rust-analyzer

diff --git a/crates/hir-expand/src/mod_path.rs b/crates/hir-expand/src/mod_path.rs
index fea09521e8..9ddafe0181 100644
--- a/crates/hir-expand/src/mod_path.rs
+++ b/crates/hir-expand/src/mod_path.rs

@@ -257,6 +257,7 @@ macro_rules! __known_path {

(core::ops::RangeToInclusive) => {};

(core::ops::RangeInclusive) => {};

(core::future::Future) => {};

+ (core::future::IntoFuture) => {};

(core::ops::Try) => {};

($path:path) => {

compile_error!("Please register your known path in the path module")

diff --git a/crates/hir-expand/src/name.rs b/crates/hir-expand/src/name.rs
index 47d191822d..757db79db4 100644
--- a/crates/hir-expand/src/name.rs
+++ b/crates/hir-expand/src/name.rs

@@ -258,6 +258,7 @@ pub mod known {

Try,

Ok,

Future,

+ IntoFuture,

Result,

Option,

Output,

@@ -391,6 +392,7 @@ pub mod known {

future_trait,

index,

index_mut,

+ into_future,

mul_assign,

mul,

neg,

diff --git a/crates/hir-ty/src/infer.rs b/crates/hir-ty/src/infer.rs
index 46eeea0e6f..95a7229e87 100644
--- a/crates/hir-ty/src/infer.rs
+++ b/crates/hir-ty/src/infer.rs

@@ -875,7 +875,10 @@ impl<'a> InferenceContext<'a> {

}

fn resolve_future_future_output(&self) -> Option<TypeAliasId> {

- let trait_ = self.resolve_lang_item(name![future_trait])?.as_trait()?;

+ let trait_ = self

+ .resolver

+ .resolve_known_trait(self.db.upcast(), &path![core::future::IntoFuture])

+ .or_else(|| self.resolve_lang_item(name![future_trait])?.as_trait())?;

self.db.trait_data(trait_).associated_type_by_name(&name![Output])

}

diff --git a/crates/hir-ty/src/tests/traits.rs b/crates/hir-ty/src/tests/traits.rs
index 75802a5eb4..730ebe2357 100644
--- a/crates/hir-ty/src/tests/traits.rs
+++ b/crates/hir-ty/src/tests/traits.rs

@@ -138,6 +138,31 @@ fn not_send() -> Box<dyn Future<Output = ()> + 'static> {

}

#[test]

+fn into_future_trait() {

+ check_types(

+ r#"

+//- minicore: future

+struct Futurable;

+impl core::future::IntoFuture for Futurable {

+ type Output = u64;

+ type IntoFuture = IntFuture;

+struct IntFuture;

+impl core::future::Future for IntFuture {

+ type Output = u64;

+fn test() {

+ let r = Futurable;

+ let v = r.await;

+ v;

+} //^ u64

+"#,

+ );

+#[test]

fn infer_try() {

check_types(

r#"

diff --git a/crates/hir/src/lib.rs b/crates/hir/src/lib.rs
index 8f984210e1..800ea58ba2 100644
--- a/crates/hir/src/lib.rs
+++ b/crates/hir/src/lib.rs

@@ -2780,6 +2780,8 @@ impl Type {

/// Checks that particular type `ty` implements `std::future::Future`.

/// This function is used in `.await` syntax completion.

pub fn impls_future(&self, db: &dyn HirDatabase) -> bool {

+ // FIXME: This should be checking for IntoFuture trait, but I don't know how to find the

+ // right TraitId in this crate.

let std_future_trait = db

.lang_item(self.env.krate, SmolStr::new_inline("future_trait"))

.and_then(|it| it.as_trait());

diff --git a/crates/hir/src/source_analyzer.rs b/crates/hir/src/source_analyzer.rs
index f5e2e44307..756772cf84 100644
--- a/crates/hir/src/source_analyzer.rs
+++ b/crates/hir/src/source_analyzer.rs

