[libcxx-commits] [libcxx] [libc++][test] Fix-up verifying test for `is_clock(_v)` (PR #166888)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-libcxx

Author: A. Jiang (frederick-vs-ja)

<details>
<summary>Changes</summary>

This fixes incompleteness and inconsistency for a test file added in adc79324618f0e95914ac0fcb26fe0d942319cab, by
- renaming `trait.is.clock.compile.verify.cpp` to `trait.is.clock.verify.cpp`, and
- adding comments clarifying what are being tested.

---
Full diff: https://github.com/llvm/llvm-project/pull/166888.diff


1 Files Affected:

- (renamed) libcxx/test/libcxx/time/time.traits.is.clock/trait.is.clock.verify.cpp (+12) 


``````````diff
diff --git a/libcxx/test/libcxx/time/time.traits.is.clock/trait.is.clock.compile.verify.cpp b/libcxx/test/libcxx/time/time.traits.is.clock/trait.is.clock.verify.cpp
similarity index 61%
rename from libcxx/test/libcxx/time/time.traits.is.clock/trait.is.clock.compile.verify.cpp
rename to libcxx/test/libcxx/time/time.traits.is.clock/trait.is.clock.verify.cpp
index e9ad59aba13cb..f4f438d348a85 100644
--- a/libcxx/test/libcxx/time/time.traits.is.clock/trait.is.clock.compile.verify.cpp
+++ b/libcxx/test/libcxx/time/time.traits.is.clock/trait.is.clock.verify.cpp
@@ -8,6 +8,18 @@
 
 // REQUIRES: std-at-least-c++20
 
+// <chrono>
+//
+// template<class T> struct is_clock;
+// template<class T> constexpr bool is_clock_v = is_clock<T>::value;
+
+// [time.traits.is.clock]/3:
+//  The behavior of a program that adds specializations for is_clock is undefined.
+
+// [namespace.std]/3:
+//   The behavior of a C++ program is undefined if it declares an explicit or partial specialization of any standard
+//   library variable template, except where explicitly permitted by the specification of that variable template.
+
 #include <chrono>
 #include <ratio>
 

``````````

</details>


https://github.com/llvm/llvm-project/pull/166888