Auto merge of #117996 - matthiaskrgr:rollup-sp48bl4, r=matthiaskrgr

Rollup of 5 pull requests

Successful merges:

 - #117892 (Detect more `=>` typos)
 - #117959 (Better handle type errors involving `Self` literals)
 - #117980 (fix: Update CONTRIBUTING.md recommend -> recommended)
 - #117982 (bootstrap: only show PGO warnings when verbose)
 - #117990 (Tweak error and move tests)

Failed merges:

 - #117944 (some additional region refactorings)

r? `@ghost`
`@rustbot` modify labels: rollup

CONTRIBUTING.md

@@ -15,7 +15,7 @@ standard library in the [Standard library developers Guide][std-dev-guide], comm
 ## About the [rustc-dev-guide]
 
 The [rustc-dev-guide] is meant to help document how rustc –the Rust compiler– works,
-as well as to help new contributors get involved in rustc development. It is recommend
+as well as to help new contributors get involved in rustc development. It is recommended
 to read and understand the [rustc-dev-guide] before making a contribution. This guide
 talks about the different bots in the Rust ecosystem, the Rust development tools,
 bootstrapping, the compiler architecture, source code representation, and more.

compiler/rustc_ast/src/token.rs

@@ -388,7 +388,8 @@ impl TokenKind {
         match *self {
             Comma => Some(vec![Dot, Lt, Semi]),
             Semi => Some(vec![Colon, Comma]),
-            FatArrow => Some(vec![Eq, RArrow]),
+            Colon => Some(vec![Semi]),
+            FatArrow => Some(vec![Eq, RArrow, Ge, Gt]),
             _ => None,
         }
     }

compiler/rustc_hir_typeck/src/demand.rs

@@ -31,6 +31,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
 
         self.annotate_alternative_method_deref(err, expr, error);
+        self.explain_self_literal(err, expr, expected, expr_ty);
 
         // Use `||` to give these suggestions a precedence
         let suggested = self.suggest_missing_parentheses(err, expr)
@@ -1027,6 +1028,59 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         return false;
     }
 
+    fn explain_self_literal(
+        &self,
+        err: &mut Diagnostic,
+        expr: &hir::Expr<'tcx>,
+        expected: Ty<'tcx>,
+        found: Ty<'tcx>,
+    ) {
+        match expr.peel_drop_temps().kind {
+            hir::ExprKind::Struct(
+                hir::QPath::Resolved(
+                    None,
+                    hir::Path { res: hir::def::Res::SelfTyAlias { alias_to, .. }, span, .. },
+                ),
+                ..,
+            )
+            | hir::ExprKind::Call(
+                hir::Expr {
+                    kind:
+                        hir::ExprKind::Path(hir::QPath::Resolved(
+                            None,
+                            hir::Path {
+                                res: hir::def::Res::SelfTyAlias { alias_to, .. },
+                                span,
+                                ..
+                            },
+                        )),
+                    ..
+                },
+                ..,
+            ) => {
+                if let Some(hir::Node::Item(hir::Item {
+                    kind: hir::ItemKind::Impl(hir::Impl { self_ty, .. }),
+                    ..
+                })) = self.tcx.hir().get_if_local(*alias_to)
+                {
+                    err.span_label(self_ty.span, "this is the type of the `Self` literal");
+                }
+                if let ty::Adt(e_def, e_args) = expected.kind()
+                    && let ty::Adt(f_def, _f_args) = found.kind()
+                    && e_def == f_def
+                {
+                    err.span_suggestion_verbose(
+                        *span,
+                        "use the type name directly",
+                        self.tcx.value_path_str_with_args(*alias_to, e_args),
+                        Applicability::MaybeIncorrect,
+                    );
+                }
+            }
+            _ => {}
+        }
+    }
+
     fn note_wrong_return_ty_due_to_generic_arg(
         &self,
         err: &mut Diagnostic,

compiler/rustc_parse/src/errors.rs

@@ -2278,9 +2278,8 @@ pub(crate) enum InvalidMutInPattern {
     #[note(parse_note_mut_pattern_usage)]
     NonIdent {
         #[primary_span]
-        #[suggestion(code = "{pat}", applicability = "machine-applicable")]
+        #[suggestion(code = "", applicability = "machine-applicable")]
         span: Span,
-        pat: String,
     },
 }
 

compiler/rustc_parse/src/parser/expr.rs

@@ -2904,15 +2904,16 @@ impl<'a> Parser<'a> {
                         "=>",
                         Applicability::MachineApplicable,
                     );
-                    err.emit();
-                    this.bump();
-                } else if matches!(
-                    (&this.prev_token.kind, &this.token.kind),
-                    (token::DotDotEq, token::Gt)
-                ) {
-                    // `error_inclusive_range_match_arrow` handles cases like `0..=> {}`,
-                    // so we suppress the error here
-                    err.delay_as_bug();
+                    if matches!(
+                        (&this.prev_token.kind, &this.token.kind),
+                        (token::DotDotEq, token::Gt)
+                    ) {
+                        // `error_inclusive_range_match_arrow` handles cases like `0..=> {}`,
+                        // so we suppress the error here
+                        err.delay_as_bug();
+                    } else {
+                        err.emit();
+                    }
                     this.bump();
                 } else {
                     return Err(err);

