[cfe-commits] [PATCH] more useful 'duplicate case' diagnostics

Terry Long macmantrl at me.com
Tue May 15 15:28:45 PDT 2012

Am 15.05.2012 um 16:09 schrieb Douglas Gregor
> I'm a bit uncomfortable with the textual approach here. Why not analyze the expressions to check whether they are references to named declarations, and use those names in the diagnostic? It won't catch some macro cases, but it's far simpler.

I was also uncomfortable with the textual approach, and in fact I first tried seeing if the case expression was a DeclRefExpr that refers to a valid NamedDecl. The problem I found with that approach was that it was not catching very many situations. Doing it that way only works for enums as far as I can tell. Macros, const ints, case overflows, casting, and more complicated expressions (like "case 2+2") are not DeclRefExprs, and I don't see any obvious way to grab the necessary diagnostic info without using a textual approach.

To be safer and simpler, it's probably best to only do these smart diagnostics for enums (through DeclRefExpr), unless someone has any suggestions for a better way to do all of this.


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