Auto merge of #104102 - Dylan-DPC:rollup-0eakshe, r=Dylan-DPC

Rollup of 6 pull requests

Successful merges:

 - #103757 (Mention const and lifetime parameters in error E0207)
 - #103986 (Don't silently eat label before block in block-like expr)
 - #104003 (Move some tests to more reasonable directories)
 - #104038 (Normalize types when deducing closure signature from supertraits)
 - #104052 (Fix `resolution_failure` ICE)
 - #104090 (Modify comment syntax error)

Failed merges:

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

compiler/rustc_error_codes/src/error_codes/E0207.md

@@ -1,4 +1,5 @@
-A type parameter that is specified for `impl` is not constrained.
+A type, const or lifetime parameter that is specified for `impl` is not
+constrained.
 
 Erroneous code example:
 
@@ -14,8 +15,8 @@ impl<T: Default> Foo {
 }
 ```
 
-Any type parameter of an `impl` must meet at least one of
-the following criteria:
+Any type or const parameter of an `impl` must meet at least one of the
+following criteria:
 
  - it appears in the _implementing type_ of the impl, e.g. `impl<T> Foo<T>`
  - for a trait impl, it appears in the _implemented trait_, e.g.
@@ -23,6 +24,9 @@ the following criteria:
  - it is bound as an associated type, e.g. `impl<T, U> SomeTrait for T
    where T: AnotherTrait<AssocType=U>`
 
+Any unconstrained lifetime parameter of an `impl` is not supported if the
+lifetime parameter is used by an associated type.
+
 ### Error example 1
 
 Suppose we have a struct `Foo` and we would like to define some methods for it.
@@ -32,7 +36,6 @@ The problem is that the parameter `T` does not appear in the implementing type
 (`Foo`) of the impl. In this case, we can fix the error by moving the type
 parameter from the `impl` to the method `get`:
 
-
 ```
 struct Foo;
 
