STR:
1. Create a new project using the 3D template.
2. Copy the attached shader to the Assets folder.
3. Add a cube to the scene.
4. Create a new material, assign to the cube.
5. Assign the shader from step 2 to the material.
Expected: cube renders solid white.
Actual: cube renders pink, errors in the console.

Affects 2020.3+.

Workaround: put at least one space between "FOO" and "\" or before "uv":
#define FOO \
uv