Steps to reproduce:

1. Open attached project
2. Select 'Occlusion' shader (Assets/AmplifyOcclusion/Resources)
3. Notice there is a bunch of "invalid preprocessor command 'LINE'" errors thrown (if not, click 'Compile and Show Code', the errors will appear).

If you change all the lines starting at line 283 in the 'Occlusion.shader' from

Pass { CGPROGRAM float4 frag( v2f_img IN ) : SV_TARGET { return FullDepth( IN ); } ENDCG }

to

Pass { CGPROGRAM
float4 frag( v2f_img IN ) : SV_TARGET { return FullDepth( IN ); } ENDCG }

(same code, just written in separate lines) the errors disappear and shader compiles successfully.

Does not reproduce with: 5.4.0f3