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adc41dc21f
compiler/cse_detection.m:
Don't pull unifications out of the arms of switches inside
require_switch_arms_detism scopes, since this can affect make
the scope ineffective, leading to error messages that should be
generated not being generated.
compiler/hlds_goal.m:
Fix some misleading variable names.
tests/invalid/require_switch_arms_detism.{m,err_exp}:
A regression test for the bug.
tests/invalid/Mmakefile:
Enable the new test.
54 lines
1.7 KiB
Mathematica
54 lines
1.7 KiB
Mathematica
%---------------------------------------------------------------------------%
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% vim: ft=mercury ts=4 sw=4 et
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%---------------------------------------------------------------------------%
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%
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% This is a regression test. Versions of the compiler before 2016 april 10
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% did not generate an error message for the violation of the requirement
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% imposed by the require_switch_arms_detism scope below, because common
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% subexpression elimination pulled the semidet unifications involving Args
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% out of the switch arms, causing two problems: first, the code remaining
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% in each switch arm was now det, so the violation had disappeared,
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% and second, since the goal inside the require_switch_arms_detism scope
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% was now not a switch but a conjunction of the pulled-out-of-the-arms
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% unifications and the modified switch, the require_switch_arms_detism scope
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% did not actually check anything anyway (since it can check only switches,
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% not conjunctions).
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:- module require_switch_arms_detism.
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:- interface.
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:- import_module io.
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:- pred main(io::di, io::uo) is det.
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:- implementation.
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:- import_module list.
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:- import_module string.
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main(!IO) :-
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( if test_switch_arms(":-", ["a", "b", "c"], Result) then
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io.format("Success: %s\n", [s(Result)], !IO)
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else
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io.format("Failure\n", [], !IO)
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).
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:- pred test_switch_arms(string::in, list(string)::in, string::out) is semidet.
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test_switch_arms(Functor, Args, Result) :-
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require_switch_arms_det [Functor]
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(
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Functor = ":-",
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Args = [Arg1, Arg2],
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Result = ":- " ++ Arg1 ++ Arg2
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;
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Functor = "--->",
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Args = [Arg1, Arg2],
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Result = "---> " ++ Arg1 ++ Arg2
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;
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Functor = "=",
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Args = [Arg1, Arg2],
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Result = "= " ++ Arg1 ++ Arg2
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).
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