On 09/30/2016 12:51 PM, Jakub Jelinek wrote:
On Fri, Sep 30, 2016 at 12:42:20PM +0200, Bernd Schmidt wrote:
On 09/30/2016 11:45 AM, Jakub Jelinek wrote:
See Tom Tromey's explanation why accepting too much is bad (at least unless
we want multiple levels).
And I still don't buy it. The case where someone writes "Don't fall through"
is artificial to begin with, and also forgetting to put the break; there
really isn't something for us to be concerned about.
It doesn't have to be exactly that, fall is a substring of 200+ english, thr
is a substring of 1000+ english words, if you allow arbitrary stuff in
between or before it or after it, it can say anything, completely unrelated
to falling through across case labels.
True, but IMO irrelevant. We have to consider what is likely in real
code. We're trying to catch likely problems without adding a prohibitive
cost to enabling -Wextra. It's not helpful to punish people for writing
code that is valid and documents intentional fallthrough, but does it in
a style or a language we didn't expect.
A complete solution would require working AI; maybe someone from Google
can contribute one. Failing that, we need heuristics, and I still like
Michael's suggestion of not printing a warning if we see _any_ comment,
on the grounds that this would still catch the vast majority of actual
errors, without the huge false positive rate we currently have.
Bernd
