a07eed99f6
Drop tracking: track borrows of projections Previous efforts to ignore partially consumed values meant we were also not considering borrows of a projection. This led to cases where we'd miss borrowed types which MIR expected to be there, leading to ICEs. This PR also includes the `-Zdrop-tracking` flag from #93313. If that PR lands first, I'll rebase to drop the commit from this one. Fixes #93648
For high-level intro to how type checking works in rustc, see the type checking chapter of the rustc dev guide.