1 files changed, 42 insertions, 0 deletions
diff --git a/test-suite/success/subst.v b/test-suite/success/subst.v
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+(* Test various subtleties of the "subst" tactics *)
+
+(* Should proceed from left to right (see #4222) *)
+Goal forall x y, x = y -> x = 3 -> y = 2 -> x = y.
+intros.
+subst.
+change (3 = 2) in H1.
+change (3 = 3).
+Abort.
+
+(* Should work with "x = y" and "x = t" equations (see #4214, failed in 8.4) *)
+Goal forall x y, x = y -> x = 3 -> x = y.
+intros.
+subst.
+change (3 = 3).
+Abort.
+
+(* Should substitute cycles once, until a recursive equation is obtained *)
+(* (failed in 8.4) *)
+Goal forall x y, x = S y -> y = S x -> x = y.
+intros.
+subst.
+change (y = S (S y)) in H0.
+change (S y = y).
+Abort.
+
+(* A bug revealed by OCaml 4.03 warnings *)
+(* fixes in 4e3d464 and 89ec88f for v8.5, 4e3d4646 and 89ec88f1e for v8.6 *)
+Goal forall y, let x:=0 in y=x -> y=y.
+intros * H;
+(* This worked as expected *)
+subst.
+Fail clear H.
+Abort.
+
+Goal forall y, let x:=0 in x=y -> y=y.
+intros * H;
+(* Before the fix, this unfolded x instead of 
+   substituting y and erasing H *)
+subst.
+Fail clear H.
+Abort.