60ce19d848
remove obsolete `givens` from regionck
Revives #107376. The only change is the last commit (2a3177a8bc) which should fix the regression.
Fixes https://github.com/rust-lang/rust/issues/106567
r? `@lcnr`
For high-level intro to how type checking works in rustc, see the type checking chapter of the rustc dev guide.