C can't do provenance

Probably the only way round it is to declare a new --pointer-provenance flag - which cannot be the default - which then says any and all integer<->pointer conversions that can be detected will be treated as pointer provenance errors by the compiler.

Bit like the laws of the Medes and the Persians :-) You're not declaring such conversions illegal, you're just saying that you're not allowed to use them in combination with pointer provenance.

Cheers,
Wol