445c8f2ee0
A round of clean-up for the context of the functional induction principle cases. * Already previously, with `match e with | p => …`, functional induction would ensure that `h : e = p` is in scope, but it wouldn’t work in dependent cases. Now it introduces heterogeneous equality where needed (fixes #4146) * These equalities are now added always (previously we omitted them when the discriminant was a variable that occurred in the goal, on the grounds that the goal gets refined through the match, but it’s more consistent to introduce the equality in any case) * We no longer use `MVarId.cleanup` to clean up the goal; it was sometimes too aggressive (fixes #5347) * Instead, we clean up more carefully and with a custom strategy: * First, we substitute all variables without a user-accessible name, if we can. * Then, we substitute all variable, if we can, outside in. * As we do that, we look for `HEq`s that we can turn into `Eq`s to substitute some more * We substitute unused `let`s. **Breaking change**: In some cases leads to a different functional induction principle (different names and order of assumptions, for example).
17 lines
477 B
Text
17 lines
477 B
Text
def f (x: Nat): Option Nat :=
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if x > 10 then some 0 else none
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def test (x: Nat): Nat :=
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match f x, x with
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| some k, _ => k
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| none, 0 => 0
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| none, n + 1 => test n
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-- set_option trace.Meta.FunInd true
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/--
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info: test.induct (motive : Nat → Prop) (case1 : ∀ (t k : Nat), f t = some k → motive t) (case2 : f 0 = none → motive 0)
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(case3 : ∀ (n : Nat), f n.succ = none → motive n → motive n.succ) (x : Nat) : motive x
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-/
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#guard_msgs in
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#check test.induct
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