diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/mod.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/mod.rs index 9aa6d1f3d46..752ef729113 100644 --- a/compiler/rustc_trait_selection/src/error_reporting/traits/mod.rs +++ b/compiler/rustc_trait_selection/src/error_reporting/traits/mod.rs @@ -344,7 +344,8 @@ pub(crate) fn to_pretty_impl_header(tcx: TyCtxt<'_>, impl_def_id: DefId) -> Opti write!( w, - " {} for {}", + " {}{} for {}", + tcx.impl_polarity(impl_def_id).as_str(), trait_ref.print_only_trait_path(), tcx.type_of(impl_def_id).instantiate_identity() ) diff --git a/compiler/rustc_type_ir/src/predicate.rs b/compiler/rustc_type_ir/src/predicate.rs index b30346ffc53..e4bf1e1379c 100644 --- a/compiler/rustc_type_ir/src/predicate.rs +++ b/compiler/rustc_type_ir/src/predicate.rs @@ -196,6 +196,17 @@ impl fmt::Display for ImplPolarity { } } +impl ImplPolarity { + /// The polarity marker in front of the impl trait ref if applicable. + pub fn as_str(self) -> &'static str { + match self { + Self::Positive => "", + Self::Negative => "!", + Self::Reservation => "", + } + } +} + /// Polarity for a trait predicate. May either be negative or positive. /// Distinguished from [`ImplPolarity`] since we never compute goals with /// "reservation" level. diff --git a/tests/ui/coherence/coherence-conflicting-repeated-negative-trait-impl-70849.rs b/tests/ui/coherence/coherence-conflicting-repeated-negative-trait-impl-70849.rs new file mode 100644 index 00000000000..88b9d9e62bf --- /dev/null +++ b/tests/ui/coherence/coherence-conflicting-repeated-negative-trait-impl-70849.rs @@ -0,0 +1,10 @@ +#![feature(negative_impls)] +//@ edition: 2021 +// Test to ensure we are printing the polarity of the impl trait ref +// when printing out conflicting trait impls + +struct MyType; + +impl !Clone for &mut MyType {} +//~^ ERROR conflicting implementations of trait `Clone` for type `&mut MyType` +fn main() {} diff --git a/tests/ui/coherence/coherence-conflicting-repeated-negative-trait-impl-70849.stderr b/tests/ui/coherence/coherence-conflicting-repeated-negative-trait-impl-70849.stderr new file mode 100644 index 00000000000..b317197eb40 --- /dev/null +++ b/tests/ui/coherence/coherence-conflicting-repeated-negative-trait-impl-70849.stderr @@ -0,0 +1,13 @@ +error[E0119]: conflicting implementations of trait `Clone` for type `&mut MyType` + --> $DIR/coherence-conflicting-repeated-negative-trait-impl-70849.rs:8:1 + | +LL | impl !Clone for &mut MyType {} + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | + = note: conflicting implementation in crate `core`: + - impl !Clone for &mut T + where T: ?Sized; + +error: aborting due to 1 previous error + +For more information about this error, try `rustc --explain E0119`.