Index: lib/Sema/SemaTemplateInstantiate.cpp
===================================================================
--- lib/Sema/SemaTemplateInstantiate.cpp
+++ lib/Sema/SemaTemplateInstantiate.cpp
@@ -1670,7 +1670,7 @@
       // Instantiate default arguments for methods of local classes (DR1484)
       // and non-defining declarations.
       Sema::ContextRAII SavedContext(*this, OwningFunc);
-      LocalInstantiationScope Local(*this);
+      LocalInstantiationScope Local(*this, true);
       ExprResult NewArg = SubstExpr(Arg, TemplateArgs);
       if (NewArg.isUsable()) {
         // It would be nice if we still had this.
Index: test/SemaTemplate/default-expr-arguments-3.cpp
===================================================================
--- /dev/null
+++ test/SemaTemplate/default-expr-arguments-3.cpp
@@ -0,0 +1,20 @@
+// RUN: %clang_cc1 -std=c++14 -ast-dump %s 2>&1 | FileCheck %s
+
+namespace PR28795 {
+  // CHECK: FunctionDecl{{.*}}func 'void (void)'
+  // CHECK:  LambdaExpr
+  // CHECK:   CXXMethodDecl{{.*}}operator() 'enum foo (enum foo) const' inline
+  // CHECK:    ParmVarDecl{{.*}}f 'enum foo' cinit
+  // CHECK:     DeclRefExpr{{.*}}'enum foo' EnumConstant{{.*}}'a' 'enum foo'
+
+  template<typename T>
+  void func() {
+    enum class foo { a, b };
+    auto bar = [](foo f = foo::a) { return f; };
+    bar();
+  }
+
+  void foo() {
+    func<int>();
+  }
+}