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f45a1a8967
The compiler was not rejecting typeclass declarations without any class
parameters, for example:
:- typeclass foo where [].
Mercury requires typeclass declarations to have at least one class parameter.
compiler/prog_io_typeclass.m:
Emit an error if we encounter a typeclass declaration with no parameters.
tests/invalid/Mmakefile:
tests/invalid/typeclass_no_param.{m,err_exp:
Add a regression test for the above.
tests/invalid/bug191.{m,err_exp}:
Avoid having a typeclass with no parameters.
33 lines
728 B
Mathematica
33 lines
728 B
Mathematica
% Regression test for bug #191:
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% This program caused the following compiler abort in rotd-2011-03-22:
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%
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% Software Error: code_gen.m: Unexpected: semidet model in det context
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%
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:- module bug191.
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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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:- type foo ---> a(int); b(string).
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:- inst a ---> a(ground).
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:- typeclass foo(T) where [pred baz(T::in, int::in, foo::out(a)) is det].
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:- instance foo(int) where [pred(baz/3) is bar].
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:- pred foo(foo::in(a), int::out) is det.
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foo(a(I), I).
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% should be bar(int::in, foo::out(a))
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:- pred bar(int::in, int::in, foo::out) is det.
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bar(_, _S, b("GOTCHA")).
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main(!IO) :-
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baz(561, 42, F),
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foo(F, I),
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print(I, !IO), nl(!IO).
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