Auto merge of #49008 - kennytm:rollup, r=kennytm

Rollup of 12 pull requests

- Successful merges: #48765, #48831, #48840, #48964, #48970, #48971, #48981, #48988, #48991, #48966, #48993, #48874
- Failed merges:

src/doc/rustdoc/src/documentation-tests.md

@@ -19,15 +19,19 @@ running `rustdoc --test foo.rs` will extract this example, and then run it as a
 Please note that by default, if no language is set for the block code, `rustdoc`
 assumes it is `Rust` code. So the following:
 
+``````markdown
 ```rust
 let x = 5;
 ```
+``````
 
 is strictly equivalent to:
 
+``````markdown
 ```
 let x = 5;
 ```
+``````
 
 There's some subtlety though! Read on for more details.
 

src/libcore/fmt/mod.rs

@@ -1379,27 +1379,159 @@ impl<'a> Formatter<'a> {
         }
     }
 
-    /// Optionally specified integer width that the output should be
+    /// Optionally specified integer width that the output should be.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fmt;
+    ///
+    /// struct Foo(i32);
+    ///
+    /// impl fmt::Display for Foo {
+    ///     fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+    ///         if let Some(width) = formatter.width() {
+    ///             // If we received a width, we use it
+    ///             write!(formatter, "{:width$}", &format!("Foo({})", self.0), width = width)
+    ///         } else {
+    ///             // Otherwise we do nothing special
+    ///             write!(formatter, "Foo({})", self.0)
+    ///         }
+    ///     }
+    /// }
+    ///
+    /// assert_eq!(&format!("{:10}", Foo(23)), "Foo(23)   ");
+    /// assert_eq!(&format!("{}", Foo(23)), "Foo(23)");
+    /// ```
     #[stable(feature = "fmt_flags", since = "1.5.0")]
     pub fn width(&self) -> Option<usize> { self.width }
 
-    /// Optionally specified precision for numeric types
+    /// Optionally specified precision for numeric types.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fmt;
+    ///
+    /// struct Foo(f32);
+    ///
+    /// impl fmt::Display for Foo {
+    ///     fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+    ///         if let Some(precision) = formatter.precision() {
+    ///             // If we received a precision, we use it.
+    ///             write!(formatter, "Foo({1:.*})", precision, self.0)
+    ///         } else {
+    ///             // Otherwise we default to 2.
+    ///             write!(formatter, "Foo({:.2})", self.0)
+    ///         }
+    ///     }
+    /// }
+    ///
+    /// assert_eq!(&format!("{:.4}", Foo(23.2)), "Foo(23.2000)");
+    /// assert_eq!(&format!("{}", Foo(23.2)), "Foo(23.20)");
+    /// ```
     #[stable(feature = "fmt_flags", since = "1.5.0")]
     pub fn precision(&self) -> Option<usize> { self.precision }
 
     /// Determines if the `+` flag was specified.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fmt;
+    ///
+    /// struct Foo(i32);
+    ///
+    /// impl fmt::Display for Foo {
+    ///     fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+    ///         if formatter.sign_plus() {
+    ///             write!(formatter,
+    ///                    "Foo({}{})",
+    ///                    if self.0 < 0 { '-' } else { '+' },
+    ///                    self.0)
+    ///         } else {
+    ///             write!(formatter, "Foo({})", self.0)
+    ///         }
+    ///     }
+    /// }
+    ///
+    /// assert_eq!(&format!("{:+}", Foo(23)), "Foo(+23)");
+    /// assert_eq!(&format!("{}", Foo(23)), "Foo(23)");
+    /// ```
     #[stable(feature = "fmt_flags", since = "1.5.0")]
     pub fn sign_plus(&self) -> bool { self.flags & (1 << FlagV1::SignPlus as u32) != 0 }
 
     /// Determines if the `-` flag was specified.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fmt;
+    ///
+    /// struct Foo(i32);
+    ///
+    /// impl fmt::Display for Foo {
+    ///     fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+    ///         if formatter.sign_minus() {
+    ///             // You want a minus sign? Have one!
+    ///             write!(formatter, "-Foo({})", self.0)
+    ///         } else {
+    ///             write!(formatter, "Foo({})", self.0)
+    ///         }
+    ///     }
+    /// }
+    ///
+    /// assert_eq!(&format!("{:-}", Foo(23)), "-Foo(23)");
+    /// assert_eq!(&format!("{}", Foo(23)), "Foo(23)");
+    /// ```
     #[stable(feature = "fmt_flags", since = "1.5.0")]
     pub fn sign_minus(&self) -> bool { self.flags & (1 << FlagV1::SignMinus as u32) != 0 }
 
