lean4-htt/tests/lean/unfold_crash2.lean
2016-07-29 13:03:23 -07:00

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import data.nat
open tactic
inductive vector (A : Type) : nat → Type :=
| nil {} : vector A 0
| cons : Π {n}, A -> vector A n -> vector A (nat.succ n)
definition vmap {A B : Type} (f : A -> B) : Π {n}, vector A n -> vector B n
| vmap vector.nil := vector.nil
| vmap (vector.cons x xs) := vector.cons (f x) (vmap xs)
definition vappend {A} : Π {n m}, vector A n -> vector A m -> vector A (m + n)
| vappend vector.nil vector.nil := vector.nil
| vappend vector.nil (vector.cons x xs) := vector.cons x xs
| vappend (vector.cons x xs) vector.nil := vector.cons x (vappend xs vector.nil)
| vappend (vector.cons x xs) (vector.cons y ys) := vector.cons x (vappend xs (vector.cons y ys))
axiom Sorry : ∀ A, A
theorem vappend_assoc :
Π {A : Type} {n m k : nat} (v1 : vector A n) (v2 : vector A m) (v3 : vector A k),
vappend (vappend v1 v2) v3 == vappend v1 (vappend v2 v3) :=
by do
intros,
-- should not unfold anything since term does not contains any of the patterns above.
unfold [`vappend],
trace_state, trace "-----------",
get_local `v1 >>= cases,
trace_state, trace "-----------",
-- should not unfold anything since term does not contains any of the patterns above.
unfold [`vappend],
trace_state, trace "-----------",
get_local `v2 >>= cases,
trace_state, trace "-----------",
-- now it should unfold
unfold [`vappend],
trace_state, trace "-----------",
repeat $ mk_const `Sorry >>= apply