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Author SHA1 Message Date
lcnr
face090ef1 rm try_normalize_mir_const_after_erasing_regions 2022-10-17 10:54:03 +02:00
Cameron Steffen
283abbf0e7 Change InferCtxtBuilder from enter to build 2022-10-07 07:10:40 -05:00
Cameron Steffen
349415d1c6 Remove TypeckResults from InferCtxt 2022-10-07 07:06:19 -05:00
Oli Scherer
c7b6ebdf7c It's not about types or consts, but the lack of regions 2022-10-04 14:10:44 +00:00
Pietro Albini
3975d55d98
remove cfg(bootstrap) 2022-09-26 10:14:45 +02:00
bors
f5193a9fcc Auto merge of #95474 - oli-obk:tait_ub, r=jackh726 
Neither require nor imply lifetime bounds on opaque type for well formedness

The actual hidden type can live arbitrarily longer than any individual lifetime and arbitrarily shorter than all but one of the lifetimes.

fixes #86218
fixes #84305

This is a **breaking change** but it is a necessary soundness fix
 2022-09-25 19:15:26 +00:00
Matthias Krüger
16de1fddee
Rollup merge of #102016 - lcnr:given-OutlivesEnvironment, r=jackh726 
implied_bounds: deal with inference vars

fixes #101951

while computing implied bounds for `<<T as ConstructionFirm>::Builder as BuilderFn<'_>>::Output` normalization replaces a projection with an inference var (adding a `Projection` obligation). Until we prove that obligation, this inference var remains unknown, which caused us to miss an implied bound necessary to prove that the unnormalized projection from the trait method signature is wf.

r? types
 2022-09-25 09:32:07 +02:00
Oli Scherer
37928f5986 Neither require nor imply lifetime bounds on opaque type for well formedness 2022-09-21 13:11:54 +00:00
lcnr
71f8fd5c58 improve infer var handling for implied bounds 2022-09-19 15:13:34 +02:00
lcnr
647052fc04 remove the Subst trait, always use EarlyBinder 2022-09-19 11:37:27 +02:00
bors
efa717bc2d Auto merge of #101924 - jackh726:revert-static-hrtb-error, r=compiler-errors 
Re-add HRTB implied static bug note

r? `@compiler-errors` since you reviewed it previously

I deleted a `normalize` call and forgot about it. Whoops.
 2022-09-19 04:56:14 +00:00
Jack Huey
1eb71f0893 Add back in normalize call 2022-09-17 11:46:04 -04:00
Dylan DPC
3ad81e0dd8
Rollup merge of #93628 - est31:stabilize_let_else, r=joshtriplett 
Stabilize `let else`

🎉  **Stabilizes the `let else` feature, added by [RFC 3137](https://github.com/rust-lang/rfcs/pull/3137).** 🎉

Reference PR: https://github.com/rust-lang/reference/pull/1156

closes #87335 (`let else` tracking issue)

FCP: https://github.com/rust-lang/rust/pull/93628#issuecomment-1029383585

----------

## Stabilization report

### Summary

The feature allows refutable patterns in `let` statements if the expression is
followed by a diverging `else`:

```Rust
fn get_count_item(s: &str) -> (u64, &str) {
    let mut it = s.split(' ');
    let (Some(count_str), Some(item)) = (it.next(), it.next()) else {
        panic!("Can't segment count item pair: '{s}'");
    };
    let Ok(count) = u64::from_str(count_str) else {
        panic!("Can't parse integer: '{count_str}'");
    };
    (count, item)
}
assert_eq!(get_count_item("3 chairs"), (3, "chairs"));
```

### Differences from the RFC / Desugaring

Outside of desugaring I'm not aware of any differences between the implementation and the RFC. The chosen desugaring has been changed from the RFC's [original](https://rust-lang.github.io/rfcs/3137-let-else.html#reference-level-explanations). You can read a detailed discussion of the implementation history of it in `@cormacrelf` 's [summary](https://github.com/rust-lang/rust/pull/93628#issuecomment-1041143670) in this thread, as well as the [followup](https://github.com/rust-lang/rust/pull/93628#issuecomment-1046598419). Since that followup, further changes have happened to the desugaring, in #98574, #99518, #99954. The later changes were mostly about the drop order: On match, temporaries drop in the same order as they would for a `let` declaration. On mismatch, temporaries drop before the `else` block.

