Problem with "Custom" material node on MacOS.

I had to use a “Custom” node for the material I am making and somehow, although it works perfectly on Windows the same code is giving me error on MacOS. Here is the custom code HLSL code:

float4x4 m1 = {a, b, c, d};
return m1 * (float1x4)e;

The error I am getting is:

Error [SM4] error: syntax error, unexpected NEW_IDENTIFIER, expecting ',' or ';'

I tried alternate simplified version of the same code. Like so:

return {a, b, c, d} * {e.x, e.y, e.z, e.a};

But that gives me an error too. It seems that however I write this code it will just not work on MacOS.
Any ideas?