From 8994bb8673920be4a5422bc3310a5e3dcd5c9d27 Mon Sep 17 00:00:00 2001 From: Woohyun Jung Date: Tue, 14 Mar 2023 10:46:40 +0900 Subject: Import async-trait 0.1.66 --- .cargo_vcs_info.json | 6 + .clippy.toml | 1 + .github/workflows/ci.yml | 84 ++ .gitignore | 3 + Cargo.toml | 62 ++ Cargo.toml.orig | 30 + LICENSE-APACHE | 176 ++++ LICENSE-MIT | 23 + README.md | 262 +++++ build.rs | 31 + src/args.rs | 36 + src/bound.rs | 48 + src/expand.rs | 495 +++++++++ src/lib.rs | 341 ++++++ src/lifetime.rs | 110 ++ src/parse.rs | 34 + src/receiver.rs | 179 ++++ tests/compiletest.rs | 7 + tests/executor/mod.rs | 36 + tests/test.rs | 1606 +++++++++++++++++++++++++++++ tests/ui/arg-implementation-detail.rs | 22 + tests/ui/arg-implementation-detail.stderr | 5 + tests/ui/bare-trait-object.rs | 15 + tests/ui/bare-trait-object.stderr | 21 + tests/ui/consider-restricting.rs | 26 + tests/ui/consider-restricting.stderr | 33 + tests/ui/delimiter-span.rs | 24 + tests/ui/delimiter-span.stderr | 21 + tests/ui/lifetime-defined-here.rs | 23 + tests/ui/lifetime-defined-here.stderr | 29 + tests/ui/lifetime-span.rs | 36 + tests/ui/lifetime-span.stderr | 24 + tests/ui/missing-async-in-impl.rs | 15 + tests/ui/missing-async-in-impl.stderr | 8 + tests/ui/missing-async-in-trait.rs | 15 + tests/ui/missing-async-in-trait.stderr | 8 + tests/ui/missing-body.rs | 15 + tests/ui/missing-body.stderr | 7 + tests/ui/must-use.rs | 21 + tests/ui/must-use.stderr | 11 + tests/ui/self-span.rs | 30 + tests/ui/self-span.stderr | 27 + tests/ui/send-not-implemented.rs | 22 + tests/ui/send-not-implemented.stderr | 47 + tests/ui/unreachable.rs | 20 + tests/ui/unreachable.stderr | 14 + tests/ui/unsupported-self.rs | 15 + tests/ui/unsupported-self.stderr | 5 + 48 files changed, 4129 insertions(+) create mode 100644 .cargo_vcs_info.json create mode 100644 .clippy.toml create mode 100644 .github/workflows/ci.yml create mode 100644 .gitignore create mode 100644 Cargo.toml create mode 100644 Cargo.toml.orig create mode 100644 LICENSE-APACHE create mode 100644 LICENSE-MIT create mode 100644 README.md create mode 100644 build.rs create mode 100644 src/args.rs create mode 100644 src/bound.rs create mode 100644 src/expand.rs create mode 100644 src/lib.rs create mode 100644 src/lifetime.rs create mode 100644 src/parse.rs create mode 100644 src/receiver.rs create mode 100644 tests/compiletest.rs create mode 100644 tests/executor/mod.rs create mode 100644 tests/test.rs create mode 100644 tests/ui/arg-implementation-detail.rs create mode 100644 tests/ui/arg-implementation-detail.stderr create mode 100644 tests/ui/bare-trait-object.rs create mode 100644 tests/ui/bare-trait-object.stderr create mode 100644 tests/ui/consider-restricting.rs create mode 100644 tests/ui/consider-restricting.stderr create mode 100644 tests/ui/delimiter-span.rs create mode 100644 tests/ui/delimiter-span.stderr create mode 100644 tests/ui/lifetime-defined-here.rs create mode 100644 tests/ui/lifetime-defined-here.stderr create mode 100644 tests/ui/lifetime-span.rs create mode 100644 tests/ui/lifetime-span.stderr create mode 100644 tests/ui/missing-async-in-impl.rs create mode 100644 tests/ui/missing-async-in-impl.stderr create mode 100644 tests/ui/missing-async-in-trait.rs create mode 100644 tests/ui/missing-async-in-trait.stderr create mode 100644 tests/ui/missing-body.rs create mode 100644 tests/ui/missing-body.stderr create mode 100644 tests/ui/must-use.rs create mode 100644 tests/ui/must-use.stderr create mode 100644 tests/ui/self-span.rs create mode 100644 tests/ui/self-span.stderr create mode 100644 tests/ui/send-not-implemented.rs create mode 100644 tests/ui/send-not-implemented.stderr create mode 100644 tests/ui/unreachable.rs create mode 100644 tests/ui/unreachable.stderr create mode 100644 tests/ui/unsupported-self.rs create mode 100644 tests/ui/unsupported-self.stderr diff --git a/.cargo_vcs_info.json b/.cargo_vcs_info.json new file mode 100644 index 0000000..df0cdd6 --- /dev/null +++ b/.cargo_vcs_info.json @@ -0,0 +1,6 @@ +{ + "git": { + "sha1": "9a9b32228707aded43b07a50e8f69f92d15ca7a3" + }, + "path_in_vcs": "" +} \ No newline at end of file diff --git a/.clippy.toml b/.clippy.toml new file mode 100644 index 0000000..21a08b0 --- /dev/null +++ b/.clippy.toml @@ -0,0 +1 @@ +msrv = "1.39.0" diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml new file mode 100644 index 0000000..51fdd49 --- /dev/null +++ b/.github/workflows/ci.yml @@ -0,0 +1,84 @@ +name: CI + +on: + push: + pull_request: + workflow_dispatch: + schedule: [cron: "40 1 * * *"] + +permissions: + contents: read + +env: + RUSTFLAGS: -Dwarnings + +jobs: + pre_ci: + uses: dtolnay/.github/.github/workflows/pre_ci.yml@master + + test: + name: Rust ${{matrix.rust}} + needs: pre_ci + if: needs.pre_ci.outputs.continue + runs-on: ubuntu-latest + strategy: + fail-fast: false + matrix: + rust: [nightly, beta, stable, 1.56.0] + timeout-minutes: 45 + steps: + - uses: actions/checkout@v3 + - uses: dtolnay/rust-toolchain@master + with: + toolchain: ${{matrix.rust}} + - name: Enable type layout randomization + run: echo RUSTFLAGS=${RUSTFLAGS}\ -Zrandomize-layout >> $GITHUB_ENV + if: matrix.rust == 'nightly' + - name: Enable nightly-only tests + run: echo RUSTFLAGS=${RUSTFLAGS}\ --cfg=async_trait_nightly_testing >> $GITHUB_ENV + if: matrix.rust == 'nightly' + - run: cargo test + + msrv: + name: Rust 1.39.0 + needs: pre_ci + if: needs.pre_ci.outputs.continue + runs-on: ubuntu-latest + timeout-minutes: 45 + steps: + - uses: actions/checkout@v3 + - uses: dtolnay/rust-toolchain@1.39.0 + - run: cargo check + + clippy: + name: Clippy + runs-on: ubuntu-latest + if: github.event_name != 'pull_request' + timeout-minutes: 45 + steps: + - uses: actions/checkout@v3 + - uses: dtolnay/rust-toolchain@clippy + - run: cargo clippy --tests -- -Dclippy::all -Dclippy::pedantic + + miri: + name: Miri + needs: pre_ci + if: needs.pre_ci.outputs.continue + runs-on: ubuntu-latest + timeout-minutes: 45 + steps: + - uses: actions/checkout@v3 + - uses: dtolnay/rust-toolchain@miri + - run: cargo miri test + env: + MIRIFLAGS: -Zmiri-strict-provenance + + outdated: + name: Outdated + runs-on: ubuntu-latest + if: github.event_name != 'pull_request' + timeout-minutes: 45 + steps: + - uses: actions/checkout@v3 + - uses: dtolnay/install@cargo-outdated + - run: cargo outdated --workspace --exit-code 1 diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..6936990 --- /dev/null +++ b/.gitignore @@ -0,0 +1,3 @@ +/target +**/*.rs.bk +Cargo.lock diff --git a/Cargo.toml b/Cargo.toml new file mode 100644 index 0000000..c29ebe2 --- /dev/null +++ b/Cargo.toml @@ -0,0 +1,62 @@ +# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO +# +# When uploading crates to the registry Cargo will automatically +# "normalize" Cargo.toml files for maximal compatibility +# with all versions of Cargo and also rewrite `path` dependencies +# to registry (e.g., crates.io) dependencies. +# +# If you are reading this file be aware that the original Cargo.toml +# will likely look very different (and much more reasonable). +# See Cargo.toml.orig for the original contents. + +[package] +edition = "2018" +rust-version = "1.39" +name = "async-trait" +version = "0.1.66" +authors = ["David Tolnay "] +description = "Type erasure for async trait methods" +documentation = "https://docs.rs/async-trait" +readme = "README.md" +keywords = ["async"] +categories = [ + "asynchronous", + "no-std", +] +license = "MIT OR Apache-2.0" +repository = "https://github.com/dtolnay/async-trait" + +[package.metadata.docs.rs] +targets = ["x86_64-unknown-linux-gnu"] + +[lib] +proc-macro = true + +[dependencies.proc-macro2] +version = "1.0" + +[dependencies.quote] +version = "1.0" + +[dependencies.syn] +version = "1.0.96" +features = [ + "full", + "visit-mut", +] + +[dev-dependencies.futures] +version = "0.3" + +[dev-dependencies.rustversion] +version = "1.0" + +[dev-dependencies.tracing] +version = "0.1.14" + +[dev-dependencies.tracing-attributes] +version = "0.1.14" + +[dev-dependencies.trybuild] +version = "1.0.49" +features = ["diff"] diff --git a/Cargo.toml.orig b/Cargo.toml.orig new file mode 100644 index 0000000..152ec78 --- /dev/null +++ b/Cargo.toml.orig @@ -0,0 +1,30 @@ +[package] +name = "async-trait" +version = "0.1.66" +authors = ["David Tolnay "] +categories = ["asynchronous", "no-std"] +description = "Type erasure for async trait methods" +documentation = "https://docs.rs/async-trait" +edition = "2018" +keywords = ["async"] +license = "MIT OR Apache-2.0" +repository = "https://github.com/dtolnay/async-trait" +rust-version = "1.39" + +[lib] +proc-macro = true + +[dependencies] +proc-macro2 = "1.0" +quote = "1.0" +syn = { version = "1.0.96", features = ["full", "visit-mut"] } + +[dev-dependencies] +futures = "0.3" +rustversion = "1.0" +tracing = "0.1.14" +tracing-attributes = "0.1.14" +trybuild = { version = "1.0.49", features = ["diff"] } + +[package.metadata.docs.rs] +targets = ["x86_64-unknown-linux-gnu"] diff --git a/LICENSE-APACHE b/LICENSE-APACHE new file mode 100644 index 0000000..1b5ec8b --- /dev/null +++ b/LICENSE-APACHE @@ -0,0 +1,176 @@ + Apache License + Version 2.0, January 2004 + http://www.apache.org/licenses/ + +TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION + +1. 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IN NO EVENT +SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY +CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION +OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR +IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER +DEALINGS IN THE SOFTWARE. diff --git a/README.md b/README.md new file mode 100644 index 0000000..39e368b --- /dev/null +++ b/README.md @@ -0,0 +1,262 @@ +Async trait methods +=================== + +[github](https://github.com/dtolnay/async-trait) +[crates.io](https://crates.io/crates/async-trait) +[docs.rs](https://docs.rs/async-trait) +[build status](https://github.com/dtolnay/async-trait/actions?query=branch%3Amaster) + +The initial round of stabilizations for the async/await language feature in Rust +1.39 did not include support for async fn in traits. Trying to include an async +fn in a trait produces the following error: + +```rust +trait MyTrait { + async fn f() {} +} +``` + +```console +error[E0706]: trait fns cannot be declared `async` + --> src/main.rs:4:5 + | +4 | async fn f() {} + | ^^^^^^^^^^^^^^^ +``` + +This crate provides an attribute macro to make async fn in traits work. + +Please refer to [*why async fn in traits are hard*][hard] for a deeper analysis +of how this implementation differs from what the compiler and language hope to +deliver in the future. + +[hard]: https://smallcultfollowing.com/babysteps/blog/2019/10/26/async-fn-in-traits-are-hard/ + +
+ +## Example + +This example implements the core of a highly effective advertising platform +using async fn in a trait. + +The only thing to notice here is that we write an `#[async_trait]` macro on top +of traits and trait impls that contain async fn, and then they work. + +```rust +use async_trait::async_trait; + +#[async_trait] +trait Advertisement { + async fn run(&self); +} + +struct Modal; + +#[async_trait] +impl Advertisement for Modal { + async fn run(&self) { + self.render_fullscreen().await; + for _ in 0..4u16 { + remind_user_to_join_mailing_list().await; + } + self.hide_for_now().await; + } +} + +struct AutoplayingVideo { + media_url: String, +} + +#[async_trait] +impl Advertisement for AutoplayingVideo { + async fn run(&self) { + let stream = connect(&self.media_url).await; + stream.play().await; + + // Video probably persuaded user to join our mailing list! + Modal.run().await; + } +} +``` + +
+ +## Supported features + +It is the intention that all features of Rust traits should work nicely with +\#\[async_trait\], but the edge cases are numerous. *Please file an issue if you +see unexpected borrow checker errors, type errors, or warnings.* There is no use +of `unsafe` in the expanded code, so rest assured that if your code compiles it +can't be that badly broken. + +- 👍 Self by value, by reference, by mut reference, or no self; +- 👍 Any number of arguments, any return value; +- 👍 Generic type parameters and lifetime parameters; +- 👍 Associated types; +- 👍 Having async and non-async functions in the same trait; +- 👍 Default implementations provided by the trait; +- 👍 Elided lifetimes; +- 👍 Dyn-capable traits. + +
+ +## Explanation + +Async fns get transformed into methods that return `Pin>` and delegate to a private async freestanding function. + +For example the `impl Advertisement for AutoplayingVideo` above would be +expanded as: + +```rust +impl Advertisement for AutoplayingVideo { + fn run<'async_trait>( + &'async_trait self, + ) -> Pin + Send + 'async_trait>> + where + Self: Sync + 'async_trait, + { + async fn run(_self: &AutoplayingVideo) { + /* the original method body */ + } + + Box::pin(run(self)) + } +} +``` + +
+ +## Non-threadsafe futures + +Not all async traits need futures that are `dyn Future + Send`. To avoid having +Send and Sync bounds placed on the async trait methods, invoke the async trait +macro as `#[async_trait(?Send)]` on both the trait and the impl blocks. + +
+ +## Elided lifetimes + +Be aware that async fn syntax does not allow lifetime elision outside of `&` and +`&mut` references. (This is true even when not using #\[async_trait\].) +Lifetimes must be named or marked by the placeholder `'_`. + +Fortunately the compiler is able to diagnose missing lifetimes with a good error +message. + +```rust +type Elided<'a> = &'a usize; + +#[async_trait] +trait Test { + async fn test(not_okay: Elided, okay: &usize) {} +} +``` + +```console +error[E0726]: implicit elided lifetime not allowed here + --> src/main.rs:9:29 + | +9 | async fn test(not_okay: Elided, okay: &usize) {} + | ^^^^^^- help: indicate the anonymous lifetime: `<'_>` +``` + +The fix is to name the lifetime or use `'_`. + +```rust +#[async_trait] +trait Test { + // either + async fn test<'e>(elided: Elided<'e>) {} + // or + async fn test(elided: Elided<'_>) {} +} +``` + +
