-trait-parens.rs:12:49
    |
-LL |     let _: Box<(for<'a> Trait<'a>) + (Copy) + (?Sized)>;
-   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn (for<'a> Trait<'a>) + (Copy) + (?Sized)`
+LL |     let _: Box<(?Sized) + (for<'a> Trait<'a>) + (Obj)>;
+   |                           -------------------   ^^^^^
+   |                           |                     |
+   |                           |                     additional non-auto trait
+   |                           |                     trait alias used in trait object type (additional use)
+   |                           first non-auto trait
+   |                           trait alias used in trait object type (first use)
 
-error[E0261]: use of undeclared lifetime name `'a`
-  --> $DIR/trait-object-trait-parens.rs:11:31
+error[E0225]: only auto traits can be used as additional traits in a trait object
+  --> $DIR/trait-object-trait-parens.rs:16:38
    |
-LL | fn main() {
-   |        - help: consider introducing lifetime `'a` here: `<'a>`
-...
-LL |     let _: Box<(for<'a> Trait<'a>) + (Copy) + (?Sized)>;
-   |                               ^^ undeclared lifetime
+LL |     let _: Box<(for<'a> Trait<'a>) + (Obj) + (?Sized)>;
+   |                 -----------------    ^^^^^
+   |                 |                    |
+   |                 |                    additional non-auto trait
+   |                 |                    trait alias used in trait object type (additional use)
+   |                 first non-auto trait
+   |                 trait alias used in trait object type (first use)
 
-error: aborting due to 3 previous errors
+error: aborting due to 6 previous errors
 
-For more information about this error, try `rustc --explain E0261`.
+For more information about this error, try `rustc --explain E0225`.

From d1822b3dcf9b02904506dd00bc783adbdb92fc72 Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Sat, 7 Mar 2020 13:15:58 +0100
Subject: [PATCH 35/40] use check_path more

---
 src/librustc_parse/parser/expr.rs     | 2 +-
 src/librustc_parse/parser/item.rs     | 2 +-
 src/librustc_parse/parser/pat.rs      | 2 +-
 src/librustc_parse/parser/stmt.rs     | 5 +----
 src/librustc_parse/parser/ty.rs       | 2 +-
 src/test/ui/parser/issue-63116.stderr | 2 +-
 6 files changed, 6 insertions(+), 9 deletions(-)

diff --git a/src/librustc_parse/parser/expr.rs b/src/librustc_parse/parser/expr.rs
index 826213ba450b9..a41beb7711928 100644
--- a/src/librustc_parse/parser/expr.rs
+++ b/src/librustc_parse/parser/expr.rs
@@ -919,7 +919,7 @@ impl<'a> Parser<'a> {
         } else if self.eat_lt() {
             let (qself, path) = self.parse_qpath(PathStyle::Expr)?;
             Ok(self.mk_expr(lo.to(path.span), ExprKind::Path(Some(qself), path), attrs))
-        } else if self.token.is_path_start() {
+        } else if self.check_path() {
             self.parse_path_start_expr(attrs)
         } else if self.check_keyword(kw::Move) || self.check_keyword(kw::Static) {
             self.parse_closure_expr(attrs)
diff --git a/src/librustc_parse/parser/item.rs b/src/librustc_parse/parser/item.rs
index 8263bd879ad86..5add3fcc8020c 100644
--- a/src/librustc_parse/parser/item.rs
+++ b/src/librustc_parse/parser/item.rs
@@ -218,7 +218,7 @@ impl<'a> Parser<'a> {
         } else if vis.node.is_pub() && self.isnt_macro_invocation() {
             self.recover_missing_kw_before_item()?;
             return Ok(None);
-        } else if macros_allowed && self.token.is_path_start() {
+        } else if macros_allowed && self.check_path() {
             // MACRO INVOCATION ITEM
             (Ident::invalid(), ItemKind::Mac(self.parse_item_macro(vis)?))
         } else {
diff --git a/src/librustc_parse/parser/pat.rs b/src/librustc_parse/parser/pat.rs
index f52a91ff5989d..5f2b3b03488b4 100644
--- a/src/librustc_parse/parser/pat.rs
+++ b/src/librustc_parse/parser/pat.rs
@@ -704,7 +704,7 @@ impl<'a> Parser<'a> {
     }
 
     fn parse_pat_range_end(&mut self) -> PResult<'a, P<Expr>> {
-        if self.token.is_path_start() {
+        if self.check_path() {
             let lo = self.token.span;
             let (qself, path) = if self.eat_lt() {
                 // Parse a qualified path
diff --git a/src/librustc_parse/parser/stmt.rs b/src/librustc_parse/parser/stmt.rs
index fb85f54b136a7..489549a57505f 100644
--- a/src/librustc_parse/parser/stmt.rs
+++ b/src/librustc_parse/parser/stmt.rs
@@ -48,10 +48,7 @@ impl<'a> Parser<'a> {
             self.bump(); // `var`
             let msg = "write `let` instead of `var` to introduce a new variable";
             self.recover_stmt_local(lo, attrs.into(), msg, "let")?
-        } else if self.token.is_path_start()
-            && !self.token.is_qpath_start()
-            && !self.is_path_start_item()
-        {
+        } else if self.check_path() && !self.token.is_qpath_start() && !self.is_path_start_item() {
             // We have avoided contextual keywords like `union`, items with `crate` visibility,
             // or `auto trait` items. We aim to parse an arbitrary path `a::b` but not something
             // that starts like a path (1 token), but it fact not a path.
diff --git a/src/librustc_parse/parser/ty.rs b/src/librustc_parse/parser/ty.rs
index 08168cf7df988..6575843b40824 100644
--- a/src/librustc_parse/parser/ty.rs
+++ b/src/librustc_parse/parser/ty.rs
@@ -158,7 +158,7 @@ impl<'a> Parser<'a> {
             // Qualified path
             let (qself, path) = self.parse_qpath(PathStyle::Type)?;
             TyKind::Path(Some(qself), path)
-        } else if self.token.is_path_start() {
+        } else if self.check_path() {
             self.parse_path_start_ty(lo, allow_plus)?
         } else if self.eat(&token::DotDotDot) {
             if allow_c_variadic == AllowCVariadic::Yes {
diff --git a/src/test/ui/parser/issue-63116.stderr b/src/test/ui/parser/issue-63116.stderr
index 2beb73d83d261..15cd3df860b0d 100644
--- a/src/test/ui/parser/issue-63116.stderr
+++ b/src/test/ui/parser/issue-63116.stderr
@@ -12,7 +12,7 @@ error: expected one of `!`, `(`, `)`, `+`, `,`, `::`, or `<`, found `;`
 LL | impl W <s(f;Y(;]
    |            ^ expected one of 7 possible tokens
 
-error: expected one of `!`, `&&`, `&`, `(`, `)`, `*`, `+`, `,`, `->`, `...`, `::`, `<`, `>`, `?`, `[`, `_`, `dyn`, `extern`, `fn`, `for`, `impl`, `unsafe`, or lifetime, found `;`
+error: expected one of `!`, `&&`, `&`, `(`, `)`, `*`, `+`, `,`, `->`, `...`, `::`, `<`, `>`, `?`, `[`, `_`, `dyn`, `extern`, `fn`, `for`, `impl`, `unsafe`, lifetime, or path, found `;`
   --> $DIR/issue-63116.rs:3:15
    |
 LL | impl W <s(f;Y(;]

From ba3ae46de972f3e70319c25a5da69378454cb88d Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Sat, 7 Mar 2020 13:52:55 +0100
Subject: [PATCH 36/40] trait-object-lifetime-parens: improve recovery.

