Rollup of 6 pull requests

.github/ISSUE_TEMPLATE/library_tracking_issue.md

@@ -33,21 +33,41 @@ For most library features, it'd be useful to include a summarized version of the
 -->
 
 ```rust
-...
+// core::magic
+
+pub struct Magic;
+
+impl Magic {
+    pub fn magic(self);
+}
 ```
 
 ### Steps / History
 
 <!--
-In the simplest case, this is a PR implementing the feature followed by a PR
-that stabilises the feature. However it's not uncommon for the feature to be
-changed before stabilization. For larger features, the implementation could be
-split up in multiple steps.
+For larger features, more steps might be involved.
+If the feature is changed later, please add those PRs here as well.
 -->
 
-- [ ] Implementation: ...
+- [ ] Implementation: #...
+- [ ] Final commenting period (FCP)
 - [ ] Stabilization PR
 
+<!--
+Once the feature has gone through a few release cycles and there are no
+unresolved questions left, the feature might be ready for stabilization.
+
+If this feature didn't go through the RFC process, a final commenting period
+(FCP) is always needed before stabilization. This works as follows:
+
+A library team member can kick off the stabilization process, at which point
+the rfcbot will ask all the team members to verify they agree with
+stabilization. Once enough members agree and there are no concerns, the final
+commenting period begins: this issue will be marked as such and will be listed
+in the next This Week in Rust newsletter. If no blocking concerns are raised in
+that period of 10 days, a stabilzation PR can be opened by anyone.
+-->
+
 ### Unresolved Questions
 
 <!--

compiler/rustc_ast_pretty/src/pprust/state.rs

@@ -2677,7 +2677,6 @@ impl<'a> State<'a> {
                     s.print_type_bounds(":", &param.bounds);
                     if let Some(ref _default) = default {
                         // FIXME(const_generics_defaults): print the `default` value here
-                        todo!();
                     }
                 }
             }

compiler/rustc_hir_pretty/src/lib.rs

@@ -2210,7 +2210,6 @@ impl<'a> State<'a> {
                 self.print_type(ty);
                 if let Some(ref _default) = default {
                     // FIXME(const_generics_defaults): print the `default` value here
-                    todo!();
                 }
             }
         }

compiler/rustc_lint_defs/src/builtin.rs

@@ -221,14 +221,10 @@ declare_lint! {
     ///
     /// ### Explanation
     ///
-    /// This lint detects code that is very likely incorrect. When possible,
-    /// the compiler will attempt to detect situations where code can be
-    /// evaluated at compile-time to generate more efficient code. While
-    /// evaluating such code, if it detects that the code will unconditionally
-    /// panic, this usually indicates that it is doing something incorrectly.
-    /// If this lint is allowed, then the code will not be evaluated at
-    /// compile-time, and instead continue to generate code to evaluate at
-    /// runtime, which may panic during runtime.
+    /// This lint detects code that is very likely incorrect because it will
+    /// always panic, such as division by zero and out-of-bounds array
+    /// accesses. Consider adjusting your code if this is a bug, or using the
+    /// `panic!` or `unreachable!` macro instead in case the panic is intended.
     pub UNCONDITIONAL_PANIC,
     Deny,
     "operation will cause a panic at runtime"

compiler/rustc_save_analysis/src/sig.rs

@@ -619,7 +619,6 @@ impl<'hir> Sig for hir::Generics<'hir> {
                 param_text.push_str(&ty_to_string(&ty));
                 if let Some(ref _default) = default {
                     // FIXME(const_generics_defaults): push the `default` value here
-                    todo!();
                 }
             }
             if !param.bounds.is_empty() {