@@ -128,6 +131,70 @@ impl<T: Default> Maker<Foo<T>> for FooMaker {
 }
 ```
 
+### Error example 3
+
+Suppose we have a struct `Foo` and we would like to define some methods for it.
+The following code example has a definition which leads to a compiler error:
+
+```compile_fail,E0207
+struct Foo;
+
+impl<const T: i32> Foo {
+    // error: the const parameter `T` is not constrained by the impl trait, self
+    // type, or predicates [E0207]
+    fn get(&self) -> i32 {
+        i32::default()
+    }
+}
+```
+
+The problem is that the const parameter `T` does not appear in the implementing
+type (`Foo`) of the impl. In this case, we can fix the error by moving the type
+parameter from the `impl` to the method `get`:
+
+
+```
+struct Foo;
+
+// Move the const parameter from the impl to the method
+impl Foo {
+    fn get<const T: i32>(&self) -> i32 {
+        i32::default()
+    }
+}
+```
+
+### Error example 4
+
+Suppose we have a struct `Foo` and a struct `Bar` that uses lifetime `'a`. We
+would like to implement trait `Contains` for `Foo`. The trait `Contains` have
+the associated type `B`. The following code example has a definition which
+leads to a compiler error:
+
+```compile_fail,E0207
+struct Foo;
+struct Bar<'a>;
+
+trait Contains {
+    type B;
+
+    fn get(&self) -> i32;
+}
+
+impl<'a> Contains for Foo {
+    type B = Bar<'a>;
+
+    // error: the lifetime parameter `'a` is not constrained by the impl trait,
+    // self type, or predicates [E0207]
+    fn get(&self) -> i32 {
+        i32::default()
+    }
+}
+```
+
+Please note that unconstrained lifetime parameters are not supported if they are
+being used by an associated type.
+
 ### Additional information
 
 For more information, please see [RFC 447].

compiler/rustc_hir_typeck/src/closure.rs

@@ -10,6 +10,7 @@ use rustc_hir_analysis::astconv::AstConv;
 use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
 use rustc_infer::infer::LateBoundRegionConversionTime;
 use rustc_infer::infer::{InferOk, InferResult};
+use rustc_macros::{TypeFoldable, TypeVisitable};
 use rustc_middle::ty::subst::InternalSubsts;
 use rustc_middle::ty::visit::TypeVisitable;
 use rustc_middle::ty::{self, Ty};
@@ -22,7 +23,7 @@ use std::cmp;
 use std::iter;
 
 /// What signature do we *expect* the closure to have from context?
-#[derive(Debug)]
+#[derive(Debug, Clone, TypeFoldable, TypeVisitable)]
 struct ExpectedSig<'tcx> {
     /// Span that gave us this expectation, if we know that.
     cause_span: Option<Span>,
@@ -241,9 +242,12 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             if expected_sig.is_none()
                 && let ty::PredicateKind::Projection(proj_predicate) = bound_predicate.skip_binder()
             {
-                expected_sig = self.deduce_sig_from_projection(
+                expected_sig = self.normalize_associated_types_in(
+                    obligation.cause.span,
+                    self.deduce_sig_from_projection(
                     Some(obligation.cause.span),
                         bound_predicate.rebind(proj_predicate),
+                    ),
                 );
             }
 

compiler/rustc_macros/src/diagnostics/error.rs

@@ -84,7 +84,7 @@ pub(crate) fn invalid_attr(attr: &Attribute, meta: &Meta) -> Diagnostic {
     }
 }
 
-/// Emit a error diagnostic for an invalid attribute (optionally performing additional decoration
+/// Emit an error diagnostic for an invalid attribute (optionally performing additional decoration
 /// using the `FnOnce` passed in `diag`) and return `Err(ErrorHandled)`.
 ///
 /// For methods that return a `Result<_, DiagnosticDeriveError>`:
@@ -126,7 +126,7 @@ pub(crate) fn invalid_nested_attr(attr: &Attribute, nested: &NestedMeta) -> Diag
     }
 }
 
-/// Emit a error diagnostic for an invalid nested attribute (optionally performing additional
+/// Emit an error diagnostic for an invalid nested attribute (optionally performing additional
 /// decoration using the `FnOnce` passed in `diag`) and return `Err(ErrorHandled)`.
 ///
 /// For methods that return a `Result<_, DiagnosticDeriveError>`:

compiler/rustc_parse/src/parser/diagnostics.rs

@@ -2468,11 +2468,15 @@ impl<'a> Parser<'a> {
     }
 
     pub(crate) fn maybe_recover_unexpected_block_label(&mut self) -> bool {
-        let Some(label) = self.eat_label().filter(|_| {
-            self.eat(&token::Colon) && self.token.kind == token::OpenDelim(Delimiter::Brace)
-        }) else {
+        // Check for `'a : {`
+        if !(self.check_lifetime()
+            && self.look_ahead(1, |tok| tok.kind == token::Colon)
+            && self.look_ahead(2, |tok| tok.kind == token::OpenDelim(Delimiter::Brace)))
+        {
             return false;
-        };
+        }
+        let label = self.eat_label().expect("just checked if a label exists");
+        self.bump(); // eat `:`
