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authorMagnus Lång <[email protected]>2016-07-04 14:12:07 +0200
committerMagnus Lång <[email protected]>2016-07-04 15:35:05 +0200
commit784f845e2d1ec66b9505339b4b0e43d55c2d49a9 (patch)
tree40ee492ba9ecc4efdbfdca696b46c759c714e01f /lib/dialyzer/src
parent1697cdea341e7d54e754e5f85e091c8bb68fb6c7 (diff)
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dialyzer: Suppress warns on generated case stmts
Warnings about clauses that cannot match and are also compiler generated are suppressed unless none of the clauses return. This feature is useful for non-Erlang BEAM languages (such as Elixir) that compile to Erlang and expand certain language constructs into case statements. In that case, as long as the language construct can succeed, these warnings are undesired and appear spurious to users that do not check the Erlang code that their program expands into. Thanks to José Valim for the test (slightly modified).
Diffstat (limited to 'lib/dialyzer/src')
-rw-r--r--lib/dialyzer/src/dialyzer_dataflow.erl62
1 files changed, 36 insertions, 26 deletions
diff --git a/lib/dialyzer/src/dialyzer_dataflow.erl b/lib/dialyzer/src/dialyzer_dataflow.erl
index 9399789464..963c953447 100644
--- a/lib/dialyzer/src/dialyzer_dataflow.erl
+++ b/lib/dialyzer/src/dialyzer_dataflow.erl
@@ -978,12 +978,21 @@ handle_case(Tree, Map, State) ->
false -> State1
end,
Map2 = join_maps_begin(Map1),
- {MapList, State3, Type} =
+ {MapList, State3, Type, Warns} =
handle_clauses(Clauses, Arg, ArgType, ArgType, State2,
- [], Map2, [], []),
+ [], Map2, [], [], []),
+ %% Non-Erlang BEAM languages, such as Elixir, expand language constructs
+ %% into case statements. In that case, we do not want to warn on
+ %% individual clauses not matching unless none of them can.
+ SupressForced = is_compiler_generated(cerl:get_ann(Tree))
+ andalso not (t_is_none(Type)),
+ State4 = lists:foldl(fun({T,R,M,F}, S) ->
+ state__add_warning(
+ S,T,R,M,F andalso (not SupressForced))
+ end, State3, Warns),
Map3 = join_maps_end(MapList, Map2),
debug_pp_map(Map3),
- {State3, Map3, Type}
+ {State4, Map3, Type}
end.
%%----------------------------------------
@@ -1082,22 +1091,24 @@ handle_receive(Tree, Map, State) ->
RaceListSize + 1, State);
false -> State
end,
- {MapList, State2, ReceiveType} =
+ {MapList, State2, ReceiveType, Warns} =
handle_clauses(Clauses, ?no_arg, t_any(), t_any(), State1, [], Map,
- [], []),
+ [], [], []),
+ State3 = lists:foldl(fun({T,R,M,F}, S) -> state__add_warning(S,T,R,M,F) end,
+ State2, Warns),
Map1 = join_maps(MapList, Map),
- {State3, Map2, TimeoutType} = traverse(Timeout, Map1, State2),
- Opaques = State3#state.opaques,
+ {State4, Map2, TimeoutType} = traverse(Timeout, Map1, State3),
+ Opaques = State4#state.opaques,
case (t_is_atom(TimeoutType, Opaques) andalso
(t_atom_vals(TimeoutType, Opaques) =:= ['infinity'])) of
true ->
- {State3, Map2, ReceiveType};
+ {State4, Map2, ReceiveType};
false ->
Action = cerl:receive_action(Tree),
- {State4, Map3, ActionType} = traverse(Action, Map, State3),
+ {State5, Map3, ActionType} = traverse(Action, Map, State4),
Map4 = join_maps([Map3, Map1], Map),
Type = t_sup(ReceiveType, ActionType),
- {State4, Map4, Type}
+ {State5, Map4, Type}
end.