+ +## Dyn traits + +Traits with async methods can be used as trait objects as long as they meet the +usual requirements for dyn -- no methods with type parameters, no self by value, +no associated types, etc. + +```rust +#[async_trait] +pub trait ObjectSafe { + async fn f(&self); + async fn g(&mut self); +} + +impl ObjectSafe for MyType {...} + +let value: MyType = ...; +let object = &value as &dyn ObjectSafe; // make trait object +``` + +The one wrinkle is in traits that provide default implementations of async +methods. In order for the default implementation to produce a future that is +Send, the async\_trait macro must emit a bound of `Self: Sync` on trait methods +that take `&self` and a bound `Self: Send` on trait methods that take `&mut +self`. An example of the former is visible in the expanded code in the +explanation section above. + +If you make a trait with async methods that have default implementations, +everything will work except that the trait cannot be used as a trait object. +Creating a value of type `&dyn Trait` will produce an error that looks like +this: + +```console +error: the trait `Test` cannot be made into an object + --> src/main.rs:8:5 + | +8 | async fn cannot_dyn(&self) {} + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ +``` + +For traits that need to be object safe and need to have default implementations +for some async methods, there are two resolutions. Either you can add Send +and/or Sync as supertraits (Send if there are `&mut self` methods with default +implementations, Sync if there are `&self` methods with default implementations) +to constrain all implementors of the trait such that the default implementations +are applicable to them: + +```rust +#[async_trait] +pub trait ObjectSafe: Sync { // added supertrait + async fn can_dyn(&self) {} +} + +let object = &value as &dyn ObjectSafe; +``` + +or you can strike the problematic methods from your trait object by bounding +them with `Self: Sized`: + +```rust +#[async_trait] +pub trait ObjectSafe { + async fn cannot_dyn(&self) where Self: Sized {} + + // presumably other methods +} + +let object = &value as &dyn ObjectSafe; +``` + +
+ +#### License + + +Licensed under either of Apache License, Version +2.0 or MIT license at your option. + + +
+ + +Unless you explicitly state otherwise, any contribution intentionally submitted +for inclusion in this crate by you, as defined in the Apache-2.0 license, shall +be dual licensed as above, without any additional terms or conditions. + diff --git a/build.rs b/build.rs new file mode 100644 index 0000000..d7f6b15 --- /dev/null +++ b/build.rs @@ -0,0 +1,31 @@ +use std::env; +use std::process::Command; +use std::str; + +fn main() { + println!("cargo:rerun-if-changed=build.rs"); + + let compiler = match rustc_minor_version() { + Some(compiler) => compiler, + None => return, + }; + + if compiler < 45 { + println!("cargo:rustc-cfg=no_span_mixed_site"); + } + + if compiler < 47 { + println!("cargo:rustc-cfg=self_span_hack"); + } +} + +fn rustc_minor_version() -> Option { + let rustc = env::var_os("RUSTC")?; + let output = Command::new(rustc).arg("--version").output().ok()?; + let version = str::from_utf8(&output.stdout).ok()?; + let mut pieces = version.split('.'); + if pieces.next() != Some("rustc 1") { + return None; + } + pieces.next()?.parse().ok() +} diff --git a/src/args.rs b/src/args.rs new file mode 100644 index 0000000..72d97e9 --- /dev/null +++ b/src/args.rs @@ -0,0 +1,36 @@ +use proc_macro2::Span; +use syn::parse::{Error, Parse, ParseStream, Result}; +use syn::Token; + +#[derive(Copy, Clone)] +pub struct Args { + pub local: bool, +} + +mod kw { + syn::custom_keyword!(Send); +} + +impl Parse for Args { + fn parse(input: ParseStream) -> Result { + match try_parse(input) { + Ok(args) if input.is_empty() => Ok(args), + _ => Err(error()), + } + } +} + +fn try_parse(input: ParseStream) -> Result { + if input.peek(Token![?]) { + input.parse::()?; + input.parse::()?; + Ok(Args { local: true }) + } else { + Ok(Args { local: false }) + } +} + +fn error() -> Error { + let msg = "expected #[async_trait] or #[async_trait(?Send)]"; + Error::new(Span::call_site(), msg) +} diff --git a/src/bound.rs b/src/bound.rs new file mode 100644 index 0000000..50182f6 --- /dev/null +++ b/src/bound.rs @@ -0,0 +1,48 @@ +use proc_macro2::{Ident, Span, TokenStream}; +use quote::quote_spanned; +use syn::punctuated::Punctuated; +use syn::{Token, TypeParamBound}; + +pub type Supertraits = Punctuated; + +pub enum InferredBound { + Send, + Sync, +} + +pub fn has_bound(supertraits: &Supertraits, bound: &InferredBound) -> bool { + for supertrait in supertraits { + if let TypeParamBound::Trait(supertrait) = supertrait { + if supertrait.path.is_ident(bound) + || supertrait.path.segments.len() == 3 + && (supertrait.path.segments[0].ident == "std" + || supertrait.path.segments[0].ident == "core") + && supertrait.path.segments[1].ident == "marker" + && supertrait.path.segments[2].ident == *bound + { + return true; + } + } + } + false +} + +impl InferredBound { + fn as_str(&self) -> &str { + match self { + InferredBound::Send => "Send", + InferredBound::Sync => "Sync", + } + } + + pub fn spanned_path(&self, span: Span) -> TokenStream { + let ident = Ident::new(self.as_str(), span); + quote_spanned!(span=> ::core::marker::#ident) + } +} + +impl PartialEq for Ident { + fn eq(&self, bound: &InferredBound) -> bool { + self == bound.as_str() + } +} diff --git a/src/expand.rs b/src/expand.rs new file mode 100644 index 0000000..2499177 --- /dev/null +++ b/src/expand.rs @@ -0,0 +1,495 @@ +use crate::bound::{has_bound, InferredBound, Supertraits}; +use crate::lifetime::{AddLifetimeToImplTrait, CollectLifetimes}; +use crate::parse::Item; +use crate::receiver::{has_self_in_block, has_self_in_sig, mut_pat, ReplaceSelf}; +use proc_macro2::{Span, TokenStream}; +use quote::{format_ident, quote, quote_spanned, ToTokens}; +use std::collections::BTreeSet as Set; +use std::mem; +use syn::punctuated::Punctuated; +use syn::visit_mut::{self, VisitMut}; +use syn::{ + parse_quote, parse_quote_spanned, Attribute, Block, FnArg, GenericArgument, GenericParam, + Generics, Ident, ImplItem, Lifetime, LifetimeDef, Pat, PatIdent, PathArguments, Receiver, + ReturnType, Signature, Stmt, Token, TraitItem, Type, TypePath, WhereClause, +}; + +impl ToTokens for Item { + fn to_tokens(&self, tokens: &mut TokenStream) { + match self { + Item::Trait(item) => item.to_tokens(tokens), + Item::Impl(item) => item.to_tokens(tokens), + } + } +} + +#[derive(Clone, Copy)] +enum Context<'a> { + Trait { + generics: &'a Generics, + supertraits: &'a Supertraits, + }, + Impl { + impl_generics: &'a Generics, + associated_type_impl_traits: &'a Set, + }, +} + +impl Context<'_> { + fn lifetimes<'a>(&'a self, used: &'a [Lifetime]) -> impl Iterator { + let generics = match self { + Context::Trait { generics, .. } => generics, + Context::Impl { impl_generics, .. } => impl_generics, + }; + generics.params.iter().filter_map(move |param| { + if let GenericParam::Lifetime(param) = param { + if used.contains(¶m.lifetime) { + return Some(param); + } + } + None + }) + } +} + +pub fn expand(input: &mut Item, is_local: bool) { + match input { + Item::Trait(input) => { + let context = Context::Trait { + generics: &input.generics, + supertraits: &input.supertraits, + }; + for inner in &mut input.items { + if let TraitItem::Method(method) = inner { + let sig = &mut method.sig; + if sig.asyncness.is_some() { + let block = &mut method.default; + let mut has_self = has_self_in_sig(sig); + method.attrs.push(parse_quote!