bjoernager/rust
bjoernager/rust
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better names and a comment

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This commit is contained in:
Michael Goulet 2022-12-28 04:16:36 +00:00
parent c7b414adb6
commit 96d8011fa8
7 changed files with 42 additions and 9 deletions
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35
compiler/rustc_hir_analysis/src/check/compare_impl_item.rs
View file

@ -441,8 +441,41 @@ fn compare_asyncness<'tcx>(
Ok(())
}
/// Given a method def-id in an impl, compare the method signature of the impl
/// against the trait that it's implementing. In doing so, infer the hidden types
/// that this method's signature provides to satisfy each return-position `impl Trait`
/// in the trait signature.
///
/// The method is also responsible for making sure that the hidden types for each
/// RPITIT actually satisfy the bounds of the `impl Trait`, i.e. that if we infer
/// `impl Trait = Foo`, that `Foo: Trait` holds.
///
/// For example, given the sample code:
///
/// ```
/// #![feature(return_position_impl_trait_in_trait)]
///
/// use std::ops::Deref;
///
/// trait Foo {
/// fn bar() -> impl Deref<Target = impl Sized>;
/// // ^- RPITIT #1 ^- RPITIT #2
/// }
///
/// impl Foo for () {
/// fn bar() -> Box<String> { Box::new(String::new()) }
/// }
/// ```
///
/// The hidden types for the RPITITs in `bar` would be inferred to:
/// * `impl Deref` (RPITIT #1) = `Box<String>`
/// * `impl Sized` (RPITIT #2) = `String`
///
/// The relationship between these two types is straightforward in this case, but
/// may be more tenuously connected via other `impl`s and normalization rules for
/// cases of more complicated nested RPITITs.
#[instrument(skip(tcx), level = "debug", ret)]
pub(super) fn collect_trait_impl_trait_tys<'tcx>(
pub(super) fn collect_return_position_impl_trait_in_trait_tys<'tcx>(
tcx: TyCtxt<'tcx>,
def_id: DefId,
) -> Result<&'tcx FxHashMap<DefId, Ty<'tcx>>, ErrorGuaranteed> {

4
compiler/rustc_hir_analysis/src/check/mod.rs
View file

@ -94,7 +94,7 @@ use std::num::NonZeroU32;
use crate::require_c_abi_if_c_variadic;
use crate::util::common::indenter;
use self::compare_impl_item::collect_trait_impl_trait_tys;
use self::compare_impl_item::collect_return_position_impl_trait_in_trait_tys;
use self::region::region_scope_tree;
pub fn provide(providers: &mut Providers) {
@ -103,7 +103,7 @@ pub fn provide(providers: &mut Providers) {
adt_destructor,
check_mod_item_types,
region_scope_tree,
collect_trait_impl_trait_tys,
collect_return_position_impl_trait_in_trait_tys,
compare_impl_const: compare_impl_item::compare_impl_const_raw,
..*providers
};