1 files changed, 6 insertions, 0 deletions

diff --git a/crates/hir_ty/src/types.rs b/crates/hir_ty/src/types.rs
index dc64e6e2b..bd89991dc 100644
--- a/crates/hir_ty/src/types.rs
+++ b/crates/hir_ty/src/types.rs
@@ -29,6 +29,12 @@ pub struct ProjectionTy {
     pub substitution: Substitution,
 }
 
+impl ProjectionTy {
+    pub fn self_type_parameter(&self, interner: &Interner) -> &Ty {
+        &self.substitution.interned()[0].assert_ty_ref(interner)
+    }
+}
+
 #[derive(Clone, PartialEq, Eq, Debug, Hash)]
 pub struct DynTy {
     /// The unknown self type.