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Add helper methods to retrieve `Future::Output` and `Iterator::Item`
| -rw-r--r-- | crates/hir-def/src/lang_item.rs | 7 | ||||
| -rw-r--r-- | crates/hir/src/lib.rs | 18 |
2 files changed, 24 insertions, 1 deletions
diff --git a/crates/hir-def/src/lang_item.rs b/crates/hir-def/src/lang_item.rs index cdcd7208f3..166c965d14 100644 --- a/crates/hir-def/src/lang_item.rs +++ b/crates/hir-def/src/lang_item.rs @@ -74,6 +74,13 @@ impl LangItemTarget { _ => None, } } + + pub fn as_type_alias(self) -> Option<TypeAliasId> { + match self { + LangItemTarget::TypeAlias(id) => Some(id), + _ => None, + } + } } #[derive(Default, Debug, Clone, PartialEq, Eq)] diff --git a/crates/hir/src/lib.rs b/crates/hir/src/lib.rs index 1e8127161d..2ff5f0d538 100644 --- a/crates/hir/src/lib.rs +++ b/crates/hir/src/lib.rs @@ -78,7 +78,7 @@ use hir_ty::{ use itertools::Itertools; use nameres::diagnostics::DefDiagnosticKind; use rustc_hash::FxHashSet; -use span::{Edition, EditionedFileId, FileId, MacroCallId}; +use span::{Edition, EditionedFileId, FileId, MacroCallId, SyntaxContextId}; use stdx::{impl_from, never}; use syntax::{ ast::{self, HasAttrs as _, HasGenericParams, HasName}, @@ -4379,6 +4379,22 @@ impl Type { method_resolution::implements_trait(&canonical_ty, db, &self.env, trait_) } + /// This does **not** resolve `IntoFuture`, only `Future`. + pub fn future_output(self, db: &dyn HirDatabase) -> Option<Type> { + let future_output = + db.lang_item(self.env.krate, LangItem::FutureOutput)?.as_type_alias()?; + self.normalize_trait_assoc_type(db, &[], future_output.into()) + } + + /// This does **not** resolve `IntoIterator`, only `Iterator`. + pub fn iterator_item(self, db: &dyn HirDatabase) -> Option<Type> { + let iterator_trait = db.lang_item(self.env.krate, LangItem::Iterator)?.as_trait()?; + let iterator_item = db + .trait_data(iterator_trait) + .associated_type_by_name(&Name::new_symbol(sym::Item.clone(), SyntaxContextId::ROOT))?; + self.normalize_trait_assoc_type(db, &[], iterator_item.into()) + } + /// Checks that particular type `ty` implements `std::ops::FnOnce`. /// /// This function can be used to check if a particular type is callable, since FnOnce is a |