Auto merge of #123468 - compiler-errors:precise-capturing, r=oli-obk

Implement syntax for `impl Trait` to specify its captures explicitly (`feature(precise_capturing)`)

Implements `impl use<'a, 'b, T, U> Sized` syntax that allows users to explicitly list the captured parameters for an opaque, rather than inferring it from the opaque's bounds (or capturing *all* lifetimes under 2024-edition capture rules). This allows us to exclude some implicit captures, so this syntax may be used as a migration strategy for changes due to #117587.

We represent this list of captured params as `PreciseCapturingArg` in AST and HIR, resolving them between `rustc_resolve` and `resolve_bound_vars`. Later on, we validate that the opaques only capture the parameters in this list.

We artificially limit the feature to *require* mentioning all type and const parameters, since we don't currently have support for non-lifetime bivariant generics. This can be relaxed in the future.

We also may need to limit this to require naming *all* lifetime parameters for RPITIT, since GATs have no variance. I have to investigate this. This can also be relaxed in the future.

r? `@oli-obk`

Tracking issue:

- https://github.com/rust-lang/rust/issues/123432

1 files changed, 1 insertions, 1 deletions

diff --git a/compiler/rustc_lint/src/unused.rs b/compiler/rustc_lint/src/unused.rs
index 503caa35358..3fe1f21d56a 100644
--- a/compiler/rustc_lint/src/unused.rs
+++ b/compiler/rustc_lint/src/unused.rs
@@ -1235,7 +1235,7 @@ impl EarlyLintPass for UnusedParens {
                     ast::TyKind::TraitObject(..) => {}
                     ast::TyKind::BareFn(b)
                         if self.with_self_ty_parens && b.generic_params.len() > 0 => {}
-                    ast::TyKind::ImplTrait(_, bounds) if bounds.len() > 1 => {}
+                    ast::TyKind::ImplTrait(_, bounds, _) if bounds.len() > 1 => {}
                     _ => {
                         let spans = if !ty.span.from_expansion() {
                             r.span