when deleting from buffer and search list both, don't try to find any matches if the DFA is empty (has a length of 0), because that means there is no search to find a match for

fcore/search-list/search-list.sml

@@ -146,15 +146,7 @@ struct
         end
     else if PersistentVector.isInRange (idx, searchList) then
       (buffer, searchList)
-    else
-      let
-        val buffer = LineGap.goToIdx (idx, buffer)
-        val chr = LineGap.sub (idx, buffer)
-        val newState = Dfa.nextState (dfa, curState, chr)
-        val prevFinalPos =
-          if Dfa.isFinal (dfa, newState) then idx else prevFinalPos
-      in
-        if Dfa.isDead newState then
+    else if Dfa.isDead curState then
       if prevFinalPos = ~1 then
         (* no match found: restart search from `startPos + 1` *)
         insertUntilMatch
@@ -167,10 +159,16 @@ struct
               (startPos, prevFinalPos, searchList)
           val newStart = prevFinalPos + 1
         in
-              insertUntilMatch
-                (newStart, buffer, searchList, dfa, 0, newStart, ~1)
+          insertUntilMatch (newStart, buffer, searchList, dfa, 0, newStart, ~1)
         end
     else
+      let
+        val buffer = LineGap.goToIdx (idx, buffer)
+        val chr = LineGap.sub (idx, buffer)
+        val newState = Dfa.nextState (dfa, curState, chr)
+        val prevFinalPos =
+          if Dfa.isFinal (dfa, newState) then idx else prevFinalPos
+      in
         (* continue *)
         insertUntilMatch
           (idx + 1, buffer, searchList, dfa, newState, startPos, prevFinalPos)
@@ -223,6 +221,9 @@ struct
         PersistentVector.helpPrevMatch (start, searchList, 0)
       val searchStart = searchStart + 1
     in
+      if Vector.length dfa = 0 then
+        (buffer, searchList)
+      else
         insertUntilMatch
           (searchStart, buffer, searchList, dfa, 0, searchStart, ~1)
     end