is it not strange that emit=mir do not emit all functions that is emitted with emit=llvm-ir?
hard to see all changes that mir opt results in when not all functions can be found
or maybe not all functions that is in the llvm-ir file is optimised by mir-opts
MIR is before monomorphization or glue generation.
It doesn't represent monomorphic functions and doesn’t attempt to represent the generated glue.