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authorMagnus Lång <[email protected]>2016-02-28 00:17:48 +0100
committerHans Bolinder <[email protected]>2016-04-28 16:16:09 +0200
commitebd967522612333e52a884181e6132b1ba7e5239 (patch)
treecd12d37cd4fe9d375cf15acbad8d08e5a4542af5 /lib/dialyzer/src/dialyzer_dataflow.erl
parente3ac51b173585f84c397ae38c27d772be2d308c6 (diff)
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dialyzer: Unfold cerl patterns containing maps
Dialyzer relies heavily on the assumption that the type of a literal that is used as a pattern is the type of any value that can match that pattern. For maps, that is not true, and it was causing bad analysis results. A new help function dialyzer_utils:refold_pattern/1 identifies maps in literal patterns, and unfolds and labels them, allowing them to be properly analysed.
Diffstat (limited to 'lib/dialyzer/src/dialyzer_dataflow.erl')
-rw-r--r--lib/dialyzer/src/dialyzer_dataflow.erl24
1 files changed, 18 insertions, 6 deletions
diff --git a/lib/dialyzer/src/dialyzer_dataflow.erl b/lib/dialyzer/src/dialyzer_dataflow.erl
index a3b3e3291c..9827fda6e3 100644
--- a/lib/dialyzer/src/dialyzer_dataflow.erl
+++ b/lib/dialyzer/src/dialyzer_dataflow.erl
@@ -1482,7 +1482,9 @@ bind_pat_vars([Pat|PatLeft], [Type|TypeLeft], Acc, Map, State, Rev) ->
{NewMap, TypeOut} =
case cerl:type(Pat) of
alias ->
- AliasPat = cerl:alias_pat(Pat),
+ %% Map patterns are more allowing than the type of their literal. We
+ %% must unfold AliasPat if it is a literal.
+ AliasPat = dialyzer_utils:refold_pattern(cerl:alias_pat(Pat)),
Var = cerl:alias_var(Pat),
Map1 = enter_subst(Var, AliasPat, Map),
{Map2, [PatType]} = bind_pat_vars([AliasPat], [Type], [],
@@ -1523,11 +1525,20 @@ bind_pat_vars([Pat|PatLeft], [Type|TypeLeft], Acc, Map, State, Rev) ->
{Map1, t_cons(HdType, TlType)}
end;
literal ->
- Literal = literal_type(Pat),
- case t_is_none(t_inf(Literal, Type, Opaques)) of
+ Pat0 = dialyzer_utils:refold_pattern(Pat),
+ case cerl:is_literal(Pat0) of
true ->
- bind_opaque_pats(Literal, Type, Pat, State);
- false -> {Map, Literal}
+ Literal = literal_type(Pat),
+ case t_is_none(t_inf(Literal, Type, Opaques)) of
+ true ->
+ bind_opaque_pats(Literal, Type, Pat, State);
+ false -> {Map, Literal}
+ end;
+ false ->
+ %% Retry with the unfolded pattern
+ {Map1, [PatType]}
+ = bind_pat_vars([Pat0], [Type], [], Map, State, Rev),
+ {Map1, PatType}
end;
map ->
MapT = t_inf(Type, t_map(), Opaques),
@@ -2742,8 +2753,9 @@ store_map(Key, Val, #map{dict = Dict, ref = undefined} = Map) ->
store_map(Key, Val, #map{dict = Dict, modified = Mod} = Map) ->
Map#map{dict = dict:store(Key, Val, Dict), modified = [Key | Mod]}.
-enter_subst(Key, Val, #map{subst = Subst} = MS) ->
+enter_subst(Key, Val0, #map{subst = Subst} = MS) ->
KeyLabel = get_label(Key),
+ Val = dialyzer_utils:refold_pattern(Val0),
case cerl:is_literal(Val) of
true ->
store_map(KeyLabel, literal_type(Val), MS);