Merge #8745

8745: Support goto_type_definition for types r=matklad a=Veykril

I'm unsure if the approach of lowering an `ast::Type` to a `hir::Type` is a good idea, it seems fine to me at least.
Fixes #2882

Co-authored-by: Lukas Tobias Wirth <lukastw97@gmail.com>

crates/hir/src/semantics.rs

@@ -196,6 +196,10 @@ impl<'db, DB: HirDatabase> Semantics<'db, DB> {
         self.imp.resolve_label(lifetime)
     }
 
+    pub fn resolve_type(&self, ty: &ast::Type) -> Option<Type> {
+        self.imp.resolve_type(ty)
+    }
+
     pub fn type_of_expr(&self, expr: &ast::Expr) -> Option<Type> {
         self.imp.type_of_expr(expr)
     }
@@ -476,6 +480,14 @@ impl<'db> SemanticsImpl<'db> {
         ToDef::to_def(self, src)
     }
 
+    fn resolve_type(&self, ty: &ast::Type) -> Option<Type> {
+        let scope = self.scope(ty.syntax());
+        let ctx = body::LowerCtx::new(self.db.upcast(), scope.file_id);
+        let ty = hir_ty::TyLoweringContext::new(self.db, &scope.resolver)
+            .lower_ty(&crate::TypeRef::from_ast(&ctx, ty.clone()));
+        Type::new_with_resolver(self.db, &scope.resolver, ty)
+    }
+
     fn type_of_expr(&self, expr: &ast::Expr) -> Option<Type> {
         self.analyze(expr.syntax()).type_of_expr(self.db, expr)
     }

crates/ide/src/goto_type_definition.rs

@@ -30,6 +30,7 @@ pub(crate) fn goto_type_definition(
                 ast::Expr(it) => sema.type_of_expr(&it)?,
                 ast::Pat(it) => sema.type_of_pat(&it)?,
                 ast::SelfParam(it) => sema.type_of_self(&it)?,
+                ast::Type(it) => sema.resolve_type(&it)?,
                 _ => return None,
             }
         };
@@ -146,6 +147,17 @@ struct Foo;
 impl Foo {
     fn f(&self$0) {}
 }
+"#,
+        )
+    }
+
+    #[test]
+    fn goto_def_for_type_fallback() {
+        check(
+            r#"
+struct Foo;
+     //^^^
+impl Foo$0 {}
 "#,
         )
     }