---
 src/librustc_parse/parser/ty.rs               | 17 +++++++++-----
 .../macro/trait-object-macro-matcher.rs       |  9 ++++++--
 .../macro/trait-object-macro-matcher.stderr   | 22 +++++++++++++++----
 .../ui/parser/trait-object-lifetime-parens.rs |  5 +----
 .../trait-object-lifetime-parens.stderr       | 20 +++--------------
 5 files changed, 40 insertions(+), 33 deletions(-)

diff --git a/src/librustc_parse/parser/ty.rs b/src/librustc_parse/parser/ty.rs
index 6575843b40824..3dd415bf37289 100644
--- a/src/librustc_parse/parser/ty.rs
+++ b/src/librustc_parse/parser/ty.rs
@@ -148,18 +148,14 @@ impl<'a> Parser<'a> {
             self.parse_impl_ty(&mut impl_dyn_multi)?
         } else if self.is_explicit_dyn_type() {
             self.parse_dyn_ty(&mut impl_dyn_multi)?
-        } else if self.check(&token::Question)
-            || self.check_lifetime() && self.look_ahead(1, |t| t.is_like_plus())
-        {
-            // Bound list (trait object type)
-            let bounds = self.parse_generic_bounds_common(allow_plus, None)?;
-            TyKind::TraitObject(bounds, TraitObjectSyntax::None)
         } else if self.eat_lt() {
             // Qualified path
             let (qself, path) = self.parse_qpath(PathStyle::Type)?;
             TyKind::Path(Some(qself), path)
         } else if self.check_path() {
             self.parse_path_start_ty(lo, allow_plus)?
+        } else if self.can_begin_bound() {
+            self.parse_bare_trait_object(lo, allow_plus)?
         } else if self.eat(&token::DotDotDot) {
             if allow_c_variadic == AllowCVariadic::Yes {
                 TyKind::CVarArgs
@@ -218,6 +214,15 @@ impl<'a> Parser<'a> {
         }
     }
 
+    fn parse_bare_trait_object(&mut self, lo: Span, allow_plus: AllowPlus) -> PResult<'a, TyKind> {
+        let lt_no_plus = self.check_lifetime() && !self.look_ahead(1, |t| t.is_like_plus());
+        let bounds = self.parse_generic_bounds_common(allow_plus, None)?;
+        if lt_no_plus {
+            self.struct_span_err(lo, "lifetime in trait object type must be followed by `+`").emit()
+        }
+        Ok(TyKind::TraitObject(bounds, TraitObjectSyntax::None))
+    }
+
     fn parse_remaining_bounds_path(
         &mut self,
         generic_params: Vec<GenericParam>,
diff --git a/src/test/ui/parser/macro/trait-object-macro-matcher.rs b/src/test/ui/parser/macro/trait-object-macro-matcher.rs
index 80d867d3b568e..170ac22780b63 100644
--- a/src/test/ui/parser/macro/trait-object-macro-matcher.rs
+++ b/src/test/ui/parser/macro/trait-object-macro-matcher.rs
@@ -2,9 +2,14 @@
 // `ty` matcher in particular doesn't accept a single lifetime
 
 macro_rules! m {
-    ($t: ty) => ( let _: $t; )
+    ($t: ty) => {
+        let _: $t;
+    };
 }
 
 fn main() {
-    m!('static); //~ ERROR expected type, found `'static`
+    m!('static);
+    //~^ ERROR lifetime in trait object type must be followed by `+`
+    //~| ERROR at least one trait is required for an object type
+    //~| WARN trait objects without an explicit `dyn` are deprecated
 }
diff --git a/src/test/ui/parser/macro/trait-object-macro-matcher.stderr b/src/test/ui/parser/macro/trait-object-macro-matcher.stderr
index f02f60e4bfb1d..230733371ddd8 100644
--- a/src/test/ui/parser/macro/trait-object-macro-matcher.stderr
+++ b/src/test/ui/parser/macro/trait-object-macro-matcher.stderr
@@ -1,8 +1,22 @@
-error: expected type, found `'static`
-  --> $DIR/trait-object-macro-matcher.rs:9:8
+error: lifetime in trait object type must be followed by `+`
+  --> $DIR/trait-object-macro-matcher.rs:11:8
    |
 LL |     m!('static);
-   |        ^^^^^^^ expected type
+   |        ^^^^^^^
 
-error: aborting due to previous error
+warning: trait objects without an explicit `dyn` are deprecated
+  --> $DIR/trait-object-macro-matcher.rs:11:8
+   |
+LL |     m!('static);
+   |        ^^^^^^^ help: use `dyn`: `dyn 'static`
+   |
+   = note: `#[warn(bare_trait_objects)]` on by default
+
+error[E0224]: at least one trait is required for an object type
+  --> $DIR/trait-object-macro-matcher.rs:11:8
+   |
+LL |     m!('static);
+   |        ^^^^^^^
+
+error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/parser/trait-object-lifetime-parens.rs b/src/test/ui/parser/trait-object-lifetime-parens.rs
index dbed17f634ae7..5a5c19f32e806 100644
--- a/src/test/ui/parser/trait-object-lifetime-parens.rs
+++ b/src/test/ui/parser/trait-object-lifetime-parens.rs
@@ -6,10 +6,7 @@ fn f<'a, T: Trait + ('a)>() {} //~ ERROR parenthesized lifetime bounds are not s
 
 fn check<'a>() {
     let _: Box<Trait + ('a)>; //~ ERROR parenthesized lifetime bounds are not supported
-    let _: Box<('a) + Trait>;
-    //~^ ERROR expected type, found `'a`
-    //~| ERROR expected `while`, `for`, `loop` or `{` after a label
-    //~| ERROR expected expression, found `)`
+    let _: Box<('a) + Trait>; //~ ERROR lifetime in trait object type must be followed by `+`
 }
 
 fn main() {}
diff --git a/src/test/ui/parser/trait-object-lifetime-parens.stderr b/src/test/ui/parser/trait-object-lifetime-parens.stderr
index 367fcc2855580..1289c248275dc 100644
--- a/src/test/ui/parser/trait-object-lifetime-parens.stderr
+++ b/src/test/ui/parser/trait-object-lifetime-parens.stderr
@@ -10,25 +10,11 @@ error: parenthesized lifetime bounds are not supported
 LL |     let _: Box<Trait + ('a)>;
    |                        ^^^^ help: remove the parentheses
 
-error: expected `while`, `for`, `loop` or `{` after a label
-  --> $DIR/trait-object-lifetime-parens.rs:9:19
-   |
-LL |     let _: Box<('a) + Trait>;
-   |                   ^ expected `while`, `for`, `loop` or `{` after a label
-
-error: expected expression, found `)`
-  --> $DIR/trait-object-lifetime-parens.rs:9:19
-   |
-LL |     let _: Box<('a) + Trait>;
-   |                   ^ expected expression
-
-error: expected type, found `'a`
+error: lifetime in trait object type must be followed by `+`
   --> $DIR/trait-object-lifetime-parens.rs:9:17
    |
 LL |     let _: Box<('a) + Trait>;
-   |         -       ^^ expected type
-   |         |
-   |         while parsing the type for `_`
+   |                 ^^
 
-error: aborting due to 5 previous errors
+error: aborting due to 3 previous errors
 

From 458383dd337f276d091fa2de81bb7c1d31dde5fa Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Sat, 7 Mar 2020 17:16:29 +0100
Subject: [PATCH 37/40] parse_if_expr: recover on attributes

---
 src/librustc_parse/lib.rs                     |  1 +
 src/librustc_parse/parser/expr.rs             | 43 ++++++++++--
 src/librustc_parse/parser/item.rs             |  3 +-
 src/test/ui/if-attrs/else-attrs.rs            |  2 +-
 src/test/ui/if-attrs/else-attrs.stderr        | 19 +++---
 src/test/ui/parser/attr-stmt-expr-attr-bad.rs | 16 ++---
 .../ui/parser/attr-stmt-expr-attr-bad.stderr  | 68 ++++++++++---------
 .../ui/parser/doc-comment-in-if-statement.rs  |  2 +-
 .../parser/doc-comment-in-if-statement.stderr |  8 +--
 9 files changed, 98 insertions(+), 64 deletions(-)

diff --git a/src/librustc_parse/lib.rs b/src/librustc_parse/lib.rs
index 10d524776a11b..fe75062ee503c 100644
--- a/src/librustc_parse/lib.rs
+++ b/src/librustc_parse/lib.rs
@@ -2,6 +2,7 @@
 