### Test cases

In chronological order as they were merged.

Added by df9a2e0687895731e12f4a2651e8d70acd08872d (#87688):

* [`ui/pattern/usefulness/top-level-alternation.rs`](https://github.com/rust-lang/rust/blob/1.58.1/src/test/ui/pattern/usefulness/top-level-alternation.rs) to ensure the unreachable pattern lint visits patterns inside `let else`.

Added by 5b95df4bdc330f34213812ad65cae86ced90d80c (#87688):

* [`ui/let-else/let-else-bool-binop-init.rs`](https://github.com/rust-lang/rust/blob/1.58.1/src/test/ui/let-else/let-else-bool-binop-init.rs) to ensure that no lazy boolean expressions (using `&&` or `||`) are allowed in the expression, as the RFC mandates.
* [`ui/let-else/let-else-brace-before-else.rs`](https://github.com/rust-lang/rust/blob/1.58.1/src/test/ui/let-else/let-else-brace-before-else.rs) to ensure that no `}` directly preceding the `else` is allowed in the expression, as the RFC mandates.
* [`ui/let-else/let-else-check.rs`](https://github.com/rust-lang/rust/blob/1.58.1/src/test/ui/let-else/let-else-check.rs) to ensure that `#[allow(...)]` attributes added to the entire `let` statement apply for the `else` block.
* [`ui/let-else/let-else-irrefutable.rs`](https://github.com/rust-lang/rust/blob/1.58.1/src/test/ui/let-else/let-else-irrefutable.rs) to ensure that the `irrefutable_let_patterns` lint fires.
* [`ui/let-else/let-else-missing-semicolon.rs`](https://github.com/rust-lang/rust/blob/1.58.1/src/test/ui/let-else/let-else-missing-semicolon.rs) to ensure the presence of semicolons at the end of the `let` statement.
* [`ui/let-else/let-else-non-diverging.rs`](https://github.com/rust-lang/rust/blob/1.58.1/src/test/ui/let-else/let-else-non-diverging.rs) to ensure the `else` block diverges.
* [`ui/let-else/let-else-run-pass.rs`](https://github.com/rust-lang/rust/blob/1.58.1/src/test/ui/let-else/let-else-run-pass.rs) to ensure the feature works in some simple test case settings.
* [`ui/let-else/let-else-scope.rs`](https://github.com/rust-lang/rust/blob/1.58.1/src/test/ui/let-else/let-else-scope.rs) to ensure the bindings created by the outer `let` expression are not available in the `else` block of it.

Added by bf7c32a4477a76bfd18fdcd8f45a939cbed82d34 (#89965):

* [`ui/let-else/issue-89960.rs`](https://github.com/rust-lang/rust/blob/1.58.1/src/test/ui/let-else/issue-89960.rs) as a regression test for the ICE-on-error bug #89960 . Later in 102b9125e1cefbb8ed8408d2db3f9f7d5afddbf0 this got removed in favour of more comprehensive tests.

Added by 856541963ce95ef4f7d4a81784bb5002ccf63c93 (#89974):

* [`ui/let-else/let-else-if.rs`](https://github.com/rust-lang/rust/blob/1.58.1/src/test/ui/let-else/let-else-if.rs) to test for the improved error message that points out that `let else if` is not possible.

Added by 9b45713b6c1775f0103a1ebee6ab7c6d9b781a21:

* [`ui/let-else/let-else-allow-unused.rs`](https://github.com/rust-lang/rust/blob/1.61.0/src/test/ui/let-else/let-else-allow-unused.rs) as a regression test for #89807, to ensure that `#[allow(...)]` attributes added to the entire `let` statement apply for bindings created by the `let else` pattern.

