Index: clang/lib/Sema/SemaStmt.cpp
===================================================================
--- clang/lib/Sema/SemaStmt.cpp
+++ clang/lib/Sema/SemaStmt.cpp
@@ -1826,7 +1826,10 @@
         VarDecl *VD = dyn_cast<VarDecl>(DI);
         if (VD && VD->isLocalVarDecl() && !VD->hasLocalStorage())
           VD = nullptr;
-        if (!VD) {
+        // It is possible to declare non-variable declarations as part of the
+        // declaration part of a 'for' statement, such as defining a structure
+        // or enum type: for (enum { zero, ten } i = zero; i < ten; ++i);
+        if (!VD && !isa<TagDecl>(DI)) {
           Diag(DI->getLocation(), diag::err_non_local_variable_decl_in_for);
           DI->setInvalidDecl();
         }
Index: clang/test/Sema/for.c
===================================================================
--- clang/test/Sema/for.c
+++ clang/test/Sema/for.c
@@ -5,3 +5,5 @@
 void b2 (void) { for (void f (void);;); }   // expected-error {{declaration of non-local variable}}
 void b3 (void) { for (static int f;;); }    // expected-error {{declaration of non-local variable}}
 void b4 (void) { for (typedef int f;;); }   // expected-error {{declaration of non-local variable}}
+void b5 (void) { for (struct { int i; } s;;); }
+void b6 (void) { for (enum { zero, ten = 10 } i;;); }