(#[must_use])); + if let Some(block) = block { + has_self |= has_self_in_block(block); + transform_block(context, sig, block); + method.attrs.push(lint_suppress_with_body()); + } else { + method.attrs.push(lint_suppress_without_body()); + } + let has_default = method.default.is_some(); + transform_sig(context, sig, has_self, has_default, is_local); + } + } + } + } + Item::Impl(input) => { + let mut associated_type_impl_traits = Set::new(); + for inner in &input.items { + if let ImplItem::Type(assoc) = inner { + if let Type::ImplTrait(_) = assoc.ty { + associated_type_impl_traits.insert(assoc.ident.clone()); + } + } + } + + let context = Context::Impl { + impl_generics: &input.generics, + associated_type_impl_traits: &associated_type_impl_traits, + }; + for inner in &mut input.items { + if let ImplItem::Method(method) = inner { + let sig = &mut method.sig; + if sig.asyncness.is_some() { + let block = &mut method.block; + let has_self = has_self_in_sig(sig) || has_self_in_block(block); + transform_block(context, sig, block); + transform_sig(context, sig, has_self, false, is_local); + method.attrs.push(lint_suppress_with_body()); + } + } + } + } + } +} + +fn lint_suppress_with_body() -> Attribute { + parse_quote! { + #[allow( + clippy::async_yields_async, + clippy::let_unit_value, + clippy::no_effect_underscore_binding, + clippy::shadow_same, + clippy::type_complexity, + clippy::type_repetition_in_bounds, + clippy::used_underscore_binding + )] + } +} + +fn lint_suppress_without_body() -> Attribute { + parse_quote! { + #[allow( + clippy::type_complexity, + clippy::type_repetition_in_bounds + )] + } +} + +// Input: +// async fn f(&self, x: &T) -> Ret; +// +// Output: +// fn f<'life0, 'life1, 'async_trait, T>( +// &'life0 self, +// x: &'life1 T, +// ) -> Pin + Send + 'async_trait>> +// where +// 'life0: 'async_trait, +// 'life1: 'async_trait, +// T: 'async_trait, +// Self: Sync + 'async_trait; +fn transform_sig( + context: Context, + sig: &mut Signature, + has_self: bool, + has_default: bool, + is_local: bool, +) { + let default_span = sig.asyncness.take().unwrap().span; + sig.fn_token.span = default_span; + + let (ret_arrow, ret) = match &sig.output { + ReturnType::Default => (Token![->](default_span), quote_spanned!(default_span=> ())), + ReturnType::Type(arrow, ret) => (*arrow, quote!(#ret)), + }; + + let mut lifetimes = CollectLifetimes::new(); + for arg in sig.inputs.iter_mut() { + match arg { + FnArg::Receiver(arg) => lifetimes.visit_receiver_mut(arg), + FnArg::Typed(arg) => lifetimes.visit_type_mut(&mut arg.ty), + } + } + + for param in &mut sig.generics.params { + match param { + GenericParam::Type(param) => { + let param_name = ¶m.ident; + let span = match param.colon_token.take() { + Some(colon_token) => colon_token.span, + None => param_name.span(), + }; + let bounds = mem::replace(&mut param.bounds, Punctuated::new()); + where_clause_or_default(&mut sig.generics.where_clause) + .predicates + .push(parse_quote_spanned!(span=> #param_name: 'async_trait + #bounds)); + } + GenericParam::Lifetime(param) => { + let param_name = ¶m.lifetime; + let span = match param.colon_token.take() { + Some(colon_token) => colon_token.span, + None => param_name.span(), + }; + let bounds = mem::replace(&mut param.bounds, Punctuated::new()); + where_clause_or_default(&mut sig.generics.where_clause) + .predicates + .push(parse_quote_spanned!(span=> #param: 'async_trait + #bounds)); + } + GenericParam::Const(_) => {} + } + } + + for param in context.lifetimes(&lifetimes.explicit) { + let param = ¶m.lifetime; + let span = param.span(); + where_clause_or_default(&mut sig.generics.where_clause) + .predicates + .push(parse_quote_spanned!(span=> #param: 'async_trait)); + } + + if sig.generics.lt_token.is_none() { + sig.generics.lt_token = Some(Token![<](sig.ident.span())); + } + if sig.generics.gt_token.is_none() { + sig.generics.gt_token = Some(Token![>](sig.paren_token.span)); + } + + for elided in lifetimes.elided { + sig.generics.params.push(parse_quote!(#elided)); + where_clause_or_default(&mut sig.generics.where_clause) + .predicates + .push(parse_quote_spanned!(elided.span()=> #elided: 'async_trait)); + } + + sig.generics + .params + .push(parse_quote_spanned!(default_span=> 'async_trait)); + + if has_self { + let bounds: &[InferredBound] = match sig.inputs.iter().next() { + Some(FnArg::Receiver(Receiver { + reference: Some(_), + mutability: None, + .. + })) => &[InferredBound::Sync], + Some(FnArg::Typed(arg)) + if match arg.pat.as_ref() { + Pat::Ident(pat) => pat.ident == "self", + _ => false, + } => + { + match arg.ty.as_ref() { + // self: &Self + Type::Reference(ty) if ty.mutability.is_none() => &[InferredBound::Sync], + // self: Arc + Type::Path(ty) + if { + let segment = ty.path.segments.last().unwrap(); + segment.ident == "Arc" + && match &segment.arguments { + PathArguments::AngleBracketed(arguments) => { + arguments.args.len() == 1 + && match &arguments.args[0] { + GenericArgument::Type(Type::Path(arg)) => { + arg.path.is_ident("Self") + } + _ => false, + } + } + _ => false, + } + } => + { + &[InferredBound::Sync, InferredBound::Send] + } + _ => &[InferredBound::Send], + } + } + _ => &[InferredBound::Send], + }; + + let bounds = bounds.iter().filter_map(|bound| { + let assume_bound = match context { + Context::Trait { supertraits, .. } => !has_default || has_bound(supertraits, bound), + Context::Impl { .. } => true, + }; + if assume_bound || is_local { + None + } else { + Some(bound.spanned_path(default_span)) + } + }); + + where_clause_or_default(&mut sig.generics.where_clause) + .predicates + .push(parse_quote_spanned! {default_span=> + Self: #(#bounds +)* 'async_trait + }); + } + + for (i, arg) in sig.inputs.iter_mut().enumerate() { + match arg { + FnArg::Receiver(Receiver { + reference: Some(_), .. + }) => {} + FnArg::Receiver(arg) => arg.mutability = None, + FnArg::Typed(arg) => { + let type_is_reference = match *arg.ty { + Type::Reference(_) => true, + _ => false, + }; + if let Pat::Ident(pat) = &mut *arg.pat { + if pat.ident == "self" || !type_is_reference { + pat.by_ref = None; + pat.mutability = None; + } + } else if !type_is_reference { + let positional = positional_arg(i, &arg.pat); + let m = mut_pat(&mut arg.pat); + arg.pat = parse_quote!(#m #positional); + } + AddLifetimeToImplTrait.visit_type_mut(&mut arg.ty); + } + } + } + + let bounds = if is_local { + quote_spanned!(default_span=> 'async_trait) + } else { + quote_spanned!(default_span=> ::core::marker::Send + 'async_trait) + }; + sig.output = parse_quote_spanned! {default_span=> + #ret_arrow ::core::pin::Pin + #bounds + >> + }; +} + +// Input: +// async fn f(&self, x: &T, (a, b): (A, B)) -> Ret { +// self + x + a + b +// } +// +// Output: +// Box::pin(async move { +// let ___ret: Ret = { +// let __self = self; +// let x = x; +// let (a, b) = __arg1; +// +// __self + x + a + b +// }; +// +// ___ret +// }) +fn transform_block(context: Context, sig: &mut Signature, block: &mut Block) { + if let Some(Stmt::Item(syn::Item::Verbatim(item))) = block.stmts.first() { + if block.stmts.len() == 1 && item.to_string() == ";" { + return; + } + } + + let mut self_span = None; + let decls = sig + .inputs + .iter() + .enumerate() + .map(|(i, arg)| match arg { + FnArg::Receiver(Receiver { + self_token, + mutability, + .. + }) => { + let ident = Ident::new("__self", self_token.span); + self_span = Some(self_token.span); + quote!