%%----------------------------------------
@@ -1245,7 +1256,7 @@ handle_tuple(Tree, Map, State) ->
%% Clauses
%%
handle_clauses([C|Left], Arg, ArgType, OrigArgType, State, CaseTypes, MapIn,
- Acc, ClauseAcc) ->
+ Acc, ClauseAcc, WarnAcc0) ->
IsRaceAnalysisEnabled = is_race_analysis_enabled(State),
State1 =
case IsRaceAnalysisEnabled of
@@ -1258,8 +1269,8 @@ handle_clauses([C|Left], Arg, ArgType, OrigArgType, State, CaseTypes, MapIn,
State);
false -> State
end,
- {State2, ClauseMap, BodyType, NewArgType} =
- do_clause(C, Arg, ArgType, OrigArgType, MapIn, State1),
+ {State2, ClauseMap, BodyType, NewArgType, WarnAcc} =
+ do_clause(C, Arg, ArgType, OrigArgType, MapIn, State1, WarnAcc0),
{NewClauseAcc, State3} =
case IsRaceAnalysisEnabled of
true ->
@@ -1277,9 +1288,9 @@ handle_clauses([C|Left], Arg, ArgType, OrigArgType, State, CaseTypes, MapIn,
false -> {[BodyType|CaseTypes], [ClauseMap|Acc]}
end,
handle_clauses(Left, Arg, NewArgType, OrigArgType, State3,
- NewCaseTypes, MapIn, NewAcc, NewClauseAcc);
+ NewCaseTypes, MapIn, NewAcc, NewClauseAcc, WarnAcc);
handle_clauses([], _Arg, _ArgType, _OrigArgType, State, CaseTypes, _MapIn, Acc,
- ClauseAcc) ->
+ ClauseAcc, WarnAcc) ->
State1 =
case is_race_analysis_enabled(State) of
true ->
@@ -1289,9 +1300,9 @@ handle_clauses([], _Arg, _ArgType, _OrigArgType, State, CaseTypes, _MapIn, Acc,
RaceListSize + 1, State);
false -> State
end,
- {lists:reverse(Acc), State1, t_sup(CaseTypes)}.
+ {lists:reverse(Acc), State1, t_sup(CaseTypes), WarnAcc}.
-do_clause(C, Arg, ArgType0, OrigArgType, Map, State) ->
+do_clause(C, Arg, ArgType0, OrigArgType, Map, State, Warns) ->
Pats = cerl:clause_pats(C),
Guard = cerl:clause_guard(C),
Body = cerl:clause_body(C),
@@ -1323,7 +1334,7 @@ do_clause(C, Arg, ArgType0, OrigArgType, Map, State) ->
[cerl_prettypr:format(C), format_type(ArgType0, State1)]),
case state__warning_mode(State1) of
false ->
- {State1, Map, t_none(), ArgType0};
+ {State1, Map, t_none(), ArgType0, Warns};
true ->
{Msg, Force} =
case t_is_none(ArgType0) of
@@ -1403,8 +1414,7 @@ do_clause(C, Arg, ArgType0, OrigArgType, Map, State) ->
{record_match, _} -> ?WARN_MATCHING;
{pattern_match_cov, _} -> ?WARN_MATCHING
end,
- {state__add_warning(State1, WarnType, C, Msg, Force),
- Map, t_none(), ArgType0}
+ {State1, Map, t_none(), ArgType0, [{WarnType, C, Msg, Force}|Warns]}
end;
{Map2, PatTypes} ->
Map3 =
@@ -1437,9 +1447,9 @@ do_clause(C, Arg, ArgType0, OrigArgType, Map, State) ->
false ->
{guard_fail_pat, [PatString, format_type(ArgType0, State1)]}
end,
- State2 =
+ Warn =
case Reason of
- none -> state__add_warning(State1, ?WARN_MATCHING, C, DefaultMsg);
+ none -> {?WARN_MATCHING, C, DefaultMsg, false};
{FailGuard, Msg} ->
case is_compiler_generated(cerl:get_ann(FailGuard)) of
false ->
@@ -1448,15 +1458,15 @@ do_clause(C, Arg, ArgType0, OrigArgType, Map, State) ->
{neg_guard_fail, _} -> ?WARN_MATCHING;
{opaque_guard, _} -> ?WARN_OPAQUE
end,
- state__add_warning(State1, WarnType, FailGuard, Msg);
+ {WarnType, FailGuard, Msg, false};
true ->
- state__add_warning(State1, ?WARN_MATCHING, C, Msg)
+ {?WARN_MATCHING, C, Msg, false}
end
end,
- {State2, Map, t_none(), NewArgType};
+ {State1, Map, t_none(), NewArgType, [Warn|Warns]};
Map4 ->
{RetState, RetMap, BodyType} = traverse(Body, Map4, State1),
- {RetState, RetMap, BodyType, NewArgType}
+ {RetState, RetMap, BodyType, NewArgType, Warns}
end
end.