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Merge #11878
11878: fix: Paper over GAT panic r=flodiebold a=flodiebold
TIL that Chalk expects the arguments to a generic associated type to come *before* the ones for the parent trait, not *after* as we have been doing with all other nested generics. Fixing this requires a larger refactoring, so for now this just papers over the problem by completely ignoring parameters of associated types.
Fixes #11769.
Co-authored-by: Florian Diebold <[email protected]>
| -rw-r--r-- | crates/hir_ty/src/tests/regression.rs | 19 | ||||
| -rw-r--r-- | crates/hir_ty/src/utils.rs | 9 |
2 files changed, 28 insertions, 0 deletions
diff --git a/crates/hir_ty/src/tests/regression.rs b/crates/hir_ty/src/tests/regression.rs index 2809b1e912..65eb2da5af 100644 --- a/crates/hir_ty/src/tests/regression.rs +++ b/crates/hir_ty/src/tests/regression.rs @@ -1497,3 +1497,22 @@ fn regression_11688_3() { "#, ); } + +#[test] +fn gat_crash() { + cov_mark::check!(ignore_gats); + check_no_mismatches( + r#" +trait ATrait {} + +trait Crash { + type Member<const N: usize>: ATrait; + fn new<const N: usize>() -> Self::Member<N>; +} + +fn test<T: Crash>() { + T::new(); +} +"#, + ); +} diff --git a/crates/hir_ty/src/utils.rs b/crates/hir_ty/src/utils.rs index 343e89eb9b..c4a11c86d4 100644 --- a/crates/hir_ty/src/utils.rs +++ b/crates/hir_ty/src/utils.rs @@ -175,6 +175,15 @@ pub(super) fn associated_type_by_name_including_super_traits( pub(crate) fn generics(db: &dyn DefDatabase, def: GenericDefId) -> Generics { let parent_generics = parent_generic_def(db, def).map(|def| Box::new(generics(db, def))); + if parent_generics.is_some() && matches!(def, GenericDefId::TypeAliasId(_)) { + // XXX: treat generic associated types as not existing to avoid crashes (#) + // + // Chalk expects the inner associated type's parameters to come + // *before*, not after the trait's generics as we've always done it. + // Adapting to this requires a larger refactoring + cov_mark::hit!(ignore_gats); + return Generics { def, params: Interned::new(Default::default()), parent_generics }; + } Generics { def, params: db.generic_params(def), parent_generics } } |