diff --git a/_tags b/_tags
index 491f9fe3..8b30136a 100644
--- a/_tags
+++ b/_tags
@@ -11,5 +11,5 @@
 
 # more warnings
 <**/*.ml>: warn_K, warn_Y, warn_X
-
 <**/*.cm*>: debug
+
diff --git a/util/vec.ml b/util/vec.ml
index 54a9588a..26b1c393 100644
--- a/util/vec.ml
+++ b/util/vec.ml
@@ -82,15 +82,14 @@ let last t =
 
 let get t i =
   if i < 0 || i >= t.sz then invalid_arg "vec.get";
-  Array.unsafe_get t.data i
+  Array.get t.data i
 
 let set t i v =
   if i < 0 || i > t.sz then invalid_arg "vec.set";
-  if i = t.sz then begin
-    grow_to_double_size t;
-    t.sz <- i + 1
-  end;
-  Array.unsafe_set t.data i v
+  if i = t.sz then
+    push t v
+  else
+    Array.set t.data i v
 
 let copy t =
   let data = Array.copy t.data in
@@ -100,7 +99,6 @@ let move_to t t' =
   t'.data <- Array.copy t.data;
   t'.sz <- t.sz
 
-
 let remove t e =
   let j = ref 0 in
   while (!j < t.sz && not (t.data.(!j) == e)) do incr j done;
@@ -132,7 +130,7 @@ let fold f acc t =
     if i=t.sz
     then acc
     else
-      let acc' = f acc (Array.unsafe_get t.data i) in
+      let acc' = f acc (Array.get t.data i) in
       _fold f acc' t (i+1)
   in _fold f acc t 0
 
@@ -141,7 +139,7 @@ exception ExitVec
 let exists p t =
   try
     for i = 0 to t.sz - 1 do
-      if p (Array.unsafe_get t.data i) then raise ExitVec
+      if p (Array.get t.data i) then raise ExitVec
     done;
     false
   with ExitVec -> true
@@ -149,7 +147,7 @@ let exists p t =
 let for_all p t =
   try
     for i = 0 to t.sz - 1 do
-      if not (p (Array.unsafe_get t.data i)) then raise ExitVec
+      if not (p (Array.get t.data i)) then raise ExitVec
     done;
     true
   with ExitVec -> false