diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -16959,6 +16959,9 @@
 
       PushOnScopeChains(AI, CurBlock->TheScope);
     }
+
+    if (AI->isInvalidDecl())
+      CurBlock->TheDecl->setInvalidDecl();
   }
 }
 
diff --git a/clang/test/AST/ast-dump-recovery.m b/clang/test/AST/ast-dump-recovery.m
--- a/clang/test/AST/ast-dump-recovery.m
+++ b/clang/test/AST/ast-dump-recovery.m
@@ -16,3 +16,9 @@
   // CHECK-NEXT:   `-DeclRefExpr {{.*}} 'foo'
   foo.undef;
 }
+
+// CHECK:      `-BlockExpr {{.*}} 'int (^)(int, int)'
+// CHECK-NEXT:   `-BlockDecl {{.*}} invalid
+int (^a)(int, int) = ^(int, undefine b) {
+   return 1;
+};