Point out the type of associated types in every method call of iterator chains
Partially address #105184 by pointing out the type of associated types in every method call of iterator chains:
```
note: the expression is of type `Map<std::slice::Iter<'_, {integer}>, [closure@src/test/ui/iterators/invalid-iterator-chain.rs:12:18: 12:21]>`
--> src/test/ui/iterators/invalid-iterator-chain.rs:12:14
|
10 | vec![0, 1]
| ---------- this expression has type `Vec<{integer}>`
11 | .iter()
| ------ associated type `std::iter::Iterator::Item` is `&{integer}` here
12 | .map(|x| { x; })
| ^^^^^^^^^^^^^^^ associated type `std::iter::Iterator::Item` is `()` here
```
We also reduce the number of impls we mention when any of the candidates is an "exact match". This benefits the output of cases with numerics greatly.
Outstanding work would be to provide a structured suggestion for appropriate changes, like in this case detecting the spurious `;` in the closure.
When encountering an unmet obligation that affects a method chain, like
in iterator chains where one of the links has the wrong associated
type, we point at every method call and mention their evaluated
associated type at that point to give context to the user of where
expectations diverged from the code as written.
```
note: the expression is of type `Map<std::slice::Iter<'_, {integer}>, [closure@$DIR/invalid-iterator-chain.rs:12:18: 12:21]>`
--> $DIR/invalid-iterator-chain.rs:12:14
|
LL | vec![0, 1]
| ---------- this expression has type `Vec<{integer}>`
LL | .iter()
| ------ associated type `std::iter::Iterator::Item` is `&{integer}` here
LL | .map(|x| { x; })
| ^^^^^^^^^^^^^^^ associated type `std::iter::Iterator::Item` is `()` here
```
Move some queries and methods
Each commit's title should be self-explanatory. Motivated to break up some large, general files and move queries into leaf crates.
normalize before handling simple checks for evaluatability of `ty::Const`
`{{{{{{{ N }}}}}}}` is desugared into a `ConstKind::Unevaluated` for an anonymous `const` item so when calling `is_const_evaluatable` on it we skip the `ConstKind::Param(_) => Ok(())` arm which is incorrect.
Make `note_obligation_cause_code` take a `impl ToPredicate` for predicate
The only usecase that wasn't `impl ToPredicate` was noting overflow errors while revealing opaque types, which passed in an `Obligation<'tcx, Ty<'tcx>>`... Since this only happens in a `RevealAll` environment, which is after typeck (and probably primarily within `normalize_erasing_regions`) we're unlikely to display anything useful while noting this code, evidenced by the lack of UI test changes.
support `ConstKind::Expr` in `is_const_evaluatable` and `WfPredicates::compute`
Fixes#105205
Currently we haven't implemented a way to evaluate `ConstKind::Expr(Expr::Binop(Add, 1, 2))` so I just left that with a `FIXME` and a `delay_span_bug` since I have no idea how to do that and it would make this a much larger (and more complicated) PR :P
Tweak "the following other types implement trait"
When *any* of the suggested impls is an exact match, *only* show the exact matches. This is particularly relevant for integer types.
r? `@compiler-errors`
Avoid some `InferCtxt::build` calls
Either because we're inside of an `InferCtxt` already, or because we're not in a place where we'd ever see inference vars.
r? types
Make sure async constructs do not `impl Generator`
Async lowering turns async functions and blocks into generators internally.
Though these special kinds of generators should not `impl Generator` themselves.
The other way around, normal generators should not `impl Future`.
This was discovered in https://github.com/rust-lang/rust/pull/105082#issuecomment-1332210907 and is a regression from https://github.com/rust-lang/rust/pull/104321.
r? `@compiler-errors`
Async lowering turns async functions and blocks into generators internally.
Though these special kinds of generators should not `impl Generator` themselves.
The other way around, normal generators should not `impl Future`.
Some initial normalization method changes
1. Rename `AtExt::normalize` to `QueryNormalizeExt::query_normalize` (using the `QueryNormalizer`)
2. Introduce `NormalizeExt::normalize` to replace `partially_normalize_associated_types_in` (using the `AssocTypeNormalizer`)
3. Rename `FnCtxt::normalize_associated_types_in` to `FnCtxt::normalize`
4. Remove some unused other normalization fns in `Inherited` and `FnCtxt`
Also includes one drive-by where we're no longer creating a `FnCtxt` inside of `check_fn`, but passing it in. This means we don't need such weird `FnCtxt` construction logic.
Stacked on top of #104835 for convenience.
r? types
Revert #104269 (to avoid spurious hang/test failure in CI)
Causes hangs/memory overflows in the test suite apparently 😢Reopens#104225Fixes#104957
r? ``@lcnr``
