lean2/tests/lean/run/tactic17.lean

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import standard
using tactic
variable A : Type.{1}
variable f : A → A → A
theorem tst {a b c : A} (H1 : a = b) (H2 : b = c) : f a b = f b c
:= by apply (@congr A A (f a) (f b));
apply (congr2 f);
!assumption