@@ -269,6 +269,8 @@ impl SourceAnalyzer {

db: &dyn HirDatabase,

await_expr: &ast::AwaitExpr,

) -> Option<FunctionId> {

+ // FIXME This should be pointing to the poll of IntoFuture::Output's Future impl, but I

+ // don't know how to resolve the Output type so that we can query for its poll method.

let ty = self.ty_of_expr(db, &await_expr.expr()?.into())?;

let op_fn = db

diff --git a/crates/ide-assists/src/utils/suggest_name.rs b/crates/ide-assists/src/utils/suggest_name.rs
index 779cdbc93c..68d59daef4 100644
--- a/crates/ide-assists/src/utils/suggest_name.rs
+++ b/crates/ide-assists/src/utils/suggest_name.rs

@@ -55,6 +55,7 @@ const USELESS_METHODS: &[&str] = &[

"iter",

"into_iter",

"iter_mut",

+ "into_future",

];

pub(crate) fn for_generic_parameter(ty: &ast::ImplTraitType) -> SmolStr {

diff --git a/crates/ide-completion/src/completions/keyword.rs b/crates/ide-completion/src/completions/keyword.rs
index 3989a451bd..032b23725f 100644
--- a/crates/ide-completion/src/completions/keyword.rs
+++ b/crates/ide-completion/src/completions/keyword.rs

@@ -75,16 +75,17 @@ impl Future for A {}

fn foo(a: A) { a.$0 }

"#,

expect![[r#"

- kw await expr.await

- sn box Box::new(expr)

- sn call function(expr)

- sn dbg dbg!(expr)

- sn dbgr dbg!(&expr)

- sn let let

- sn letm let mut

- sn match match expr {}

- sn ref &expr

- sn refm &mut expr

+ kw await expr.await

+ me into_future() (as IntoFuture) fn(self) -> <Self as IntoFuture>::IntoFuture

+ sn box Box::new(expr)

+ sn call function(expr)

+ sn dbg dbg!(expr)

+ sn dbgr dbg!(&expr)

+ sn let let

+ sn letm let mut

+ sn match match expr {}

+ sn ref &expr

+ sn refm &mut expr

"#]],

);

@@ -98,18 +99,19 @@ fn foo() {

}

"#,

expect![[r#"

- kw await expr.await

- sn box Box::new(expr)

- sn call function(expr)

- sn dbg dbg!(expr)

- sn dbgr dbg!(&expr)

- sn let let

- sn letm let mut

- sn match match expr {}

- sn ref &expr

- sn refm &mut expr

+ kw await expr.await

+ me into_future() (use core::future::IntoFuture) fn(self) -> <Self as IntoFuture>::IntoFuture

+ sn box Box::new(expr)

+ sn call function(expr)

+ sn dbg dbg!(expr)

+ sn dbgr dbg!(&expr)

+ sn let let

+ sn letm let mut

+ sn match match expr {}

+ sn ref &expr

+ sn refm &mut expr

"#]],

- )

+ );

}

#[test]

diff --git a/crates/test-utils/src/minicore.rs b/crates/test-utils/src/minicore.rs
index f48d1ec66a..6df29db474 100644
--- a/crates/test-utils/src/minicore.rs
+++ b/crates/test-utils/src/minicore.rs

@@ -471,6 +471,21 @@ pub mod future {

#[lang = "poll"]

fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output>;

}

+ pub trait IntoFuture {

+ type Output;

+ type IntoFuture: Future<Output = Self::Output>;

+ #[lang = "into_future"]

+ fn into_future(self) -> Self::IntoFuture;

+ }

+ impl<F: Future> IntoFuture for F {

+ type Output = F::Output;

+ type IntoFuture = F;

+ fn into_future(self) -> F {

+ self

+ }

}

pub mod task {

pub enum Poll<T> {