Step stage0 to bootstrap from 1.42
This also includes a commit which fixes the rustfmt downloading logic to redownload when the rustfmt channel changes, and bumps rustfmt to a more recent version.
Always use lazy qualif getters during const-checking
`has_mut_interior_eager_seek` was needed to work around an overly restrictive bound on the `per_local` argument to the `Qualif` trait. This PR makes that bound `FnMut` instead of `Fn` so we can seek cursors inside of it, resolving a FIXME in the const-checking code.
Implement MIR lowering for or-patterns
This is the last thing needed to get meaningful run-pass tests for or-patterns. There probably need to be more tests before stabilizing this, but the most important cases should have been covered.
Note: we can generate exponentially large MIR CFGs when using or-patterns containing bindings, type ascriptions, or that are for a match arm with a guard. `src/test/mir-opt/exponential-or.rs` shows the best case for what we currently do.
cc #54883closes#60350closes#67514
cc @Centril
r? @pnkfelix
Added upper bound of what vecs and boxes can allocate
Fixed issue #68593
I added a line of documentation to these two files to reflect that vectors and boxes ensure that they never allocate more than `isize::MAX` bytes.
r? @steveklabnik
Install robots.txt into rust-docs tarballs
Fixes#68677.
I believe this might just work out from the central-station perspective, but even if it doesn't, this is a prerequisite step anyway.
codegen: create DIVariables ahead of using them with llvm.dbg.declare.
Instead of having `rustc_codegen_llvm` bundle creation of a `DIVariable` and `llvm.dbg.declare` into a single operation, they are now two separate methods, and the `DIVariable` is created earlier, specifically when `mir::VarDebugInfo`s are being partitioned into locals.
While this isn't currently needed, it's a prerequisite for #48300, which adds fragmented debuginfo, where one `mir::VarDebugInfo` has multiple parts of itself mapped to different `mir::Place`s.
For debuggers to see one composite variable instead of several ones with the same name, we need to create a single `DIVariable` and share it between multiple `llvm.dbg.declare` calls, which are likely pointing to different MIR locals.
That makes the `per_local_var_debug_info` partitioning a good spot to do this in, as we can create *exactly* one `DIVariable` per `mir::VarDebugInfo`, and refer to it as many things as needed.
I'm opening this PR separately because I want to test its perf impact in isolation (see https://github.com/rust-lang/rust/pull/48300#issuecomment-580121438).
r? @nagisa or @oli-obk cc @michaelwoerister @nikomatsakis
Avoid exponential behaviour when relating types
When equating bound types we check subtyping in both directions. Since closures are invariant in their substs, we end up comparing the two types an exponential number of times. If there are no bound variables this isn't needed.
Closes#68061