 #![feature(bool_to_option)]
 #![feature(crate_visibility_modifier)]
+#![feature(bindings_after_at)]
 
 use rustc_ast::ast;
 use rustc_ast::token::{self, Nonterminal};
diff --git a/src/librustc_parse/parser/expr.rs b/src/librustc_parse/parser/expr.rs
index a41beb7711928..7f6f90431fc94 100644
--- a/src/librustc_parse/parser/expr.rs
+++ b/src/librustc_parse/parser/expr.rs
@@ -1514,13 +1514,16 @@ impl<'a> Parser<'a> {
         let thn = if self.eat_keyword(kw::Else) || !cond.returns() {
             self.error_missing_if_cond(lo, cond.span)
         } else {
+            let attrs = self.parse_outer_attributes()?; // For recovery.
             let not_block = self.token != token::OpenDelim(token::Brace);
-            self.parse_block().map_err(|mut err| {
+            let block = self.parse_block().map_err(|mut err| {
                 if not_block {
                     err.span_label(lo, "this `if` expression has a condition, but no block");
                 }
                 err
-            })?
+            })?;
+            self.error_on_if_block_attrs(lo, false, block.span, &attrs);
+            block
         };
         let els = if self.eat_keyword(kw::Else) { Some(self.parse_else_expr()?) } else { None };
         Ok(self.mk_expr(lo.to(self.prev_token.span), ExprKind::If(cond, thn, els), attrs))
@@ -1562,12 +1565,40 @@ impl<'a> Parser<'a> {
 
     /// Parses an `else { ... }` expression (`else` token already eaten).
     fn parse_else_expr(&mut self) -> PResult<'a, P<Expr>> {
-        if self.eat_keyword(kw::If) {
-            self.parse_if_expr(AttrVec::new())
+        let ctx_span = self.prev_token.span; // `else`
+        let attrs = self.parse_outer_attributes()?; // For recovery.
+        let expr = if self.eat_keyword(kw::If) {
+            self.parse_if_expr(AttrVec::new())?
         } else {
             let blk = self.parse_block()?;
-            Ok(self.mk_expr(blk.span, ExprKind::Block(blk, None), AttrVec::new()))
-        }
+            self.mk_expr(blk.span, ExprKind::Block(blk, None), AttrVec::new())
+        };
+        self.error_on_if_block_attrs(ctx_span, true, expr.span, &attrs);
+        Ok(expr)
+    }
+
+    fn error_on_if_block_attrs(
+        &self,
+        ctx_span: Span,
+        is_ctx_else: bool,
+        branch_span: Span,
+        attrs: &[ast::Attribute],
+    ) {
+        let (span, last) = match attrs {
+            [] => return,
+            [x0 @ xn] | [x0, .., xn] => (x0.span.to(xn.span), xn.span),
+        };
+        let ctx = if is_ctx_else { "else" } else { "if" };
+        self.struct_span_err(last, "outer attributes are not allowed on `if` and `else` branches")
+            .span_label(branch_span, "the attributes are attached to this branch")
+            .span_label(ctx_span, format!("the branch belongs to this `{}`", ctx))
+            .span_suggestion(
+                span,
+                "remove the attributes",
+                String::new(),
+                Applicability::MachineApplicable,
+            )
+            .emit();
     }
 
     /// Parses `for <src_pat> in <src_expr> <src_loop_block>` (`for` token already eaten).
diff --git a/src/librustc_parse/parser/item.rs b/src/librustc_parse/parser/item.rs
index 5add3fcc8020c..15cafef97fb77 100644
--- a/src/librustc_parse/parser/item.rs
+++ b/src/librustc_parse/parser/item.rs
@@ -352,8 +352,7 @@ impl<'a> Parser<'a> {
     fn recover_attrs_no_item(&mut self, attrs: &[Attribute]) -> PResult<'a, ()> {
         let (start, end) = match attrs {
             [] => return Ok(()),
-            [x0] => (x0, x0),
-            [x0, .., xn] => (x0, xn),
+            [x0 @ xn] | [x0, .., xn] => (x0, xn),
         };
         let msg = if end.is_doc_comment() {
             "expected item after doc comment"
diff --git a/src/test/ui/if-attrs/else-attrs.rs b/src/test/ui/if-attrs/else-attrs.rs
index 4394b2100c1b5..85da7cf6bb8c3 100644
--- a/src/test/ui/if-attrs/else-attrs.rs
+++ b/src/test/ui/if-attrs/else-attrs.rs
@@ -8,7 +8,7 @@ fn if_else_parse_error() {
 #[cfg(FALSE)]
 fn else_attr_ifparse_error() {
     if true {
-    } else #[attr] if false { //~ ERROR expected
+    } else #[attr] if false { //~ ERROR outer attributes are not allowed
     } else {
     }
 }
diff --git a/src/test/ui/if-attrs/else-attrs.stderr b/src/test/ui/if-attrs/else-attrs.stderr
index af25b6abc0a3a..2733377054d7d 100644
--- a/src/test/ui/if-attrs/else-attrs.stderr
+++ b/src/test/ui/if-attrs/else-attrs.stderr
@@ -4,18 +4,17 @@ error: expected expression, found keyword `else`
 LL |     } #[attr] else if false {
    |               ^^^^ expected expression
 
-error: expected `{`, found `#`
+error: outer attributes are not allowed on `if` and `else` branches
   --> $DIR/else-attrs.rs:11:12
    |
-LL |     } else #[attr] if false {
-   |            ^ expected `{`
-   |
-help: try placing this code inside a block
-   |
-LL |     } else #[attr] { if false {
-LL |     } else {
-LL |     } }
-   |
+LL |       } else #[attr] if false {
+   |  _______----_^^^^^^^_-
+   | |       |    |
+   | |       |    help: remove the attributes
+   | |       the branch belongs to this `else`
+LL | |     } else {
+LL | |     }
+   | |_____- the attributes are attached to this branch
 
 error: expected expression, found keyword `else`
   --> $DIR/else-attrs.rs:20:15
diff --git a/src/test/ui/parser/attr-stmt-expr-attr-bad.rs b/src/test/ui/parser/attr-stmt-expr-attr-bad.rs
index f3980a596481c..09f494bdc2fed 100644
--- a/src/test/ui/parser/attr-stmt-expr-attr-bad.rs
+++ b/src/test/ui/parser/attr-stmt-expr-attr-bad.rs
@@ -39,35 +39,35 @@ fn main() {}
 #[cfg(FALSE)] fn e() { let _ = #[attr] &mut #![attr] 0; }
 //~^ ERROR an inner attribute is not permitted in this context
 #[cfg(FALSE)] fn e() { let _ = if 0 #[attr] {}; }
-//~^ ERROR expected `{`, found `#`
+//~^ ERROR outer attributes are not allowed on `if`
 #[cfg(FALSE)] fn e() { let _ = if 0 {#![attr]}; }
 //~^ ERROR an inner attribute is not permitted in this context
 #[cfg(FALSE)] fn e() { let _ = if 0 {} #[attr] else {}; }
 //~^ ERROR expected one of
 #[cfg(FALSE)] fn e() { let _ = if 0 {} else #[attr] {}; }
-//~^ ERROR expected `{`, found `#`
+//~^ ERROR outer attributes are not allowed on `if`
 #[cfg(FALSE)] fn e() { let _ = if 0 {} else {#![attr]}; }
 //~^ ERROR an inner attribute is not permitted in this context
 #[cfg(FALSE)] fn e() { let _ = if 0 {} else #[attr] if 0 {}; }
-//~^ ERROR expected `{`, found `#`
+//~^ ERROR outer attributes are not allowed on `if`
 #[cfg(FALSE)] fn e() { let _ = if 0 {} else if 0 #[attr] {}; }
-//~^ ERROR expected `{`, found `#`
+//~^ ERROR outer attributes are not allowed on `if`
 #[cfg(FALSE)] fn e() { let _ = if 0 {} else if 0 {#![attr]}; }
 //~^ ERROR an inner attribute is not permitted in this context
 #[cfg(FALSE)] fn e() { let _ = if let _ = 0 #[attr] {}; }
-//~^ ERROR expected `{`, found `#`
+//~^ ERROR outer attributes are not allowed on `if`
 #[cfg(FALSE)] fn e() { let _ = if let _ = 0 {#![attr]}; }
 //~^ ERROR an inner attribute is not permitted in this context
 #[cfg(FALSE)] fn e() { let _ = if let _ = 0 {} #[attr] else {}; }
 //~^ ERROR expected one of
 #[cfg(FALSE)] fn e() { let _ = if let _ = 0 {} else #[attr] {}; }
-//~^ ERROR expected `{`, found `#`
+//~^ ERROR outer attributes are not allowed on `if`
 #[cfg(FALSE)] fn e() { let _ = if let _ = 0 {} else {#![attr]}; }
 //~^ ERROR an inner attribute is not permitted in this context
 #[cfg(FALSE)] fn e() { let _ = if let _ = 0 {} else #[attr] if let _ = 0 {}; }
-//~^ ERROR expected `{`, found `#`
+//~^ ERROR outer attributes are not allowed on `if`
 #[cfg(FALSE)] fn e() { let _ = if let _ = 0 {} else if let _ = 0 #[attr] {}; }
-//~^ ERROR expected `{`, found `#`
+//~^ ERROR outer attributes are not allowed on `if`
 #[cfg(FALSE)] fn e() { let _ = if let _ = 0 {} else if let _ = 0 {#![attr]}; }
 //~^ ERROR an inner attribute is not permitted in this context
 