compiler/rustc_parse/src/parser/mod.rs

@@ -830,8 +830,8 @@ impl<'a> Parser<'a> {
                             // https://github.com/rust-lang/rust/issues/72373
                             if self.prev_token.is_ident() && self.token.kind == token::DotDot {
                                 let msg = format!(
-                                    "if you meant to bind the contents of \
-                                    the rest of the array pattern into `{}`, use `@`",
+                                    "if you meant to bind the contents of the rest of the array \
+                                     pattern into `{}`, use `@`",
                                     pprust::token_to_string(&self.prev_token)
                                 );
                                 expect_err

compiler/rustc_parse/src/parser/pat.rs

@@ -638,13 +638,13 @@ impl<'a> Parser<'a> {
 
     /// Error on `mut $pat` where `$pat` is not an ident.
     fn ban_mut_general_pat(&self, lo: Span, pat: &Pat, changed_any_binding: bool) {
-        let span = lo.to(pat.span);
-        let pat = pprust::pat_to_string(&pat);
-
         self.sess.emit_err(if changed_any_binding {
-            InvalidMutInPattern::NestedIdent { span, pat }
+            InvalidMutInPattern::NestedIdent {
+                span: lo.to(pat.span),
+                pat: pprust::pat_to_string(&pat),
+            }
         } else {
-            InvalidMutInPattern::NonIdent { span, pat }
+            InvalidMutInPattern::NonIdent { span: lo.until(pat.span) }
         });
     }
 

src/bootstrap/src/core/build_steps/compile.rs

@@ -887,7 +887,9 @@ impl Step for Rustc {
         } else if let Some(path) = &builder.config.rust_profile_use {
             if compiler.stage == 1 {
                 cargo.rustflag(&format!("-Cprofile-use={path}"));
-                cargo.rustflag("-Cllvm-args=-pgo-warn-missing-function");
+                if builder.is_verbose() {
+                    cargo.rustflag("-Cllvm-args=-pgo-warn-missing-function");
+                }
                 true
             } else {
                 false

tests/ui/parser/issues/issue-32501.stderr

@@ -2,7 +2,7 @@ error: `mut` must be followed by a named binding
   --> $DIR/issue-32501.rs:7:9
    |
 LL |     let mut _ = 0;
-   |         ^^^^^ help: remove the `mut` prefix: `_`
+   |         ^^^^ help: remove the `mut` prefix
    |
    = note: `mut` may be followed by `variable` and `variable @ pattern`
 

tests/ui/parser/issues/issue-65122-mac-invoc-in-mut-patterns.stderr

@@ -2,7 +2,7 @@ error: `mut` must be followed by a named binding
   --> $DIR/issue-65122-mac-invoc-in-mut-patterns.rs:6:13
    |
 LL |         let mut $eval = ();
-   |             ^^^^^^^^^ help: remove the `mut` prefix: `does_not_exist!()`
+   |             ^^^^ help: remove the `mut` prefix
 ...
 LL |     mac1! { does_not_exist!() }
    |     --------------------------- in this macro invocation
@@ -25,7 +25,7 @@ error: `mut` must be followed by a named binding
   --> $DIR/issue-65122-mac-invoc-in-mut-patterns.rs:13:13
    |
 LL |         let mut $eval = ();
-   |             ^^^ help: remove the `mut` prefix: `does_not_exist!()`
+   |             ^^^ help: remove the `mut` prefix
 ...
 LL |     mac2! { does_not_exist!() }
    |     --------------------------- in this macro invocation

tests/ui/parser/issues/recover-ge-as-fat-arrow.fixed

@@ -0,0 +1,7 @@
+// run-rustfix
+fn main() {
+    match 1 {
+        1 => {} //~ ERROR
+        _ => { let _: u16 = 2u16; } //~ ERROR
+    }
+}

tests/ui/parser/issues/recover-ge-as-fat-arrow.rs

@@ -0,0 +1,7 @@
+// run-rustfix
+fn main() {
+    match 1 {
+        1 >= {} //~ ERROR
+        _ => { let _: u16 = 2u8; } //~ ERROR
+    }
+}

tests/ui/parser/issues/recover-ge-as-fat-arrow.stderr

@@ -0,0 +1,25 @@
+error: expected one of `...`, `..=`, `..`, `=>`, `if`, or `|`, found `>=`
+  --> $DIR/recover-ge-as-fat-arrow.rs:4:11
+   |
+LL |         1 >= {}
+   |           ^^
+   |           |
+   |           expected one of `...`, `..=`, `..`, `=>`, `if`, or `|`
+   |           help: use a fat arrow to start a match arm: `=>`
+
+error[E0308]: mismatched types
+  --> $DIR/recover-ge-as-fat-arrow.rs:5:29
+   |
+LL |         _ => { let _: u16 = 2u8; }
+   |                       ---   ^^^ expected `u16`, found `u8`
+   |                       |
+   |                       expected due to this
+   |
+help: change the type of the numeric literal from `u8` to `u16`
+   |
+LL |         _ => { let _: u16 = 2u16; }
+   |                              ~~~
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0308`.

