[Bug preprocessor/20262] __LINE__ implementation flaky.

[aaw at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20262

Ollie Wild <aaw at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |aaw at gcc dot gnu.org

--- Comment #4 from Ollie Wild <aaw at gcc dot gnu.org> ---
We recently ran into this issue in a context where __LINE__ was being used to
produce goto labels inside a macro-wrapped block of code.  The code in question
compiled fine with Clang/LLVM but produced a compiler error with GCC.

I've read through the standard (in this case, C++11), and as I read it
"presumed source line" is used to allow for the possibility of modifying the
source line via #line directives (which it says immediately thereafter in a
footnote), not as general consent to be liberal with line numbering. 
Regardless, using the true physical line conforms to the principle of least
surprise.

Would anyone be opposed to revisiting this?