diff --git a/src/test/ui/parser/attr-stmt-expr-attr-bad.stderr b/src/test/ui/parser/attr-stmt-expr-attr-bad.stderr
index af4901509135a..6dfe7aad6ea64 100644
--- a/src/test/ui/parser/attr-stmt-expr-attr-bad.stderr
+++ b/src/test/ui/parser/attr-stmt-expr-attr-bad.stderr
@@ -136,14 +136,14 @@ LL | #[cfg(FALSE)] fn e() { let _ = #[attr] &mut #![attr] 0; }
    |
    = note: inner attributes, like `#![no_std]`, annotate the item enclosing them, and are usually found at the beginning of source files. Outer attributes, like `#[test]`, annotate the item following them.
 
-error: expected `{`, found `#`
+error: outer attributes are not allowed on `if` and `else` branches
   --> $DIR/attr-stmt-expr-attr-bad.rs:41:37
    |
 LL | #[cfg(FALSE)] fn e() { let _ = if 0 #[attr] {}; }
-   |                                --   ^       -- help: try placing this code inside a block: `{ {} }`
+   |                                --   ^^^^^^^ -- the attributes are attached to this branch
    |                                |    |
-   |                                |    expected `{`
-   |                                this `if` expression has a condition, but no block
+   |                                |    help: remove the attributes
+   |                                the branch belongs to this `if`
 
 error: an inner attribute is not permitted in this context
   --> $DIR/attr-stmt-expr-attr-bad.rs:43:38
@@ -159,13 +159,14 @@ error: expected one of `.`, `;`, `?`, `else`, or an operator, found `#`
 LL | #[cfg(FALSE)] fn e() { let _ = if 0 {} #[attr] else {}; }
    |                                        ^ expected one of `.`, `;`, `?`, `else`, or an operator
 
-error: expected `{`, found `#`
+error: outer attributes are not allowed on `if` and `else` branches
   --> $DIR/attr-stmt-expr-attr-bad.rs:47:45
    |
 LL | #[cfg(FALSE)] fn e() { let _ = if 0 {} else #[attr] {}; }
-   |                                             ^       -- help: try placing this code inside a block: `{ {} }`
-   |                                             |
-   |                                             expected `{`
+   |                                        ---- ^^^^^^^ -- the attributes are attached to this branch
+   |                                        |    |
+   |                                        |    help: remove the attributes
+   |                                        the branch belongs to this `else`
 
 error: an inner attribute is not permitted in this context
   --> $DIR/attr-stmt-expr-attr-bad.rs:49:46
@@ -175,22 +176,23 @@ LL | #[cfg(FALSE)] fn e() { let _ = if 0 {} else {#![attr]}; }
    |
    = note: inner attributes, like `#![no_std]`, annotate the item enclosing them, and are usually found at the beginning of source files. Outer attributes, like `#[test]`, annotate the item following them.
 
-error: expected `{`, found `#`
+error: outer attributes are not allowed on `if` and `else` branches
   --> $DIR/attr-stmt-expr-attr-bad.rs:51:45
    |
 LL | #[cfg(FALSE)] fn e() { let _ = if 0 {} else #[attr] if 0 {}; }
-   |                                             ^       ------- help: try placing this code inside a block: `{ if 0 {} }`
-   |                                             |
-   |                                             expected `{`
+   |                                        ---- ^^^^^^^ ------- the attributes are attached to this branch
+   |                                        |    |
+   |                                        |    help: remove the attributes
+   |                                        the branch belongs to this `else`
 
-error: expected `{`, found `#`
+error: outer attributes are not allowed on `if` and `else` branches
   --> $DIR/attr-stmt-expr-attr-bad.rs:53:50
    |
 LL | #[cfg(FALSE)] fn e() { let _ = if 0 {} else if 0 #[attr] {}; }
-   |                                             --   ^       -- help: try placing this code inside a block: `{ {} }`
+   |                                             --   ^^^^^^^ -- the attributes are attached to this branch
    |                                             |    |
-   |                                             |    expected `{`
-   |                                             this `if` expression has a condition, but no block
+   |                                             |    help: remove the attributes
+   |                                             the branch belongs to this `if`
 
 error: an inner attribute is not permitted in this context
   --> $DIR/attr-stmt-expr-attr-bad.rs:55:51
@@ -200,14 +202,14 @@ LL | #[cfg(FALSE)] fn e() { let _ = if 0 {} else if 0 {#![attr]}; }
    |
    = note: inner attributes, like `#![no_std]`, annotate the item enclosing them, and are usually found at the beginning of source files. Outer attributes, like `#[test]`, annotate the item following them.
 
-error: expected `{`, found `#`
+error: outer attributes are not allowed on `if` and `else` branches
   --> $DIR/attr-stmt-expr-attr-bad.rs:57:45
    |
 LL | #[cfg(FALSE)] fn e() { let _ = if let _ = 0 #[attr] {}; }
-   |                                --           ^       -- help: try placing this code inside a block: `{ {} }`
+   |                                --           ^^^^^^^ -- the attributes are attached to this branch
    |                                |            |
-   |                                |            expected `{`
-   |                                this `if` expression has a condition, but no block
+   |                                |            help: remove the attributes
+   |                                the branch belongs to this `if`
 
 error: an inner attribute is not permitted in this context
   --> $DIR/attr-stmt-expr-attr-bad.rs:59:46
@@ -223,13 +225,14 @@ error: expected one of `.`, `;`, `?`, `else`, or an operator, found `#`
 LL | #[cfg(FALSE)] fn e() { let _ = if let _ = 0 {} #[attr] else {}; }
    |                                                ^ expected one of `.`, `;`, `?`, `else`, or an operator
 
-error: expected `{`, found `#`
+error: outer attributes are not allowed on `if` and `else` branches
   --> $DIR/attr-stmt-expr-attr-bad.rs:63:53
    |
 LL | #[cfg(FALSE)] fn e() { let _ = if let _ = 0 {} else #[attr] {}; }
-   |                                                     ^       -- help: try placing this code inside a block: `{ {} }`
-   |                                                     |
-   |                                                     expected `{`
+   |                                                ---- ^^^^^^^ -- the attributes are attached to this branch
+   |                                                |    |
+   |                                                |    help: remove the attributes
+   |                                                the branch belongs to this `else`
 
 error: an inner attribute is not permitted in this context
   --> $DIR/attr-stmt-expr-attr-bad.rs:65:54
@@ -239,22 +242,23 @@ LL | #[cfg(FALSE)] fn e() { let _ = if let _ = 0 {} else {#![attr]}; }
    |
    = note: inner attributes, like `#![no_std]`, annotate the item enclosing them, and are usually found at the beginning of source files. Outer attributes, like `#[test]`, annotate the item following them.
 
