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Extend builtin/auto trait args with error when they have >1 argument
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compiler-errors committed Nov 6, 2023
1 parent aea82b2 commit c17d33f
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Showing 3 changed files with 36 additions and 6 deletions.
21 changes: 15 additions & 6 deletions compiler/rustc_trait_selection/src/traits/select/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -2389,12 +2389,21 @@ impl<'tcx> SelectionContext<'_, 'tcx> {
)
});

let obligation = Obligation::new(
self.tcx(),
cause.clone(),
param_env,
ty::TraitRef::new(self.tcx(), trait_def_id, [normalized_ty]),
);
let tcx = self.tcx();
let trait_ref = if tcx.generics_of(trait_def_id).params.len() == 1 {
ty::TraitRef::new(tcx, trait_def_id, [normalized_ty])
} else {
// If this is an ill-formed auto/built-in trait, then synthesize
// new error args for the missing generics.
let err_args = ty::GenericArgs::extend_with_error(
tcx,
trait_def_id,
&[normalized_ty.into()],
);
ty::TraitRef::new(tcx, trait_def_id, err_args)
};

let obligation = Obligation::new(self.tcx(), cause.clone(), param_env, trait_ref);
obligations.push(obligation);
obligations
})
Expand Down
10 changes: 10 additions & 0 deletions tests/ui/auto-traits/has-arguments.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,10 @@
#![feature(auto_traits)]

auto trait Trait1<'outer> {}
//~^ ERROR auto traits cannot have generic parameters

fn f<'a>(x: impl Trait1<'a>) {}

fn main() {
f("");
}
11 changes: 11 additions & 0 deletions tests/ui/auto-traits/has-arguments.stderr
Original file line number Diff line number Diff line change
@@ -0,0 +1,11 @@
error[E0567]: auto traits cannot have generic parameters
--> $DIR/has-arguments.rs:3:18
|
LL | auto trait Trait1<'outer> {}
| ------^^^^^^^^ help: remove the parameters
| |
| auto trait cannot have generic parameters

error: aborting due to previous error

For more information about this error, try `rustc --explain E0567`.

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