diff options
6 files changed, 137 insertions, 14 deletions
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs index 30ff07ee6c3..da6244acb31 100644 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs @@ -1234,6 +1234,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { _ => None, }; + let found_node = found_did.and_then(|did| self.tcx.hir().get_if_local(did)); let found_span = found_did.and_then(|did| self.tcx.hir().span_if_local(did)); if self.reported_closure_mismatch.borrow().contains(&(span, found_span)) { @@ -1287,6 +1288,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { found_trait_ref, expected_trait_ref, obligation.cause.code(), + found_node, ) } else { let (closure_span, closure_arg_span, found) = found_did diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs index 40c81025471..6f79ca078d7 100644 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs @@ -1,4 +1,5 @@ // ignore-tidy-filelength + use super::{DefIdOrName, Obligation, ObligationCause, ObligationCauseCode, PredicateObligation}; use crate::autoderef::Autoderef; @@ -258,6 +259,7 @@ pub trait TypeErrCtxtExt<'tcx> { found: ty::PolyTraitRef<'tcx>, expected: ty::PolyTraitRef<'tcx>, cause: &ObligationCauseCode<'tcx>, + found_node: Option<Node<'_>>, ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed>; fn note_conflicting_closure_bounds( @@ -1695,6 +1697,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { found: ty::PolyTraitRef<'tcx>, expected: ty::PolyTraitRef<'tcx>, cause: &ObligationCauseCode<'tcx>, + found_node: Option<Node<'_>>, ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> { pub(crate) fn build_fn_sig_ty<'tcx>( infcx: &InferCtxt<'tcx>, @@ -1756,6 +1759,10 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { self.note_conflicting_closure_bounds(cause, &mut err); + if let Some(found_node) = found_node { + hint_missing_borrow(span, found_span, found, expected, found_node, &mut err); + } + err } @@ -3384,6 +3391,78 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { } } +/// Add a hint to add a missing borrow or remove an unnecessary one. +fn hint_missing_borrow<'tcx>( + span: Span, + found_span: Span, + found: Ty<'tcx>, + expected: Ty<'tcx>, + found_node: Node<'_>, + err: &mut Diagnostic, +) { + let found_args = match found.kind() { + ty::FnPtr(f) => f.inputs().skip_binder().iter(), + kind => { + span_bug!(span, "found was converted to a FnPtr above but is now {:?}", kind) + } + }; + let expected_args = match expected.kind() { + ty::FnPtr(f) => f.inputs().skip_binder().iter(), + kind => { + span_bug!(span, "expected was converted to a FnPtr above but is now {:?}", kind) + } + }; + + let fn_decl = found_node + .fn_decl() + .unwrap_or_else(|| span_bug!(found_span, "found node must be a function")); + + let arg_spans = fn_decl.inputs.iter().map(|ty| ty.span); + + fn get_deref_type_and_refs<'tcx>(mut ty: Ty<'tcx>) -> (Ty<'tcx>, usize) { + let mut refs = 0; + + while let ty::Ref(_, new_ty, _) = ty.kind() { + ty = *new_ty; + refs += 1; + } + + (ty, refs) + } + + let mut to_borrow = Vec::new(); + let mut remove_borrow = Vec::new(); + + for ((found_arg, expected_arg), arg_span) in found_args.zip(expected_args).zip(arg_spans) { + let (found_ty, found_refs) = get_deref_type_and_refs(*found_arg); + let (expected_ty, expected_refs) = get_deref_type_and_refs(*expected_arg); + + if found_ty == expected_ty { + if found_refs < expected_refs { + to_borrow.push((arg_span, expected_arg.to_string())); + } else if found_refs > expected_refs { + remove_borrow.push((arg_span, expected_arg.to_string())); + } + } + } + + if !to_borrow.is_empty() { + err.multipart_suggestion( + "consider borrowing the argument", + to_borrow, + Applicability::MaybeIncorrect, + ); + } + + if !remove_borrow.is_empty() { + err.multipart_suggestion( + "do not borrow the argument", + remove_borrow, + Applicability::MaybeIncorrect, + ); + } +} + /// Collect all the returned expressions within the input expression. /// Used to point at the return spans when we want to suggest some change to them. #[derive(Default)] diff --git a/src/test/ui/anonymous-higher-ranked-lifetime.stderr b/src/test/ui/anonymous-higher-ranked-lifetime.stderr index bf5f642ca82..afb7f8fea92 100644 --- a/src/test/ui/anonymous-higher-ranked-lifetime.stderr +++ b/src/test/ui/anonymous-higher-ranked-lifetime.stderr @@ -13,6 +13,10 @@ note: required by a bound in `f1` | LL | fn f1<F>(_: F) where F: Fn(&(), &()) {} | ^^^^^^^^^^^^ required by this bound in `f1` +help: consider borrowing the argument + | +LL | f1(|_: &(), _: &()| {}); + | ~~~ ~~~ error[E0631]: type mismatch in closure arguments --> $DIR/anonymous-higher-ranked-lifetime.rs:3:5 @@ -29,6 +33,10 @@ note: required by a bound in `f2` | LL | fn f2<F>(_: F) where F: for<'a> Fn(&'a (), &()) {} | ^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `f2` +help: consider borrowing the argument + | +LL | f2(|_: &'a (), _: &()| {}); + | ~~~~~~ ~~~ error[E0631]: type mismatch in closure arguments --> $DIR/anonymous-higher-ranked-lifetime.rs:4:5 @@ -45,6 +53,10 @@ note: required by a bound in `f3` | LL | fn f3<'a, F>(_: F) where F: Fn(&'a (), &()) {} | ^^^^^^^^^^^^^^^ required by this bound in `f3` +help: consider borrowing the argument + | +LL | f3(|_: &(), _: &()| {}); + | ~~~ ~~~ error[E0631]: type mismatch in closure arguments --> $DIR/anonymous-higher-ranked-lifetime.rs:5:5 @@ -61,6 +73,10 @@ note: required by a bound in `f4` | LL | fn f4<F>(_: F) where F: for<'r> Fn(&(), &'r ()) {} | ^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `f4` +help: consider borrowing the argument + | +LL | f4(|_: &(), _: &'r ()| {}); + | ~~~ ~~~~~~ error[E0631]: type mismatch in closure arguments --> $DIR/anonymous-higher-ranked-lifetime.rs:6:5 @@ -77,13 +93,19 @@ note: required by a bound in `f5` | LL | fn f5<F>(_: F) where F: for<'r> Fn(&'r (), &'r ()) {} | ^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `f5` +help: consider borrowing the argument + | +LL | f5(|_: &'r (), _: &'r ()| {}); + | ~~~~~~ ~~~~~~ error[E0631]: type mismatch in closure arguments --> $DIR/anonymous-higher-ranked-lifetime.rs:7:5 | LL | g1(|_: (), _: ()| {}); - | ^^ -------------- found signature defined here - | | + | ^^ -------------- + | | | | + | | | help: consider borrowing the argument: `&()` + | | found signature defined here | expected due to this | = note: expected closure signature `for<'a> fn(&'a (), Box<(dyn for<'a> Fn(&'a ()) + 'static)>) -> _` @@ -98,8 +120,10 @@ error[E0631]: type mismatch in closure arguments --> $DIR/anonymous-higher-ranked-lifetime.rs:8:5 | LL | g2(|_: (), _: ()| {}); - | ^^ -------------- found signature defined here - | | + | ^^ -------------- + | | | | + | | | help: consider borrowing the argument: `&()` + | | found signature defined here | expected due to this | = note: expected closure signature `for<'a> fn(&'a (), for<'a> fn(&'a ())) -> _` @@ -114,8 +138,10 @@ error[E0631]: type mismatch in closure arguments --> $DIR/anonymous-higher-ranked-lifetime.rs:9:5 | LL | g3(|_: (), _: ()| {}); - | ^^ -------------- found