     /// Determines if the `#` flag was specified.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fmt;
+    ///
+    /// struct Foo(i32);
+    ///
+    /// impl fmt::Display for Foo {
+    ///     fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+    ///         if formatter.alternate() {
+    ///             write!(formatter, "Foo({})", self.0)
+    ///         } else {
+    ///             write!(formatter, "{}", self.0)
+    ///         }
+    ///     }
+    /// }
+    ///
+    /// assert_eq!(&format!("{:#}", Foo(23)), "Foo(23)");
+    /// assert_eq!(&format!("{}", Foo(23)), "23");
+    /// ```
     #[stable(feature = "fmt_flags", since = "1.5.0")]
     pub fn alternate(&self) -> bool { self.flags & (1 << FlagV1::Alternate as u32) != 0 }
 
     /// Determines if the `0` flag was specified.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fmt;
+    ///
+    /// struct Foo(i32);
+    ///
+    /// impl fmt::Display for Foo {
+    ///     fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+    ///         assert!(formatter.sign_aware_zero_pad());
+    ///         assert_eq!(formatter.width(), Some(4));
+    ///         // We ignore the formatter's options.
+    ///         write!(formatter, "{}", self.0)
+    ///     }
+    /// }
+    ///
+    /// assert_eq!(&format!("{:04}", Foo(23)), "23");
+    /// ```
     #[stable(feature = "fmt_flags", since = "1.5.0")]
     pub fn sign_aware_zero_pad(&self) -> bool {
         self.flags & (1 << FlagV1::SignAwareZeroPad as u32) != 0

src/librustc/hir/map/collector.rs

@@ -13,6 +13,7 @@ use dep_graph::{DepGraph, DepKind, DepNodeIndex};
 use hir::def_id::{LOCAL_CRATE, CrateNum};
 use hir::intravisit::{Visitor, NestedVisitorMap};
 use hir::svh::Svh;
+use ich::Fingerprint;
 use middle::cstore::CrateStore;
 use session::CrateDisambiguator;
 use std::iter::repeat;
@@ -121,21 +122,24 @@ impl<'a, 'hir> NodeCollector<'a, 'hir> {
         collector
     }
 
-    pub(super) fn finalize_and_compute_crate_hash(self,
+    pub(super) fn finalize_and_compute_crate_hash(mut self,
                                                   crate_disambiguator: CrateDisambiguator,
                                                   cstore: &dyn CrateStore,
                                                   codemap: &CodeMap,
                                                   commandline_args_hash: u64)
                                                   -> (Vec<MapEntry<'hir>>, Svh) {
-        let mut node_hashes: Vec<_> = self
+        self
             .hir_body_nodes
-            .iter()
-            .map(|&(def_path_hash, dep_node_index)| {
-                (def_path_hash, self.dep_graph.fingerprint_of(dep_node_index))
-            })
-            .collect();
+            .sort_unstable_by(|&(ref d1, _), &(ref d2, _)| d1.cmp(d2));
 
-        node_hashes.sort_unstable_by(|&(ref d1, _), &(ref d2, _)| d1.cmp(d2));
+        let node_hashes = self
+            .hir_body_nodes
+            .iter()
+            .fold(Fingerprint::ZERO, |fingerprint , &(def_path_hash, dep_node_index)| {
+                fingerprint.combine(
+                    def_path_hash.0.combine(self.dep_graph.fingerprint_of(dep_node_index))
+                )
+            });
 
         let mut upstream_crates: Vec<_> = cstore.crates_untracked().iter().map(|&cnum| {
             let name = cstore.crate_name_untracked(cnum).as_str();

src/librustc/session/config.rs

@@ -1641,7 +1641,7 @@ pub fn rustc_optgroups() -> Vec<RustcOptGroup> {
         opt::multi_s(
             "",
             "remap-path-prefix",
-            "remap source names in output",
+            "Remap source names in all output (compiler messages and output files)",
             "FROM=TO",
         ),
     ]);

src/librustc_back/target/mips_unknown_linux_gnu.rs

@@ -25,7 +25,7 @@ pub fn target() -> TargetResult {
         linker_flavor: LinkerFlavor::Gcc,
         options: TargetOptions {
             cpu: "mips32r2".to_string(),
-            features: "+mips32r2".to_string(),
+            features: "+mips32r2,+fpxx,+nooddspreg".to_string(),
             max_atomic_width: Some(32),
 
             // see #36994

src/librustc_back/target/mipsel_unknown_linux_gnu.rs

@@ -25,8 +25,8 @@ pub fn target() -> TargetResult {
         linker_flavor: LinkerFlavor::Gcc,
 
         options: TargetOptions {
-            cpu: "mips32".to_string(),
-            features: "+mips32".to_string(),
+            cpu: "mips32r2".to_string(),
+            features: "+mips32r2,+fpxx,+nooddspreg".to_string(),
             max_atomic_width: Some(32),
 
