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bf0e0b944a
Estimated hours taken: 1
Fix a bug in type specialization which caused no-tag types
with user-defined equality to be specialized incorrectly.
compiler/higher_order.m:
Check for user-defined equality before unwrapping
a no-tag type.
tests/hard_coded/Mmakefile:
tests/hard_coded/user_defined_equality.{m,exp}:
Test case.
36 lines
733 B
Mathematica
36 lines
733 B
Mathematica
% This is a regression test.
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%
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% The Mercury compiler of 27/10/2000 failed this test
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% due to overeager specialization of unifications
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% involving no-tag types with user-defined equality.
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:- module user_defined_equality2.
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:- interface.
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:- import_module io.
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:- pred main(io__state::di, io__state::uo) is cc_multi.
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:- implementation.
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:- import_module std_util.
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:- type foo ---> foo(int)
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where equality is foo_equal.
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:- pred foo_equal(foo::in, foo::in) is semidet.
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foo_equal(_, _) :-
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semidet_succeed.
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main -->
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( { unify_no_tag(foo(1), foo(2)) } ->
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io__write_string("yes\n")
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;
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io__write_string("no\n")
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).
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:- pred unify_no_tag(T::in, T::in) is semidet.
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:- pragma type_spec(unify_no_tag/2, T = foo).
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unify_no_tag(T, T).
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