Rust Vec not implemented for usize

[Timmmm]

Maybe this is intentional, but when we put a Vec<usize> in our cxxbridge the Rust code builds fine, but when linking the C++ stuff we get unresolved symbols like this:

Undefined symbols for architecture x86_64:
  "rust::cxxbridge1::Vec<unsigned long>::Vec()", referenced from:
      rust::cxxbridge1::Vec<unsigned long>::Vec(rust::cxxbridge1::Vec<unsigned long>&&) in libanalysis_cxx_interface.a(lib.rs.cc.o)

This is on Mac by the way - you may not get the same errors on Linux because of its crazy linking behaviour (not all symbols have to be defined at compile time IIRC).

Anyway, I checked the Rust crate that we build (which depends on the cxx crate), and it seems to be missing the definition for Vec<unsigned long>, whereas it has definitions for other Vec<some int> types:

$ objdump -t analysis_rust/release/libanalysis_rust.a | grep __ZN4rust10cxxbridge13VecI | c++filt
...
0000000000000000         *UND* rust::cxxbridge1::Vec<rust::cxxbridge1::String>::Vec()
0000000000000000         *UND* rust::cxxbridge1::Vec<unsigned int>::Vec()
0000000000000000         *UND* rust::cxxbridge1::Vec<unsigned long long>::Vec()
0000000000003f30 __float128     F __TEXT,__text rust::cxxbridge1::Vec<rust::cxxbridge1::Str>::reserve_total(unsigned long)
0000000000003ef0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<rust::cxxbridge1::Str>::drop()
0000000000003f40 __float128     F __TEXT,__text rust::cxxbridge1::Vec<rust::cxxbridge1::Str>::set_len(unsigned long)
0000000000003ee0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<rust::cxxbridge1::Str>::Vec()
0000000000003ed0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<rust::cxxbridge1::Str>::Vec()
0000000000003eb0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<rust::cxxbridge1::String>::reserve_total(unsigned long)
0000000000003e70 __float128     F __TEXT,__text rust::cxxbridge1::Vec<rust::cxxbridge1::String>::drop()
0000000000003ec0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<rust::cxxbridge1::String>::set_len(unsigned long)
0000000000003e60 __float128     F __TEXT,__text rust::cxxbridge1::Vec<rust::cxxbridge1::String>::Vec()
0000000000003e50 __float128     F __TEXT,__text rust::cxxbridge1::Vec<rust::cxxbridge1::String>::Vec()
0000000000003ab0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<signed char>::reserve_total(unsigned long)
0000000000003a70 __float128     F __TEXT,__text rust::cxxbridge1::Vec<signed char>::drop()
0000000000003ac0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<signed char>::set_len(unsigned long)
0000000000003a60 __float128     F __TEXT,__text rust::cxxbridge1::Vec<signed char>::Vec()
0000000000003a50 __float128     F __TEXT,__text rust::cxxbridge1::Vec<signed char>::Vec()
0000000000003db0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<bool>::reserve_total(unsigned long)
0000000000003d70 __float128     F __TEXT,__text rust::cxxbridge1::Vec<bool>::drop()
0000000000003dc0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<bool>::set_len(unsigned long)
0000000000003d60 __float128     F __TEXT,__text rust::cxxbridge1::Vec<bool>::Vec()
0000000000003d50 __float128     F __TEXT,__text rust::cxxbridge1::Vec<bool>::Vec()
0000000000003e30 __float128     F __TEXT,__text rust::cxxbridge1::Vec<char>::reserve_total(unsigned long)
0000000000003df0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<char>::drop()
0000000000003e40 __float128     F __TEXT,__text rust::cxxbridge1::Vec<char>::set_len(unsigned long)
0000000000003de0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<char>::Vec()
0000000000003dd0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<char>::Vec()
0000000000003d30 __float128     F __TEXT,__text rust::cxxbridge1::Vec<double>::reserve_total(unsigned long)
0000000000003cf0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<double>::drop()
0000000000003d40 __float128     F __TEXT,__text rust::cxxbridge1::Vec<double>::set_len(unsigned long)
0000000000003ce0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<double>::Vec()
0000000000003cd0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<double>::Vec()
