[Sema] UsingShadowDecl shouldn't be hidden by the UsingDecl that owns it

rdar://23454249

Differential Revision: https://reviews.llvm.org/D28514

llvm-svn: 292805

clang/lib/Sema/SemaLookup.cpp

@@ -3428,6 +3428,12 @@ NamedDecl *VisibleDeclsRecord::checkHidden(NamedDecl *ND) {
           SM == ShadowMaps.rbegin())
         continue;
 
+      // A shadow declaration that's created by a resolved using declaration
+      // is not hidden by the same using declaration.
+      if (isa<UsingShadowDecl>(ND) && isa<UsingDecl>(D) &&
+          cast<UsingShadowDecl>(ND)->getUsingDecl() == D)
+        continue;
+
       // We've found a declaration that hides this one.
       return D;
     }

clang/test/Index/complete-cached-globals.cpp

@@ -0,0 +1,25 @@
+// Note: the run lines follow their respective tests, since line/column
+// matter in this test.
+
+namespace SomeNamespace {
+    class SomeClass {
+    };
+    void SomeFunction();
+}
+
+using SomeNamespace::SomeClass;
+using SomeNamespace::SomeFunction;
+
+static void foo() {
+  return;
+}
+
+// rdar://23454249
+
+// RUN: c-index-test -code-completion-at=%s:14:3 %s | FileCheck -check-prefix=CHECK-CC1 %s
+// RUN: env CINDEXTEST_EDITING=1 CINDEXTEST_COMPLETION_CACHING=1 c-index-test -code-completion-at=%s:14:3 %s | FileCheck -check-prefix=CHECK-CC1 %s
+
+// CHECK-CC1: ClassDecl:{TypedText SomeClass} (50)
+// CHECK-CC1: FunctionDecl:{ResultType void}{TypedText SomeFunction}{LeftParen (}{RightParen )} (50)
+// CHECK-CC1-NOT: {Text SomeNamespace::}{TypedText SomeClass}
+// CHECK-CC1-NOT: {Text SomeNamespace::}{TypedText SomeFunction}