signature defined here - | | + | ^^ -------------- + | | | | + | | | help: consider borrowing the argument: `&'s ()` + | | found signature defined here | expected due to this | = note: expected closure signature `for<'s> fn(&'s (), Box<(dyn for<'a> Fn(&'a ()) + 'static)>) -> _` @@ -130,8 +156,10 @@ error[E0631]: type mismatch in closure arguments --> $DIR/anonymous-higher-ranked-lifetime.rs:10:5 | LL | g4(|_: (), _: ()| {}); - | ^^ -------------- found signature defined here - | | + | ^^ -------------- + | | | | + | | | help: consider borrowing the argument: `&()` + | | found signature defined here | expected due to this | = note: expected closure signature `for<'a> fn(&'a (), for<'r> fn(&'r ())) -> _` @@ -157,6 +185,10 @@ note: required by a bound in `h1` | LL | fn h1<F>(_: F) where F: Fn(&(), Box<dyn Fn(&())>, &(), fn(&(), &())) {} | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `h1` +help: consider borrowing the argument + | +LL | h1(|_: &(), _: (), _: &(), _: ()| {}); + | ~~~ ~~~ error[E0631]: type mismatch in closure arguments --> $DIR/anonymous-higher-ranked-lifetime.rs:12:5 @@ -173,6 +205,10 @@ note: required by a bound in `h2` | LL | fn h2<F>(_: F) where F: for<'t0> Fn(&(), Box<dyn Fn(&())>, &'t0 (), fn(&(), &())) {} | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `h2` +help: consider borrowing the argument + | +LL | h2(|_: &(), _: (), _: &'t0 (), _: ()| {}); + | ~~~ ~~~~~~~ error: aborting due to 11 previous errors diff --git a/src/test/ui/closures/multiple-fn-bounds.stderr b/src/test/ui/closures/multiple-fn-bounds.stderr index eefc123fed7..da26302c9d8 100644 --- a/src/test/ui/closures/multiple-fn-bounds.stderr +++ b/src/test/ui/closures/multiple-fn-bounds.stderr @@ -2,8 +2,10 @@ error[E0631]: type mismatch in closure arguments --> $DIR/multiple-fn-bounds.rs:10:5 | LL | foo(move |x| v); - | ^^^ -------- found signature defined here - | | + | ^^^ -------- + | | | | + | | | help: do not borrow the argument: `char` + | | found signature defined here | expected due to this | = note: expected closure signature `fn(char) -> _` diff --git a/src/test/ui/mismatched_types/closure-arg-type-mismatch.stderr b/src/test/ui/mismatched_types/closure-arg-type-mismatch.stderr index f2e2a4c7fd5..961ef32cbd3 100644 --- a/src/test/ui/mismatched_types/closure-arg-type-mismatch.stderr +++ b/src/test/ui/mismatched_types/closure-arg-type-mismatch.stderr @@ -2,8 +2,10 @@ error[E0631]: type mismatch in closure arguments --> $DIR/closure-arg-type-mismatch.rs:3:14 | LL | a.iter().map(|_: (u32, u32)| 45); - | ^^^ --------------- found signature defined here - | | + | ^^^ --------------- + | | | | + | | | help: consider borrowing the argument: `&(u32, u32)` + | | found signature defined here | expected due to this | = note: expected closure signature `fn(&(u32, u32)) -> _` diff --git a/src/test/ui/mismatched_types/issue-36053-2.stderr b/src/test/ui/mismatched_types/issue-36053-2.stderr index b3509abbf84..1a696752e87 100644 --- a/src/test/ui/mismatched_types/issue-36053-2.stderr +++ b/src/test/ui/mismatched_types/issue-36053-2.stderr @@ -2,8 +2,10 @@ error[E0631]: type mismatch in closure arguments --> $DIR/issue-36053-2.rs:7:32 | LL | once::<&str>("str").fuse().filter(|a: &str| true).count(); - | ^^^^^^ --------- found signature defined here - | | + | ^^^^^^ --------- + | | | | + | | | help: consider borrowing the argument: `&&str` + | | found signature defined here | expected due to this | = note: expected closure signature `for<'a> fn(&'a &str) -> _` |