Auto merge of rust-lang#106034 - matthiaskrgr:rollup-2zpql33, r=matth…

…iaskrgr

Rollup of 8 pull requests

Successful merges:

 - rust-lang#104741 (Switch `#[track_caller]` back to a no-op unless feature gate is enabled)
 - rust-lang#105769 (add function to tell the identical errors for ambiguity_errors)
 - rust-lang#105843 (Suggest associated const on possible capitalization mistake)
 - rust-lang#105966 (Re-enable `Fn` trait call notation error for non-tuple argument)
 - rust-lang#106002 (codegen tests: adapt patterns to also work with v0 symbol mangling)
 - rust-lang#106010 (Give opaque types a better coherence error)
 - rust-lang#106016 (rustdoc: simplify link anchor to section expand JS)
 - rust-lang#106024 (Fix ICE due to `todo!()` in `rustdoc` for `Term`s)

Failed merges:

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

compiler/rustc_ast_lowering/src/expr.rs

@@ -656,18 +656,14 @@ impl<'hir> LoweringContext<'_, 'hir> {
             hir::ExprKind::Closure(c)
         };
 
-        let track_caller = self
-            .attrs
-            .get(&outer_hir_id.local_id)
-            .map_or(false, |attrs| attrs.into_iter().any(|attr| attr.has_name(sym::track_caller)));
-
         let hir_id = self.lower_node_id(closure_node_id);
-        if track_caller {
-            let unstable_span = self.mark_span_with_reason(
-                DesugaringKind::Async,
-                span,
-                self.allow_gen_future.clone(),
-            );
+        let unstable_span =
+            self.mark_span_with_reason(DesugaringKind::Async, span, self.allow_gen_future.clone());
+
+        if self.tcx.features().closure_track_caller
+            && let Some(attrs) = self.attrs.get(&outer_hir_id.local_id)
+            && attrs.into_iter().any(|attr| attr.has_name(sym::track_caller))
+        {
             self.lower_attrs(
                 hir_id,
                 &[Attribute {

compiler/rustc_error_messages/locales/en-US/lint.ftl

@@ -350,6 +350,9 @@ lint_builtin_mutable_transmutes =
 
 lint_builtin_unstable_features = unstable feature
 
+lint_ungated_async_fn_track_caller = `#[track_caller]` on async functions is a no-op
+     .label = this function will not propagate the caller location
+
 lint_builtin_unreachable_pub = unreachable `pub` {$what}
     .suggestion = consider restricting its visibility
     .help = or consider exporting it for use by other crates

compiler/rustc_hir_analysis/src/coherence/orphan.rs

@@ -184,11 +184,19 @@ fn emit_orphan_check_error<'tcx>(
                     ty::Adt(def, _) => tcx.mk_adt(*def, ty::List::empty()),
                     _ => ty,
                 };
-                let this = "this".to_string();
-                let (ty, postfix) = match &ty.kind() {
-                    ty::Slice(_) => (this, " because slices are always foreign"),
-                    ty::Array(..) => (this, " because arrays are always foreign"),
-                    ty::Tuple(..) => (this, " because tuples are always foreign"),
+                let msg = |ty: &str, postfix: &str| {
+                    format!("{ty} is not defined in the current crate{postfix}")
+                };
+                let this = |name: &str| msg("this", &format!(" because {name} are always foreign"));
+                let msg = match &ty.kind() {
+                    ty::Slice(_) => this("slices"),
+                    ty::Array(..) => this("arrays"),
+                    ty::Tuple(..) => this("tuples"),
+                    ty::Alias(ty::Opaque, ..) => {
+                        "type alias impl trait is treated as if it were foreign, \
+                        because its hidden type could be from a foreign crate"
+                            .to_string()
+                    }
                     ty::RawPtr(ptr_ty) => {
                         emit_newtype_suggestion_for_raw_ptr(
                             full_impl_span,
@@ -198,12 +206,11 @@ fn emit_orphan_check_error<'tcx>(
                             &mut err,
                         );
 
-                        (format!("`{}`", ty), " because raw pointers are always foreign")
+                        msg(&format!("`{ty}`"), " because raw pointers are always foreign")
                     }
-                    _ => (format!("`{}`", ty), ""),
+                    _ => msg(&format!("`{ty}`"), ""),
                 };
 
