[erlang-questions] Lack of warning for overlapping clauses with

Attila Rajmund Nohl <>
Wed Jul 21 11:48:13 CEST 2010


2010/7/21, Torben Hoffmann <>:
> On Tue, Jul 20, 2010 at 23:53, Richard O'Keefe <> wrote:
[...]
>> So nhc98 was completely silent, and ghc 6.6.1 did notice the
>> explicit pattern duplication but did *NOT* notice the duplication
>> of a pattern in a guard, any more than Erlang did.
>>
> I stand corrected! Thanks for putting my assumptions to a timely death!!

I think there's one more thing: Erlang function clauses overlap all
the time. It's a common pattern that:

f(1) -> ok;
f(2) -> ok;
f(_) -> not_ok.

and obviously the third pattern overlaps with the first two, but we
really don't want a warning for that.


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