-error: expected `{`, found `#`
+error: outer attributes are not allowed on `if` and `else` branches
   --> $DIR/attr-stmt-expr-attr-bad.rs:67:53
    |
 LL | #[cfg(FALSE)] fn e() { let _ = if let _ = 0 {} else #[attr] if let _ = 0 {}; }
-   |                                                     ^       --------------- help: try placing this code inside a block: `{ if let _ = 0 {} }`
-   |                                                     |
-   |                                                     expected `{`
+   |                                                ---- ^^^^^^^ --------------- the attributes are attached to this branch
+   |                                                |    |
+   |                                                |    help: remove the attributes
+   |                                                the branch belongs to this `else`
 
-error: expected `{`, found `#`
+error: outer attributes are not allowed on `if` and `else` branches
   --> $DIR/attr-stmt-expr-attr-bad.rs:69:66
    |
 LL | #[cfg(FALSE)] fn e() { let _ = if let _ = 0 {} else if let _ = 0 #[attr] {}; }
-   |                                                     --           ^       -- help: try placing this code inside a block: `{ {} }`
+   |                                                     --           ^^^^^^^ -- the attributes are attached to this branch
    |                                                     |            |
-   |                                                     |            expected `{`
-   |                                                     this `if` expression has a condition, but no block
+   |                                                     |            help: remove the attributes
+   |                                                     the branch belongs to this `if`
 
 error: an inner attribute is not permitted in this context
   --> $DIR/attr-stmt-expr-attr-bad.rs:71:67
diff --git a/src/test/ui/parser/doc-comment-in-if-statement.rs b/src/test/ui/parser/doc-comment-in-if-statement.rs
index 69b174b4cb3c7..343eac1b81ff0 100644
--- a/src/test/ui/parser/doc-comment-in-if-statement.rs
+++ b/src/test/ui/parser/doc-comment-in-if-statement.rs
@@ -1,5 +1,5 @@
 fn main() {
     if true /*!*/ {}
-    //~^ ERROR expected `{`, found doc comment `/*!*/`
+    //~^ ERROR outer attributes are not allowed on
     //~| ERROR expected outer doc comment
 }
diff --git a/src/test/ui/parser/doc-comment-in-if-statement.stderr b/src/test/ui/parser/doc-comment-in-if-statement.stderr
index 1fe3735daf09b..af21b78733f90 100644
--- a/src/test/ui/parser/doc-comment-in-if-statement.stderr
+++ b/src/test/ui/parser/doc-comment-in-if-statement.stderr
@@ -6,14 +6,14 @@ LL |     if true /*!*/ {}
    |
    = note: inner doc comments like this (starting with `//!` or `/*!`) can only appear before items
 
-error: expected `{`, found doc comment `/*!*/`
+error: outer attributes are not allowed on `if` and `else` branches
   --> $DIR/doc-comment-in-if-statement.rs:2:13
    |
 LL |     if true /*!*/ {}
-   |     --      ^^^^^ -- help: try placing this code inside a block: `{ {} }`
+   |     --      ^^^^^ -- the attributes are attached to this branch
    |     |       |
-   |     |       expected `{`
-   |     this `if` expression has a condition, but no block
+   |     |       help: remove the attributes
+   |     the branch belongs to this `if`
 
 error: aborting due to 2 previous errors
 

From 0b2329da9a9a61dc70f9e607628977302f8144b4 Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Tue, 10 Mar 2020 10:31:03 +0100
Subject: [PATCH 38/40] also make panic_fmt track_caller

---
 src/libcore/macros/mod.rs | 21 +++++++++++++++++++++
 src/libcore/panicking.rs  | 22 +++++++++++++++-------
 2 files changed, 36 insertions(+), 7 deletions(-)

diff --git a/src/libcore/macros/mod.rs b/src/libcore/macros/mod.rs
index 76e58f0cc62bc..04af5b5f76828 100644
--- a/src/libcore/macros/mod.rs
+++ b/src/libcore/macros/mod.rs
@@ -1,3 +1,4 @@
+#[cfg(bootstrap)]
 #[doc(include = "panic.md")]
 #[macro_export]
 #[allow_internal_unstable(core_panic, track_caller)]
@@ -20,6 +21,26 @@ macro_rules! panic {
     );
 }
 
+#[cfg(not(bootstrap))]
+#[doc(include = "panic.md")]
+#[macro_export]
+#[allow_internal_unstable(core_panic, track_caller)]
+#[stable(feature = "core", since = "1.6.0")]
+macro_rules! panic {
+    () => (
+        $crate::panic!("explicit panic")
+    );
+    ($msg:expr) => (
+        $crate::panicking::panic($msg)
+    );
+    ($msg:expr,) => (
+        $crate::panic!($msg)
+    );
+    ($fmt:expr, $($arg:tt)+) => (
+        $crate::panicking::panic_fmt($crate::format_args!($fmt, $($arg)+))
+    );
+}
+
 /// Asserts that two expressions are equal to each other (using [`PartialEq`]).
 ///
 /// On panic, this macro will print the values of the expressions with their
diff --git a/src/libcore/panicking.rs b/src/libcore/panicking.rs
index d58a7cfec951b..3587f3f0ebf56 100644
--- a/src/libcore/panicking.rs
+++ b/src/libcore/panicking.rs
@@ -32,6 +32,7 @@
 use crate::fmt;
 use crate::panic::{Location, PanicInfo};
 
+/// The underlying implementation of libcore's `panic!` macro when no formatting is used.
 #[cold]
 // never inline unless panic_immediate_abort to avoid code
 // bloat at the call sites as much as possible
@@ -49,7 +50,10 @@ pub fn panic(expr: &str) -> ! {
     // truncation and padding (even though none is used here). Using
     // Arguments::new_v1 may allow the compiler to omit Formatter::pad from the
     // output binary, saving up to a few kilobytes.
-    panic_fmt(fmt::Arguments::new_v1(&[expr], &[]), Location::caller())
+    #[cfg(not(bootstrap))]
+    panic_fmt(fmt::Arguments::new_v1(&[expr], &[]));
+    #[cfg(bootstrap)]
+    panic_fmt(fmt::Arguments::new_v1(&[expr], &[]), Location::caller());
 }
 
 #[cfg(not(bootstrap))]
@@ -62,13 +66,11 @@ fn panic_bounds_check(index: usize, len: usize) -> ! {
         unsafe { super::intrinsics::abort() }
     }
 
-    panic_fmt(
-        format_args!("index out of bounds: the len is {} but the index is {}", len, index),
-        Location::caller(),
-    )
+    panic!("index out of bounds: the len is {} but the index is {}", len, index)
 }
 
-// For bootstrap, we need a variant with the old argument order.
+// For bootstrap, we need a variant with the old argument order, and a corresponding
+// `panic_fmt`.
 #[cfg(bootstrap)]
 #[cold]
 #[cfg_attr(not(feature = "panic_immediate_abort"), inline(never))]
@@ -84,10 +86,12 @@ fn panic_bounds_check(location: &Location<'_>, index: usize, len: usize) -> ! {
     )
 }
 