(let #mutability #ident = #self_token;) + } + FnArg::Typed(arg) => { + // If there is a #[cfg(...)] attribute that selectively enables + // the parameter, forward it to the variable. + // + // This is currently not applied to the `self` parameter. + let attrs = arg.attrs.iter().filter(|attr| attr.path.is_ident("cfg")); + + if let Pat::Ident(PatIdent { + ident, mutability, .. + }) = &*arg.pat + { + if ident == "self" { + self_span = Some(ident.span()); + let prefixed = Ident::new("__self", ident.span()); + quote!(let #mutability #prefixed = #ident;) + } else if let Type::Reference(_) = *arg.ty { + quote!() + } else { + quote! { + #(#attrs)* + let #mutability #ident = #ident; + } + } + } else if let Type::Reference(_) = *arg.ty { + quote!() + } else { + let pat = &arg.pat; + let ident = positional_arg(i, pat); + if let Pat::Wild(_) = **pat { + quote! { + #(#attrs)* + let #ident = #ident; + } + } else { + quote! { + #(#attrs)* + let #pat = { + let #ident = #ident; + #ident + }; + } + } + } + } + }) + .collect::>(); + + if let Some(span) = self_span { + let mut replace_self = ReplaceSelf(span); + replace_self.visit_block_mut(block); + } + + let stmts = &block.stmts; + let let_ret = match &mut sig.output { + ReturnType::Default => quote_spanned! {block.brace_token.span=> + #(#decls)* + let _: () = { #(#stmts)* }; + }, + ReturnType::Type(_, ret) => { + if contains_associated_type_impl_trait(context, ret) { + if decls.is_empty() { + quote!(#(#stmts)*) + } else { + quote!(#(#decls)* { #(#stmts)* }) + } + } else { + quote_spanned! {block.brace_token.span=> + if let ::core::option::Option::Some(__ret) = ::core::option::Option::None::<#ret> { + return __ret; + } + #(#decls)* + let __ret: #ret = { #(#stmts)* }; + #[allow(unreachable_code)] + __ret + } + } + } + }; + let box_pin = quote_spanned!(block.brace_token.span=> + Box::pin(async move { #let_ret }) + ); + block.stmts = parse_quote!(#box_pin); +} + +fn positional_arg(i: usize, pat: &Pat) -> Ident { + let span: Span = syn::spanned::Spanned::span(pat); + #[cfg(not(no_span_mixed_site))] + let span = span.resolved_at(Span::mixed_site()); + format_ident!("__arg{}", i, span = span) +} + +fn contains_associated_type_impl_trait(context: Context, ret: &mut Type) -> bool { + struct AssociatedTypeImplTraits<'a> { + set: &'a Set, + contains: bool, + } + + impl<'a> VisitMut for AssociatedTypeImplTraits<'a> { + fn visit_type_path_mut(&mut self, ty: &mut TypePath) { + if ty.qself.is_none() + && ty.path.segments.len() == 2 + && ty.path.segments[0].ident == "Self" + && self.set.contains(&ty.path.segments[1].ident) + { + self.contains = true; + } + visit_mut::visit_type_path_mut(self, ty); + } + } + + match context { + Context::Trait { .. } => false, + Context::Impl { + associated_type_impl_traits, + .. + } => { + let mut visit = AssociatedTypeImplTraits { + set: associated_type_impl_traits, + contains: false, + }; + visit.visit_type_mut(ret); + visit.contains + } + } +} + +fn where_clause_or_default(clause: &mut Option) -> &mut WhereClause { + clause.get_or_insert_with(|| WhereClause { + where_token: Default::default(), + predicates: Punctuated::new(), + }) +} diff --git a/src/lib.rs b/src/lib.rs new file mode 100644 index 0000000..b973640 --- /dev/null +++ b/src/lib.rs @@ -0,0 +1,341 @@ +//! [![github]](https://github.com/dtolnay/async-trait) [![crates-io]](https://crates.io/crates/async-trait) [![docs-rs]](https://docs.rs/async-trait) +//! +//! [github]: https://img.shields.io/badge/github-8da0cb?style=for-the-badge&labelColor=555555&logo=github +//! [crates-io]: https://img.shields.io/badge/crates.io-fc8d62?style=for-the-badge&labelColor=555555&logo=rust +//! [docs-rs]: https://img.shields.io/badge/docs.rs-66c2a5?style=for-the-badge&labelColor=555555&logo=docs.rs +//! +//!
+//! +//!
Type erasure for async trait methods
+//! +//! The initial round of stabilizations for the async/await language feature in +//! Rust 1.39 did not include support for async fn in traits. Trying to include +//! an async fn in a trait produces the following error: +//! +//! ```compile_fail +//! trait MyTrait { +//! async fn f() {} +//! } +//! ``` +//! +//! ```text +//! error[E0706]: trait fns cannot be declared `async` +//! --> src/main.rs:4:5 +//! | +//! 4 | async fn f() {} +//! | ^^^^^^^^^^^^^^^ +//! ``` +//! +//! This crate provides an attribute macro to make async fn in traits work. +//! +//! Please refer to [*why async fn in traits are hard*][hard] for a deeper +//! analysis of how this implementation differs from what the compiler and +//! language hope to deliver in the future. +//! +//! [hard]: https://smallcultfollowing.com/babysteps/blog/2019/10/26/async-fn-in-traits-are-hard/ +//! +//!
+//! +//! # Example +//! +//! This example implements the core of a highly effective advertising platform +//! using async fn in a trait. +//! +//! The only thing to notice here is that we write an `#[async_trait]` macro on +//! top of traits and trait impls that contain async fn, and then they work. +//! +//! ``` +//! use async_trait::async_trait; +//! +//! #[async_trait] +//! trait Advertisement { +//! async fn run(&self); +//! } +//! +//! struct Modal; +//! +//! #[async_trait] +//! impl Advertisement for Modal { +//! async fn run(&self) { +//! self.render_fullscreen().await; +//! for _ in 0..4u16 { +//! remind_user_to_join_mailing_list().await; +//! } +//! self.hide_for_now().await; +//! } +//! } +//! +//! struct AutoplayingVideo { +//! media_url: String, +//! } +//! +//! #[async_trait] +//! impl Advertisement for AutoplayingVideo { +//! async fn run(&self) { +//! let stream = connect(&self.media_url).await; +//! stream.play().await; +//! +//! // Video probably persuaded user to join our mailing list! +//! Modal.run().await; +//! } +//! } +//! # +//! # impl Modal { +//! # async fn render_fullscreen(&self) {} +//! # async fn hide_for_now(&self) {} +//! # } +//! # +//! # async fn remind_user_to_join_mailing_list() {} +//! # +//! # struct Stream; +//! # async fn connect(_media_url: &str) -> Stream { Stream } +//! # impl Stream { +//! # async fn play(&self) {} +//! # } +//! ``` +//! +//!

+//! +//! # Supported features +//! +//! It is the intention that all features of Rust traits should work nicely with +//! #\[async_trait\], but the edge cases are numerous. Please file an issue if +//! you see unexpected borrow checker errors, type errors, or warnings. There is +//! no use of `unsafe` in the expanded code, so rest assured that if your code +//! compiles it can't be that badly broken. +//! +//! > ☑ Self by value, by reference, by mut reference, or no self;
+//! > ☑ Any number of arguments, any return value;
+//! > ☑ Generic type parameters and lifetime parameters;
+//! > ☑ Associated types;
+//! > ☑ Having async and non-async functions in the same trait;
+//! > ☑ Default implementations provided by the trait;
+//! > ☑ Elided lifetimes;
+//! > ☑ Dyn-capable traits.
+//! +//!