tests/ui/parser/mut-patterns.stderr

@@ -2,7 +2,7 @@ error: `mut` must be followed by a named binding
   --> $DIR/mut-patterns.rs:9:9
    |
 LL |     let mut _ = 0;
-   |         ^^^^^ help: remove the `mut` prefix: `_`
+   |         ^^^^ help: remove the `mut` prefix
    |
    = note: `mut` may be followed by `variable` and `variable @ pattern`
 
@@ -10,7 +10,7 @@ error: `mut` must be followed by a named binding
   --> $DIR/mut-patterns.rs:10:9
    |
 LL |     let mut (_, _) = (0, 0);
-   |         ^^^^^^^^^^ help: remove the `mut` prefix: `(_, _)`
+   |         ^^^^ help: remove the `mut` prefix
    |
    = note: `mut` may be followed by `variable` and `variable @ pattern`
 

tests/ui/parser/recover/recover-parens-around-match-arm-head.rs

@@ -0,0 +1,14 @@
+fn main() {
+    let val = 42;
+    let x = match val {
+        (0 if true) => {
+        //~^ ERROR expected identifier, found keyword `if`
+        //~| ERROR expected one of `)`, `,`, `...`, `..=`, `..`, or `|`, found keyword `if`
+        //~| ERROR expected one of `)`, `,`, `@`, or `|`, found keyword `true`
+        //~| ERROR mismatched types
+            42u8
+        }
+        _ => 0u8,
+    };
+    let _y: u32 = x; //~ ERROR mismatched types
+}

tests/ui/parser/recover/recover-parens-around-match-arm-head.stderr

@@ -0,0 +1,49 @@
+error: expected identifier, found keyword `if`
+  --> $DIR/recover-parens-around-match-arm-head.rs:4:12
+   |
+LL |         (0 if true) => {
+   |            ^^ expected identifier, found keyword
+
+error: expected one of `)`, `,`, `...`, `..=`, `..`, or `|`, found keyword `if`
+  --> $DIR/recover-parens-around-match-arm-head.rs:4:12
+   |
+LL |         (0 if true) => {
+   |           -^^ expected one of `)`, `,`, `...`, `..=`, `..`, or `|`
+   |           |
+   |           help: missing `,`
+
+error: expected one of `)`, `,`, `@`, or `|`, found keyword `true`
+  --> $DIR/recover-parens-around-match-arm-head.rs:4:15
+   |
+LL |         (0 if true) => {
+   |              -^^^^ expected one of `)`, `,`, `@`, or `|`
+   |              |
+   |              help: missing `,`
+
+error[E0308]: mismatched types
+  --> $DIR/recover-parens-around-match-arm-head.rs:4:9
+   |
+LL |     let x = match val {
+   |                   --- this expression has type `{integer}`
+LL |         (0 if true) => {
+   |         ^^^^^^^^^^^ expected integer, found `(_, _, _)`
+   |
+   = note: expected type `{integer}`
+             found tuple `(_, _, _)`
+
+error[E0308]: mismatched types
+  --> $DIR/recover-parens-around-match-arm-head.rs:13:19
+   |
+LL |     let _y: u32 = x;
+   |             ---   ^ expected `u32`, found `u8`
+   |             |
+   |             expected due to this
+   |
+help: you can convert a `u8` to a `u32`
+   |
+LL |     let _y: u32 = x.into();
+   |                    +++++++
+
+error: aborting due to 5 previous errors
+
+For more information about this error, try `rustc --explain E0308`.

tests/ui/self/self_type_keyword.stderr

@@ -14,7 +14,7 @@ error: `mut` must be followed by a named binding
   --> $DIR/self_type_keyword.rs:16:9
    |
 LL |         mut Self => (),
-   |         ^^^^^^^^ help: remove the `mut` prefix: `Self`
+   |         ^^^^ help: remove the `mut` prefix
    |
    = note: `mut` may be followed by `variable` and `variable @ pattern`
 

tests/ui/structs/struct-path-self-type-mismatch.stderr

@@ -24,7 +24,9 @@ error[E0308]: mismatched types
   --> $DIR/struct-path-self-type-mismatch.rs:13:9
    |
 LL |   impl<T> Foo<T> {
-   |        - found type parameter
+   |        -  ------ this is the type of the `Self` literal
+   |        |
+   |        found type parameter
 LL |       fn new<U>(u: U) -> Foo<U> {
    |              -           ------ expected `Foo<U>` because of return type
    |              |
@@ -40,6 +42,10 @@ LL | |         }
               found struct `Foo<T>`
    = note: a type parameter was expected, but a different one was found; you might be missing a type parameter or trait bound
    = note: for more information, visit https://doc.rust-lang.org/book/ch10-02-traits.html#traits-as-parameters
+help: use the type name directly
+   |
+LL |         Foo::<U> {
+   |         ~~~~~~~~
 
 error: aborting due to 3 previous errors