ASTPrinter: never synthesize extensions for raw types of enum decls.

Even thought raw types are specified in inheritance clauses, their
members are not usable through an enum instance. Thus, there is no
point to synthesize their members.

lib/AST/ASTPrinter.cpp

@@ -528,6 +528,14 @@ struct SynthesizedExtensionAnalyzer::Implementation {
     return InfoMap;
   }
 
+  static bool isEnumRawType(const Decl* D, TypeLoc TL) {
+    assert (TL.getType());
+    if (auto ED = dyn_cast<EnumDecl>(D)) {
+      return ED->hasRawType() && ED->getRawType()->isEqual(TL.getType());
+    }
+    return false;
+  }
+
   std::unique_ptr<ExtensionInfoMap>
   collectSynthesizedExtensionInfo(MergeGroupVector &AllGroups) {
     if (Target->getKind() == DeclKind::Protocol) {
@@ -544,7 +552,8 @@ struct SynthesizedExtensionAnalyzer::Implementation {
       }
     };
     for (auto TL : Target->getInherited()) {
-      addTypeLocNominal(TL);
+      if (!isEnumRawType(Target, TL))
+        addTypeLocNominal(TL);
     }
     while (!Unhandled.empty()) {
       NominalTypeDecl* Back = Unhandled.back();
@@ -558,7 +567,8 @@ struct SynthesizedExtensionAnalyzer::Implementation {
           MergeInfoMap.insert({E, Pair.second});
         }
         for (auto TL : Back->getInherited()) {
-          addTypeLocNominal(TL);
+          if (!isEnumRawType(Target, TL))
+            addTypeLocNominal(TL);
         }
       }
     }