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Coq: How do I match inside a binder properly?
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| Ltac detect := | |
| match goal with | |
| | [ |- context G [ forall x : ?T, _ (* ?E *) ] ] => | |
| idtac G T; fail | |
| end. | |
| Theorem test : (forall x, x = 1) = (forall x, x = 2). | |
| Proof. | |
| try detect. | |
| (* As shown above: _ matches inside binders expectedly | |
| (?CONTEXT-HOLE = (forall x : nat, x = 2)) nat | |
| ((forall x : nat, x = 1) = ?CONTEXT-HOLE) nat | |
| *) | |
| (* Change _ into ?E (no output) -> doesn't match anymore | |
| *) |
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