Implement RFC 2056 trivial constraints in where clauses
This is an implementation of the new behaviour for #48214. Tests are mostly updated to show the effects of this. Feature gate hasn't been added yet.
Some things that are worth noting and are maybe not want we want
* `&mut T: Copy` doesn't allow as much as someone might expect because there is often an implicit reborrow.
* ~There isn't a check that a where clause is well-formed any more, so `where Vec<str>: Debug` is now allowed (without a `str: Sized` bound).~
r? @nikomatsakis
This leads to a lot of simplifications, as most code doesn't actually need to know about the specific lifetime/type data; rather, it's concerned with properties like name, index and def_id.
This is sort of confusing "side step". All it does is to change the
representation of a skolemized region. but the source of that universe
index is not the inference context, which is what we eventually want,
but rather an internal counter in the region inference context.
We'll patch that up later. But doing this now ought to help with
confusing diffs later.
Rollup of 7 pull requests
Successful merges:
- #49707 (Add "the Rustc book")
- #50222 (Bump bootstrap compiler to 2018-04-24)
- #50227 (Fix ICE with erroneous `impl Trait` in a trait impl)
- #50229 (Add setting to go to item if there is only one result)
- #50231 (Add more doc aliases)
- #50246 (Make dump_{alloc,allocs,local}() no-ops when tracing is disabled.)
- #49894 (Rename InternedString to LocalInternedString and introduce a new thread-safe InternedString)
Failed merges:
Remove universes from `ty::ParamEnv`
This change was never meant to land. #48407 takes an alternate approach. However, that PR is now blocked on some issues with canonicalization, and rebasing these reverts gets harder each time, so let's just get this bit out of the way now.
r? @nikomatsakis
Introduce UnpackedKind
This adds an `UnpackedKind` type as a typesafe counterpart to `Kind`. This should make future changes to kinds (such as const generics!) more resilient, as the type-checker will be able to catch more potential issues.
r? @eddyb
cc @yodaldevoid
This adds an `UnpackedKind` type as a typesafe counterpart to `Kind`. This should make future changes to kinds (such as const generics!) more resilient, as the type-checker should catch more potential issues.
Refactor diverging and numeric fallback.
This refactoring tries to make numeric fallback easier to reason about. Instead of applying all fallbacks at an arbitrary point in the middle of inference, we apply the fallback only when necessary and only for
the variable that requires it. The only place that requires early fallback is the target of numeric casts.
The visible consequences is that some error messages that got `i32` now get `{integer}` because we are less eager about fallback.
The bigger goal is to make it easier to integrate user fallbacks into inference, if we ever figure that out.
This refactoring tries to make numeric fallback easier to reason about.
Instead of applying all fallbacks at an arbitrary point in the middle
of inference, we apply the fallback only when necessary and only for
the variable that requires it, which for numeric fallback turns out to
be just casts.
The only visible consequence seems to be some error messages where
instead of getting `i32` we get `{integer}` because we are less eager
about fallback.
The bigger goal is to make it easier to integrate user fallbacks into
inference, if we ever figure that out.
[perf] Use std based dedup in projection
Unstable sort was added recently, and the code that is being modified is 3 years old. As quicksort doesn't allocate it will likely perform as well as, or better than linear search.
I didn't benchmark. Have a perf run.
Santiago Pastorino
toidiu
John Kåre Alsaker
Eduard-Mihai Burtescu
Oliver Schneider
Irina Popa
bors
Matthew Jasper
varkor
Sean Griffin
Niko Matsakis
Tyler Mandry
Josh Stone
Guillaume Gomez
Michael Woerister
Alex Crichton
Oliver Schneider
Mark Mansi
Andrew Cann
Manish Goregaokar
Tatsuyuki Ishi
leonardo.yvens