stop considering location when computing outlives relationships
This doesn't (yet?) use SEME regions, but it does ignore the location for outlives constraints. This makes (I believe) NLL significantly faster -- but we should do some benchmarks. It regresses the "get-default" family of use cases for NLL, which is a shame, but keeps the other benefits, and thus represents a decent step forward.
r? @pnkfelix
prep work for using timely dataflow with NLL
Two major changes:
**Two-phase borrows are overhauled.** We no longer have two bits per borrow. Instead, we track -- for each borrow -- an (optional) "activation point". Then, for each point P where the borrow is in scope, we check where P falls relative to the activation point. If P is between the reservation point and the activation point, then this is the "reservation" phase of the borrow, else the borrow is considered active. This is simpler and means that the dataflow doesn't have to care about 2-phase at all, at last not yet.
**We no longer support using the MIR borrow checker without NLL.** It is going to be increasingly untenable to support lexical mode as we go forward, I think, and also of increasingly little value. This also exposed a few bugs in NLL mode due to increased testing.
r? @pnkfelix
cc @bobtwinkles
Rollup of 14 pull requests
Successful merges:
- #49525 (Use sort_by_cached_key where appropriate)
- #49575 (Stabilize `Option::filter`.)
- #49614 (in which the non-shorthand patterns lint keeps its own counsel in macros)
- #49665 (Small nits to make couple of tests pass on mips targets.)
- #49781 (add regression test for #16223 (NLL): use of collaterally moved value)
- #49795 (Properly look for uninhabitedness of variants in niche-filling check)
- #49809 (Stop emitting color codes on TERM=dumb)
- #49856 (Do not uppercase-lint #[no_mangle] statics)
- #49863 (fixed typo)
- #49857 (Fix "fp" target feature for AArch64)
- #49849 (Add --enable-debug flag to musl CI build script)
- #49734 (proc_macro: Generalize `FromIterator` impl)
- #49730 (Fix ICE with impl Trait)
- #48270 (Replace `structurally_resolved_type` in casts check.)
Failed merges:
Blindly checkpoint status of NLL mode ui tests
This takes the next (and potentially final?) step with #48879.
Namely, this PR got things to the point where I can successfully run `compiletest` on `src/test/ui` with `--compile-mode=nll`.
Here are the main pieces of it:
1. To figure out how to even run `compiletest` normally on the ui directory, I ran `x.py test -vv`, and then looked for the `compiletest` invocation that mentioned `src/test/ui`.
2. I took the aforementioned `compiletest` invocation and used it, adding `--compile-mode=nll` to the end. It had 170 failing cases.
3. Due to #49855, I had to edit some of the tests so that they fail even under NLL, via `#[rustc_error]`. That's the first commit. (Then goto 2 to double-check no such tests remain.)
4. I took the generated `build/target/test/foo.stderr` file for every case that failed, and blindly copied it to `src/test/foo.nll.stderr`. That's the second commit.
5. Goto 2 until there were no failing cases.
6. Remove any stamp files, and re-run `x.py test` to make sure that the edits and new `.nll.stderr` files haven't broken the pre-existing test suite.
add regression test for #16223 (NLL): use of collaterally moved value
Adds regression test for https://github.com/rust-lang/rust/issues/16223 which NLL fixes.
The current downside of this test is that it uses the `#![feature(box_patterns)]` and I haven't come up with a proper test that only uses the `#![feature(nll)]` - however, I don't know if this is even possible to test without `#![feature(box_syntax)]` or `#![feature(box_patterns)]`.
rustc_mir: insert a dummy access to places being matched on, when building MIR.
Fixes#47412 by adding a `_dummy = Discriminant(place)` before each `match place {...}`.
r? @nikomatsakis