Added by 61bcd8d3075471b3867428788c49f54fffe53f52 (#89841):

* [`ui/let-else/let-else-non-copy.rs`](https://github.com/rust-lang/rust/blob/1.61.0/src/test/ui/let-else/let-else-non-copy.rs) to ensure that a copy is performed out of non-copy wrapper types. This mirrors `if let` behaviour. The test case bases on rustc internal changes originally meant for #89933 but then removed from the PR due to the error prior to the improvements of #89841.
* [`ui/let-else/let-else-source-expr-nomove-pass.rs `](https://github.com/rust-lang/rust/blob/1.61.0/src/test/ui/let-else/let-else-source-expr-nomove-pass.rs) to ensure that while there is a move of the binding in the successful case, the `else` case can still access the non-matching value. This mirrors `if let` behaviour.

Added by 102b9125e1cefbb8ed8408d2db3f9f7d5afddbf0 (#89841):

* [`ui/let-else/let-else-ref-bindings.rs`](https://github.com/rust-lang/rust/blob/1.61.0/src/test/ui/let-else/let-else-ref-bindings.rs) and [`ui/let-else/let-else-ref-bindings-pass.rs `](https://github.com/rust-lang/rust/blob/1.61.0/src/test/ui/let-else/let-else-ref-bindings-pass.rs) to check `ref` and `ref mut` keywords in the pattern work correctly and error when needed.

Added by 2715c5f984fda7faa156d1c9cf91aa4934f0e00f (#89841):

* Match ergonomic tests adapted from the `rfc2005` test suite.

Added by fec8a507a27de1b08a0b95592dc8ec93bf0a321a (#89841):

* [`ui/let-else/let-else-deref-coercion-annotated.rs`](https://github.com/rust-lang/rust/blob/1.61.0/src/test/ui/let-else/let-else-deref-coercion-annotated.rs) and [`ui/let-else/let-else-deref-coercion.rs`](https://github.com/rust-lang/rust/blob/1.61.0/src/test/ui/let-else/let-else-deref-coercion.rs) to check deref coercions.

#### Added since this stabilization report was originally written (2022-02-09)

Added by 76ea56667703ac06689ff1d6fba5d170fa7392a7 (#94211):

* [`ui/let-else/let-else-destructuring.rs`](https://github.com/rust-lang/rust/blob/1.63.0/src/test/ui/let-else/let-else-destructuring.rs) to give a nice error message if an user tries to do an assignment with a (possibly refutable) pattern and an `else` block, like asked for in #93995.

Added by e7730dcb7eb29a10ee73f269f4dc6e9d606db0da (#94208):

* [`ui/let-else/let-else-allow-in-expr.rs`](https://github.com/rust-lang/rust/blob/1.61.0/src/test/ui/let-else/let-else-allow-in-expr.rs) to test whether `#[allow(unused_variables)]` works in the expr, as well as its non presence, as well as putting it on the entire `let else` *affects* the expr, too. This was adding a missing test as pointed out by the stabilization report.
* Expansion of `ui/let-else/let-else-allow-unused.rs` and `ui/let-else/let-else-check.rs` to ensure that non-presence of `#[allow(unused)]` does issue the unused lint. This was adding a missing test case as pointed out by the stabilization report.

Added by 5bd71063b3810d977aa376d1e6dd7cec359330cc (#94208):

* [`ui/let-else/let-else-slicing-error.rs`](https://github.com/rust-lang/rust/blob/1.61.0/src/test/ui/let-else/let-else-slicing-error.rs), a regression test for #92069, which got fixed without addition of a regression test. This resolves a missing test as pointed out by the stabilization report.