-                let msg = format!("{} is not defined in the current crate{}", ty, postfix);
                 if is_target_ty {
                     // Point at `D<A>` in `impl<A, B> for C<B> in D<A>`
                     err.span_label(self_ty_span, &msg);

compiler/rustc_hir_typeck/src/demand.rs

@@ -23,24 +23,24 @@ use std::cmp::min;
 use std::iter;
 
 impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
-    pub fn emit_coerce_suggestions(
+    pub fn emit_type_mismatch_suggestions(
         &self,
         err: &mut Diagnostic,
         expr: &hir::Expr<'tcx>,
         expr_ty: Ty<'tcx>,
         expected: Ty<'tcx>,
         expected_ty_expr: Option<&'tcx hir::Expr<'tcx>>,
-        error: Option<TypeError<'tcx>>,
+        _error: Option<TypeError<'tcx>>,
     ) {
         if expr_ty == expected {
             return;
         }
 
-        self.annotate_expected_due_to_let_ty(err, expr, error);
-
         // Use `||` to give these suggestions a precedence
         let _ = self.suggest_missing_parentheses(err, expr)
+            || self.suggest_associated_const(err, expr, expected)
             || self.suggest_deref_ref_or_into(err, expr, expected, expr_ty, expected_ty_expr)
+            || self.suggest_option_to_bool(err, expr, expr_ty, expected)
             || self.suggest_compatible_variants(err, expr, expected, expr_ty)
             || self.suggest_non_zero_new_unwrap(err, expr, expected, expr_ty)
             || self.suggest_calling_boxed_future_when_appropriate(err, expr, expected, expr_ty)
@@ -49,9 +49,24 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             || self.suggest_block_to_brackets_peeling_refs(err, expr, expr_ty, expected)
             || self.suggest_copied_or_cloned(err, expr, expr_ty, expected)
             || self.suggest_into(err, expr, expr_ty, expected)
-            || self.suggest_option_to_bool(err, expr, expr_ty, expected)
             || self.suggest_floating_point_literal(err, expr, expected);
+    }
 
+    pub fn emit_coerce_suggestions(
+        &self,
+        err: &mut Diagnostic,
+        expr: &hir::Expr<'tcx>,
+        expr_ty: Ty<'tcx>,
+        expected: Ty<'tcx>,
+        expected_ty_expr: Option<&'tcx hir::Expr<'tcx>>,
+        error: Option<TypeError<'tcx>>,
+    ) {
+        if expr_ty == expected {
+            return;
+        }
+
+        self.annotate_expected_due_to_let_ty(err, expr, error);
+        self.emit_type_mismatch_suggestions(err, expr, expr_ty, expected, expected_ty_expr, error);
         self.note_type_is_not_clone(err, expected, expr_ty, expr);
         self.note_need_for_fn_pointer(err, expected, expr_ty);
         self.note_internal_mutation_in_method(err, expr, expected, expr_ty);

compiler/rustc_hir_typeck/src/expr.rs

@@ -104,16 +104,14 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
 
         if let Some(mut err) = self.demand_suptype_diag(expr.span, expected_ty, ty) {
-            // FIXME(compiler-errors): We probably should fold some of the
-            // `suggest_` functions from  `emit_coerce_suggestions` into here,
-            // since some of those aren't necessarily just coerce suggestions.
-            let _ = self.suggest_deref_ref_or_into(
+            let _ = self.emit_type_mismatch_suggestions(
                 &mut err,
                 expr.peel_drop_temps(),
-                expected_ty,
                 ty,
+                expected_ty,
                 None,
-            ) || self.suggest_option_to_bool(&mut err, expr, ty, expected_ty);
+                None,
+            );
             extend_err(&mut err);
             err.emit();
         }

compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs

@@ -214,7 +214,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         "cannot use call notation; the first type parameter \
                          for the function trait is neither a tuple nor unit"
                     )
-                    .delay_as_bug();
+                    .emit();
                     (self.err_args(provided_args.len()), None)
                 }
             }

compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs

@@ -1,6 +1,7 @@
 use super::FnCtxt;
 