+/// The underlying implementation of libcore's `panic!` macro when formatting is used.
 #[cold]
 #[cfg_attr(not(feature = "panic_immediate_abort"), inline(never))]
 #[cfg_attr(feature = "panic_immediate_abort", inline)]
-pub fn panic_fmt(fmt: fmt::Arguments<'_>, location: &Location<'_>) -> ! {
+#[cfg_attr(not(bootstrap), track_caller)]
+pub fn panic_fmt(fmt: fmt::Arguments<'_>, #[cfg(bootstrap)] location: &Location<'_>) -> ! {
     if cfg!(feature = "panic_immediate_abort") {
         unsafe { super::intrinsics::abort() }
     }
@@ -99,6 +103,10 @@ pub fn panic_fmt(fmt: fmt::Arguments<'_>, location: &Location<'_>) -> ! {
         fn panic_impl(pi: &PanicInfo<'_>) -> !;
     }
 
+    #[cfg(bootstrap)]
     let pi = PanicInfo::internal_constructor(Some(&fmt), location);
+    #[cfg(not(bootstrap))]
+    let pi = PanicInfo::internal_constructor(Some(&fmt), Location::caller());
+
     unsafe { panic_impl(&pi) }
 }

From 5357f83ee81bd1c11b4223f1531d9b2e2cb66ae7 Mon Sep 17 00:00:00 2001
From: Wesley Wiser <wwiser@gmail.com>
Date: Sun, 16 Feb 2020 20:32:25 -0500
Subject: [PATCH 39/40] [Miri] Use a session variable instead of checking for
 an env var always

In CTFE heavy code, checking the env var everytime is inefficient. We
can do a lot better by using a `Session` variable instead.
---
 src/librustc/mir/interpret/error.rs | 33 +++++++++++++++++------------
 src/librustc_session/session.rs     | 24 +++++++++++++++++++++
 2 files changed, 44 insertions(+), 13 deletions(-)

diff --git a/src/librustc/mir/interpret/error.rs b/src/librustc/mir/interpret/error.rs
index b46095927b709..0b33408edf02d 100644
--- a/src/librustc/mir/interpret/error.rs
+++ b/src/librustc/mir/interpret/error.rs
@@ -5,15 +5,18 @@ use crate::mir;
 use crate::mir::interpret::ConstValue;
 use crate::ty::layout::{Align, LayoutError, Size};
 use crate::ty::query::TyCtxtAt;
+use crate::ty::tls;
 use crate::ty::{self, layout, Ty};
 
 use backtrace::Backtrace;
+use rustc_data_structures::sync::Lock;
 use rustc_errors::{struct_span_err, DiagnosticBuilder};
 use rustc_hir as hir;
 use rustc_macros::HashStable;
+use rustc_session::CtfeBacktrace;
 use rustc_span::{Pos, Span};
 use rustc_target::spec::abi::Abi;
-use std::{any::Any, env, fmt};
+use std::{any::Any, fmt};
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq, HashStable, RustcEncodable, RustcDecodable)]
 pub enum ErrorHandled {
@@ -257,21 +260,25 @@ impl From<ErrorHandled> for InterpErrorInfo<'_> {
 
 impl<'tcx> From<InterpError<'tcx>> for InterpErrorInfo<'tcx> {
     fn from(kind: InterpError<'tcx>) -> Self {
-        let backtrace = match env::var("RUSTC_CTFE_BACKTRACE") {
-            // Matching `RUST_BACKTRACE` -- we treat "0" the same as "not present".
-            Ok(ref val) if val != "0" => {
-                let mut backtrace = Backtrace::new_unresolved();
+        let capture_backtrace = tls::with_context_opt(|ctxt| {
+            if let Some(ctxt) = ctxt {
+                *Lock::borrow(&ctxt.tcx.sess.ctfe_backtrace)
+            } else {
+                CtfeBacktrace::Disabled
+            }
+        });
 
-                if val == "immediate" {
-                    // Print it now.
-                    print_backtrace(&mut backtrace);
-                    None
-                } else {
-                    Some(Box::new(backtrace))
-                }
+        let backtrace = match capture_backtrace {
+            CtfeBacktrace::Disabled => None,
+            CtfeBacktrace::Capture => Some(Box::new(Backtrace::new_unresolved())),
+            CtfeBacktrace::Immediate => {
+                // Print it now.
+                let mut backtrace = Backtrace::new_unresolved();
+                print_backtrace(&mut backtrace);
+                None
             }
-            _ => None,
         };
+
         InterpErrorInfo { kind, backtrace }
     }
 }
diff --git a/src/librustc_session/session.rs b/src/librustc_session/session.rs
index 173b120e1f6d7..8cda95783a8a9 100644
--- a/src/librustc_session/session.rs
+++ b/src/librustc_session/session.rs
@@ -49,6 +49,18 @@ pub struct OptimizationFuel {
     out_of_fuel: bool,
 }
 
+/// The behavior of the CTFE engine when an error occurs with regards to backtraces.
+#[derive(Clone, Copy)]
+pub enum CtfeBacktrace {
+    /// Do nothing special, return the error as usual without a backtrace.
+    Disabled,
+    /// Capture a backtrace at the point the error is created and return it in the error
+    /// (to be printed later if/when the error ever actually gets shown to the user).
+    Capture,
+    /// Capture a backtrace at the point the error is created and immediately print it out.
+    Immediate,
+}
+
 /// Represents the data associated with a compilation
 /// session for a single crate.
 pub struct Session {
@@ -139,6 +151,11 @@ pub struct Session {
     /// Path for libraries that will take preference over libraries shipped by Rust.
     /// Used by windows-gnu targets to priortize system mingw-w64 libraries.
     pub system_library_path: OneThread<RefCell<Option<Option<PathBuf>>>>,
+
+    /// Tracks the current behavior of the CTFE engine when an error occurs.
+    /// Options range from returning the error without a backtrace to returning an error
+    /// and immediately printing the backtrace to stderr.
+    pub ctfe_backtrace: Lock<CtfeBacktrace>,
 }
 
 pub struct PerfStats {
@@ -1040,6 +1057,12 @@ fn build_session_(
         sopts.debugging_opts.time_passes,
     );
 
+    let ctfe_backtrace = Lock::new(match env::var("RUSTC_CTFE_BACKTRACE") {
+        Ok(ref val) if val == "immediate" => CtfeBacktrace::Immediate,
+        Ok(ref val) if val != "0" => CtfeBacktrace::Capture,
+        _ => CtfeBacktrace::Disabled,
+    });
+
     let sess = Session {
         target: target_cfg,
         host,
@@ -1078,6 +1101,7 @@ fn build_session_(
         trait_methods_not_found: Lock::new(Default::default()),
         confused_type_with_std_module: Lock::new(Default::default()),
         system_library_path: OneThread::new(RefCell::new(Default::default())),
+        ctfe_backtrace,
     };
 
     validate_commandline_args_with_session_available(&sess);

From 1106579c780ceafc3493be0c3f43f821920554ae Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tomasz=20Mi=C4=85sko?= <tomasz.miasko@gmail.com>
Date: Tue, 10 Mar 2020 00:00:00 +0000
Subject: [PATCH 40/40] librustc_codegen_llvm: Use slices instead of
 0-terminated strings

