Index: packages/Python/lldbsuite/test/expression_command/completion-crash-lambda/TestCompletionCrashInLambda.py
===================================================================
--- packages/Python/lldbsuite/test/expression_command/completion-crash-lambda/TestCompletionCrashInLambda.py
+++ packages/Python/lldbsuite/test/expression_command/completion-crash-lambda/TestCompletionCrashInLambda.py
@@ -1,4 +1,4 @@
 from lldbsuite.test import lldbinline
 from lldbsuite.test import decorators
 
-lldbinline.MakeInlineTest(__file__, globals(), [decorators.skipIf(bugnumber="rdar://53755023")])
+lldbinline.MakeInlineTest(__file__, globals(), [])
Index: source/Symbol/ClangASTContext.cpp
===================================================================
--- source/Symbol/ClangASTContext.cpp
+++ source/Symbol/ClangASTContext.cpp
@@ -1508,8 +1508,25 @@
       *ast, (TagDecl::TagKind)kind, decl_ctx, SourceLocation(),
       SourceLocation(), is_anonymous ? nullptr : &ast->Idents.get(name));
 
-  if (is_anonymous)
-    decl->setAnonymousStructOrUnion(true);
+  if (is_anonymous) {
+    // The current heuristic for checking if a CXXRecordDecl is anonymous is if
+    // there is no name or if it is just a null terminator.
+    // This is not accurate since currently this can sweep up both unnamed
+    // classes and lambdas as anonymous classes, which they are not.
+    //
+    // Anonymous classes is a GNU/MSVC extension that clang supports. It
+    // requires the anonymous class be embedded within a class. So the new
+    // heuristic verifies this condition.
+    //
+    // This fix will unfortunately still mislabel unnamed classes within a class
+    // but this improves the situation greatly since getting this wrong in the
+    // other cases can lead to an assert in clang CodeCompletion since
+    // SemaAccess assumes the DeclContext of an anonymous class is a
+    // CXXRecordDecl.
+    if (CXXRecordDecl *record = dyn_cast<CXXRecordDecl>(decl_ctx)) {
+      decl->setAnonymousStructOrUnion(true);
+    }
+  }
 
   if (decl) {
     if (metadata)