ObjC generics are representable in ObjC.

Author: jckarter

lib/AST/Type.cpp

@@ -1942,8 +1942,7 @@ static ForeignRepresentableKind getObjCObjectRepresentable(Type type) {
     type = dynSelf->getSelfType();
 
   // @objc classes.
-  if (auto classType = type->getAs<ClassType>()) {
-    auto classDecl = classType->getDecl();
+  if (auto classDecl = type->getClassOrBoundGenericClass()) {
     auto &ctx = classDecl->getASTContext();
     if (auto resolver = ctx.getLazyResolver())
       resolver->resolveDeclSignature(classDecl);

test/ClangModules/objc_bridging_generics.swift

@@ -76,6 +76,9 @@ func testImportedTypeParamRequirements() {
 
 extension GenericClass {
   func doesntUseGenericParam() {}
+  @objc func doesntUseGenericParam2() -> Self {}
+  // Doesn't technically use 'T', since it's type-erased at runtime
+  func doesntUseGenericParam3() -> GenericClass<T> {}
 
   // expected-error@+1{{Extension of a generic Objective-C class cannot access the class's generic parameters}}
   func usesGenericParamA(_ x: T) {}
@@ -97,6 +100,9 @@ extension GenericClass {
   }
 
   static func doesntUseGenericParam() {}
+  static func doesntUseGenericParam2() -> Self {}
+  // Doesn't technically use 'T', since it's type-erased at runtime
+  static func doesntUseGenericParam3() -> GenericClass<T> {}
 
   // expected-error@+1{{Extension of a generic Objective-C class cannot access the class's generic parameters}}
   static func usesGenericParamA(_ x: T) {}
@@ -116,4 +122,10 @@ extension GenericClass {
   static func usesGenericParamF(_ x: Int) {
     _ = x is T
   }
+
+  func checkThatMethodsAreObjC() {
+    _ = #selector(GenericClass.doesntUseGenericParam)
+    _ = #selector(GenericClass.doesntUseGenericParam2)
+    _ = #selector(GenericClass.doesntUseGenericParam3)
+  }
 }