[libcxx-commits] [libcxx] [libc++][test] Fix construction and comparison for testing allocators (PR #212702)

[Louis Dionne via libcxx-commits]

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@@ -195,8 +195,14 @@ class test_allocator {
       ++stats_->destroy_count;
     p->~T();
   }
-  TEST_CONSTEXPR friend bool operator==(const test_allocator& x, const test_allocator& y) { return x.data_ == y.data_; }
-  TEST_CONSTEXPR friend bool operator!=(const test_allocator& x, const test_allocator& y) { return !(x == y); }
+  template <class U>
+  TEST_CONSTEXPR friend bool operator==(const test_allocator& x, const test_allocator<U>& y) {
+    return x.data_ == static_cast<const test_allocator&>(y).data_;
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ldionne wrote:

I'm probably missing something obvious, but I don't see how the current `static_cast<test_allocator const&>` is working. `test_allocator<T>` and `test_allocator<U>` are unrelated, so how does this static cast even work?

https://github.com/llvm/llvm-project/pull/212702