t1: f (g x) y
loc(t1): 1 | f (g x) y
             ^^^^^^^^^
         
t2: let x := 1 in f (f x 2)
loc(t2): 1 | let x:= 1 in f (f x 2)
             ^^^^^^^^^^^^^^^^^^^^^^
         
t3: let l := map f (list 1 2 3) in let l2 := rev l in = (rev l2) l
loc(t3): 1 | let l := map f (list 1 2 3) in
         1 | let l2 := rev l in rev l2 = l
         
t4: let assm := ==> (is_foo p) (= (filter p l) nil) in true
loc(t4): 1 | let assm := is_foo p ==> (filter p l = nil) in true
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
         
t5: let f := lam (x y : int) (z : bool). (= (+ x y) z)
    and g := lam x. (f (f x)) in is_g g
loc(t5): 1 | let f := fn (x y : int) (z:bool). ( x+ y) = z
         1 |       and g := fn x. f (f x) in is_g g
         
d1:
  def f (x y : list int) : list int := if (= x 0) y whatever;
  #ty f;
  #sledgehammer lam x y. (= (f x y) (f x y));