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Auto merge of #12982 - jridgewell:into_future, r=Veykril
Implement IntoFuture type inference
One of my projects is using [IntoFuture](https://doc.rust-lang.org/std/future/trait.IntoFuture.html) to make our async code a little less verbose. However, rust-analyzer can't infer the output type of an await expression if the value uses `IntoFuture` to convert into another type. So we're getting `{unknown}` types everywhere since switching.
`foo.await` itself [desugars](https://github.com/rust-lang/rust/blob/e4417cf020fbcd6182c11637bc6b8694434bd81a/compiler/rustc_ast_lowering/src/expr.rs#L644-L658) into a `match into_future(foo) {}`, with every `Future` impl getting a [default](https://github.com/rust-lang/rust/blob/e4417cf020fbcd6182c11637bc6b8694434bd81a/library/core/src/future/into_future.rs#L131-L139) `IntoFuture` implementation. I'm not sure if we want to disable the old `future_trait` paths, since this only recently [stabilize](https://github.com/rust-lang/rust/pull/98718).
| -rw-r--r-- | crates/hir-expand/src/mod_path.rs | 1 | ||||
| -rw-r--r-- | crates/hir-expand/src/name.rs | 2 | ||||
| -rw-r--r-- | crates/hir-ty/src/infer.rs | 5 | ||||
| -rw-r--r-- | crates/hir-ty/src/tests/traits.rs | 25 | ||||
| -rw-r--r-- | crates/hir/src/lib.rs | 26 | ||||
| -rw-r--r-- | crates/hir/src/source_analyzer.rs | 32 | ||||
| -rw-r--r-- | crates/ide-assists/src/utils/suggest_name.rs | 1 | ||||
| -rw-r--r-- | crates/ide-completion/src/completions/dot.rs | 2 | ||||
| -rw-r--r-- | crates/ide-completion/src/completions/keyword.rs | 70 | ||||
| -rw-r--r-- | crates/ide/src/goto_definition.rs | 34 | ||||
| -rw-r--r-- | crates/test-utils/src/minicore.rs | 15 |
11 files changed, 178 insertions, 35 deletions
diff --git a/crates/hir-expand/src/mod_path.rs b/crates/hir-expand/src/mod_path.rs index d0f73ec820..d7586d129b 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 a1bb353374..2b859f7750 100644 --- a/crates/hir-expand/src/name.rs +++ b/crates/hir-expand/src/name.rs @@ -266,6 +266,7 @@ pub mod known { Try, Ok, Future, + IntoFuture, Result, Option, Output, @@ -399,6 +400,7 @@ 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 c128a051f7..0f37970e2b 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 3561bdeba7..aa019ca483 100644 --- a/crates/hir/src/lib.rs +++ b/crates/hir/src/lib.rs @@ -2778,20 +2778,32 @@ impl Type { self.ty.is_unknown() } - /// Checks that particular type `ty` implements `std::future::Future`. + /// Checks that particular type `ty` implements `std::future::IntoFuture` or + /// `std::future::Future`. /// This function is used in `.await` syntax completion. - pub fn impls_future(&self, db: &dyn HirDatabase) -> bool { - let std_future_trait = db - .lang_item(self.env.krate, SmolStr::new_inline("future_trait")) - .and_then(|it| it.as_trait()); - let std_future_trait = match std_future_trait { + pub fn impls_into_future(&self, db: &dyn HirDatabase) -> bool { + let trait_ = db + .lang_item(self.env.krate, SmolStr::new_inline("into_future")) + .and_then(|it| { + let into_future_fn = it.as_function()?; + let assoc_item = as_assoc_item(db, AssocItem::Function, into_future_fn)?; + let into_future_trait = assoc_item.containing_trait_or_trait_impl(db)?; + Some(into_future_trait.id) + }) + .or_else(|| { + let future_trait = + db.lang_item(self.env.krate, SmolStr::new_inline("future_trait"))?; + future_trait.as_trait() + }); + + let trait_ = match trait_ { Some(it) => it, None => return false, }; let canonical_ty = Canonical { value: self.ty.clone(), binders: CanonicalVarKinds::empty(Interner) }; - method_resolution::implements_trait(&canonical_ty, db, self.env.clone(), std_future_trait) + method_resolution::implements_trait(&canonical_ty, db, self.env.clone(), trait_) } /// Checks that particular type `ty` implements `std::ops::FnOnce`. diff --git a/crates/hir/src/source_analyzer.rs b/crates/hir/src/source_analyzer.rs index ae2896e193..bd35af06e2 100644 --- a/crates/hir/src/source_analyzer.rs +++ b/crates/hir/src/source_analyzer.rs @@ -27,6 +27,7 @@ use hir_def::{ use hir_expand::{ builtin_fn_macro::BuiltinFnLikeExpander, hygiene::Hygiene, + mod_path::path, name, name::{AsName, Name}, HirFileId, InFile, @@ -269,14 +270,35 @@ impl SourceAnalyzer { db: &dyn HirDatabase, await_expr: &ast::AwaitExpr, ) -> Option<FunctionId> { - let ty = self.ty_of_expr(db, &await_expr.expr()?.into())?; + let mut ty = self.ty_of_expr(db, &await_expr.expr()?.into())?.clone(); + + let into_future_trait = self + .resolver + .resolve_known_trait(db.upcast(), &path![core::future::IntoFuture]) + .map(Trait::from); + + if let Some(into_future_trait) = into_future_trait { + let type_ = Type::new_with_resolver(db, &self.resolver, ty.clone()); + if type_.impls_trait(db, into_future_trait, &[]) { + let items = into_future_trait.items(db); + let into_future_type = items.into_iter().find_map(|item| match item { + AssocItem::TypeAlias(alias) + if alias.name(db) == hir_expand::name![IntoFuture] => + { + Some(alias) + } + _ => None, + })?; + let future_trait = type_.normalize_trait_assoc_type(db, &[], into_future_type)?; + ty = future_trait.ty; + } + } - let op_fn = db + let poll_fn = db .lang_item(self.resolver.krate(), hir_expand::name![poll].to_smol_str())? .as_function()?; - let substs = hir_ty::TyBuilder::subst_for_def(db, op_fn).push(ty.clone()).build(); - - Some(self.resolve_impl_method_or_trait_def(db, op_fn, &substs)) + let substs = hir_ty::TyBuilder::subst_for_def(db, poll_fn).push(ty.clone()).build(); + Some(self.resolve_impl_method_or_trait_def(db, poll_fn, &substs)) } pub(crate) fn resolve_prefix_expr( diff --git a/crates/ide-assists/src/utils/suggest_name.rs b/crates/ide-assists/src/utils/suggest_name.rs index 662ddd063f..c521a10fcc 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/dot.rs b/crates/ide-completion/src/completions/dot.rs index cf40ca489c..02004ff7b6 100644 --- a/crates/ide-completion/src/completions/dot.rs +++ b/crates/ide-completion/src/completions/dot.rs @@ -19,7 +19,7 @@ pub(crate) fn complete_dot( }; // Suggest .await syntax for types that implement Future trait - if receiver_ty.impls_future(ctx.db) { + if receiver_ty.impls_into_future(ctx.db) { let mut item = CompletionItem::new(CompletionItemKind::Keyword, ctx.source_range(), "await"); item.detail("expr.await"); diff --git a/crates/ide-completion/src/completions/keyword.rs b/crates/ide-completion/src/completions/keyword.rs index 3989a451bd..1d03c8cc5c 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 +99,45 @@ 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] + fn test_completion_await_impls_into_future() { + check( + r#" +//- minicore: future +use core::future::*; +struct A {} +impl IntoFuture for A {} +fn foo(a: A) { a.$0 } +"#, + expect![[r#" + 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 + "#]], + ); } #[test] diff --git a/crates/ide/src/goto_definition.rs b/crates/ide/src/goto_definition.rs index d6cd5783f0..36a648fe4a 100644 --- a/crates/ide/src/goto_definition.rs +++ b/crates/ide/src/goto_definition.rs @@ -1665,6 +1665,40 @@ fn f() { } #[test] + fn goto_await_into_future_poll() { + check( + r#" +//- minicore: future + +struct Futurable; + +impl core::future::IntoFuture for Futurable { + type IntoFuture = MyFut; +} + +struct MyFut; + +impl core::future::Future for MyFut { + type Output = (); + + fn poll( + //^^^^ + self: std::pin::Pin<&mut Self>, + cx: &mut std::task::Context<'_> + ) -> std::task::Poll<Self::Output> + { + () + } +} + +fn f() { + Futurable.await$0; +} +"#, + ); + } + + #[test] fn goto_try_op() { check( r#" 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> { |