Revert accidentally checked in change in r281315.

llvm-svn: 281316
diff --git a/clang/lib/Sema/SemaLookup.cpp b/clang/lib/Sema/SemaLookup.cpp
index 7f9d22d..044a3aa 100644
--- a/clang/lib/Sema/SemaLookup.cpp
+++ b/clang/lib/Sema/SemaLookup.cpp
@@ -1339,7 +1339,7 @@
     // instance, maybe this is a lazily-declared special member of an imported
     // class).
     auto *Parent = cast<NamedDecl>(Entity->getDeclContext());
-    assert(!Parent->isHidden() && "unexpectedly hidden decl");
+    assert(Parent->isHidden() && "unexpectedly hidden decl");
     return getOwningModule(Parent);
   }