         let span = label.ident.span.to(self.prev_token.span);
         let mut err = self.struct_span_err(span, "block label not supported here");
         err.span_label(span, "not supported here");

library/alloc/src/collections/mod.rs

@@ -139,7 +139,7 @@ impl Display for TryReserveError {
                 " because the computed capacity exceeded the collection's maximum"
             }
             TryReserveErrorKind::AllocError { .. } => {
-                " because the memory allocator returned a error"
+                " because the memory allocator returned an error"
             }
         };
         fmt.write_str(reason)

src/librustdoc/passes/collect_intra_doc_links.rs

@@ -402,6 +402,7 @@ impl<'a, 'tcx> LinkCollector<'a, 'tcx> {
             })
             .and_then(|self_id| match tcx.def_kind(self_id) {
                 DefKind::Impl => self.def_id_to_res(self_id),
+                DefKind::Use => None,
                 def_kind => Some(Res::Def(def_kind, self_id)),
             })
     }
@@ -1772,7 +1773,6 @@ fn resolution_failure(
 
                     // Otherwise, it must be an associated item or variant
                     let res = partial_res.expect("None case was handled by `last_found_module`");
-                    let name = res.name(tcx);
                     let kind = match res {
                         Res::Def(kind, _) => Some(kind),
                         Res::Primitive(_) => None,
@@ -1814,6 +1814,7 @@ fn resolution_failure(
                     } else {
                         "associated item"
                     };
+                    let name = res.name(tcx);
                     let note = format!(
                         "the {} `{}` has no {} named `{}`",
                         res.descr(),

src/test/rustdoc-ui/issue-103997.rs

@@ -0,0 +1,6 @@
+// check-pass
+
+pub fn foo() {}
+
+/// [`foo`](Self::foo) //~ WARNING unresolved link to `Self::foo`
+pub use foo as bar;

src/test/rustdoc-ui/issue-103997.stderr

@@ -0,0 +1,10 @@
+warning: unresolved link to `Self::foo`
+  --> $DIR/issue-103997.rs:5:13
+   |
+LL | /// [`foo`](Self::foo)
+   |             ^^^^^^^^^ no item named `Self` in scope
+   |
+   = note: `#[warn(rustdoc::broken_intra_doc_links)]` on by default
+
+warning: 1 warning emitted
+

src/test/ui/closures/supertrait-hint-references-assoc-ty.rs

@@ -0,0 +1,17 @@
+// check-pass
+
+pub trait Fn0: Fn(i32) -> Self::Out {
+    type Out;
+}
+
+impl<F: Fn(i32) -> ()> Fn0 for F {
+    type Out = ();
+}
+
+pub fn closure_typer(_: impl Fn0) {}
+
+fn main() {
+    closure_typer(move |x| {
+        let _: i64 = x.into();
+    });
+}

src/test/ui/conditional-compilation/cfg_accessible-not_sure.rs

@@ -46,7 +46,7 @@ const C: bool = true;
 trait Trait {}
 impl dyn Trait { fn existing() {} }
 
-// FIXME: Should be a error for edition > 2015
+// FIXME: Should be an error for edition > 2015
 #[cfg_accessible(Trait::existing)] //~ ERROR not sure
 const A: bool = true;
 #[cfg_accessible(Trait::unresolved)] //~ ERROR not sure

src/test/ui/parser/label-after-block-like.rs

@@ -0,0 +1,43 @@
+fn a() {
+    if let () = () 'a {}
+    //~^ ERROR labeled expression must be followed by `:`
+    //~| ERROR expected `{`, found `'a`
+}
+
+fn b() {
+    if true 'a {}
+    //~^ ERROR labeled expression must be followed by `:`
+    //~| ERROR expected `{`, found `'a`
+}
+
+fn c() {
+    loop 'a {}
+    //~^ ERROR labeled expression must be followed by `:`
+    //~| ERROR expected `{`, found `'a`
+}
+
+fn d() {
+    while true 'a {}
+    //~^ ERROR labeled expression must be followed by `:`
+    //~| ERROR expected `{`, found `'a`
+}
+
+fn e() {
+    while let () = () 'a {}
+    //~^ ERROR labeled expression must be followed by `:`
+    //~| ERROR expected `{`, found `'a`
+}
+
+fn f() {
+    for _ in 0..0 'a {}
+    //~^ ERROR labeled expression must be followed by `:`
+    //~| ERROR expected `{`, found `'a`
+}
+
+fn g() {
+    unsafe 'a {}
+    //~^ ERROR labeled expression must be followed by `:`
+    //~| ERROR expected `{`, found `'a`
+}
+
+fn main() {}

src/test/ui/parser/label-after-block-like.stderr

@@ -0,0 +1,176 @@
+error: labeled expression must be followed by `:`
+  --> $DIR/label-after-block-like.rs:2:20
+   |
+LL |     if let () = () 'a {}
+   |                    ---^^
+   |                    | |
+   |                    | help: add `:` after the label
+   |                    the label
+   |
+   = note: labels are used before loops and blocks, allowing e.g., `break 'label` to them
+
+error: expected `{`, found `'a`
+  --> $DIR/label-after-block-like.rs:2:20
+   |
+LL |     if let () = () 'a {}
+   |                    ^^ expected `{`
+   |
+note: the `if` expression is missing a block after this condition
+  --> $DIR/label-after-block-like.rs:2:8
+   |
+LL |     if let () = () 'a {}
+   |        ^^^^^^^^^^^
+help: try placing this code inside a block
