diff --git a/clang/lib/Sema/SemaTemplateVariadic.cpp b/clang/lib/Sema/SemaTemplateVariadic.cpp
index 4909414c0c78d..a4b681ae4f008 100644
--- a/clang/lib/Sema/SemaTemplateVariadic.cpp
+++ b/clang/lib/Sema/SemaTemplateVariadic.cpp
@@ -1085,9 +1085,11 @@ ExprResult Sema::ActOnPackIndexingExpr(Scope *S, Expr *PackExpression,
                                        SourceLocation RSquareLoc) {
   bool isParameterPack = ::isParameterPack(PackExpression);
   if (!isParameterPack) {
-    CorrectDelayedTyposInExpr(IndexExpr);
-    Diag(PackExpression->getBeginLoc(), diag::err_expected_name_of_pack)
-        << PackExpression;
+    if (!PackExpression->containsErrors()) {
+      CorrectDelayedTyposInExpr(IndexExpr);
+      Diag(PackExpression->getBeginLoc(), diag::err_expected_name_of_pack)
+          << PackExpression;
+    }
     return ExprError();
   }
   ExprResult Res =
diff --git a/clang/test/SemaCXX/cxx2c-pack-indexing.cpp b/clang/test/SemaCXX/cxx2c-pack-indexing.cpp
index e13635383b6ca..606715e6aacff 100644
--- a/clang/test/SemaCXX/cxx2c-pack-indexing.cpp
+++ b/clang/test/SemaCXX/cxx2c-pack-indexing.cpp
@@ -154,3 +154,9 @@ void f() {
 }
 
 }
+
+namespace GH88929 {
+    bool b = a...[0];  // expected-error {{use of undeclared identifier 'a'}}
+    using E = P...[0]; // expected-error {{unknown type name 'P'}} \
+                       // expected-error {{expected ';' after alias declaration}}
+}