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| author | Anthony Ramine <[email protected]> | 2014-03-08 02:31:53 +0100 |
|---|---|---|
| committer | Anthony Ramine <[email protected]> | 2014-03-10 02:37:10 +0100 |
| commit | 4777f33ece33aaaa5066730b950f185cbd5ae816 (patch) | |
| tree | db57597f62d5c6eda64f12f6274900655e2ac194 /lib/compiler/src/sys_core_fold.erl | |
| parent | 870737ab657433c5e8751255fe3c4d298202d142 (diff) | |
| download | otp-4777f33ece33aaaa5066730b950f185cbd5ae816.tar.gz otp-4777f33ece33aaaa5066730b950f185cbd5ae816.tar.bz2 otp-4777f33ece33aaaa5066730b950f185cbd5ae816.zip | |
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/compiler/src/sys_core_fold.erl')
| -rw-r--r-- | lib/compiler/src/sys_core_fold.erl | 11 |
1 files changed, 8 insertions, 3 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) -> |