+//! +//! # Explanation +//! +//! Async fns get transformed into methods that return `Pin>` and delegate to a private async freestanding function. +//! +//! For example the `impl Advertisement for AutoplayingVideo` above would be +//! expanded as: +//! +//! ``` +//! # const IGNORE: &str = stringify! { +//! impl Advertisement for AutoplayingVideo { +//! fn run<'async>( +//! &'async self, +//! ) -> Pin + Send + 'async>> +//! where +//! Self: Sync + 'async, +//! { +//! async fn run(_self: &AutoplayingVideo) { +//! /* the original method body */ +//! } +//! +//! Box::pin(run(self)) +//! } +//! } +//! # }; +//! ``` +//! +//!

+//! +//! # Non-threadsafe futures +//! +//! Not all async traits need futures that are `dyn Future + Send`. To avoid +//! having Send and Sync bounds placed on the async trait methods, invoke the +//! async trait macro as `#[async_trait(?Send)]` on both the trait and the impl +//! blocks. +//! +//!
+//! +//! # Elided lifetimes +//! +//! Be aware that async fn syntax does not allow lifetime elision outside of `&` +//! and `&mut` references. (This is true even when not using #\[async_trait\].) +//! Lifetimes must be named or marked by the placeholder `'_`. +//! +//! Fortunately the compiler is able to diagnose missing lifetimes with a good +//! error message. +//! +//! ```compile_fail +//! # use async_trait::async_trait; +//! # +//! type Elided<'a> = &'a usize; +//! +//! #[async_trait] +//! trait Test { +//! async fn test(not_okay: Elided, okay: &usize) {} +//! } +//! ``` +//! +//! ```text +//! error[E0726]: implicit elided lifetime not allowed here +//! --> src/main.rs:9:29 +//! | +//! 9 | async fn test(not_okay: Elided, okay: &usize) {} +//! | ^^^^^^- help: indicate the anonymous lifetime: `<'_>` +//! ``` +//! +//! The fix is to name the lifetime or use `'_`. +//! +//! ``` +//! # use async_trait::async_trait; +//! # +//! # type Elided<'a> = &'a usize; +//! # +//! #[async_trait] +//! trait Test { +//! // either +//! async fn test<'e>(elided: Elided<'e>) {} +//! # } +//! # #[async_trait] +//! # trait Test2 { +//! // or +//! async fn test(elided: Elided<'_>) {} +//! } +//! ``` +//! +//!

+//! +//! # Dyn traits +//! +//! Traits with async methods can be used as trait objects as long as they meet +//! the usual requirements for dyn -- no methods with type parameters, no self +//! by value, no associated types, etc. +//! +//! ``` +//! # use async_trait::async_trait; +//! # +//! #[async_trait] +//! pub trait ObjectSafe { +//! async fn f(&self); +//! async fn g(&mut self); +//! } +//! +//! # const IGNORE: &str = stringify! { +//! impl ObjectSafe for MyType {...} +//! +//! let value: MyType = ...; +//! # }; +//! # +//! # struct MyType; +//! # +//! # #[async_trait] +//! # impl ObjectSafe for MyType { +//! # async fn f(&self) {} +//! # async fn g(&mut self) {} +//! # } +//! # +//! # let value: MyType = MyType; +//! let object = &value as &dyn ObjectSafe; // make trait object +//! ``` +//! +//! The one wrinkle is in traits that provide default implementations of async +//! methods. In order for the default implementation to produce a future that is +//! Send, the async_trait macro must emit a bound of `Self: Sync` on trait +//! methods that take `&self` and a bound `Self: Send` on trait methods that +//! take `&mut self`. An example of the former is visible in the expanded code +//! in the explanation section above. +//! +//! If you make a trait with async methods that have default implementations, +//! everything will work except that the trait cannot be used as a trait object. +//! Creating a value of type `&dyn Trait` will produce an error that looks like +//! this: +//! +//! ```text +//! error: the trait `Test` cannot be made into an object +//! --> src/main.rs:8:5 +//! | +//! 8 | async fn cannot_dyn(&self) {} +//! | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ +//! ``` +//! +//! For traits that need to be object safe and need to have default +//! implementations for some async methods, there are two resolutions. Either +//! you can add Send and/or Sync as supertraits (Send if there are `&mut self` +//! methods with default implementations, Sync if there are `&self` methods with +//! default implementations) to constrain all implementors of the trait such that +//! the default implementations are applicable to them: +//! +//! ``` +//! # use async_trait::async_trait; +//! # +//! #[async_trait] +//! pub trait ObjectSafe: Sync { // added supertrait +//! async fn can_dyn(&self) {} +//! } +//! # +//! # struct MyType; +//! # +//! # #[async_trait] +//! # impl ObjectSafe for MyType {} +//! # +//! # let value = MyType; +//! +//! let object = &value as &dyn ObjectSafe; +//! ``` +//! +//! or you can strike the problematic methods from your trait object by +//! bounding them with `Self: Sized`: +//! +//! ``` +//! # use async_trait::async_trait; +//! # +//! #[async_trait] +//! pub trait ObjectSafe { +//! async fn cannot_dyn(&self) where Self: Sized {} +//! +//! // presumably other methods +//! } +//! # +//! # struct MyType; +//! # +//! # #[async_trait] +//! # impl ObjectSafe for MyType {} +//! # +//! # let value = MyType; +//! +//! let object = &value as &dyn ObjectSafe; +//! ``` + +#![doc(html_root_url = "https://docs.rs/async-trait/0.1.66")] +#![allow( + clippy::default_trait_access, + clippy::doc_markdown, + clippy::explicit_auto_deref, + clippy::if_not_else, + clippy::items_after_statements, + clippy::module_name_repetitions, + clippy::shadow_unrelated, + clippy::similar_names, + clippy::too_many_lines +)] + +extern crate proc_macro; + +mod args; +mod bound; +mod expand; +mod lifetime; +mod parse; +mod receiver; + +use crate::args::Args; +use crate::expand::expand; +use crate::parse::Item; +use proc_macro::TokenStream; +use quote::quote; +use syn::parse_macro_input; + +#[proc_macro_attribute] +pub fn async_trait(args: TokenStream, input: TokenStream) -> TokenStream { + let args = parse_macro_input!(args as Args); + let mut item = parse_macro_input!(input as Item); + expand(&mut item, args.local); + TokenStream::from(quote!(#item)) +} diff --git a/src/lifetime.rs b/src/lifetime.rs new file mode 100644 index 0000000..1e5a658 --- /dev/null +++ b/src/lifetime.rs @@ -0,0 +1,110 @@ +use proc_macro2::{Span, TokenStream}; +use std::mem; +use syn::visit_mut::{self, VisitMut}; +use syn::{ + parse_quote_spanned, token, Expr, GenericArgument, Lifetime, Receiver, ReturnType, Token, Type, + TypeBareFn, TypeImplTrait, TypeParen, TypePtr, TypeReference, +}; + +pub struct CollectLifetimes { + pub elided: Vec, + pub explicit: Vec, +} + +impl CollectLifetimes { + pub fn new() -> Self { + CollectLifetimes { + elided: Vec::new(), + explicit: Vec::new(), + } + } + + fn visit_opt_lifetime(&mut self, reference: Token![&], lifetime: &mut Option) { + match lifetime { + None => *lifetime = Some(self.next_lifetime(reference.span)), + Some(lifetime) => self.visit_lifetime(lifetime), + } + } + + fn visit_lifetime(&mut self, lifetime: &mut Lifetime) { + if lifetime.ident == "_" { + *lifetime = self.next_lifetime(lifetime.span()); + } else { + self.explicit.push(lifetime.clone()); + } + } + + fn next_lifetime(&mut self, span: Span) -> Lifetime { + let name = format!