failed to optimize SPIR-V: Id is 0 #1676

When compiling for Spirv:
With:

uint4 a[6];
uint b[24];
a = (uint4[6])b;

Gives the error: failed to optimize SPIR-V: Id is 0

Also with:
uint4 a[6];
uint b[24];
b = (uint[24])a;

Gives the same error: failed to optimize SPIR-V: Id is 0

All compiling fine with glslc.