SubstTactic: bug fix

[helm.git] / helm / software / components / tactics / substTactic.ml

diff --git a/helm/software/components/tactics/substTactic.ml b/helm/software/components/tactics/substTactic.ml
index ef2a297e1cfc81e32d9b42e84d294421eb4fd73e..cc107451ee70182c1bbabbb4b8f557534bb87ef7 100644 (file)
--- a/helm/software/components/tactics/substTactic.ml
+++ b/helm/software/components/tactics/substTactic.ml
@@ -67,6 +67,11 @@ let msg3 = lazy "Subst: no progress"
 let rec subst_tac ~try_tactic ~hyp =
    let hole = C.Implicit (Some `Hole) in
    let meta = C.Implicit None in
+   let rec ind = function
+      | C.MutInd _       -> true
+      | C.Appl (t :: tl) -> ind t
+      | _                -> false
+   in
    let rec constr = function
       | C.MutConstruct _ -> true
       | C.Appl (t :: tl) -> constr t
@@ -105,7 +110,7 @@ let rec subst_tac ~try_tactic ~hyp =
          [lift_destruct_tac ~context ~what; PESR.clear ~hyps:[hyp]]
       in
       let whd_g () =
-         let whd_pattern = C.Appl [meta; meta; hole; hole] in
+         let whd_pattern = C.Appl [meta; hole; hole; hole] in
         let pattern = None, [hyp, whd_pattern], None in
         [RT.whd_tac ~pattern; subst_tac ~try_tactic ~hyp]
       in
@@ -114,8 +119,8 @@ let rec subst_tac ~try_tactic ~hyp =
            when LO.is_eq_URI uri -> subst_g `LeftToRight i t
          | (C.Appl [(C.MutInd (uri, 0, [])); _; t; C.Rel i]) 
            when LO.is_eq_URI uri -> subst_g `RightToLeft i t
-        | (C.Appl [(C.MutInd (uri, 0, [])); _; t1; t2]) 
-           when LO.is_eq_URI uri && constr t1 && constr t2 -> destruct_g ()
+        | (C.Appl [(C.MutInd (uri, 0, [])); t; t1; t2]) 
+           when LO.is_eq_URI uri && ind t && constr t1 && constr t2 -> destruct_g ()
         | (C.Appl [(C.MutInd (uri, 0, [])); _; t1; t2])
            when LO.is_eq_URI uri -> whd_g ()    
         | _ -> raise (PET.Fail msg1)