test(lean/run): add elaborator tests

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>

tests/lean/run/e4.lean

@@ -0,0 +1,33 @@
+definition Bool [inline] := Type.{0}
+
+definition false : Bool := ∀x : Bool, x
+check false
+
+theorem false_elim (C : Bool) (H : false) : C
+:= H C
+
+definition eq {A : Type} (a b : A)
+:= ∀ P : A → Bool, P a → P b
+
+check eq
+
+infix `=` 50 := eq
+
+theorem refl {A : Type} (a : A) : a = a
+:= λ P H, H
+
+definition true : Bool
+:= false = false
+
+theorem trivial : true
+:= refl false
+
+theorem subst {A : Type} {P : A -> Bool} {a b : A} (H1 : a = b) (H2 : P a) : P b
+:= H1 _ H2
+
+theorem symm {A : Type} {a b : A} (H : a = b) : b = a
+:= subst H (refl a)
+
+theorem trans {A : Type} {a b c : A} (H1 : a = b) (H2 : b = c) : a = c
+:= subst H2 H1
+