[ModuleInterface] Don't print access on extensions

This ends up meaning "don't print access attributes, then print access
uniformly on ValueDecls if you're not printing access attributes".

Author: jrose-apple

lib/AST/ASTPrinter.cpp

@@ -90,6 +90,8 @@ PrintOptions PrintOptions::printTextualInterfaceFile() {
   // the default to 'public' and mark the 'internal' things.
   result.PrintAccess = true;
 
+  result.ExcludeAttrList.push_back(DAK_AccessControl);
+
   // FIXME: We'll need the actual default parameter expression.
   result.PrintDefaultParameterPlaceholder = false;
 
@@ -493,8 +495,10 @@ class PrintAST : public ASTVisitor<PrintAST> {
   }
 
   void printAccess(const ValueDecl *D) {
-    if (!Options.PrintAccess || !D->hasAccess() ||
-        D->getAttrs().hasAttribute<AccessControlAttr>())
+    if (!Options.PrintAccess || !D->hasAccess())
+      return;
+    if (D->getAttrs().hasAttribute<AccessControlAttr>() &&
+        !llvm::is_contained(Options.ExcludeAttrList, DAK_AccessControl))
       return;
 
     printAccess(D->getFormalAccess());

test/ModuleInterface/access-filter.swift

@@ -60,8 +60,7 @@ extension PublicProto {
   @usableFromInline internal func ufiMethod() {}
 } // CHECK: {{^[}]$}}
 
-// FIXME: We shouldn't print access on extensions in textual interface files.
-// CHECK: {{^}}public extension PublicProto {{[{]$}}
+// CHECK: {{^}}extension PublicProto {{[{]$}}
 public extension PublicProto {
   // CHECK: public func publicExtPublicMethod(){{$}}
   func publicExtPublicMethod() {}