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authorMagnus Lång <[email protected]>2016-04-18 19:01:54 +0200
committerHans Bolinder <[email protected]>2016-04-28 16:16:10 +0200
commit81234c978d1ff1295d20158ed83b296b1f5b1c9f (patch)
tree8cc1e9d6c608f76aa5b3330d410c9c483aedb78f /lib
parent80bda0beb9c45a016414009d3a84c502301bece8 (diff)
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dialyzer: Fix another pattern literal bug
dialyzer_typesig:traverse/3 would perform an unsafe optimisation when given a cons pattern that contained a map and could be folded into a literal with cerl:fold_literal/1. In this case, when traversing the map a type variable would be generated, but this variable would be dropped by the erl_types:t_cons/2 constructor by in turn calling t_sup(), producing the overapproximation any(). However, in this particular case, dialyzer_typesig:traverse/3 is not allowed to overapproximate, since its result is used in an EQ-constraint. Although erl_types:t_tuple/1 does not overapproximate like t_cons/2, which makes the bug unlikely to affect tuples too, the fix was nevertheless applied defensively to the case of tuples as well. Also, fix a bug where dialyzer_utils:refold_pattern/1 would generate syntax nodes with two {label, _} attributes.
Diffstat (limited to 'lib')
-rw-r--r--lib/dialyzer/src/dialyzer_typesig.erl17
-rw-r--r--lib/dialyzer/src/dialyzer_utils.erl11
-rw-r--r--lib/dialyzer/test/map_SUITE_data/src/bug.erl51
3 files changed, 73 insertions, 6 deletions
diff --git a/lib/dialyzer/src/dialyzer_typesig.erl b/lib/dialyzer/src/dialyzer_typesig.erl
index 5b40376352..ae8b195345 100644
--- a/lib/dialyzer/src/dialyzer_typesig.erl
+++ b/lib/dialyzer/src/dialyzer_typesig.erl
@@ -127,6 +127,8 @@
solvers = [] :: [solver()]
}).
+-type state() :: #state{}.
+
%%-----------------------------------------------------------------------------
-define(TYPE_LIMIT, 4).
@@ -312,7 +314,7 @@ traverse(Tree, DefinedVars, State) ->
Hd = cerl:cons_hd(Tree),
Tl = cerl:cons_tl(Tree),
{State1, [HdVar, TlVar]} = traverse_list([Hd, Tl], DefinedVars, State),
- case cerl:is_literal(cerl:fold_literal(Tree)) of
+ case cerl:is_literal(fold_literal_maybe_match(Tree, State)) of
true ->
%% We do not need to do anything more here.
{State, t_cons(HdVar, TlVar)};
@@ -448,7 +450,7 @@ traverse(Tree, DefinedVars, State) ->
Elements = cerl:tuple_es(Tree),
{State1, EVars} = traverse_list(Elements, DefinedVars, State),
{State2, TupleType} =
- case cerl:is_literal(cerl:fold_literal(Tree)) of
+ case cerl:is_literal(fold_literal_maybe_match(Tree, State1)) of
true ->
%% We do not need to do anything more here.
{State, t_tuple(EVars)};
@@ -2056,7 +2058,7 @@ sane_maps(Map1, Map2, Keys, _S1, _S2) ->
%% Solver v2
-record(v2_state, {constr_data = dict:new() :: dict:dict(),
- state :: #state{}}).
+ state :: state()}).
v2_solve_ref(Fun, Map, State) ->
V2State = #v2_state{state = State},
@@ -3430,6 +3432,15 @@ find_constraint(Tuple, [#constraint_list{list = List}|Cs]) ->
find_constraint(Tuple, [_|Cs]) ->
find_constraint(Tuple, Cs).
+-spec fold_literal_maybe_match(cerl:tree(), state()) -> cerl:tree().
+
+fold_literal_maybe_match(Tree0, State) ->
+ Tree1 = cerl:fold_literal(Tree0),
+ case state__is_in_match(State) of
+ false -> Tree1;
+ true -> dialyzer_utils:refold_pattern(Tree1)
+ end.
+
lookup_record(Records, Tag, Arity) ->
case erl_types:lookup_record(Tag, Arity, Records) of
{ok, Fields} ->
diff --git a/lib/dialyzer/src/dialyzer_utils.erl b/lib/dialyzer/src/dialyzer_utils.erl
index 721c2c000a..d37701f03b 100644
--- a/lib/dialyzer/src/dialyzer_utils.erl
+++ b/lib/dialyzer/src/dialyzer_utils.erl
@@ -873,8 +873,15 @@ refold_pattern(Pat) ->
case cerl:is_literal(Pat) andalso find_map(cerl:concrete(Pat)) of
true ->
Tree = refold_concrete_pat(cerl:concrete(Pat)),
- [{label, Label}] = cerl:get_ann(Tree),
- cerl:set_ann(Tree, [{label, Label}|cerl:get_ann(Pat)]);
+ PatAnn = cerl:get_ann(Pat),
+ case proplists:is_defined(label, PatAnn) of
+ %% Literals are not normally annotated with a label, but can be if, for
+ %% example, they were created by cerl:fold_literal/1.
+ true -> cerl:set_ann(Tree, PatAnn);
+ false ->
+ [{label, Label}] = cerl:get_ann(Tree),
+ cerl:set_ann(Tree, [{label, Label}|PatAnn])
+ end;
false -> Pat
end.
diff --git a/lib/dialyzer/test/map_SUITE_data/src/bug.erl b/lib/dialyzer/test/map_SUITE_data/src/bug.erl
index 9e152bf461..fc32f5641a 100644
--- a/lib/dialyzer/test/map_SUITE_data/src/bug.erl
+++ b/lib/dialyzer/test/map_SUITE_data/src/bug.erl
@@ -1,6 +1,11 @@
-module(bug).
--export([t1/0, f1/1]).
+-export([t1/0, f1/1
+ ,t2/0, f2/1
+ ,t3/0, f3/1
+ ,t4/0, f4/1
+ ,t5/0, f5/1
+ ]).
t1() ->
V = f1(#{a=>b}),
@@ -12,3 +17,47 @@ t1() ->
f1(M) -> %% Should get map() succ typing
#{} = M.
+
+t2() ->
+ V = f2([#{a=>b}]),
+ case V of
+ [#{a := P}] -> P; %% Must not warn here
+ _ -> ok
+ end,
+ ok.
+
+f2(M) -> %% Should get [map(),...] succ typing
+ [#{}] = M.
+
+t3() ->
+ V = f3([#{a=>b},a]),
+ case V of
+ [#{a := P}, _Q] -> P; %% Must not warn here
+ _ -> ok
+ end,
+ ok.
+
+f3(M) -> %% Should get [map()|a,...] succ typing
+ [#{},a] = M.
+
+t4() ->
+ V = f4({#{a=>b},{}}),
+ case V of
+ {#{a := P},{}} -> P; %% Must not warn here
+ _ -> ok
+ end,
+ ok.
+
+f4(M) -> %% Should get {map(),{}} succ typing
+ {#{},{}} = M.
+
+t5() ->
+ V = f5(#{k=>q,a=>b}),
+ case V of
+ #{k := q, a := P} -> P; %% Must not warn here
+ _ -> ok
+ end,
+ ok.
+
+f5(M) -> %% Should get #{k:=q, ...} succ typing
+ #{k:=q} = M.