Changed functions:
* LLVMRustGetOrInsertFunction
* LLVMRustGetNamedValue
* LLVMRustBuildCall (removed unused name argument)
* LLVMRustInlineAsm
* LLVMRustInlineAsmVerify
* LLVMRustAppendModuleInlineAsm
---
 src/librustc_codegen_llvm/allocator.rs | 21 ++++--------
 src/librustc_codegen_llvm/asm.rs       | 22 ++++++------
 src/librustc_codegen_llvm/builder.rs   |  1 -
 src/librustc_codegen_llvm/declare.rs   |  9 +++--
 src/librustc_codegen_llvm/llvm/ffi.rs  | 18 +++++++---
 src/rustllvm/RustWrapper.cpp           | 47 ++++++++++++++------------
 6 files changed, 62 insertions(+), 56 deletions(-)

diff --git a/src/librustc_codegen_llvm/allocator.rs b/src/librustc_codegen_llvm/allocator.rs
index 821377db0ee15..4e7bc9fa0e2ae 100644
--- a/src/librustc_codegen_llvm/allocator.rs
+++ b/src/librustc_codegen_llvm/allocator.rs
@@ -1,5 +1,3 @@
-use std::ffi::CString;
-
 use crate::attributes;
 use libc::c_uint;
 use rustc::bug;
@@ -50,8 +48,8 @@ pub(crate) unsafe fn codegen(tcx: TyCtxt<'_>, mods: &mut ModuleLlvm, kind: Alloc
             args.len() as c_uint,
             False,
         );
-        let name = CString::new(format!("__rust_{}", method.name)).unwrap();
-        let llfn = llvm::LLVMRustGetOrInsertFunction(llmod, name.as_ptr(), ty);
+        let name = format!("__rust_{}", method.name);
+        let llfn = llvm::LLVMRustGetOrInsertFunction(llmod, name.as_ptr().cast(), name.len(), ty);
 
         if tcx.sess.target.target.options.default_hidden_visibility {
             llvm::LLVMRustSetVisibility(llfn, llvm::Visibility::Hidden);
@@ -60,8 +58,9 @@ pub(crate) unsafe fn codegen(tcx: TyCtxt<'_>, mods: &mut ModuleLlvm, kind: Alloc
             attributes::emit_uwtable(llfn, true);
         }
 
-        let callee = CString::new(kind.fn_name(method.name)).unwrap();
-        let callee = llvm::LLVMRustGetOrInsertFunction(llmod, callee.as_ptr(), ty);
+        let callee = kind.fn_name(method.name);
+        let callee =
+            llvm::LLVMRustGetOrInsertFunction(llmod, callee.as_ptr().cast(), callee.len(), ty);
         llvm::LLVMRustSetVisibility(callee, llvm::Visibility::Hidden);
 
         let llbb = llvm::LLVMAppendBasicBlockInContext(llcx, llfn, "entry\0".as_ptr().cast());
@@ -73,14 +72,8 @@ pub(crate) unsafe fn codegen(tcx: TyCtxt<'_>, mods: &mut ModuleLlvm, kind: Alloc
             .enumerate()
             .map(|(i, _)| llvm::LLVMGetParam(llfn, i as c_uint))
             .collect::<Vec<_>>();
-        let ret = llvm::LLVMRustBuildCall(
-            llbuilder,
-            callee,
-            args.as_ptr(),
-            args.len() as c_uint,
-            None,
-            "\0".as_ptr().cast(),
-        );
+        let ret =
+            llvm::LLVMRustBuildCall(llbuilder, callee, args.as_ptr(), args.len() as c_uint, None);
         llvm::LLVMSetTailCall(ret, True);
         if output.is_some() {
             llvm::LLVMBuildRet(llbuilder, ret);
diff --git a/src/librustc_codegen_llvm/asm.rs b/src/librustc_codegen_llvm/asm.rs
index c8f0fe8c72395..64bd618c332d3 100644
--- a/src/librustc_codegen_llvm/asm.rs
+++ b/src/librustc_codegen_llvm/asm.rs
@@ -12,7 +12,6 @@ use rustc_span::Span;
 
 use libc::{c_char, c_uint};
 use log::debug;
-use std::ffi::{CStr, CString};
 
 impl AsmBuilderMethods<'tcx> for Builder<'a, 'll, 'tcx> {
     fn codegen_inline_asm(
@@ -74,12 +73,11 @@ impl AsmBuilderMethods<'tcx> for Builder<'a, 'll, 'tcx> {
             _ => self.type_struct(&output_types, false),
         };
 
-        let asm = CString::new(ia.asm.as_str().as_bytes()).unwrap();
-        let constraint_cstr = CString::new(all_constraints).unwrap();
+        let asm = ia.asm.as_str();
         let r = inline_asm_call(
             self,
             &asm,
-            &constraint_cstr,
+            &all_constraints,
             &inputs,
             output_type,
             ia.volatile,
@@ -119,17 +117,17 @@ impl AsmBuilderMethods<'tcx> for Builder<'a, 'll, 'tcx> {
 
 impl AsmMethods for CodegenCx<'ll, 'tcx> {
     fn codegen_global_asm(&self, ga: &hir::GlobalAsm) {
-        let asm = CString::new(ga.asm.as_str().as_bytes()).unwrap();
+        let asm = ga.asm.as_str();
         unsafe {
-            llvm::LLVMRustAppendModuleInlineAsm(self.llmod, asm.as_ptr());
+            llvm::LLVMRustAppendModuleInlineAsm(self.llmod, asm.as_ptr().cast(), asm.len());
         }
     }
 }
 
 fn inline_asm_call(
     bx: &mut Builder<'a, 'll, 'tcx>,
-    asm: &CStr,
-    cons: &CStr,
+    asm: &str,
+    cons: &str,
     inputs: &[&'ll Value],
     output: &'ll llvm::Type,
     volatile: bool,
@@ -151,13 +149,15 @@ fn inline_asm_call(
     let fty = bx.cx.type_func(&argtys[..], output);
     unsafe {
         // Ask LLVM to verify that the constraints are well-formed.
-        let constraints_ok = llvm::LLVMRustInlineAsmVerify(fty, cons.as_ptr());
+        let constraints_ok = llvm::LLVMRustInlineAsmVerify(fty, cons.as_ptr().cast(), cons.len());
         debug!("constraint verification result: {:?}", constraints_ok);
         if constraints_ok {
             let v = llvm::LLVMRustInlineAsm(
                 fty,
-                asm.as_ptr(),
-                cons.as_ptr(),
+                asm.as_ptr().cast(),
+                asm.len(),
+                cons.as_ptr().cast(),
+                cons.len(),
                 volatile,
                 alignstack,
                 llvm::AsmDialect::from_generic(dia),
diff --git a/src/librustc_codegen_llvm/builder.rs b/src/librustc_codegen_llvm/builder.rs
index 32604d5601d30..1c5987f26f129 100644
--- a/src/librustc_codegen_llvm/builder.rs
+++ b/src/librustc_codegen_llvm/builder.rs
@@ -1016,7 +1016,6 @@ impl BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
                 args.as_ptr() as *const &llvm::Value,
                 args.len() as c_uint,
                 bundle,
-                UNNAMED,
             )
         }
     }
diff --git a/src/librustc_codegen_llvm/declare.rs b/src/librustc_codegen_llvm/declare.rs
index 691f32dd85a05..fab6321186b2c 100644
--- a/src/librustc_codegen_llvm/declare.rs
+++ b/src/librustc_codegen_llvm/declare.rs
@@ -21,7 +21,6 @@ use crate::value::Value;
 use log::debug;
 use rustc::ty::Ty;
 use rustc_codegen_ssa::traits::*;
-use rustc_data_structures::small_c_str::SmallCStr;
 
 /// Declare a function.
 ///
@@ -34,8 +33,9 @@ fn declare_raw_fn(
     ty: &'ll Type,
 ) -> &'ll Value {
     debug!("declare_raw_fn(name={:?}, ty={:?})", name, ty);
-    let namebuf = SmallCStr::new(name);
-    let llfn = unsafe { llvm::LLVMRustGetOrInsertFunction(cx.llmod, namebuf.as_ptr(), ty) };
+    let llfn = unsafe {
+        llvm::LLVMRustGetOrInsertFunction(cx.llmod, name.as_ptr().cast(), name.len(), ty)
+    };
 
     llvm::SetFunctionCallConv(llfn, callconv);
     // Function addresses in Rust are never significant, allowing functions to
@@ -83,8 +83,7 @@ impl DeclareMethods<'tcx> for CodegenCx<'ll, 'tcx> {
 
     fn get_declared_value(&self, name: &str) -> Option<&'ll Value> {
         debug!("get_declared_value(name={:?})", name);
-        let namebuf = SmallCStr::new(name);
-        unsafe { llvm::LLVMRustGetNamedValue(self.llmod, namebuf.as_ptr()) }
+        unsafe { llvm::LLVMRustGetNamedValue(self.llmod, name.as_ptr().cast(), name.len()) }
     }
 
     fn get_defined_value(&self, name: &str) -> Option<&'ll Value> {
diff --git a/src/librustc_codegen_llvm/llvm/ffi.rs b/src/librustc_codegen_llvm/llvm/ffi.rs
index 31a0f52809088..388b6c7483958 100644
--- a/src/librustc_codegen_llvm/llvm/ffi.rs
+++ b/src/librustc_codegen_llvm/llvm/ffi.rs
@@ -732,7 +732,7 @@ extern "C" {
 
