On Mon, 15 Sep 2014, Marek Polacek wrote: > We must be careful to properly handle code such as "1 //**/ 2", which > has a different meaning in C90 and GNU90 mode. New testcases test this.
I don't think there's sufficient allowance here for other valid cases. It's valid to have // inside #if 0 in C90, for example, so that must not be diagnosed (must not have a pedwarn or error, at least, that is). It's also valid to have it in a macro expansion; e.g.: #define h(x) #x #define s(x) h(x) #define foo // and then s(foo) must expand to the string "//". Clearly, in any case, with or without the diagnostics, these cases should have testcases in the testsuite. But because // is only invalid in C90 if it actually results in two consecutive / tokens (not just preprocessing tokens), as such consecutive tokens are not part of any valid C90 program, a more conservative approach may be needed to avoid errors for valid cases. -- Joseph S. Myers jos...@codesourcery.com
