[erlang-patches] Dialyzer warnings for gen_stream

Kostis Sagonas <>
Mon May 31 13:43:52 CEST 2010


Björn Gustavsson wrote:
> 2010/5/31 Kostis Sagonas <>:
> 
>> These dialyzer warnings are correct but some of them look a bit weird.
> 
> It is dialyzer run based on the 'pu' branch, using an escript
> that formats the warnings as HTML code.

Bjorn,

The problem is that the warnings as output by the escript do not make 
much sense.  For example, the warning:

./gen_stream.erl:439: gen_stream.erl:439: The pattern <Reason,
{'gstr_state', {'behaviour', Module, _ModArgs}, _, Procs, ModState, _,
_, _, _}> can never match the type <_,_>

is problematic because the type contains two underscores, i.e. two any()

Instead, the vanilla dialyzer specifies some type which indeed does not 
match the pattern:

gen_stream.erl:439: The pattern <Reason, {'gstr_state', {'behaviour', 
Module, _ModArgs}, _, Procs, ModState, _, _, _, _}> can never match the 
type <_,#gstr_state{stream_type::'undefined' | {'behaviour',atom()} | 
{'binary',binary()} | {'file',string()},procs::'end_of_stream' | 
{pid()},active_proc::non_neg_integer(),source_size::atom() | 
non_neg_integer(),report_size::atom() | non_neg_integer()}>

the stream_type is {'behaviour',Module,_ModArgs} while the type 
declaration of the #gstr_state{} record reads: {'behaviour',atom()} 
(among others).

So, either the dialyzer in 'pu' or the escript needs fixing here.

Kostis


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