5cef84709f
See Section "Other goodies" at https://github.com/leanprover/lean/wiki/Refactoring-structures This commit also improves the support for projections in the unifier/matcher. Now, we consider the extra case-split for projections. Given a projection `proj`, and the constraint `proj s =?= proj t`, we need to try first `s =?= t` and if it fails, then try to reduce. This is needed in the standard library because we now have constraints such as: ``` @has_le.le ?A ?s ?a ?b =?= @has_le.le nat nat.has_add x y ``` If we reduce the right hand side, we get the unsolvable constraint ``` @has_le.le ?A ?s ?a ?b =?= nat.le x y ``` Before this change, the constraint was `@le ?A ?s ?a ?b =?= @le nat nat.has_add x y`, and we already perform a case-split in this case. Moreover, projections were eagerly reduced whenever possible. The extra case-split generates a performance problem in several tests. For example `fib 8 = 34` was timing out. I worked around this issue by performing the case-split only when the constraint contains meta-variables. There are also minor issues. Example. `<` is notation for `has_lt.lt`, but `>` is for `gt`.
25 lines
405 B
Text
25 lines
405 B
Text
definition foo.subst := @eq.subst
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definition boo.subst := @eq.subst
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definition foo.add := @has_add.add
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definition boo.add := @has_add.add
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set_option pp.all true
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open foo boo has_add
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#print raw subst -- subst is overloaded
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#print raw add -- add is overloaded
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#check @subst
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#check @@subst
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open eq
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#check subst
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constants a b : nat
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constant H1 : a = b
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constant H2 : a + b > 0
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#check eq.subst H1 H2
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