Custom HLSL Block failure without `in` identifier

Steps to reproduce:

1. Create CustomHLSL block
2. Edit HLSL code
3. Remove `in` before `float speedFactor`

Actual results: Compilation failure & missing slot
Expected results: Compilation success & speedFactor slot

Reproducible with versions: 6000.0.0b14
Not reproducible with versions:  6000.0.0b13
Can’t test with versions: N/A

Tested on (OS): Windows

Notes: