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authorAnthony Ramine <n.oxyde@gmail.com>2014-03-08 02:31:53 +0100
committerAnthony Ramine <n.oxyde@gmail.com>2014-03-10 02:37:10 +0100
commit4777f33ece33aaaa5066730b950f185cbd5ae816 (patch)
treedb57597f62d5c6eda64f12f6274900655e2ac194 /lib
parent870737ab657433c5e8751255fe3c4d298202d142 (diff)
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Properly handle redundant boolean clauses in sys_core_fold
Boolean case expressions with redundant clauses could make the compiler crash: case X == 0 of false -> no; false -> no; true -> yes end. Reported-by: Ulf Norell
Diffstat (limited to 'lib')
-rw-r--r--lib/compiler/src/sys_core_fold.erl11
-rw-r--r--lib/compiler/test/core_fold_SUITE.erl13
-rw-r--r--lib/compiler/test/warnings_SUITE.erl22
3 files changed, 39 insertions, 7 deletions
diff --git a/lib/compiler/src/sys_core_fold.erl b/lib/compiler/src/sys_core_fold.erl
index 6fdeea51d1..058abd3357 100644
--- a/lib/compiler/src/sys_core_fold.erl
+++ b/lib/compiler/src/sys_core_fold.erl
@@ -1810,9 +1810,14 @@ opt_bool_clauses([#c_clause{pats=[#c_literal{val=Lit}],
true ->
%% This clause will match.
C = C0#c_clause{body=opt_bool_case(B)},
- case Lit of
- false -> [C|opt_bool_clauses(Cs, SeenT, true)];
- true -> [C|opt_bool_clauses(Cs, true, SeenF)]
+ case {Lit,SeenT,SeenF} of
+ {false,_,false} ->
+ [C|opt_bool_clauses(Cs, SeenT, true)];
+ {true,false,_} ->
+ [C|opt_bool_clauses(Cs, true, SeenF)];
+ _ ->
+ add_warning(C, nomatch_shadow),
+ opt_bool_clauses(Cs, SeenT, SeenF)
end
end;
opt_bool_clauses([#c_clause{pats=Ps,guard=#c_literal{val=true}}=C|Cs], SeenT, SeenF) ->
diff --git a/lib/compiler/test/core_fold_SUITE.erl b/lib/compiler/test/core_fold_SUITE.erl
index 8151dc1b16..9c986576d5 100644
--- a/lib/compiler/test/core_fold_SUITE.erl
+++ b/lib/compiler/test/core_fold_SUITE.erl
@@ -23,7 +23,7 @@
t_element/1,setelement/1,t_length/1,append/1,t_apply/1,bifs/1,
eq/1,nested_call_in_case/1,guard_try_catch/1,coverage/1,
unused_multiple_values_error/1,unused_multiple_values/1,
- multiple_aliases/1]).
+ multiple_aliases/1,redundant_boolean_clauses/1]).
-export([foo/0,foo/1,foo/2,foo/3]).
@@ -40,7 +40,7 @@ groups() ->
[t_element,setelement,t_length,append,t_apply,bifs,
eq,nested_call_in_case,guard_try_catch,coverage,
unused_multiple_values_error,unused_multiple_values,
- multiple_aliases]}].
+ multiple_aliases,redundant_boolean_clauses]}].
init_per_suite(Config) ->
@@ -365,4 +365,13 @@ run_once() ->
ok.
+redundant_boolean_clauses(Config) when is_list(Config) ->
+ X = id(0),
+ yes = case X == 0 of
+ false -> no;
+ false -> no;
+ true -> yes
+ end.
+
+
id(I) -> I.
diff --git a/lib/compiler/test/warnings_SUITE.erl b/lib/compiler/test/warnings_SUITE.erl
index f63299ea35..de56a59e12 100644
--- a/lib/compiler/test/warnings_SUITE.erl
+++ b/lib/compiler/test/warnings_SUITE.erl
@@ -38,7 +38,7 @@
-export([pattern/1,pattern2/1,pattern3/1,pattern4/1,
guard/1,bad_arith/1,bool_cases/1,bad_apply/1,
files/1,effect/1,bin_opt_info/1,bin_construction/1, comprehensions/1,
- maps/1]).
+ maps/1,redundant_boolean_clauses/1]).
% Default timetrap timeout (set in init_per_testcase).
-define(default_timeout, ?t:minutes(2)).
@@ -62,7 +62,8 @@ groups() ->
[{p,test_lib:parallel(),
[pattern,pattern2,pattern3,pattern4,guard,
bad_arith,bool_cases,bad_apply,files,effect,
- bin_opt_info,bin_construction,comprehensions,maps]}].
+ bin_opt_info,bin_construction,comprehensions,maps,
+ redundant_boolean_clauses]}].
init_per_suite(Config) ->
Config.
@@ -201,6 +202,8 @@ pattern4(Config) when is_list(Config) ->
[nowarn_unused_vars],
{warnings,
[{9,sys_core_fold,no_clause_match},
+ {11,sys_core_fold,nomatch_shadow},
+ {15,sys_core_fold,nomatch_shadow},
{18,sys_core_fold,no_clause_match},
{23,sys_core_fold,no_clause_match},
{33,sys_core_fold,no_clause_match}
@@ -573,6 +576,21 @@ maps(Config) when is_list(Config) ->
run(Config, Ts),
ok.
+redundant_boolean_clauses(Config) when is_list(Config) ->
+ Ts = [{redundant_boolean_clauses,
+ <<"
+ t(X) ->
+ case X == 0 of
+ false -> no;
+ false -> no;
+ true -> yes
+ end.
+ ">>,
+ [],
+ {warnings,[{5,sys_core_fold,nomatch_shadow}]}}],
+ run(Config, Ts),
+ ok.
+
%%%
%%% End of test cases.
%%%