Merge pull request swiftlang#32761 from slavapestov/typealias-member-reference-nonsense

Sema: Don't look through nested typealiases when checking for unsupported member reference

Author: slavapestov

lib/Sema/TypeCheckNameLookup.cpp

@@ -353,8 +353,7 @@ bool TypeChecker::isUnsupportedMemberTypeAccess(Type type, TypeDecl *typeDecl) {
     // underlying type is not dependent.
     if (auto *aliasDecl = dyn_cast<TypeAliasDecl>(typeDecl)) {
       if (!aliasDecl->isGeneric() &&
-          aliasDecl->getUnderlyingType()->getCanonicalType()
-            ->hasTypeParameter()) {
+          aliasDecl->getUnderlyingType()->hasTypeParameter()) {
         return true;
       }
     }

test/decl/typealias/dependent_types.swift

@@ -23,11 +23,12 @@ struct X1<T> : P1 {
   }
 }
 
-struct GenericStruct<T> { // expected-note 2{{generic type 'GenericStruct' declared here}}
+struct GenericStruct<T> { // expected-note 3{{generic type 'GenericStruct' declared here}}
   typealias Alias = T
   typealias MetaAlias = T.Type
 
   typealias Concrete = Int
+  typealias ReferencesConcrete = Concrete
 
   func methodOne() -> Alias.Type {}
   func methodTwo() -> MetaAlias {}
@@ -59,6 +60,9 @@ let _: GenericStruct.MetaAlias = metaFoo()
 // we are OK.
 let _: GenericStruct.Concrete = foo()
 
+let _: GenericStruct.ReferencesConcrete = foo()
+// expected-error@-1 {{reference to generic type 'GenericStruct' requires arguments in <...>}}
+
 class SuperG<T, U> {
   typealias Composed = (T, U)
 }