     /// See Module::setModuleInlineAsm.
     pub fn LLVMSetModuleInlineAsm(M: &Module, Asm: *const c_char);
-    pub fn LLVMRustAppendModuleInlineAsm(M: &Module, Asm: *const c_char);
+    pub fn LLVMRustAppendModuleInlineAsm(M: &Module, Asm: *const c_char, AsmLen: size_t);
 
     /// See llvm::LLVMTypeKind::getTypeID.
     pub fn LLVMRustGetTypeKind(Ty: &Type) -> TypeKind;
@@ -879,13 +879,18 @@ extern "C" {
     pub fn LLVMSetThreadLocalMode(GlobalVar: &Value, Mode: ThreadLocalMode);
     pub fn LLVMIsGlobalConstant(GlobalVar: &Value) -> Bool;
     pub fn LLVMSetGlobalConstant(GlobalVar: &Value, IsConstant: Bool);
-    pub fn LLVMRustGetNamedValue(M: &Module, Name: *const c_char) -> Option<&Value>;
+    pub fn LLVMRustGetNamedValue(
+        M: &Module,
+        Name: *const c_char,
+        NameLen: size_t,
+    ) -> Option<&Value>;
     pub fn LLVMSetTailCall(CallInst: &Value, IsTailCall: Bool);
 
     // Operations on functions
     pub fn LLVMRustGetOrInsertFunction(
         M: &'a Module,
         Name: *const c_char,
+        NameLen: size_t,
         FunctionTy: &'a Type,
     ) -> &'a Value;
     pub fn LLVMSetFunctionCallConv(Fn: &Value, CC: c_uint);
@@ -1332,7 +1337,6 @@ extern "C" {
         Args: *const &'a Value,
         NumArgs: c_uint,
         Bundle: Option<&OperandBundleDef<'a>>,
-        Name: *const c_char,
     ) -> &'a Value;
     pub fn LLVMRustBuildMemCpy(
         B: &Builder<'a>,
@@ -1581,12 +1585,18 @@ extern "C" {
     pub fn LLVMRustInlineAsm(
         Ty: &Type,
         AsmString: *const c_char,
+        AsmStringLen: size_t,
         Constraints: *const c_char,
+        ConstraintsLen: size_t,
         SideEffects: Bool,
         AlignStack: Bool,
         Dialect: AsmDialect,
     ) -> &Value;
-    pub fn LLVMRustInlineAsmVerify(Ty: &Type, Constraints: *const c_char) -> bool;
+    pub fn LLVMRustInlineAsmVerify(
+        Ty: &Type,
+        Constraints: *const c_char,
+        ConstraintsLen: size_t,
+    ) -> bool;
 
     pub fn LLVMRustDebugMetadataVersion() -> u32;
     pub fn LLVMRustVersionMajor() -> u32;
diff --git a/src/rustllvm/RustWrapper.cpp b/src/rustllvm/RustWrapper.cpp
index aeddd4cfb9fe9..25cfee3373dc4 100644
--- a/src/rustllvm/RustWrapper.cpp
+++ b/src/rustllvm/RustWrapper.cpp
@@ -112,20 +112,22 @@ extern "C" void LLVMRustPrintPassTimings() {
   TimerGroup::printAll(OS);
 }
 
-extern "C" LLVMValueRef LLVMRustGetNamedValue(LLVMModuleRef M,
-                                              const char *Name) {
-  return wrap(unwrap(M)->getNamedValue(Name));
+extern "C" LLVMValueRef LLVMRustGetNamedValue(LLVMModuleRef M, const char *Name,
+                                              size_t NameLen) {
+  return wrap(unwrap(M)->getNamedValue(StringRef(Name, NameLen)));
 }
 
 extern "C" LLVMValueRef LLVMRustGetOrInsertFunction(LLVMModuleRef M,
                                                     const char *Name,
+                                                    size_t NameLen,
                                                     LLVMTypeRef FunctionTy) {
-  return wrap(
-      unwrap(M)->getOrInsertFunction(Name, unwrap<FunctionType>(FunctionTy))
+  return wrap(unwrap(M)
+                  ->getOrInsertFunction(StringRef(Name, NameLen),
+                                        unwrap<FunctionType>(FunctionTy))
 #if LLVM_VERSION_GE(9, 0)
-      .getCallee()
+                  .getCallee()
 #endif
-      );
+  );
 }
 
 extern "C" LLVMValueRef
@@ -395,22 +397,26 @@ static InlineAsm::AsmDialect fromRust(LLVMRustAsmDialect Dialect) {
   }
 }
 
-extern "C" LLVMValueRef LLVMRustInlineAsm(LLVMTypeRef Ty, char *AsmString,
-                                          char *Constraints,
-                                          LLVMBool HasSideEffects,
-                                          LLVMBool IsAlignStack,
-                                          LLVMRustAsmDialect Dialect) {
-  return wrap(InlineAsm::get(unwrap<FunctionType>(Ty), AsmString, Constraints,
+extern "C" LLVMValueRef
+LLVMRustInlineAsm(LLVMTypeRef Ty, char *AsmString, size_t AsmStringLen,
+                  char *Constraints, size_t ConstraintsLen,
+                  LLVMBool HasSideEffects, LLVMBool IsAlignStack,
+                  LLVMRustAsmDialect Dialect) {
+  return wrap(InlineAsm::get(unwrap<FunctionType>(Ty),
+                             StringRef(AsmString, AsmStringLen),
+                             StringRef(Constraints, ConstraintsLen),
                              HasSideEffects, IsAlignStack, fromRust(Dialect)));
 }
 
-extern "C" bool LLVMRustInlineAsmVerify(LLVMTypeRef Ty,
-                                          char *Constraints) {
-  return InlineAsm::Verify(unwrap<FunctionType>(Ty), Constraints);
+extern "C" bool LLVMRustInlineAsmVerify(LLVMTypeRef Ty, char *Constraints,
+                                        size_t ConstraintsLen) {
+  return InlineAsm::Verify(unwrap<FunctionType>(Ty),
+                           StringRef(Constraints, ConstraintsLen));
 }
 
-extern "C" void LLVMRustAppendModuleInlineAsm(LLVMModuleRef M, const char *Asm) {
-  unwrap(M)->appendModuleInlineAsm(StringRef(Asm));
+extern "C" void LLVMRustAppendModuleInlineAsm(LLVMModuleRef M, const char *Asm,
+                                              size_t AsmLen) {
+  unwrap(M)->appendModuleInlineAsm(StringRef(Asm, AsmLen));
 }
 
 typedef DIBuilder *LLVMRustDIBuilderRef;
@@ -1282,12 +1288,11 @@ extern "C" void LLVMRustFreeOperandBundleDef(OperandBundleDef *Bundle) {
 
 extern "C" LLVMValueRef LLVMRustBuildCall(LLVMBuilderRef B, LLVMValueRef Fn,
                                           LLVMValueRef *Args, unsigned NumArgs,
-                                          OperandBundleDef *Bundle,
-                                          const char *Name) {
+                                          OperandBundleDef *Bundle) {
   unsigned Len = Bundle ? 1 : 0;
   ArrayRef<OperandBundleDef> Bundles = makeArrayRef(Bundle, Len);
   return wrap(unwrap(B)->CreateCall(
-      unwrap(Fn), makeArrayRef(unwrap(Args), NumArgs), Bundles, Name));
+      unwrap(Fn), makeArrayRef(unwrap(Args), NumArgs), Bundles));
 }
 
 extern "C" LLVMValueRef LLVMRustBuildMemCpy(LLVMBuilderRef B,