compiler/rustc_typeck/src/check/expr.rs

@@ -1381,19 +1381,42 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             ty,
         );
         match variant.ctor_kind {
-            CtorKind::Fn => {
-                err.span_label(variant.ident.span, format!("`{adt}` defined here", adt = ty));
-                err.span_label(field.ident.span, "field does not exist");
-                err.span_label(
-                    ty_span,
-                    format!(
-                        "`{adt}` is a tuple {kind_name}, \
-                         use the appropriate syntax: `{adt}(/* fields */)`",
-                        adt = ty,
-                        kind_name = kind_name
-                    ),
-                );
-            }
+            CtorKind::Fn => match ty.kind() {
+                ty::Adt(adt, ..) if adt.is_enum() => {
+                    err.span_label(
+                        variant.ident.span,
+                        format!(
+                            "`{adt}::{variant}` defined here",
+                            adt = ty,
+                            variant = variant.ident,
+                        ),
+                    );
+                    err.span_label(field.ident.span, "field does not exist");
+                    err.span_label(
+                        ty_span,
+                        format!(
+                            "`{adt}::{variant}` is a tuple {kind_name}, \
+                             use the appropriate syntax: `{adt}::{variant}(/* fields */)`",
+                            adt = ty,
+                            variant = variant.ident,
+                            kind_name = kind_name
+                        ),
+                    );
+                }
+                _ => {
+                    err.span_label(variant.ident.span, format!("`{adt}` defined here", adt = ty));
+                    err.span_label(field.ident.span, "field does not exist");
+                    err.span_label(
+                        ty_span,
+                        format!(
+                            "`{adt}` is a tuple {kind_name}, \
+                                 use the appropriate syntax: `{adt}(/* fields */)`",
+                            adt = ty,
+                            kind_name = kind_name
+                        ),
+                    );
+                }
+            },
             _ => {
                 // prevent all specified fields from being suggested
                 let skip_fields = skip_fields.iter().map(|ref x| x.ident.name);

src/bootstrap/clean.rs

@@ -21,6 +21,7 @@ pub fn clean(build: &Build, all: bool) {
     } else {
         rm_rf(&build.out.join("tmp"));
         rm_rf(&build.out.join("dist"));
+        rm_rf(&build.out.join("bootstrap"));
 
         for host in &build.hosts {
             let entries = match build.out.join(host.triple).read_dir() {

src/librustdoc/clean/auto_trait.rs

@@ -738,11 +738,11 @@ impl<'a, 'tcx> AutoTraitFinder<'a, 'tcx> {
     }
 
     fn is_fn_ty(&self, tcx: TyCtxt<'_>, ty: &Type) -> bool {
-        match &ty {
-            &&Type::ResolvedPath { ref did, .. } => {
-                *did == tcx.require_lang_item(LangItem::Fn, None)
-                    || *did == tcx.require_lang_item(LangItem::FnMut, None)
-                    || *did == tcx.require_lang_item(LangItem::FnOnce, None)
+        match ty {
+            &Type::ResolvedPath { did, .. } => {
+                did == tcx.require_lang_item(LangItem::Fn, None)
+                    || did == tcx.require_lang_item(LangItem::FnMut, None)
+                    || did == tcx.require_lang_item(LangItem::FnOnce, None)
             }
             _ => false,
         }

src/librustdoc/clean/cfg.rs

@@ -177,29 +177,21 @@ impl Cfg {
             Cfg::Any(ref sub_cfgs) | Cfg::All(ref sub_cfgs) => {
                 sub_cfgs.first().map(Cfg::should_capitalize_first_letter).unwrap_or(false)
             }
-            Cfg::Cfg(name, _) => match name {
-                sym::debug_assertions | sym::target_endian => true,
-                _ => false,
-            },
+            Cfg::Cfg(name, _) => name == sym::debug_assertions || name == sym::target_endian,
         }
     }
 
     fn should_append_only_to_description(&self) -> bool {
         match *self {
             Cfg::False | Cfg::True => false,
             Cfg::Any(..) | Cfg::All(..) | Cfg::Cfg(..) => true,
-            Cfg::Not(ref child) => match **child {
-                Cfg::Cfg(..) => true,
-                _ => false,
-            },
+            Cfg::Not(box Cfg::Cfg(..)) => true,
+            Cfg::Not(..) => false,
         }
     }
 
     fn should_use_with_in_description(&self) -> bool {
-        match *self {
-            Cfg::Cfg(name, _) if name == sym::target_feature => true,
-            _ => false,
-        }
+        matches!(self, Cfg::Cfg(sym::target_feature, _))
     }
 
     /// Attempt to simplify this cfg by assuming that `assume` is already known to be true, will

src/librustdoc/clean/mod.rs

@@ -640,10 +640,10 @@ impl Clean<Generics> for hir::Generics<'_> {
         ///
         /// [`lifetime_to_generic_param`]: rustc_ast_lowering::LoweringContext::lifetime_to_generic_param
         fn is_elided_lifetime(param: &hir::GenericParam<'_>) -> bool {
-            match param.kind {
-                hir::GenericParamKind::Lifetime { kind: hir::LifetimeParamKind::Elided } => true,
-                _ => false,
-            }
+            matches!(
+                param.kind,
+                hir::GenericParamKind::Lifetime { kind: hir::LifetimeParamKind::Elided }
+            )
         }
 
