Index: lib/Sema/SemaDecl.cpp
===================================================================
--- lib/Sema/SemaDecl.cpp
+++ lib/Sema/SemaDecl.cpp
@@ -6999,6 +6999,21 @@
           return;
         }
       }
+
+      if (cast<VarDecl>(ShadowedDecl)->hasLocalStorage()) {
+        // A variable can't shadow a local variable in an enclosing scope, if
+        // they are separated by a non-capturing declaration context.
+        for (DeclContext *ParentDC = NewDC;
+             ParentDC && !ParentDC->Equals(OldDC);
+             ParentDC = getLambdaAwareParentOfDeclContext(ParentDC)) {
+          // Only block literals, captured statements, and lambda expressions
+          // can capture; other scopes don't.
+          if (!isa<BlockDecl>(ParentDC) && !isa<CapturedDecl>(ParentDC) &&
+              !isLambdaCallOperator(ParentDC)) {
+            return;
+          }
+        }
+      }
     }
   }
 
Index: test/SemaCXX/warn-shadow.cpp
===================================================================
--- test/SemaCXX/warn-shadow.cpp
+++ test/SemaCXX/warn-shadow.cpp
@@ -213,3 +213,12 @@
 void handleLinkageSpec() {
   typedef void externC; // expected-warning {{declaration shadows a typedef in the global namespace}}
 }
+
+namespace PR33947 {
+void f(int a) {
+  struct A {
+    void g(int a) {}
+    A() { int a; }
+  };
+}
+}