Fix linkage diagnostic so it doesn't ICE for external crates Fix linkage diagnostic so it doesn't ICE for external crates (As a drive-by improvement, improved the diagnostic to indicate *why* `*const T` or `*mut T` is required.) Fix #59548 Fix #61232
The codegen
crate contains the code to convert from MIR into LLVM IR,
and then from LLVM IR into machine code. In general it contains code
that runs towards the end of the compilation process.
For more information about how codegen works, see the rustc guide.