diff options
Diffstat (limited to 'compiler/rustc_middle/src/traits/select.rs')
| -rw-r--r-- | compiler/rustc_middle/src/traits/select.rs | 16 |
1 files changed, 10 insertions, 6 deletions
diff --git a/compiler/rustc_middle/src/traits/select.rs b/compiler/rustc_middle/src/traits/select.rs index 85ead3171..ec69864c9 100644 --- a/compiler/rustc_middle/src/traits/select.rs +++ b/compiler/rustc_middle/src/traits/select.rs @@ -105,6 +105,12 @@ pub type EvaluationCache<'tcx> = Cache< /// parameter environment. #[derive(PartialEq, Eq, Debug, Clone, TypeFoldable, TypeVisitable)] pub enum SelectionCandidate<'tcx> { + /// A builtin implementation for some specific traits, used in cases + /// where we cannot rely an ordinary library implementations. + /// + /// The most notable examples are `sized`, `Copy` and `Clone`. This is also + /// used for the `DiscriminantKind` and `Pointee` trait, both of which have + /// an associated type. BuiltinCandidate { /// `false` if there are no *further* obligations. has_nested: bool, @@ -131,18 +137,16 @@ pub enum SelectionCandidate<'tcx> { /// generated for a generator. GeneratorCandidate, + /// Implementation of a `Future` trait by one of the generator types + /// generated for an async construct. + FutureCandidate, + /// Implementation of a `Fn`-family trait by one of the anonymous /// types generated for a fn pointer type (e.g., `fn(int) -> int`) FnPointerCandidate { is_const: bool, }, - /// Builtin implementation of `DiscriminantKind`. - DiscriminantKindCandidate, - - /// Builtin implementation of `Pointee`. - PointeeCandidate, - TraitAliasCandidate, /// Matching `dyn Trait` with a supertrait of `Trait`. The index is the |