 use crate::errors::{AddReturnTypeSuggestion, ExpectedReturnTypeLabel};
+use crate::method::probe::{IsSuggestion, Mode, ProbeScope};
 use rustc_ast::util::parser::{ExprPrecedence, PREC_POSTFIX};
 use rustc_errors::{Applicability, Diagnostic, MultiSpan};
 use rustc_hir as hir;
@@ -15,10 +16,11 @@ use rustc_infer::traits::{self, StatementAsExpression};
 use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::{
     self, suggest_constraining_type_params, Binder, DefIdTree, IsSuggestable, ToPredicate, Ty,
+    TypeVisitable,
 };
 use rustc_session::errors::ExprParenthesesNeeded;
-use rustc_span::symbol::sym;
-use rustc_span::Span;
+use rustc_span::symbol::{sym, Ident};
+use rustc_span::{Span, Symbol};
 use rustc_trait_selection::infer::InferCtxtExt;
 use rustc_trait_selection::traits::error_reporting::DefIdOrName;
 use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt as _;
@@ -1236,6 +1238,84 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
     }
 
+    pub(crate) fn suggest_associated_const(
+        &self,
+        err: &mut Diagnostic,
+        expr: &hir::Expr<'_>,
+        expected_ty: Ty<'tcx>,
+    ) -> bool {
+        let Some((DefKind::AssocFn, old_def_id)) = self.typeck_results.borrow().type_dependent_def(expr.hir_id) else {
+            return false;
+        };
+        let old_item_name = self.tcx.item_name(old_def_id);
+        let capitalized_name = Symbol::intern(&old_item_name.as_str().to_uppercase());
+        if old_item_name == capitalized_name {
+            return false;
+        }
+        let (item, segment) = match expr.kind {
+            hir::ExprKind::Path(QPath::Resolved(
+                Some(ty),
+                hir::Path { segments: [segment], .. },
+            ))
+            | hir::ExprKind::Path(QPath::TypeRelative(ty, segment)) => {
+                let self_ty = <dyn AstConv<'_>>::ast_ty_to_ty(self, ty);
+                if let Ok(pick) = self.probe_for_name(
+                    Mode::Path,
+                    Ident::new(capitalized_name, segment.ident.span),
+                    IsSuggestion(true),
+                    self_ty,
+                    expr.hir_id,
+                    ProbeScope::TraitsInScope,
+                ) {
+                    (pick.item, segment)
+                } else {
+                    return false;
+                }
+            }
+            hir::ExprKind::Path(QPath::Resolved(
+                None,
+                hir::Path { segments: [.., segment], .. },
+            )) => {
+                // we resolved through some path that doesn't end in the item name,
+                // better not do a bad suggestion by accident.
+                if old_item_name != segment.ident.name {
+                    return false;
+                }
+                if let Some(item) = self
+                    .tcx
+                    .associated_items(self.tcx.parent(old_def_id))
+                    .filter_by_name_unhygienic(capitalized_name)
+                    .next()
+                {
+                    (*item, segment)
+                } else {
+                    return false;
+                }
+            }
+            _ => return false,
+        };
+        if item.def_id == old_def_id || self.tcx.def_kind(item.def_id) != DefKind::AssocConst {
+            // Same item
+            return false;
+        }
+        let item_ty = self.tcx.type_of(item.def_id);
+        // FIXME(compiler-errors): This check is *so* rudimentary
+        if item_ty.needs_subst() {
+            return false;
+        }
+        if self.can_coerce(item_ty, expected_ty) {
+            err.span_suggestion_verbose(
+                segment.ident.span,
+                format!("try referring to the associated const `{capitalized_name}` instead",),
+                capitalized_name,
+                Applicability::MachineApplicable,
+            );
+            true
+        } else {
+            false
+        }
+    }
+
     fn is_loop(&self, id: hir::HirId) -> bool {
         let node = self.tcx.hir().get(id);
         matches!(node, Node::Expr(Expr { kind: ExprKind::Loop(..), .. }))