Added by 5374688e1d8cbcff7d1d14bb34e38fe6fe7c233e (#98574):

* [`src/test/ui/async-await/async-await-let-else.rs`](https://github.com/rust-lang/rust/blob/master/src/test/ui/async-await/async-await-let-else.rs) to test the interaction of async/await with `let else`

Added by 6c529ded8674b89c46052da92399227c3b764c6a (#98574):

* [`src/test/ui/let-else/let-else-temporary-lifetime.rs`](https://github.com/rust-lang/rust/blob/master/src/test/ui/let-else/let-else-temporary-lifetime.rs) as a (partial) regression test for #98672

Added by 9b566401068cb8450912f6ab48f3d0e60f5cb482 (#99518):

* [`src/test/ui/let-else/let-else-temp-borrowck.rs`](https://github.com/rust-lang/rust/blob/master/src/test/ui/let-else/let-else-temporary-lifetime.rs) as a regression test for #93951
* Extension of `src/test/ui/let-else/let-else-temporary-lifetime.rs` to include a partial regression test for #98672 (especially regarding `else` drop order)

Added by baf9a7cb57120ec1411196214fd0d1c33fb18bf6 (#99518):

* Extension of `src/test/ui/let-else/let-else-temporary-lifetime.rs` to include a partial regression test for #93951, similar to `let-else-temp-borrowck.rs`

Added by 60be2de8b7b8a1c4eee7e065b8cef38ea629a6a3 (#99518):

* Extension of `src/test/ui/let-else/let-else-temporary-lifetime.rs` to include a program that can now be compiled thanks to borrow checker implications of #99518

Added by 47a7a91c969ed2edd12c674ca05c1baf867f6f6f (#100132):

* [`src/test/ui/let-else/issue-100103.rs`](https://github.com/rust-lang/rust/blob/master/src/test/ui/let-else/issue-100103.rs), as a regression test for #100103, to ensure that there is no ICE when doing `Err(...)?` inside else blocks.

Added by e3c5bd617d040b5ee0bc79e6e7f01772adce791b (#100443):

* [`src/test/ui/let-else/let-else-then-diverge.rs`](https://github.com/rust-lang/rust/blob/master/src/test/ui/let-else/let-else-then-diverge.rs), to verify that there is no unreachable code error with the current desugaring.

Added by 981852677c531d52f701b870bb27b45668a44d52 (#100443):

* [`src/test/ui/let-else/issue-94176.rs`](https://github.com/rust-lang/rust/blob/master/src/test/ui/let-else/issue-94176.rs), to make sure that a correct span is emitted for a missing trailing expression error. Regression test for #94176.

Added by e182d12a8493b40a557394325a3a713b6528de60 (#100434):

* [src/test/ui/unpretty/pretty-let-else.rs](https://github.com/rust-lang/rust/blob/master/src/test/ui/unpretty/pretty-let-else.rs), as a regression test to ensure pretty printing works for `let else` (this bug surfaced in many different ways)

Added by e26285603ca8b83b9d06e56f74e10e3d410553ff (#99954):

* [`src/test/ui/let-else/let-else-temporary-lifetime.rs`](https://github.com/rust-lang/rust/blob/master/src/test/ui/let-else/let-else-temporary-lifetime.rs) extended to contain & borrows as well, as this was identified as an earlier issue with the desugaring: https://github.com/rust-lang/rust/issues/98672#issuecomment-1200196921

Added by 2d8460ef43d902f34ba2133fe38f66ee8d2fdafc (#99291):

* [`src/test/ui/let-else/let-else-drop-order.rs`](https://github.com/rust-lang/rust/blob/master/src/test/ui/let-else/let-else-drop-order.rs) a matrix based test for various drop order behaviour of `let else`. Especially, it verifies equality of `let` and `let else` drop orders, [resolving](https://github.com/rust-lang/rust/pull/93628#issuecomment-1238498468) a [stabilization blocker](https://github.com/rust-lang/rust/pull/93628#issuecomment-1055738523).

Added by 1b87ce0d4092045728c1c68282769d555706f273 (#101410):

* Edit to `src/test/ui/let-else/let-else-temporary-lifetime.rs` to add the `-Zvalidate-mir` flag, as a regression test for #99228

Added by af591ebe4d0cf2097a5fdc0bb710442d0f2e7876 (#101410):

* [`src/test/ui/let-else/issue-99975.rs`](https://github.com/rust-lang/rust/blob/master/src/test/ui/let-else/issue-99975.rs) as a regression test for the ICE #99975.

