[Bug d/123454] d: error overlapping initializer for bitfield with -m32 -fpreview=bitfields

[ibuclaw at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123454

--- Comment #2 from Iain Buclaw <ibuclaw at gcc dot gnu.org> ---
Same overflow occurs for -m64 too (0UL - 4UL), int_bit_position just returns
zero for whatever reason.