REFACTOR NEEDED: Added another special case; insert instead of appending into currentStates

regex/matching.go

@@ -379,17 +379,17 @@ func findAllSubmatchHelper(start *nfaState, str []rune, offset int, numGroups in
 				if currentState.isKleene { // Reverse order of adding things
 					rightState := currentState.splitState
 					copyThread(rightState, currentState)
-					currentStates = append(currentStates, *currentState.splitState)
+					currentStates = slices.Insert(currentStates, currentStateIdx+1, *rightState)
 					leftState := currentState.next
 					copyThread(leftState, currentState)
-					currentStates = append(currentStates, *currentState.next)
+					currentStates = slices.Insert(currentStates, currentStateIdx+2, *leftState)
 				} else {
 					leftState := currentState.next
 					copyThread(leftState, currentState)
-					currentStates = append(currentStates, *currentState.next)
+					currentStates = slices.Insert(currentStates, currentStateIdx+1, *leftState)
 					rightState := currentState.splitState
 					copyThread(rightState, currentState)
-					currentStates = append(currentStates, *currentState.splitState)
+					currentStates = slices.Insert(currentStates, currentStateIdx+2, *rightState)
 				}
 				continue
 			}
@@ -417,6 +417,8 @@ func findAllSubmatchHelper(start *nfaState, str []rune, offset int, numGroups in
 					currentStates = slices.Insert(currentStates, currentStateIdx+1, allMatches...)
 				} else if currentState.groupEnd {
 					currentStates = append(currentStates, allMatches...)
+				} else if currentState.assert != noneAssert {
+					currentStates = append(currentStates, allMatches...)
 				} else {
 					nextStates = append(nextStates, allMatches...)
 				}