Added by this PR:

* `ui/let-else/let-else.rs`, a simple run-pass check, similar to `ui/let-else/let-else-run-pass.rs`.

### Things not currently tested

* ~~The `#[allow(...)]` tests check whether allow works, but they don't check whether the non-presence of allow causes a lint to fire.~~ → *test added by e7730dcb7eb29a10ee73f269f4dc6e9d606db0da*
* ~~There is no `#[allow(...)]` test for the expression, as there are tests for the pattern and the else block.~~ → *test added by e7730dcb7eb29a10ee73f269f4dc6e9d606db0da*
* ~~`let-else-brace-before-else.rs` forbids the `let ... = {} else {}` pattern and there is a rustfix to obtain `let ... = ({}) else {}`. I'm not sure whether the `.fixed` files are checked by the tooling that they compile. But if there is no such check, it would be neat to make sure that `let ... = ({}) else {}` compiles.~~ → *test added by e7730dcb7eb29a10ee73f269f4dc6e9d606db0da*
* ~~#92069 got closed as fixed, but no regression test was added. Not sure it's worth to add one.~~ → *test added by 5bd71063b3810d977aa376d1e6dd7cec359330cc*
* ~~consistency between `let else` and `if let` regarding lifetimes and drop order: https://github.com/rust-lang/rust/pull/93628#issuecomment-1055738523~~ → *test added by 2d8460ef43d902f34ba2133fe38f66ee8d2fdafc*

Edit: they are all tested now.

### Possible future work / Refutable destructuring assignments

[RFC 2909](https://rust-lang.github.io/rfcs/2909-destructuring-assignment.html) specifies destructuring assignment, allowing statements like `FooBar { a, b, c } = foo();`.
As it was stabilized, destructuring assignment only allows *irrefutable* patterns, which before the advent of `let else` were the only patterns that `let` supported.
So the combination of `let else` and destructuring assignments gives reason to think about extensions of the destructuring assignments feature that allow refutable patterns, discussed in #93995.

A naive mapping of `let else` to destructuring assignments in the form of `Some(v) = foo() else { ... };` might not be the ideal way. `let else` needs a diverging `else` clause as it introduces new bindings, while assignments have a default behaviour to fall back to if the pattern does not match, in the form of not performing the assignment. Thus, there is no good case to require divergence, or even an `else` clause at all, beyond the need for having *some* introducer syntax so that it is clear to readers that the assignment is not a given (enums and structs look similar). There are better candidates for introducer syntax however than an empty `else {}` clause, like `maybe` which could be added as a keyword on an edition boundary:

```Rust
let mut v = 0;
maybe Some(v) = foo(&v);
maybe Some(v) = foo(&v) else { bar() };
```

Further design discussion is left to an RFC, or the linked issue.
 2022-09-17 15:31:06 +05:30
Jack Huey
e09242d5b8 Final bits 2022-09-16 17:47:53 -04:00
Jack Huey
92b759f517 Revert "Better errors for implied static bound" 
This reverts commit c75817b0a75d4b6b01ee10900ba5d01d4915e6a8.
 2022-09-16 09:47:07 -04:00
est31
173eb6f407 Only enable the let_else feature on bootstrap 
On later stages, the feature is already stable.

Result of running:

rg -l "feature.let_else" compiler/ src/librustdoc/ library/ | xargs sed -s -i "s#\\[feature.let_else#\\[cfg_attr\\(bootstrap, feature\\(let_else\\)#"
 2022-09-15 21:06:45 +02:00
bors
6153d3cbe6 Auto merge of #101212 - eholk:dyn-star, r=compiler-errors 
Initial implementation of dyn*

This PR adds extremely basic and incomplete support for [dyn*](https://smallcultfollowing.com/babysteps//blog/2022/03/29/dyn-can-we-make-dyn-sized/). The goal is to get something in tree behind a flag to make collaboration easier, and also to make sure the implementation so far is not unreasonable. This PR does quite a few things:

* Introduce `dyn_star` feature flag
* Adds parsing for `dyn* Trait` types
* Defines `dyn* Trait` as a sized type
* Adds support for explicit casts, like `42usize as dyn* Debug`
  * Including const evaluation of such casts
* Adds codegen for drop glue so things are cleaned up properly when a `dyn* Trait` object goes out of scope
* Adds codegen for method calls, at least for methods that take `&self`

Quite a bit is still missing, but this gives us a starting point. Note that this is never intended to become stable surface syntax for Rust, but rather `dyn*` is planned to be used as an implementation detail for async functions in dyn traits.

