Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/hir/src/lib.rs')
| -rw-r--r-- | crates/hir/src/lib.rs | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/crates/hir/src/lib.rs b/crates/hir/src/lib.rs index ac8a62ee85..f8af04302f 100644 --- a/crates/hir/src/lib.rs +++ b/crates/hir/src/lib.rs @@ -101,7 +101,6 @@ pub use crate::{ PathResolution, Semantics, SemanticsImpl, SemanticsScope, TypeInfo, VisibleTraits, }, }; -pub use hir_ty::method_resolution::TyFingerprint; // Be careful with these re-exports. // @@ -151,8 +150,9 @@ pub use { display::{ClosureStyle, HirDisplay, HirDisplayError, HirWrite}, dyn_compatibility::{DynCompatibilityViolation, MethodViolationCode}, layout::LayoutError, + method_resolution::TyFingerprint, mir::{MirEvalError, MirLowerError}, - CastError, FnAbi, PointerCast, Safety, + CastError, FnAbi, PointerCast, Safety, Variance, }, // FIXME: Properly encapsulate mir hir_ty::{mir, Interner as ChalkTyInterner}, @@ -3957,6 +3957,22 @@ impl GenericParam { GenericParam::LifetimeParam(it) => it.id.parent.into(), } } + + pub fn variance(self, db: &dyn HirDatabase) -> Option<Variance> { + let parent = match self { + GenericParam::TypeParam(it) => it.id.parent(), + // const parameters are always invariant + GenericParam::ConstParam(_) => return None, + GenericParam::LifetimeParam(it) => it.id.parent, + }; + let generics = hir_ty::generics::generics(db.upcast(), parent); + let index = match self { + GenericParam::TypeParam(it) => generics.type_or_const_param_idx(it.id.into())?, + GenericParam::ConstParam(_) => return None, + GenericParam::LifetimeParam(it) => generics.lifetime_idx(it.id)?, + }; + db.variances_of(parent)?.get(index).copied() + } } #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)] |