> If a non-polymorphic, non-inline function may have its address taken (as a function pointer), either because it is exported out of the crate or the crate take

> If a non-polymorphic, non-inline function may have its address taken (as a function pointer), either because it is exported out of the crate or the crate takes a function pointer to it, generate a shim that uses -Zcallconv=legacy and immediately tail-calls the real implementation. This is necessary to preserve function pointer equality. If the legacy shim tail calls the Rust-calling-convention function, won't that prevent it from fixing any return value differences in the calling convention?