**System Information**
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: GeForce RTX 3090/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 461.40
**Blender Version**
Broken: version: 2.92.0 Release Candidate, branch: master, commit date: 2021-02-22 12:21, hash: `rBe497c1b93ca5`
Worked: (newest version of Blender that worked as expected)
**Short description of error**
When I make a Mix Shader with a Holdout node and Principled BSDF，The function of mask cannot be realized.
**Exact steps for others to reproduce the error**
1 Create a new scene and choose a geometry.
2 Open Shader Editor.
3 Add a Mix Shader
4 Add a Holdout Shader
5 Add a Principled BSDF
6 conenct Principled BSDF and Holdout to Mix Shader, then connect this Mix Shader to Material Output.
7 Drag the Fac value we will find the function of mask cannot be realized.
Please check the sample file.{F9829341}