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author | Björn Gustavsson <bjorn@erlang.org> | 2010-04-15 10:18:53 +0200 |
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committer | Björn Gustavsson <bjorn@erlang.org> | 2010-04-15 16:41:50 +0200 |
commit | c34ad2d537e41c9b31e240aa1e6fadd994115a16 (patch) | |
tree | 2cbe3141d13a1ac40fdfa7486eef89be053f3100 /EPLICENCE | |
parent | ab47252a5f7d540d4119d38dffe69acca86d2a41 (diff) | |
download | otp-c34ad2d537e41c9b31e240aa1e6fadd994115a16.tar.gz otp-c34ad2d537e41c9b31e240aa1e6fadd994115a16.tar.bz2 otp-c34ad2d537e41c9b31e240aa1e6fadd994115a16.zip |
Silence warnings for expressions that are assigned to "_"
There is currently no zero-cost way to silence the warning
"the result of the expression is ignored", which is issued
for code such as:
list_to_integer(S),
ok
Such code can be useful for assertions or input validation.
Teach the compiler to silence the warning for expressions
that are explicitly assigned to to the "_" variable,
such as:
_ = list_to_integer(S),
ok
Implement it by having the v3_core pass annotate calls in
Core Erlang like this:
let <_> = ( call 'erlang':'list_to_integer'(S) -| ['result_not_wanted'] )
in 'ok'
and modifiy sys_core_fold to suppress the warning for any call
having the annotation.
We deliberately do not make it possible to silence the warnings
for expressions like:
{build,an,unnecessary,term}, ok
or
is_list(L), ok
because we don't know of any real-world scenarios in which that would
be useful.
Diffstat (limited to 'EPLICENCE')
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