From 781e86477cf71c7850d4d1f169c58d7e398654f7 Mon Sep 17 00:00:00 2001 From: Esteban Küber Date: Fri, 29 Sep 2023 03:16:11 +0000 Subject: Suggest trait bounds for used associated type on type param Fix #101351. When an associated type on a type parameter is used, and the type parameter isn't constrained by the correct trait, suggest the appropriate trait bound: ``` error[E0220]: associated type `Associated` not found for `T` --> file.rs:6:15 | 6 | field: T::Associated, | ^^^^^^^^^^ there is a similarly named associated type `Associated` in the trait `Foo` | help: consider restricting type parameter `T` | 5 | struct Generic { | +++++ ``` When an associated type on a type parameter has a typo, suggest fixing it: ``` error[E0220]: associated type `Baa` not found for `T` --> $DIR/issue-55673.rs:9:8 | LL | T::Baa: std::fmt::Debug, | ^^^ there is a similarly named associated type `Bar` in the trait `Foo` | help: change the associated type name to use `Bar` from `Foo` | LL | T::Bar: std::fmt::Debug, | ~~~ ``` --- .../rustc_trait_selection/src/traits/error_reporting/suggestions.rs | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'compiler/rustc_trait_selection/src') 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 9aebe77a104..1c8536ba11e 100644 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs @@ -364,7 +364,7 @@ fn predicate_constraint(generics: &hir::Generics<'_>, pred: ty::Predicate<'_>) - /// Type parameter needs more bounds. The trivial case is `T` `where T: Bound`, but /// it can also be an `impl Trait` param that needs to be decomposed to a type /// param for cleaner code. -fn suggest_restriction<'tcx>( +pub fn suggest_restriction<'tcx>( tcx: TyCtxt<'tcx>, item_id: LocalDefId, hir_generics: &hir::Generics<'tcx>, -- cgit 1.4.1-3-g733a5