[PATCH] D125771: [clang-tidy] Add a useful note about -std=c++11-or-later

[Whisperity via Phabricator via cfe-commits]

whisperity added a comment.

In D125771#3519606 <https://reviews.llvm.org/D125771#3519606>, @LegalizeAdulthood wrote:

> I thought there wasn't any support for validating fixits applied to header files?

It is not specifically about the fixits, but diagnostics as a whole. It was not clear that if you say `-std=c++11-or-later` it will actually run **multiple** executions without giving you the ability to observe the contents of the files.

Technically, you can always match a diagnostic that is positioned into a header from the TU that is producing that diagnostic, because `// CHECK-MESSAGES:` does a regular expression-like matching. For example, `misc-unused-parameters` does the following <http://github.com/llvm/llvm-project/blob/dd12c3433ee9b4ef15c633bd325ab5a0c9c5e03b/clang-tools-extra/test/clang-tidy/checkers/misc-unused-parameters.cpp>:

  #include "header.h"
  // CHECK-MESSAGES: header.h:1:38: warning

And because LIT can execute arbitrary commands, you can always go about your way running `FileCheck` and everything else manually.

But it is good to be reminded early on that `-or-later` will result in execution of potentially changed code outside of your (test file's) control. Saves the debugging time which we had to endure!


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  https://reviews.llvm.org/D125771/new/

https://reviews.llvm.org/D125771