diff --git a/compiler/rustc_infer/src/infer/error_reporting/mod.rs b/compiler/rustc_infer/src/infer/error_reporting/mod.rs index fcb87a9f32f1e..3c7dac2bfd816 100644 --- a/compiler/rustc_infer/src/infer/error_reporting/mod.rs +++ b/compiler/rustc_infer/src/infer/error_reporting/mod.rs @@ -1750,6 +1750,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> { if let Some(ValuePairs::PolyTraitRefs(exp_found)) = values && let ty::Closure(def_id, _) = exp_found.expected.skip_binder().self_ty().kind() && let Some(def_id) = def_id.as_local() + && terr.involves_regions() { let span = self.tcx.def_span(def_id); diag.span_note(span, "this closure does not fulfill the lifetime requirements"); diff --git a/compiler/rustc_infer/src/infer/mod.rs b/compiler/rustc_infer/src/infer/mod.rs index 1e26e7bb86ef0..444817f396e56 100644 --- a/compiler/rustc_infer/src/infer/mod.rs +++ b/compiler/rustc_infer/src/infer/mod.rs @@ -1935,6 +1935,18 @@ impl<'tcx> TypeTrace<'tcx> { } } + pub fn poly_trait_refs( + cause: &ObligationCause<'tcx>, + a_is_expected: bool, + a: ty::PolyTraitRef<'tcx>, + b: ty::PolyTraitRef<'tcx>, + ) -> TypeTrace<'tcx> { + TypeTrace { + cause: cause.clone(), + values: PolyTraitRefs(ExpectedFound::new(a_is_expected, a.into(), b.into())), + } + } + pub fn consts( cause: &ObligationCause<'tcx>, a_is_expected: bool, diff --git a/compiler/rustc_middle/src/ty/error.rs b/compiler/rustc_middle/src/ty/error.rs index 8e6af936ded18..1e521e5781dae 100644 --- a/compiler/rustc_middle/src/ty/error.rs +++ b/compiler/rustc_middle/src/ty/error.rs @@ -74,6 +74,18 @@ pub enum TypeError<'tcx> { TargetFeatureCast(DefId), } +impl TypeError<'_> { + pub fn involves_regions(&self) -> bool { + match self { + TypeError::RegionsDoesNotOutlive(_, _) + | TypeError::RegionsInsufficientlyPolymorphic(_, _) + | TypeError::RegionsOverlyPolymorphic(_, _) + | TypeError::RegionsPlaceholderMismatch => true, + _ => false, + } + } +} + /// Explains the source of a type err in a short, human readable way. This is meant to be placed /// in parentheses after some larger message. You should also invoke `note_and_explain_type_err()` /// afterwards to present additional details, particularly when it comes to lifetime-related 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 4260cb53adc1c..165cc3e792123 100644 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs @@ -22,6 +22,7 @@ use rustc_hir::intravisit::Visitor; use rustc_hir::GenericParam; use rustc_hir::Item; use rustc_hir::Node; +use rustc_infer::infer::TypeTrace; use rustc_infer::traits::TraitEngine; use rustc_middle::traits::select::OverflowError; use rustc_middle::ty::abstract_const::NotConstEvaluatable; @@ -941,9 +942,14 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { self.reported_closure_mismatch.borrow_mut().insert((span, found_span)); + let mut not_tupled = false; + let found = match found_trait_ref.skip_binder().substs.type_at(1).kind() { ty::Tuple(ref tys) => vec![ArgKind::empty(); tys.len()], - _ => vec![ArgKind::empty()], + _ => { + not_tupled = true; + vec![ArgKind::empty()] + } }; let expected_ty = expected_trait_ref.skip_binder().substs.type_at(1); @@ -951,10 +957,28 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { ty::Tuple(ref tys) => { tys.iter().map(|t| ArgKind::from_expected_ty(t, Some(span))).collect() } - _ => vec![ArgKind::Arg("_".to_owned(), expected_ty.to_string())], + _ => { + not_tupled = true; + vec![ArgKind::Arg("_".to_owned(), expected_ty.to_string())] + } }; - if found.len() == expected.len() { + // If this is a `Fn` family trait and either the expected or found + // is not tupled, then fall back to just a regular mismatch error. + // This shouldn't be common unless manually implementing one of the + // traits manually, but don't make it more confusing when it does + // happen. + if Some(expected_trait_ref.def_id()) != tcx.lang_items().gen_trait() && not_tupled { + self.report_and_explain_type_error( + TypeTrace::poly_trait_refs( + &obligation.cause, + true, + expected_trait_ref, + found_trait_ref, + ), + &ty::error::TypeError::Mismatch, + ) + } else if found.len() == expected.len() { self.report_closure_arg_mismatch( span, found_span, diff --git a/src/test/ui/mismatched_types/E0631.rs b/src/test/ui/mismatched_types/E0631.rs index a293946583069..83dbdb77abeb5 100644 --- a/src/test/ui/mismatched_types/E0631.rs +++ b/src/test/ui/mismatched_types/E0631.rs @@ -1,7 +1,7 @@ #![feature(unboxed_closures)] fn foo(_: F) {} -fn bar>(_: F) {} +fn bar>(_: F) {} fn main() { fn f(_: u64) {} foo(|_: isize| {}); //~ ERROR type mismatch diff --git a/src/test/ui/mismatched_types/E0631.stderr b/src/test/ui/mismatched_types/E0631.stderr index 4d673d45559a9..410ea4b0b3439 100644 --- a/src/test/ui/mismatched_types/E0631.stderr +++ b/src/test/ui/mismatched_types/E0631.stderr @@ -27,8 +27,8 @@ LL | bar(|_: isize| {}); note: required by a bound in `bar` --> $DIR/E0631.rs:4:11 | -LL | fn bar>(_: F) {} - | ^^^^^^^^^ required by this bound in `bar` +LL | fn bar>(_: F) {} + | ^^^^^^^^^^^^ required by this bound in `bar` error[E0631]: type mismatch in function arguments --> $DIR/E0631.rs:9:9 @@ -65,8 +65,8 @@ LL | bar(f); note: required by a bound in `bar` --> $DIR/E0631.rs:4:11 | -LL | fn bar>(_: F) {} - | ^^^^^^^^^ required by this bound in `bar` +LL | fn bar>(_: F) {} + | ^^^^^^^^^^^^ required by this bound in `bar` error: aborting due to 4 previous errors diff --git a/src/test/ui/mismatched_types/closure-arg-count.rs b/src/test/ui/mismatched_types/closure-arg-count.rs index e817631ad5d79..65c8d6a7e936e 100644 --- a/src/test/ui/mismatched_types/closure-arg-count.rs +++ b/src/test/ui/mismatched_types/closure-arg-count.rs @@ -1,6 +1,6 @@ #![feature(unboxed_closures)] -fn f>(_: F) {} +fn f>(_: F) {} fn main() { [1, 2, 3].sort_by(|| panic!()); //~^ ERROR closure is expected to take diff --git a/src/test/ui/mismatched_types/closure-arg-count.stderr b/src/test/ui/mismatched_types/closure-arg-count.stderr index 3968774e35793..a02ec81983883 100644 --- a/src/test/ui/mismatched_types/closure-arg-count.stderr +++ b/src/test/ui/mismatched_types/closure-arg-count.stderr @@ -56,8 +56,8 @@ LL | f(|| panic!()); note: required by a bound in `f` --> $DIR/closure-arg-count.rs:3:9 | -LL | fn f>(_: F) {} - | ^^^^^^^^^ required by this bound in `f` +LL | fn f>(_: F) {} + | ^^^^^^^^^^^^ required by this bound in `f` help: consider changing the closure to take and ignore the expected argument | LL | f(|_| panic!()); @@ -74,8 +74,8 @@ LL | f( move || panic!()); note: required by a bound in `f` --> $DIR/closure-arg-count.rs:3:9 | -LL | fn f>(_: F) {} - | ^^^^^^^^^ required by this bound in `f` +LL | fn f>(_: F) {} + | ^^^^^^^^^^^^ required by this bound in `f` help: consider changing the closure to take and ignore the expected argument | LL | f( move |_| panic!()); diff --git a/src/test/ui/unboxed-closures/non-tupled-arg-mismatch.rs b/src/test/ui/unboxed-closures/non-tupled-arg-mismatch.rs new file mode 100644 index 0000000000000..925463d6deedc --- /dev/null +++ b/src/test/ui/unboxed-closures/non-tupled-arg-mismatch.rs @@ -0,0 +1,8 @@ +#![feature(unboxed_closures)] + +fn a>(f: F) {} + +fn main() { + a(|_: usize| {}); + //~^ ERROR mismatched types +} diff --git a/src/test/ui/unboxed-closures/non-tupled-arg-mismatch.stderr b/src/test/ui/unboxed-closures/non-tupled-arg-mismatch.stderr new file mode 100644 index 0000000000000..9a24fb8c2beec --- /dev/null +++ b/src/test/ui/unboxed-closures/non-tupled-arg-mismatch.stderr @@ -0,0 +1,17 @@ +error[E0308]: mismatched types + --> $DIR/non-tupled-arg-mismatch.rs:6:5 + | +LL | a(|_: usize| {}); + | ^ types differ + | + = note: expected trait `Fn` + found trait `Fn<(usize,)>` +note: required by a bound in `a` + --> $DIR/non-tupled-arg-mismatch.rs:3:9 + | +LL | fn a>(f: F) {} + | ^^^^^^^^^ required by this bound in `a` + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0308`.