e0c1afd12d
Closes #3386 Currently, when generating the signature of an injectivity lemma for a certain constructor `c : forall xs, Foo a_1 ... a_n`, `mkInjectiveTheoremTypeCore?` will differentiate between variables which are bound to stay the same between the two equal values (i.e inductive indices), and non-fixed ones. To do that, the function currently checks whether a variable `x ∈ xs` appears in the final co-domain `Foo a_1 ... a_n` of the constructor. This condition isn't enough however. As shown in the linked issue, the codomain may also depend on variables which appears in the type of free vars contained in `Foo a_1 ... a_n`, but not in the term itself. This PR fixes the issue by also checking the types of any free variable occuring in the final codomain, so as to ensure injectivity lemmas are well-typed.
9 lines
301 B
Text
9 lines
301 B
Text
/- Verify that injectivity lemmas are constructed with the right level of generality
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in order to avoid type errors.
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-/
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inductive Tyₛ : Type (u+1)
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| SPi : (T : Type u) -> (T -> Tyₛ) -> Tyₛ
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inductive Tmₛ.{u} : Tyₛ.{u} -> Type (u+1)
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| app : Tmₛ (.SPi T A) -> (arg : T) -> Tmₛ (A arg)
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