[PATCH] D130058: [Clang] Diagnose ill-formed constant expression when setting a non fixed enum to a value outside the range of the enumeration values

[Nico Weber via Phabricator via cfe-commits]

thakis added a comment.

Here's a reduced repro of one case:

  % cat test.cc
  typedef enum VkResult {
      VK_ERROR_INVALID_OPAQUE_CAPTURE_ADDRESS = -1000257000,
      VK_RESULT_MAX_ENUM = 0x7FFFFFFF
  } VkResult;
  
  constexpr VkResult VK_FAKE_DEVICE_OOM_FOR_TESTING = static_cast<VkResult>(VK_RESULT_MAX_ENUM - 1);
  
  % out/gn/bin/clang -c test.cc -std=c++17
  test.cc:6:20: error: constexpr variable 'VK_FAKE_DEVICE_OOM_FOR_TESTING' must be initialized by a constant expression
  constexpr VkResult VK_FAKE_DEVICE_OOM_FOR_TESTING = static_cast<VkResult>(VK_RESULT_MAX_ENUM - 1);
                     ^                                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  test.cc:6:53: note: integer value 2147483646 is outside the valid range of values [-2147483648, -2147483648) for this enumeration type
  constexpr VkResult VK_FAKE_DEVICE_OOM_FOR_TESTING = static_cast<VkResult>(VK_RESULT_MAX_ENUM - 1);
                                                      ^
  1 error generated.

Isn't `valid range of values [-2147483648, -2147483648)` just wrong here?


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  https://reviews.llvm.org/D130058/new/

https://reviews.llvm.org/D130058