         let impl_trait_params = self
@@ -801,7 +801,7 @@ impl<'a, 'tcx> Clean<Generics> for (&'a ty::Generics, ty::GenericPredicates<'tcx
 
         for (param, mut bounds) in impl_trait {
             // Move trait bounds to the front.
-            bounds.sort_by_key(|b| if let GenericBound::TraitBound(..) = b { false } else { true });
+            bounds.sort_by_key(|b| !matches!(b, GenericBound::TraitBound(..)));
 
             if let crate::core::ImplTraitParam::ParamIndex(idx) = param {
                 if let Some(proj) = impl_trait_proj.remove(&idx) {

src/librustdoc/clean/types.rs

@@ -175,11 +175,9 @@ impl Item {
     }
 
     crate fn is_crate(&self) -> bool {
-        match *self.kind {
+        matches!(*self.kind,
             StrippedItem(box ModuleItem(Module { is_crate: true, .. }))
-            | ModuleItem(Module { is_crate: true, .. }) => true,
-            _ => false,
-        }
+            | ModuleItem(Module { is_crate: true, .. }))
     }
     crate fn is_mod(&self) -> bool {
         self.type_() == ItemType::Module
@@ -378,10 +376,7 @@ impl ItemKind {
     }
 
     crate fn is_type_alias(&self) -> bool {
-        match *self {
-            ItemKind::TypedefItem(_, _) | ItemKind::AssocTypeItem(_, _) => true,
-            _ => false,
-        }
+        matches!(self, ItemKind::TypedefItem(..) | ItemKind::AssocTypeItem(..))
     }
 }
 
@@ -674,7 +669,7 @@ impl Attributes {
                                 span: attr.span,
                                 doc: contents,
                                 kind: DocFragmentKind::Include { filename },
-                                parent_module: parent_module,
+                                parent_module,
                             });
                         }
                     }
@@ -750,7 +745,7 @@ impl Attributes {
                     Some(did) => {
                         if let Some((mut href, ..)) = href(did) {
                             if let Some(ref fragment) = *fragment {
-                                href.push_str("#");
+                                href.push('#');
                                 href.push_str(fragment);
                             }
                             Some(RenderedLink {
@@ -945,10 +940,7 @@ crate enum GenericParamDefKind {
 
 impl GenericParamDefKind {
     crate fn is_type(&self) -> bool {
-        match *self {
-            GenericParamDefKind::Type { .. } => true,
-            _ => false,
-        }
+        matches!(self, GenericParamDefKind::Type { .. })
     }
 
     // FIXME(eddyb) this either returns the default of a type parameter, or the
@@ -1292,15 +1284,12 @@ impl Type {
     }
 
     crate fn is_full_generic(&self) -> bool {
-        match *self {
-            Type::Generic(_) => true,
-            _ => false,
-        }
+        matches!(self, Type::Generic(_))
     }
 
     crate fn projection(&self) -> Option<(&Type, DefId, Symbol)> {
         let (self_, trait_, name) = match self {
-            QPath { ref self_type, ref trait_, name } => (self_type, trait_, name),
+            QPath { self_type, trait_, name } => (self_type, trait_, name),
             _ => return None,
         };
         let trait_did = match **trait_ {

src/librustdoc/config.rs

@@ -37,10 +37,7 @@ crate enum OutputFormat {
 
 impl OutputFormat {
     crate fn is_json(&self) -> bool {
-        match self {
-            OutputFormat::Json => true,
-            _ => false,
-        }
+        matches!(self, OutputFormat::Json)
     }
 }
 

src/librustdoc/doctest.rs

@@ -636,15 +636,15 @@ fn partition_source(s: &str) -> (String, String, String) {
         match state {
             PartitionState::Attrs => {
                 before.push_str(line);
-                before.push_str("\n");
+                before.push('\n');
             }
             PartitionState::Crates => {
                 crates.push_str(line);
-                crates.push_str("\n");
+                crates.push('\n');
             }
             PartitionState::Other => {
                 after.push_str(line);
-                after.push_str("\n");
+                after.push('\n');
             }
         }
     }

src/librustdoc/fold.rs

@@ -61,7 +61,7 @@ crate trait DocFolder: Sized {
                         j.fields = j.fields.into_iter().filter_map(|x| self.fold_item(x)).collect();
                         j.fields_stripped |= num_fields != j.fields.len()
                             || j.fields.iter().any(|f| f.is_stripped());
-                        VariantItem(Variant { kind: VariantKind::Struct(j), ..i2 })
+                        VariantItem(Variant { kind: VariantKind::Struct(j) })
                     }
                     _ => VariantItem(i2),
                 }