Rollup merge of #69349 - spastorino:mir-not-an-experiment, r=Dylan-DPC
Rollup merge of #69349 - spastorino:mir-not-an-experiment, r=Dylan-DPC

MIR is not an experiment anymore

At least I hope is not :stuck_out_tongue_closed_eyes:

r? @oli-obk

graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust