Error ‘cannot use casts on l-values’ when a variable is assigned inside a second-level nested if statement before being used in a conversion

How to reproduce:
1. Open the project “IN-123001_D3DTest”
2. Observe the Console

Expected result: No shader error appears in the Console
Actual result: Shader error “… cannot use casts on l-values at Assets/SampleShader.shader(98) (on d3d11)” in the Console

Reproducible with: 2023.1.0a1, 6000.0.62f1, 6000.2.11f1, 6000.3.0b9, 6000.4.0a4

Reproducible on: Windows 11
Not reproducible on: No other environments tested

Notes:

• If the error does not appear, reimport the SampleShader asset (in the Assets tab, right click the asset → Reimport)
• The shader experiencing the error does not work, appears pink
• The issue reproduces on both DX11 and DX12
• The error appears when nesting the variable in the second level of an if statement