
Attach (recommended) or Link to PDF file here:
[NAPEN16171380959.pdf](https://github.com/mozilla/pdf.js/files/6143802/NAPEN16171380959.pdf)

Configuration:
- Web browser and its version: Firefox 88 Nightly
- Operating system and its version: Windows 10
- PDF.js version:
- Is a browser extension: No

What went wrong? (add screenshot)
![](https://user-media-prod-cdn.itsre-sumo.mozilla.net/uploads/images/2021-03-15-10-58-27-ce2796.png)


ttContext.functionsDefined[funcId] = { data, i };
          } else if (op === 0x2d) {
            
            if (inFDEF) {
              inFDEF = false;
              lastEndf = i;
            } else {
              pc = callstack.pop();
              if (!pc) {
                warn("TT: ENDF bad stack");
                ttContext.hintsValid = false;
                return;
              }
              funcId = functionsCalled.pop();
              data = pc.data;
              i = pc.i;
              ttContext.functionsStackDeltas[funcId] =
                stack.length - pc.stackTop;
            }
          } else if (op === 0x89) {
            
            if (inFDEF || inELSE) {
              warn("TT: nested IDEFs not allowed");
              tooComplexToFollowFunctions = true;
            }
            inFDEF = true;
            
            lastDeff = i;
          } else if (op === 0x58) {