compiler/rustc_lint/src/builtin.rs

@@ -25,6 +25,7 @@ use crate::{
     types::{transparent_newtype_field, CItemKind},
     EarlyContext, EarlyLintPass, LateContext, LateLintPass, LintContext,
 };
+use hir::IsAsync;
 use rustc_ast::attr;
 use rustc_ast::tokenstream::{TokenStream, TokenTree};
 use rustc_ast::visit::{FnCtxt, FnKind};
@@ -40,7 +41,10 @@ use rustc_feature::{deprecated_attributes, AttributeGate, BuiltinAttribute, Gate
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::def_id::{DefId, LocalDefId, LocalDefIdSet, CRATE_DEF_ID};
-use rustc_hir::{ForeignItemKind, GenericParamKind, HirId, Node, PatKind, PredicateOrigin};
+use rustc_hir::intravisit::FnKind as HirFnKind;
+use rustc_hir::{
+    Body, FnDecl, ForeignItemKind, GenericParamKind, HirId, Node, PatKind, PredicateOrigin,
+};
 use rustc_index::vec::Idx;
 use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::layout::{LayoutError, LayoutOf};
@@ -1370,6 +1374,72 @@ impl<'tcx> LateLintPass<'tcx> for UnstableFeatures {
     }
 }
 
+declare_lint! {
+    /// The `ungated_async_fn_track_caller` lint warns when the
+    /// `#[track_caller]` attribute is used on an async function, method, or
+    /// closure, without enabling the corresponding unstable feature flag.
+    ///
+    /// ### Example
+    ///
+    /// ```rust
+    /// #[track_caller]
+    /// async fn foo() {}
+    /// ```
+    ///
+    /// {{produces}}
+    ///
+    /// ### Explanation
+    ///
+    /// The attribute must be used in conjunction with the
+    /// [`closure_track_caller` feature flag]. Otherwise, the `#[track_caller]`
+    /// annotation will function as as no-op.
+    ///
+    /// [`closure_track_caller` feature flag]: https://doc.rust-lang.org/beta/unstable-book/language-features/closure-track-caller.html
+    UNGATED_ASYNC_FN_TRACK_CALLER,
+    Warn,
+    "enabling track_caller on an async fn is a no-op unless the closure_track_caller feature is enabled"
+}
+
+declare_lint_pass!(
+    /// Explains corresponding feature flag must be enabled for the `#[track_caller] attribute to
+    /// do anything
+    UngatedAsyncFnTrackCaller => [UNGATED_ASYNC_FN_TRACK_CALLER]
+);
+
+impl<'tcx> LateLintPass<'tcx> for UngatedAsyncFnTrackCaller {
+    fn check_fn(
+        &mut self,
+        cx: &LateContext<'_>,
+        fn_kind: HirFnKind<'_>,
+        _: &'tcx FnDecl<'_>,
+        _: &'tcx Body<'_>,
+        span: Span,
+        hir_id: HirId,
+    ) {
+        if fn_kind.asyncness() == IsAsync::Async
+            && !cx.tcx.features().closure_track_caller
+            && let attrs = cx.tcx.hir().attrs(hir_id)
+            // Now, check if the function has the `#[track_caller]` attribute
+            && let Some(attr) = attrs.iter().find(|attr| attr.has_name(sym::track_caller))
+            {
+                cx.struct_span_lint(
+                    UNGATED_ASYNC_FN_TRACK_CALLER,
+                    attr.span,
+                    fluent::lint_ungated_async_fn_track_caller,
+                    |lint| {
+                        lint.span_label(span, fluent::label);
+                        rustc_session::parse::add_feature_diagnostics(
+                            lint,
+                            &cx.tcx.sess.parse_sess,
+                            sym::closure_track_caller,
+                        );
+                        lint
+                    },
+                );
+            }
+    }
+}
+
 declare_lint! {
     /// The `unreachable_pub` lint triggers for `pub` items not reachable from
     /// the crate root.

compiler/rustc_lint/src/lib.rs

@@ -219,6 +219,7 @@ late_lint_methods!(
             // May Depend on constants elsewhere
             UnusedBrokenConst: UnusedBrokenConst,
             UnstableFeatures: UnstableFeatures,
+            UngatedAsyncFnTrackCaller: UngatedAsyncFnTrackCaller,
             ArrayIntoIter: ArrayIntoIter::default(),
             DropTraitConstraints: DropTraitConstraints,
             TemporaryCStringAsPtr: TemporaryCStringAsPtr,