Joint work with `@nikomatsakis` and `@compiler-errors.`

r? `@bjorn3`
 2022-09-14 18:10:51 +00:00
Jack Huey
c75817b0a7 Better errors for implied static bound 2022-09-13 20:18:04 -04:00
Eric Holk
cf04547b0b Address code review comments 2022-09-13 14:50:12 -07:00
Eric Holk
6c01273a15 Plumb dyn trait representation through ty::Dynamic 2022-09-12 16:55:55 -07:00
Jack Huey
1ca9eb8ec3 Remove ReEmpty 2022-09-08 20:55:55 -04:00
Dezhi Wu
b1430fb7ca Fix a bunch of typo 
This PR will fix some typos detected by [typos].

I only picked the ones I was sure were spelling errors to fix, mostly in
the comments.

[typos]: https://github.com/crate-ci/typos
 2022-08-31 18:24:55 +08:00
Jack Huey
8033c3c27d Various changes to logging of borrowck-related code 2022-08-29 10:59:21 -04:00
5225225
09ea9f0a87 Add diagnostic translation lints to crates that don't emit them 2022-08-18 19:29:02 +01:00
Matthias Krüger
01ccde5ec8
Rollup merge of #100095 - jackh726:early-binder, r=lcnr 
More EarlyBinder cleanups

Each commit is independent

r? types
 2022-08-04 22:25:04 +02:00
Matthias Krüger
0de7f756f0
Rollup merge of #99746 - compiler-errors:more-trait-engine, r=jackh726 
Use `TraitEngine` in more places that don't specifically need `FulfillmentContext::new_in_snapshot`

Not sure if this change is worthwhile, but couldn't hurt re: chalkification

r? types
 2022-08-03 22:29:27 +02:00
Jack Huey
e21624dc80 Add bound_predicates_of and bound_explicit_predicates_of 2022-08-02 22:44:08 -04:00
bors
06f4950cbd Auto merge of #100032 - BoxyUwU:no_ty_in_placeholder_const, r=compiler-errors 
make `PlaceholderConst` not store the type of the const

Currently the `Placeholder` variant on `ConstKind` is 28 bytes when with this PR its 8 bytes, i am not sure this is really useful at all rn since `Unevaluated` and `Value` variants are huge still but eventually it should be possible to get both down to 16 bytes 🤔. Mostly opening this to see if this change has any perf impact when done before it can make `ConstKind`/`ConstS` smaller
 2022-08-02 13:10:49 +00:00
Camille GILLOT
d7ea161b7e Remove DefId from AssocItemContainer. 2022-08-01 21:38:45 +02:00
Ellen
825a7cc65c make PlaceholderConst not store the type of the const 2022-08-01 15:42:38 +01:00
Dylan DPC
91b8b9ba4b
Rollup merge of #99714 - ouz-a:issue_57961, r=oli-obk 
Fix regression introduced with #99383

