[libcxx-commits] [libcxx] [libc++][test] Fix invalid low-level const conversion in limited_allocator (PR #118189)

[Louis Dionne via libcxx-commits]

================
@@ -467,7 +467,10 @@ class limited_allocator {
   TEST_CONSTEXPR_CXX20 pointer allocate(size_type n) { return handle_->template allocate<T>(n); }
   TEST_CONSTEXPR_CXX20 void deallocate(pointer p, size_type n) { handle_->template deallocate<T>(p, n); }
   TEST_CONSTEXPR size_type max_size() const { return N; }
-  TEST_CONSTEXPR BuffT* getHandle() const { return handle_.get(); }
+
+  // In C++11, constexpr non-static member functions are implicitly const, but this is no longer the case since C++14.
+  TEST_CONSTEXPR_CXX14 BuffT* getHandle() { return handle_.get(); }
+  TEST_CONSTEXPR const BuffT* getHandle() const { return handle_.get(); }
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ldionne wrote:

IMO we should instead do this:

```suggestion
  TEST_CONSTEXPR const BuffT* getHandle() const { return handle_.get(); }
```

Let's just provide the `const` version, since the non-const version is not needed. This method is only used by `operator==` below.

The comment can also be removed if we only have the `const` version. WDYT?

https://github.com/llvm/llvm-project/pull/118189