[clang] Fix test added in #154418 to work when the default is C++20. (PR #154463)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: None (dyung)

<details>
<summary>Changes</summary>

The test added for #<!-- -->154418 specifically tests for a warning that the compiler should emit informing the user that a feature is a C++20 extension, but the compiler does not emit that when the default is C++20, so we should skip that test. This change checks whether the C++ default standard is less than C++20, and if so, skips the test.

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Full diff: https://github.com/llvm/llvm-project/pull/154463.diff


1 Files Affected:

- (modified) clang/test/SemaTemplate/nested-name-spec-template.cpp (+1-1) 


``````````diff
diff --git a/clang/test/SemaTemplate/nested-name-spec-template.cpp b/clang/test/SemaTemplate/nested-name-spec-template.cpp
index c99e1eed456cc..833f76218212a 100644
--- a/clang/test/SemaTemplate/nested-name-spec-template.cpp
+++ b/clang/test/SemaTemplate/nested-name-spec-template.cpp
@@ -168,7 +168,7 @@ namespace unresolved_using {
   template struct C<int>;
 } // namespace unresolved_using
 
-#if __cplusplus >= 201703L
+#if (__cplusplus >= 201703L && __cplusplus < 202002L)
 namespace SubstTemplateTypeParmPackType {
   template <int...> struct A {};
 

``````````

</details>


https://github.com/llvm/llvm-project/pull/154463