Tolerant record construction #2
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Update Dialyzer so that functions
that construct bad records are not
treated as `no_return`ing.
Constructing a record in a way that
doesn't match the type signature is
never a runtime error.
By having Dialyzer reflect this behavior,
we can avoid false positives
and helps find real bugs.
For example, before this change, running
Dialyzer on the code below would produce
4 false positives before the user sees
a meaningful warnings. And any
genuine bugs after the bad record
construction were hidden:
-record(rec, {field :: float() }).
a() -> b().
b() -> c().
c() -> d().
d() ->
#rec{field = 3},
% ... more code here
ok.
sample.erl:6: Function a/0 has no local return
sample.erl:7: Function b/0 has no local return
sample.erl:8: Function c/0 has no local return
sample.erl:9: Function d/0 has no local return
sample.erl:9: Record construction
#rec{field :: 3} violates the declared type of field field ::
float()
With this change, only a single warning is shown
when there are no more discrepancies in d/0.
Update small_SUITE to reflect that there are no more no_returns errors caused by bad record constructions And update typer_SUITE to make sure typer still shows functions with bad constructions as returning none()
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Update Dialyzer so that functions
that construct bad records are not
treated as
no_returning.Constructing a record in a way that
doesn't match the type signature is
never a runtime error.
By having Dialyzer reflect this behavior,
we can avoid false positives
and helps find real bugs.
For example, before this change, running
Dialyzer on the code below would produce
4 false positives before the user sees
a meaningful warnings. And any
genuine bugs after the bad record
construction were hidden:
-record(rec, {field :: float() }).
a() -> b().
b() -> c().
c() -> d().
d() ->
#rec{field = 3},
% ... more code here
ok.
sample.erl:6: Function a/0 has no local return
sample.erl:7: Function b/0 has no local return
sample.erl:8: Function c/0 has no local return
sample.erl:9: Function d/0 has no local return
sample.erl:9: Record construction
#rec{field :: 3} violates the declared type of field field ::
float()
With this change, only a single warning is shown
when there are no more discrepancies in d/0.