0000000000003cb0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<float>::reserve_total(unsigned long)
0000000000003c70 __float128     F __TEXT,__text rust::cxxbridge1::Vec<float>::drop()
0000000000003cc0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<float>::set_len(unsigned long)
0000000000003c60 __float128     F __TEXT,__text rust::cxxbridge1::Vec<float>::Vec()
0000000000003c50 __float128     F __TEXT,__text rust::cxxbridge1::Vec<float>::Vec()
00000000000038b0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<unsigned char>::reserve_total(unsigned long)
0000000000003870 __float128     F __TEXT,__text rust::cxxbridge1::Vec<unsigned char>::drop()
00000000000038c0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<unsigned char>::set_len(unsigned long)
0000000000003860 __float128     F __TEXT,__text rust::cxxbridge1::Vec<unsigned char>::Vec()
0000000000003850 __float128     F __TEXT,__text rust::cxxbridge1::Vec<unsigned char>::Vec()
0000000000003bb0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<int>::reserve_total(unsigned long)
0000000000003b70 __float128     F __TEXT,__text rust::cxxbridge1::Vec<int>::drop()
0000000000003bc0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<int>::set_len(unsigned long)
0000000000003b60 __float128     F __TEXT,__text rust::cxxbridge1::Vec<int>::Vec()
0000000000003b50 __float128     F __TEXT,__text rust::cxxbridge1::Vec<int>::Vec()
00000000000039b0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<unsigned int>::reserve_total(unsigned long)
0000000000003970 __float128     F __TEXT,__text rust::cxxbridge1::Vec<unsigned int>::drop()
00000000000039c0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<unsigned int>::set_len(unsigned long)
0000000000003960 __float128     F __TEXT,__text rust::cxxbridge1::Vec<unsigned int>::Vec()
0000000000003950 __float128     F __TEXT,__text rust::cxxbridge1::Vec<unsigned int>::Vec()
0000000000003b30 __float128     F __TEXT,__text rust::cxxbridge1::Vec<short>::reserve_total(unsigned long)
0000000000003af0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<short>::drop()
0000000000003b40 __float128     F __TEXT,__text rust::cxxbridge1::Vec<short>::set_len(unsigned long)
0000000000003ae0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<short>::Vec()
0000000000003ad0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<short>::Vec()
0000000000003930 __float128     F __TEXT,__text rust::cxxbridge1::Vec<unsigned short>::reserve_total(unsigned long)
00000000000038f0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<unsigned short>::drop()
0000000000003940 __float128     F __TEXT,__text rust::cxxbridge1::Vec<unsigned short>::set_len(unsigned long)
00000000000038e0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<unsigned short>::Vec()
00000000000038d0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<unsigned short>::Vec()
0000000000003c30 __float128     F __TEXT,__text rust::cxxbridge1::Vec<long long>::reserve_total(unsigned long)
0000000000003bf0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<long long>::drop()
0000000000003c40 __float128     F __TEXT,__text rust::cxxbridge1::Vec<long long>::set_len(unsigned long)
0000000000003be0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<long long>::Vec()
0000000000003bd0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<long long>::Vec()
0000000000003a30 __float128     F __TEXT,__text rust::cxxbridge1::Vec<unsigned long long>::reserve_total(unsigned long)
00000000000039f0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<unsigned long long>::drop()
0000000000003a40 __float128     F __TEXT,__text rust::cxxbridge1::Vec<unsigned long long>::set_len(unsigned long)
00000000000039e0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<unsigned long long>::Vec()
00000000000039d0 __float128     F __TEXT,__text rust::cxxbridge1::Vec<unsigned long long>::Vec()

As far as I can tell, the C++ symbols are implemented here which has this note:

// Usize and isize are the same type as one of the below.

Which is true, however the symbol name mangling scheme actually has distinct encodings for unsigned long and unsigned long long even if they are actually identical types. Pretty stupid.