+   |
+LL |     if let () = () { 'a {} }
+   |                    +       +
+
+error: labeled expression must be followed by `:`
+  --> $DIR/label-after-block-like.rs:8:13
+   |
+LL |     if true 'a {}
+   |             ---^^
+   |             | |
+   |             | help: add `:` after the label
+   |             the label
+   |
+   = note: labels are used before loops and blocks, allowing e.g., `break 'label` to them
+
+error: expected `{`, found `'a`
+  --> $DIR/label-after-block-like.rs:8:13
+   |
+LL |     if true 'a {}
+   |             ^^ expected `{`
+   |
+note: the `if` expression is missing a block after this condition
+  --> $DIR/label-after-block-like.rs:8:8
+   |
+LL |     if true 'a {}
+   |        ^^^^
+help: try placing this code inside a block
+   |
+LL |     if true { 'a {} }
+   |             +       +
+
+error: labeled expression must be followed by `:`
+  --> $DIR/label-after-block-like.rs:14:10
+   |
+LL |     loop 'a {}
+   |          ---^^
+   |          | |
+   |          | help: add `:` after the label
+   |          the label
+   |
+   = note: labels are used before loops and blocks, allowing e.g., `break 'label` to them
+
+error: expected `{`, found `'a`
+  --> $DIR/label-after-block-like.rs:14:10
+   |
+LL |     loop 'a {}
+   |     ---- ^^ expected `{`
+   |     |
+   |     while parsing this `loop` expression
+   |
+help: try placing this code inside a block
+   |
+LL |     loop { 'a {} }
+   |          +       +
+
+error: labeled expression must be followed by `:`
+  --> $DIR/label-after-block-like.rs:20:16
+   |
+LL |     while true 'a {}
+   |                ---^^
+   |                | |
+   |                | help: add `:` after the label
+   |                the label
+   |
+   = note: labels are used before loops and blocks, allowing e.g., `break 'label` to them
+
+error: expected `{`, found `'a`
+  --> $DIR/label-after-block-like.rs:20:16
+   |
+LL |     while true 'a {}
+   |     ----- ---- ^^ expected `{`
+   |     |     |
+   |     |     this `while` condition successfully parsed
+   |     while parsing the body of this `while` expression
+   |
+help: try placing this code inside a block
+   |
+LL |     while true { 'a {} }
+   |                +       +
+
+error: labeled expression must be followed by `:`
+  --> $DIR/label-after-block-like.rs:26:23
+   |
+LL |     while let () = () 'a {}
+   |                       ---^^
+   |                       | |
+   |                       | help: add `:` after the label
+   |                       the label
+   |
+   = note: labels are used before loops and blocks, allowing e.g., `break 'label` to them
+
+error: expected `{`, found `'a`
+  --> $DIR/label-after-block-like.rs:26:23
+   |
+LL |     while let () = () 'a {}
+   |     ----- ----------- ^^ expected `{`
+   |     |     |
+   |     |     this `while` condition successfully parsed
+   |     while parsing the body of this `while` expression
+   |
+help: try placing this code inside a block
+   |
+LL |     while let () = () { 'a {} }
+   |                       +       +
+
+error: labeled expression must be followed by `:`
+  --> $DIR/label-after-block-like.rs:32:19
+   |
+LL |     for _ in 0..0 'a {}
+   |                   ---^^
+   |                   | |
+   |                   | help: add `:` after the label
+   |                   the label
+   |
+   = note: labels are used before loops and blocks, allowing e.g., `break 'label` to them
+
+error: expected `{`, found `'a`
+  --> $DIR/label-after-block-like.rs:32:19
+   |
+LL |     for _ in 0..0 'a {}
+   |                   ^^ expected `{`
+   |
+help: try placing this code inside a block
+   |
+LL |     for _ in 0..0 { 'a {} }
+   |                   +       +
+
+error: labeled expression must be followed by `:`
+  --> $DIR/label-after-block-like.rs:38:12
+   |
+LL |     unsafe 'a {}
+   |            ---^^
+   |            | |
+   |            | help: add `:` after the label
+   |            the label
+   |
+   = note: labels are used before loops and blocks, allowing e.g., `break 'label` to them
+
+error: expected `{`, found `'a`
+  --> $DIR/label-after-block-like.rs:38:12
+   |
+LL |     unsafe 'a {}
+   |     ------ ^^ expected `{`
+   |     |
+   |     while parsing this `unsafe` expression
+   |
+help: try placing this code inside a block
+   |
+LL |     unsafe { 'a {} }
+   |            +       +
+
+error: aborting due to 14 previous errors
+

src/tools/tidy/src/ui_tests.rs

@@ -9,8 +9,8 @@ use std::path::Path;
 
 const ENTRY_LIMIT: usize = 1000;
 // FIXME: The following limits should be reduced eventually.
-const ROOT_ENTRY_LIMIT: usize = 941;
-const ISSUES_ENTRY_LIMIT: usize = 2117;
+const ROOT_ENTRY_LIMIT: usize = 939;
+const ISSUES_ENTRY_LIMIT: usize = 2105;
 
 fn check_entries(path: &Path, bad: &mut bool) {
     for dir in Walk::new(&path.join("test/ui")) {