Program: 135932
Project: 135932
Buggy source:
private final void belchDEF(){
  Token previousT=initPreviewToken();
  Token currentT=getNextPreviewToken(previousT);
  previousT.next=null;
  Token nextT=getNextPreviewToken(currentT);
  currentT.next=previousT;
  while (nextT.kind != EOF && nextT.kind != THEOREM && nextT.kind != PROPOSITION && nextT.kind != ASSUME && nextT.kind != ASSUMPTION && nextT.kind != END_MODULE) {
    if (currentT.kind == DEF) {
      Token t=previousT;
      if (t.kind == RBR || t.kind == RSB) {
        int depth=1;
        while (t.next != null) {
          t=t.next;
          if ((t.kind == LBR || t.kind == LSB) && depth == 1)           break;
          if ((t.kind == LBR || t.kind == LSB) && depth > 1)           depth--;
          if ((t.kind == RBR || t.kind == RSB))           depth++;
        }
        if (t.next == null)         break;
 else         if (t.next.kind == IDENTIFIER)         t=t.next;
      }
 else       if (t.kind == IDENTIFIER) {
        Token identifier=t;
        if (isOp(t.next) && !isPostfixOp(t.next)) {
          t=t.next;
          if (t.next.kind == SUBSTITUTE)           t=identifier;
 else           if (isInfixOp(t))           t=t.next;
        }
      }
 else {
        if (isOp(t)) {
          t=t.next;
        }
      }
      if ((t.next == null) || (t.next.kind != DEFBREAK)) {
        Token i=new Token();
        i.kind=DEFBREAK;
        i.image="String_Node_Str";
        i.beginLine=t.beginLine;
        i.beginColumn=t.beginColumn;
        i.endLine=t.endLine;
        i.endColumn=t.endColumn;
        i.next=t.next;
        t.next=i;
      }
      ;
      break;
    }
 else {
      previousT=currentT;
      currentT=nextT;
      nextT=getNextPreviewToken(currentT);
      currentT.next=previousT;
    }
  }
  while (previousT != null) {
    currentT.next=nextT;
    nextT=currentT;
    currentT=previousT;
    previousT=currentT.next;
  }
  currentT.next=nextT;
}

Fixed version (ground truth):
private final void belchDEF(){
  Token previousT=initPreviewToken();
  Token currentT=getNextPreviewToken(previousT);
  previousT.next=null;
  Token nextT=getNextPreviewToken(currentT);
  currentT.next=previousT;
  while (nextT.kind != EOF && nextT.kind != THEOREM && nextT.kind != PROPOSITION && nextT.kind != ASSUMPTION && nextT.kind != END_MODULE) {
    if (currentT.kind == DEF) {
      Token t=previousT;
      if (t.kind == RBR || t.kind == RSB) {
        int depth=1;
        while (t.next != null) {
          t=t.next;
          if ((t.kind == LBR || t.kind == LSB) && depth == 1)           break;
          if ((t.kind == LBR || t.kind == LSB) && depth > 1)           depth--;
          if ((t.kind == RBR || t.kind == RSB))           depth++;
        }
        if (t.next == null)         break;
 else         if (t.next.kind == IDENTIFIER)         t=t.next;
      }
 else       if (t.kind == IDENTIFIER) {
        Token identifier=t;
        if (isOp(t.next) && !isPostfixOp(t.next)) {
          t=t.next;
          if (t.next.kind == SUBSTITUTE)           t=identifier;
 else           if (isInfixOp(t))           t=t.next;
        }
      }
 else {
        if (isOp(t)) {
          t=t.next;
        }
      }
      if ((t.next == null) || (t.next.kind != DEFBREAK)) {
        Token i=new Token();
        i.kind=DEFBREAK;
        i.image="String_Node_Str";
        i.beginLine=t.beginLine;
        i.beginColumn=t.beginColumn;
        i.endLine=t.endLine;
        i.endColumn=t.endColumn;
        i.next=t.next;
        t.next=i;
      }
      ;
      break;
    }
 else {
      previousT=currentT;
      currentT=nextT;
      nextT=getNextPreviewToken(currentT);
      currentT.next=previousT;
    }
  }
  while (previousT != null) {
    currentT.next=nextT;
    nextT=currentT;
    currentT=previousT;
    previousT=currentT.next;
  }
  currentT.next=nextT;
}