("'life{}", self.elided.len()); + let life = Lifetime::new(&name, span); + self.elided.push(life.clone()); + life + } +} + +impl VisitMut for CollectLifetimes { + fn visit_receiver_mut(&mut self, arg: &mut Receiver) { + if let Some((reference, lifetime)) = &mut arg.reference { + self.visit_opt_lifetime(*reference, lifetime); + } + } + + fn visit_type_reference_mut(&mut self, ty: &mut TypeReference) { + self.visit_opt_lifetime(ty.and_token, &mut ty.lifetime); + visit_mut::visit_type_reference_mut(self, ty); + } + + fn visit_generic_argument_mut(&mut self, gen: &mut GenericArgument) { + if let GenericArgument::Lifetime(lifetime) = gen { + self.visit_lifetime(lifetime); + } + visit_mut::visit_generic_argument_mut(self, gen); + } +} + +pub struct AddLifetimeToImplTrait; + +impl VisitMut for AddLifetimeToImplTrait { + fn visit_type_impl_trait_mut(&mut self, ty: &mut TypeImplTrait) { + let span = ty.impl_token.span; + let lifetime = parse_quote_spanned!(span=> 'async_trait); + ty.bounds.insert(0, lifetime); + if let Some(punct) = ty.bounds.pairs_mut().next().unwrap().punct_mut() { + punct.span = span; + } + visit_mut::visit_type_impl_trait_mut(self, ty); + } + + fn visit_type_reference_mut(&mut self, ty: &mut TypeReference) { + parenthesize_impl_trait(&mut ty.elem, ty.and_token.span); + visit_mut::visit_type_reference_mut(self, ty); + } + + fn visit_type_ptr_mut(&mut self, ty: &mut TypePtr) { + parenthesize_impl_trait(&mut ty.elem, ty.star_token.span); + visit_mut::visit_type_ptr_mut(self, ty); + } + + fn visit_type_bare_fn_mut(&mut self, ty: &mut TypeBareFn) { + if let ReturnType::Type(arrow, return_type) = &mut ty.output { + parenthesize_impl_trait(return_type, arrow.spans[0]); + } + visit_mut::visit_type_bare_fn_mut(self, ty); + } + + fn visit_expr_mut(&mut self, _e: &mut Expr) { + // Do not recurse into impl Traits inside of an array length expression. + // + // fn outer(arg: [u8; { fn inner(_: impl Trait) {}; 0 }]); + } +} + +fn parenthesize_impl_trait(elem: &mut Type, paren_span: Span) { + if let Type::ImplTrait(_) = *elem { + let placeholder = Type::Verbatim(TokenStream::new()); + *elem = Type::Paren(TypeParen { + paren_token: token::Paren(paren_span), + elem: Box::new(mem::replace(elem, placeholder)), + }); + } +} diff --git a/src/parse.rs b/src/parse.rs new file mode 100644 index 0000000..ebd2535 --- /dev/null +++ b/src/parse.rs @@ -0,0 +1,34 @@ +use proc_macro2::Span; +use syn::parse::{Error, Parse, ParseStream, Result}; +use syn::{Attribute, ItemImpl, ItemTrait, Token}; + +pub enum Item { + Trait(ItemTrait), + Impl(ItemImpl), +} + +impl Parse for Item { + fn parse(input: ParseStream) -> Result { + let attrs = input.call(Attribute::parse_outer)?; + let mut lookahead = input.lookahead1(); + if lookahead.peek(Token![unsafe]) { + let ahead = input.fork(); + ahead.parse::()?; + lookahead = ahead.lookahead1(); + } + if lookahead.peek(Token![pub]) || lookahead.peek(Token![trait]) { + let mut item: ItemTrait = input.parse()?; + item.attrs = attrs; + Ok(Item::Trait(item)) + } else if lookahead.peek(Token![impl]) { + let mut item: ItemImpl = input.parse()?; + if item.trait_.is_none() { + return Err(Error::new(Span::call_site(), "expected a trait impl")); + } + item.attrs = attrs; + Ok(Item::Impl(item)) + } else { + Err(lookahead.error()) + } + } +} diff --git a/src/receiver.rs b/src/receiver.rs new file mode 100644 index 0000000..2230db6 --- /dev/null +++ b/src/receiver.rs @@ -0,0 +1,179 @@ +use proc_macro2::{Group, Span, TokenStream, TokenTree}; +use std::iter::FromIterator; +use syn::visit_mut::{self, VisitMut}; +use syn::{ + Block, ExprPath, Ident, Item, Macro, Pat, PatIdent, PatPath, Path, Receiver, Signature, Token, + TypePath, +}; + +pub fn has_self_in_sig(sig: &mut Signature) -> bool { + let mut visitor = HasSelf(false); + visitor.visit_signature_mut(sig); + visitor.0 +} + +pub fn has_self_in_block(block: &mut Block) -> bool { + let mut visitor = HasSelf(false); + visitor.visit_block_mut(block); + visitor.0 +} + +fn has_self_in_token_stream(tokens: TokenStream) -> bool { + tokens.into_iter().any(|tt| match tt { + TokenTree::Ident(ident) => ident == "Self", + TokenTree::Group(group) => has_self_in_token_stream(group.stream()), + _ => false, + }) +} + +pub fn mut_pat(pat: &mut Pat) -> Option { + let mut visitor = HasMutPat(None); + visitor.visit_pat_mut(pat); + visitor.0 +} + +fn contains_fn(tokens: TokenStream) -> bool { + tokens.into_iter().any(|tt| match tt { + TokenTree::Ident(ident) => ident == "fn", + TokenTree::Group(group) => contains_fn(group.stream()), + _ => false, + }) +} + +struct HasMutPat(Option); + +impl VisitMut for HasMutPat { + fn visit_pat_ident_mut(&mut self, i: &mut PatIdent) { + if let Some(m) = i.mutability { + self.0 = Some(m); + } else { + visit_mut::visit_pat_ident_mut(self, i); + } + } +} + +struct HasSelf(bool); + +impl VisitMut for HasSelf { + fn visit_expr_path_mut(&mut self, expr: &mut ExprPath) { + self.0 |= expr.path.segments[0].ident == "Self"; + visit_mut::visit_expr_path_mut(self, expr); + } + + fn visit_pat_path_mut(&mut self, pat: &mut PatPath) { + self.0 |= pat.path.segments[0].ident == "Self"; + visit_mut::visit_pat_path_mut(self, pat); + } + + fn visit_type_path_mut(&mut self, ty: &mut TypePath) { + self.0 |= ty.path.segments[0].ident == "Self"; + visit_mut::visit_type_path_mut(self, ty); + } + + fn visit_receiver_mut(&mut self, _arg: &mut Receiver) { + self.0 = true; + } + + fn visit_item_mut(&mut self, _: &mut Item) { + // Do not recurse into nested items. + } + + fn visit_macro_mut(&mut self, mac: &mut Macro) { + if !contains_fn(mac.tokens.clone()) { + self.0 |= has_self_in_token_stream(mac.tokens.clone()); + } + } +} + +pub struct ReplaceSelf(pub Span); + +impl ReplaceSelf { + #[cfg_attr(not(self_span_hack), allow(clippy::unused_self))] + fn prepend_underscore_to_self(&self, ident: &mut Ident) -> bool { + let modified = ident == "self"; + if modified { + *ident = Ident::new("__self", ident.span()); + #[cfg(self_span_hack)] + ident.set_span(self.0); + } + modified + } + + fn visit_token_stream(&mut self, tokens: &mut TokenStream) -> bool { + let mut out = Vec::new(); + let mut modified = false; + visit_token_stream_impl(self, tokens.clone(), &mut modified, &mut out); + if modified { + *tokens = TokenStream::from_iter(out); + } + return modified; + + fn visit_token_stream_impl( + visitor: &mut ReplaceSelf, + tokens: TokenStream, + modified: &mut bool, + out: &mut Vec, + ) { + for tt in tokens { + match tt { + TokenTree::Ident(mut ident) => { + *modified |= visitor.prepend_underscore_to_self(&mut ident); + out.push(TokenTree::Ident(ident)); + } + TokenTree::Group(group) => { + let mut content = group.stream(); + *modified |= visitor.visit_token_stream(&mut content); + let mut new = Group::new(group.delimiter(), content); + new.set_span(group.span()); + out.push(TokenTree::Group(new)); + } + other => out.push(other), + } + } + } + } +} + +impl VisitMut for ReplaceSelf { + fn visit_ident_mut(&mut self, i: &mut Ident) { + self.prepend_underscore_to_self(i); + } + + fn visit_path_mut(&mut self, p: &mut Path) { + if p.segments.len() == 1 { + // Replace `self`, but not `self::function`. + self.visit_ident_mut(&mut p.segments[0].ident); + } + for segment in &mut p.segments { + self.visit_path_arguments_mut(&mut segment.arguments); + } + } + + fn visit_item_mut(&mut self, i: &mut Item) { + // Visit `macro_rules!