Description
Trying to get servo/rust-bindgen working with win32 today, I ran into rust-lang/rust-bindgen#541, where the __thiscall calling convention wasn't supported in bindgen. (My use of bindgen doesn't actually generate calls to __thiscall functions, but the function representations need to support __thiscall AFAICT.) Tracing back through the stack, it's not supported in syntex_syntax, and adding that support is AFAICT tricky until it's supported by rustc in some way.
Adding __thiscall was already proposed in #37 and/or #5853, but tangled up in much grander plans about FFI interfaces; this bug is more narrowly scoped to just adding support for the calling convention. People can then experiment with it via bindgen and nightly Rust. In this way, I think it's essentially like the existing support for vectorcall.
I think it's straightforward to do the work and am happy to sign up for doing it, but I'd like to know if there are strenuous objections to doing so.