             // see #36994

src/librustc_back/target/mipsel_unknown_linux_musl.rs

@@ -13,8 +13,8 @@ use target::{Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::linux_musl_base::opts();
-    base.cpu = "mips32".to_string();
-    base.features = "+mips32,+soft-float".to_string();
+    base.cpu = "mips32r2".to_string();
+    base.features = "+mips32r2,+soft-float".to_string();
     base.max_atomic_width = Some(32);
     // see #36994
     base.exe_allocation_crate = None;

src/librustc_back/target/mipsel_unknown_linux_uclibc.rs

@@ -25,8 +25,8 @@ pub fn target() -> TargetResult {
         linker_flavor: LinkerFlavor::Gcc,
 
         options: TargetOptions {
-            cpu: "mips32".to_string(),
-            features: "+mips32,+soft-float".to_string(),
+            cpu: "mips32r2".to_string(),
+            features: "+mips32r2,+soft-float".to_string(),
             max_atomic_width: Some(32),
 
             // see #36994

src/librustc_data_structures/indexed_set.rs

@@ -224,70 +224,6 @@ impl<T: Idx> IdxSet<T> {
             _pd: PhantomData,
         }
     }
-
-    /// Calls `f` on each index value held in this set, up to the
-    /// bound `max_bits` on the size of universe of indexes.
-    pub fn each_bit<F>(&self, max_bits: usize, f: F) where F: FnMut(T) {
-        each_bit(self, max_bits, f)
-    }
-
-    /// Removes all elements from this set.
-    pub fn reset_to_empty(&mut self) {
-        for word in self.words_mut() { *word = 0; }
-    }
-
-    pub fn elems(&self, universe_size: usize) -> Elems<T> {
-        Elems { i: 0, set: self, universe_size: universe_size }
-    }
-}
-
-pub struct Elems<'a, T: Idx> { i: usize, set: &'a IdxSet<T>, universe_size: usize }
-
-impl<'a, T: Idx> Iterator for Elems<'a, T> {
-    type Item = T;
-    fn next(&mut self) -> Option<T> {
-        if self.i >= self.universe_size { return None; }
-        let mut i = self.i;
-        loop {
-            if i >= self.universe_size {
-                self.i = i; // (mark iteration as complete.)
-                return None;
-            }
-            if self.set.contains(&T::new(i)) {
-                self.i = i + 1; // (next element to start at.)
-                return Some(T::new(i));
-            }
-            i = i + 1;
-        }
-    }
-}
-
-fn each_bit<T: Idx, F>(words: &IdxSet<T>, max_bits: usize, mut f: F) where F: FnMut(T) {
-    let usize_bits: usize = mem::size_of::<usize>() * 8;
-
-    for (word_index, &word) in words.words().iter().enumerate() {
-        if word != 0 {
-            let base_index = word_index * usize_bits;
-            for offset in 0..usize_bits {
-                let bit = 1 << offset;
-                if (word & bit) != 0 {
-                    // NB: we round up the total number of bits
-                    // that we store in any given bit set so that
-                    // it is an even multiple of usize::BITS. This
-                    // means that there may be some stray bits at
-                    // the end that do not correspond to any
-                    // actual value; that's why we first check
-                    // that we are in range of bits_per_block.
-                    let bit_index = base_index + offset as usize;
-                    if bit_index >= max_bits {
-                        return;
-                    } else {
-                        f(Idx::new(bit_index));
-                    }
-                }
-            }
-        }
-    }
 }
 
 pub struct Iter<'a, T: Idx> {

src/librustc_driver/lib.rs

@@ -1147,6 +1147,15 @@ fn usage(verbose: bool, include_unstable_options: bool) {
              verbose_help);
 }
 
+fn print_wall_help() {
+    println!("
+The flag `-Wall` does not exist in `rustc`. Most useful lints are enabled by
+default. Use `rustc -W help` to see all available lints. It's more common to put
+warning settings in the crate root using `#![warn(LINT_NAME)]` instead of using
+the command line flag directly.
+");
+}
+
 fn describe_lints(sess: &Session, lint_store: &lint::LintStore, loaded_plugins: bool) {
     println!("
 Available lint options:
@@ -1391,6 +1400,13 @@ pub fn handle_options(args: &[String]) -> Option<getopts::Matches> {
         return None;
     }
 
+    // Handle the special case of -Wall.
+    let wall = matches.opt_strs("W");
+    if wall.iter().any(|x| *x == "all") {
+        print_wall_help();
+        return None;
+    }
+
     // Don't handle -W help here, because we might first load plugins.
     let r = matches.opt_strs("Z");
     if r.iter().any(|x| *x == "help") {
@@ -1468,6 +1484,12 @@ fn extra_compiler_flags() -> Option<(Vec<String>, bool)> {
         args.push(arg.to_string_lossy().to_string());
     }
 
+    // Avoid printing help because of empty args. This can suggest the compiler
+    // itself is not the program root (consider RLS).
+    if args.len() < 2 {
+        return None;
+    }
+
     let matches = if let Some(matches) = handle_options(&args) {
         matches
     } else {