Check arg/ret sizedness at ExprKind::Path
This PR solves three problems:
- #50940: ICE on casting unsized tuple struct constructors
- Unsized tuple struct constructors were callable in presence of `unsized_locals`.
- https://github.com/rust-lang/rust/issues/48055#issuecomment-437178966: we cannot relax `Sized` bounds on stable functions because of fn ptr casting
These are caused by lack of `Sized`ness checks for arguments/retvals at **reference sites of `FnDef` items** (not call sites of the functions). Therefore we can basically add more `Sized` obligations on typeck. However, adding `Sized` obligations arbitrarily breaks type inference; to prevent that I added a new method `require_type_is_sized_deferred` which doesn't interfere usual type inference.
Cleanup from lexical MIR borrowck removal
Lexical MIR borrowck was removed months ago now, and `EndRegion`s are no longer used for MIRI verification.
* Remove `rustc::mir::StatementKind::EndRegion` and the `-Zemit_end_regions` flag
* Use `RegionVid` instead of `Region` in BorrowSet
* Rewrite drop generation to create fewer goto terminators.
r? @nikomatsakis
Suggest correct syntax when writing type arg instead of assoc type
- When confusing an associated type with a type argument, suggest the appropriate syntax. Given `Iterator<isize>`, suggest `Iterator<Item = isize>`.
- When encountering multiple missing associated types, emit only one diagnostic.
- Point at associated type def span for context.
- Point at each extra type argument.
Follow up to #48288, fix#20977.
Issue 56128 segment id ice nightly
Tentative fix for #56128
From what I can tell, the problem is that if you have `pub(super) use foo::{a, b}`, then when we explode the `a` and `b`, the segment ids from the `super` path were not getting cloned. However, once I fixed *that*, then I ran into a problem that the "visibility" node-ids were not present in the final HIR -- this is because the visibility of the "stem" that is returned in this case was getting reset to inherited. I don't *think* it is a problem to undo that, so that the visibility is returned unmodified.
Fixes#55475Fixes#56128
cc @nrc @petrochenkov
resolve: Make "empty import canaries" invisible from other crates
Empty imports `use prefix::{};` are desugared into `use prefix::{self as _};` to make sure the prefix is checked for privacy/stability/etc.
This caused issues in cross-crate scenarios because gensyms are lost in crate metadata (the `_` is a gensym).
Fixes https://github.com/rust-lang/rust/issues/55811
