[PATCH] Fix "warning: fallthrough annotation does not directly precede switch label" in lambdas.

Alexander Kornienko alexfh at google.com
Tue Jun 24 09:07:57 PDT 2014


On Tue, Jun 24, 2014 at 4:43 PM, Richard Smith <richard at metafoo.co.uk>
wrote:

> LGTM
>
> If blocks also need a fix, feel free to do that in a later patch :)
>

Oh, you're right, I didn't think about blocks. For some reason bodies of
blocks are not duplicated in the AST, as it is with lambdas, so the warning
works fine with them. If you want, I can add a test for this:

$ cat test/SemaCXX/switch-implicit-fallthrough-blocks.cpp
// RUN: %clang_cc1 -fsyntax-only -verify -fblocks -std=c++11
-Wimplicit-fallthrough %s

void fallthrough_in_blocks() {
  void (^block)() = ^{
    int x = 0;
    switch (x) {
    case 0:
      x++;
      [[clang::fallthrough]]; // no diagnostics
    case 1:
      x++;
    default: // \
        expected-warning{{unannotated fall-through between switch labels}} \
        expected-note{{insert 'break;' to avoid fall-through}}
      break;
    }
  };
  block();
}
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