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Branches: main, 10.04 Work around bug #142. The symptom is an assertion failure in hlds.hlds_rtti.apply_substs_to_constraint_map. It occurs when: - a variable holding a typeclass_info is used multiple times in a call; - the called procedure is inlined into the caller; - the corresponding head variables have class constraints with functional dependencies; - the type variables in those constraints should be unified, but type variables in the ranges of functional dependencies are not unified; - a single typeclass_info variable ends up being for two different constraints. The work around adopted here is to prevent inlining of a call when a single typeclass_info variable appears multiple times in the argument list, for which the head variables have differing class constraints. compiler/inlining.m: As above. tests/valid/Mercury.options: tests/valid/Mmakefile: tests/valid/bug142.m: Add test case.
54 lines
1.4 KiB
Mathematica
54 lines
1.4 KiB
Mathematica
% Regression test for bug #142 (worked around in inlining.m)
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%
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% mmc --optimise-higher-order --inline-single-use -C bug142.m
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% Uncaught Mercury exception:
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% Software Error: hlds_rtti.m: Unexpected: inconsistent typeclass_infos
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:- module bug142.
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:- interface.
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:- type r(T)
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---> ok(T)
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; err.
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:- type dcg(T, State) == (pred(r(T), State, State)).
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:- mode dcg == in(pred(out, in, out) is det).
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:- typeclass dcg(Token, State) <= ((State -> (Token))) where [
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].
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:- pred or(dcg(T, State)::dcg, dcg(T, State)::dcg,
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r(T)::out, State::in, State::out) is det <= dcg(Token, State).
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:- pred orr(dcg(T, State)::dcg, dcg(T, State)::dcg, dcg(T, State)::dcg,
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r(T)::out, State::in, State::out) is det <= dcg(Token, State).
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%------------------------------------------------------------------------------%
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%------------------------------------------------------------------------------%
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:- implementation.
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or(PA, PB, Result, S0, S) :-
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PA(RA, S0, S1),
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(
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RA = ok(V),
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S = S1,
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Result = ok(V)
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;
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RA = err,
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PB(RB, S0, S),
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(
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RB = ok(V),
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Result = ok(V)
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;
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RB = err,
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Result = err
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)
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).
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orr(PA, PB, PC, Result, S0, S) :-
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or(or(PA, PB), PC, Result, S0, S).
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%------------------------------------------------------------------------------%
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% vim: ft=mercury ts=4 sw=4 et
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