[ASTPrinter] Use TypeLoc printing for extended types.

When the -module-interface-preserve-types-as-written flag is used,
the extended type should be printed similar to other types. The
checking for that flag happens in TypeLoc printing, not Type printing.
So we change extended type printing to use a TypeLoc instead.

Fixes rdar://79563937.

Author: varungandhi-apple

lib/AST/ASTPrinter.cpp

@@ -913,6 +913,7 @@ class PrintAST : public ASTVisitor<PrintAST> {
   void printSynthesizedExtension(Type ExtendedType, ExtensionDecl *ExtDecl);
 
   void printExtension(ExtensionDecl* ExtDecl);
+  void printExtendedTypeName(TypeLoc ExtendedTypeLoc);
 
 public:
   PrintAST(ASTPrinter &Printer, const PrintOptions &Options)
@@ -2331,8 +2332,7 @@ void PrintAST::visitImportDecl(ImportDecl *decl) {
                    [&] { Printer << "."; });
 }
 
-static void printExtendedTypeName(Type ExtendedType, ASTPrinter &Printer,
-                                  PrintOptions &Options) {
+void PrintAST::printExtendedTypeName(TypeLoc ExtendedTypeLoc) {
   bool OldFullyQualifiedTypesIfAmbiguous =
     Options.FullyQualifiedTypesIfAmbiguous;
   Options.FullyQualifiedTypesIfAmbiguous =
@@ -2342,9 +2342,8 @@ static void printExtendedTypeName(Type ExtendedType, ASTPrinter &Printer,
   };
 
   // Strip off generic arguments, if any.
-  auto Ty = ExtendedType->getAnyNominal()->getDeclaredType();
-
-  Ty->print(Printer, Options);
+  auto Ty = ExtendedTypeLoc.getType()->getAnyNominal()->getDeclaredType();
+  printTypeLoc(TypeLoc(ExtendedTypeLoc.getTypeRepr(), Ty));
 }
 
 
@@ -2402,7 +2401,7 @@ void PrintAST::printSynthesizedExtension(Type ExtendedType,
     printAttributes(ExtDecl);
     Printer << tok::kw_extension << " ";
 
-    printExtendedTypeName(ExtendedType, Printer, Options);
+    printExtendedTypeName(TypeLoc::withoutLoc(ExtendedType));
     printInherited(ExtDecl);
 
     // We may need to combine requirements from ExtDecl (which has the members
@@ -2453,7 +2452,7 @@ void PrintAST::printExtension(ExtensionDecl *decl) {
         printTypeLoc(TypeLoc::withoutLoc(extendedType));
         return;
       }
-      printExtendedTypeName(extendedType, Printer, Options);
+      printExtendedTypeName(TypeLoc(decl->getExtendedTypeRepr(), extendedType));
     });
     printInherited(decl);
 

test/ModuleInterface/preserve-type-repr.swift

@@ -1,5 +1,30 @@
-// RUN: %target-swift-frontend -typecheck -emit-module-interface-path - %s -enable-library-evolution -module-name PreferTypeRepr -module-interface-preserve-types-as-written | %FileCheck %s --check-prefix PREFER
-// RUN: %target-swift-frontend -typecheck -emit-module-interface-path - %s -enable-library-evolution -module-name PreferTypeRepr | %FileCheck %s --check-prefix DONTPREFER
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend %s -typecheck -enable-library-evolution -emit-module-interface-path %t/External.swiftinterface -module-name External -DEXTERNAL
+// RUN: %target-swift-frontend -typecheck -emit-module-interface-path - %s -enable-library-evolution -module-name PreferTypeRepr -module-interface-preserve-types-as-written -I %t | %FileCheck %s --check-prefix PREFER
+// RUN: %target-swift-frontend -typecheck -emit-module-interface-path - %s -enable-library-evolution -module-name PreferTypeRepr -I %t | %FileCheck %s --check-prefix DONTPREFER
+
+#if EXTERNAL
+public struct Toy {
+    public init() {}
+}
+
+public struct GenericToy<T> {
+    public init() {}
+}
+#else
+import External
+
+// PREFER: extension Toy
+// DONTPREFER: extension External.Toy
+extension Toy {
+    public static var new: Toy { Toy() }
+}
+
+// PREFER: extension GenericToy {
+// DONTPREFER: extension External.GenericToy {
+extension GenericToy {
+    public static var new: GenericToy<T> { GenericToy() }
+}
 
 public protocol Pet {}
 
@@ -32,3 +57,4 @@ extension My where T: Pet {
 // PREFER: public func isNoMore(_ pet: Ex<Parrot>) -> Bool
 // DONTPREFER: public func isNoMore(_ pet: PreferTypeRepr.Ex<PreferTypeRepr.Parrot>) -> Swift.Bool
 public func isNoMore(_ pet: Ex<Parrot>) -> Bool {}
+#endif