Fixes #99642
 2022-07-28 16:38:30 +05:30
ouz-a
8716eae3b1 add tests and comment 2022-07-27 14:43:46 +03:00
Michael Goulet
58f107ab56 Use TraitEngine in more places that don't specifically need FulfillmentCtxt::new_in_snapshot 2022-07-26 04:55:06 +00:00
ouz-a
4a0473c0f5 Bubble up obligations 2022-07-25 15:45:36 +03:00
Michael Woerister
88f6c6d8a0 Remove unused StableMap and StableSet types from rustc_data_structures 2022-07-20 13:11:39 +02:00
Alan Egerton
4f0a64736b
Update TypeVisitor paths 2022-07-06 06:41:53 +01:00
Alan Egerton
e9e5d0685b
Relax constrained generics to TypeVisitable 2022-07-05 22:25:43 +01:00
Jack Huey
e16dbb5076 Make empty bounds lower to WellFormed and make WellFormed coinductive 2022-06-28 00:17:40 -04:00
b-naber
705d818bd5 implement valtrees as the type-system representation for constant values 2022-06-14 16:07:11 +02:00
Nicholas Nethercote
93e4b6ef06 Rename the ConstS::val field as kind. 
And likewise for the `Const::val` method.

Because its type is called `ConstKind`. Also `val` is a confusing name
because `ConstKind` is an enum with seven variants, one of which is
called `Value`. Also, this gives consistency with `TyS` and `PredicateS`
which have `kind` fields.

The commit also renames a few `Const` variables from `val` to `c`, to
avoid confusion with the `ConstKind::Value` variant.
 2022-06-14 13:06:44 +10:00
Nicholas Nethercote
90db033955 Folding revamp. 
This commit makes type folding more like the way chalk does it.

Currently, `TypeFoldable` has `fold_with` and `super_fold_with` methods.
- `fold_with` is the standard entry point, and defaults to calling
  `super_fold_with`.
- `super_fold_with` does the actual work of traversing a type.
- For a few types of interest (`Ty`, `Region`, etc.) `fold_with` instead
  calls into a `TypeFolder`, which can then call back into
  `super_fold_with`.

With the new approach, `TypeFoldable` has `fold_with` and
`TypeSuperFoldable` has `super_fold_with`.
- `fold_with` is still the standard entry point, *and* it does the
  actual work of traversing a type, for all types except types of
  interest.
- `super_fold_with` is only implemented for the types of interest.

Benefits of the new model.
- I find it easier to understand. The distinction between types of
  interest and other types is clearer, and `super_fold_with` doesn't
  exist for most types.
- With the current model is easy to get confused and implement a
  `super_fold_with` method that should be left defaulted. (Some of the
  precursor commits fixed such cases.)
- With the current model it's easy to call `super_fold_with` within
  `TypeFolder` impls where `fold_with` should be called. The new
  approach makes this mistake impossible, and this commit fixes a number
  of such cases.
- It's potentially faster, because it avoids the `fold_with` ->
  `super_fold_with` call in all cases except types of interest. A lot of
  the time the compile would inline those away, but not necessarily
  always.
 2022-06-08 09:24:03 +10:00
Jack Huey
410dcc9674 Fully stabilize NLL 2022-06-03 17:16:41 -04:00
Jacob Pratt
49c82f31a8
Remove crate visibility usage in compiler 2022-05-20 20:04:54 -04:00
Jack Huey
0247faed29 Add bound_impl_trait_ref 2022-05-13 18:27:40 -04:00
Jack Huey
c92248ab9f Add bound_type_of 2022-05-13 18:27:18 -04:00
Jack Huey
319575ae8c Introduce EarlyBinder 2022-05-10 22:47:18 -04:00
Oli Scherer
1163aa7e72 Remove opaque type obligation and just register opaque types as they are encountered. 
This also registers obligations for the hidden type immediately.
 2022-03-28 16:57:45 +00:00
Oli Scherer
264cd05b16 Revert "Auto merge of #93893 - oli-obk:sad_revert, r=oli-obk" 
This reverts commit 6499c5e7fc173a3f55b7a3bd1e6a50e9edef782d, reversing
changes made to 78450d2d602b06d9b94349aaf8cece1a4acaf3a8.
 2022-03-28 16:27:14 +00:00
InfRandomness
645620b3b3 Swap DtorckConstraint to DropckConstraint 
This change was made as per suspicion that this struct was never renamed after consistent use of DropCk.

This also clarifies the meaning behind the name of this structure.
 2022-03-24 20:35:35 +01:00
Michael Goulet
376d100e74 make rustc work again 2022-03-23 21:52:17 -07:00