` because locally defined macros can refer to + // `self`. + // + // Visit `futures::select` and similar select macros, which commonly + // appear syntactically like an item despite expanding to an expression. + // + // Otherwise, do not recurse into nested items. + if let Item::Macro(i) = i { + if i.mac.path.is_ident("macro_rules") + || i.mac.path.segments.last().unwrap().ident == "select" + { + self.visit_macro_mut(&mut i.mac); + } + } + } + + fn visit_macro_mut(&mut self, mac: &mut Macro) { + // We can't tell in general whether `self` inside a macro invocation + // refers to the self in the argument list or a different self + // introduced within the macro. Heuristic: if the macro input contains + // `fn`, then `self` is more likely to refer to something other than the + // outer function's self argument. + if !contains_fn(mac.tokens.clone()) { + self.visit_token_stream(&mut mac.tokens); + } + } +} diff --git a/tests/compiletest.rs b/tests/compiletest.rs new file mode 100644 index 0000000..7974a62 --- /dev/null +++ b/tests/compiletest.rs @@ -0,0 +1,7 @@ +#[rustversion::attr(not(nightly), ignore)] +#[cfg_attr(miri, ignore)] +#[test] +fn ui() { + let t = trybuild::TestCases::new(); + t.compile_fail("tests/ui/*.rs"); +} diff --git a/tests/executor/mod.rs b/tests/executor/mod.rs new file mode 100644 index 0000000..912fb79 --- /dev/null +++ b/tests/executor/mod.rs @@ -0,0 +1,36 @@ +use std::future::Future; +use std::pin::Pin; +use std::ptr; +use std::task::{Context, Poll, RawWaker, RawWakerVTable, Waker}; + +// Executor for a future that resolves immediately (test only). +#[allow(clippy::missing_panics_doc)] +pub fn block_on_simple(mut fut: F) -> F::Output { + unsafe fn clone(_null: *const ()) -> RawWaker { + unimplemented!() + } + + unsafe fn wake(_null: *const ()) { + unimplemented!() + } + + unsafe fn wake_by_ref(_null: *const ()) { + unimplemented!() + } + + unsafe fn drop(_null: *const ()) {} + + let data = ptr::null(); + let vtable = &RawWakerVTable::new(clone, wake, wake_by_ref, drop); + let raw_waker = RawWaker::new(data, vtable); + let waker = unsafe { Waker::from_raw(raw_waker) }; + let mut cx = Context::from_waker(&waker); + + // fut does not move until it gets dropped. + let fut = unsafe { Pin::new_unchecked(&mut fut) }; + + match fut.poll(&mut cx) { + Poll::Ready(output) => output, + Poll::Pending => panic!("future did not resolve immediately"), + } +} diff --git a/tests/test.rs b/tests/test.rs new file mode 100644 index 0000000..4fc46f0 --- /dev/null +++ b/tests/test.rs @@ -0,0 +1,1606 @@ +#![cfg_attr( + async_trait_nightly_testing, + feature(min_specialization, type_alias_impl_trait) +)] +#![deny(rust_2021_compatibility)] +#![allow( + clippy::let_underscore_untyped, + clippy::let_unit_value, + clippy::missing_panics_doc, + clippy::missing_safety_doc, + clippy::needless_return, + clippy::trivially_copy_pass_by_ref, + clippy::unused_async +)] + +use async_trait::async_trait; + +pub mod executor; + +// Dummy module to check that the expansion refer to rust's core crate +mod core {} + +#[async_trait] +trait Trait { + type Assoc; + + async fn selfvalue(self) + where + Self: Sized, + { + } + + async fn selfref(&self) {} + + async fn selfmut(&mut self) {} + + async fn required() -> Self::Assoc; + + async fn elided_lifetime(_x: &str) {} + + async fn explicit_lifetime<'a>(_x: &'a str) {} + + async fn generic_type_param(x: Box) -> T { + *x + } + + async fn calls(&self) { + self.selfref().await; + Self::elided_lifetime("").await; + ::elided_lifetime("").await; + } + + async fn calls_mut(&mut self) { + self.selfmut().await; + } +} + +struct Struct; + +#[async_trait] +impl Trait for Struct { + type Assoc = (); + + async fn selfvalue(self) {} + + async fn selfref(&self) {} + + async fn selfmut(&mut self) {} + + async fn required() -> Self::Assoc {} + + async fn elided_lifetime(_x: &str) {} + + async fn explicit_lifetime<'a>(_x: &'a str) {} + + async fn generic_type_param(x: Box) -> T { + *x + } + + async fn calls(&self) { + self.selfref().await; + Self::elided_lifetime("").await; + ::elided_lifetime("").await; + } + + async fn calls_mut(&mut self) { + self.selfmut().await; + } +} + +pub async fn test() { + let mut s = Struct; + s.selfref().await; + s.selfmut().await; + s.selfvalue().await; + + Struct::required().await; + Struct::elided_lifetime("").await; + Struct::explicit_lifetime("").await; + Struct::generic_type_param(Box::new("")).await; + + let mut s = Struct; + s.calls().await; + s.calls_mut().await; +} + +pub async fn test_object_safe_without_default() { + #[async_trait] + trait ObjectSafe { + async fn f(&self); + } + + #[async_trait] + impl ObjectSafe for Struct { + async fn f(&self) {} + } + + let object = &Struct as &dyn ObjectSafe; + object.f().await; +} + +pub async fn test_object_safe_with_default() { + #[async_trait] + trait ObjectSafe: Sync { + async fn f(&self) {} + } + + #[async_trait] + impl ObjectSafe for Struct { + async fn f(&self) {} + } + + let object = &Struct as &dyn ObjectSafe; + object.f().await; +} + +pub async fn test_object_no_send() { + #[async_trait(?Send)] + trait ObjectSafe: Sync { + async fn f(&self) {} + } + + #[async_trait(?Send)] + impl ObjectSafe for Struct { + async fn f(&self) {} + } + + let object = &Struct as &dyn ObjectSafe; + object.f().await; +} + +#[async_trait] +pub unsafe trait UnsafeTrait {} + +#[async_trait] +unsafe impl UnsafeTrait for () {} + +#[async_trait] +pub(crate) unsafe trait UnsafeTraitPubCrate {} + +#[async_trait] +unsafe trait UnsafeTraitPrivate {} + +pub async fn test_can_destruct() { + #[async_trait] + trait CanDestruct { + async fn f(&self, foos: (u8, u8, u8, u8)); + } + + #[async_trait] + impl CanDestruct for Struct { + async fn f(&self, (a, ref mut b, ref c, d): (u8, u8, u8, u8)) { + let _a: u8 = a; + let _b: &mut u8 = b; + let _c: &u8 = c; + let _d: u8 = d; + } + } +} + +pub async fn test_self_in_macro() { + #[async_trait] + trait Trait { + async fn a(self); + async fn b(&mut self); + async fn c(&self); + } + + #[async_trait] + impl Trait for String { + async fn a(self) { + println!("{}", self); + } + async fn b(&mut self) { + println!("{}", self); + } + async fn c(&self) { + println!("{}", self); + } + } +} + +pub async fn test_inference() { + #[async_trait] + pub trait Trait { + async fn f() -> Box> { + Box::new(std::iter::empty()) + } + } +} + +pub async fn test_internal_items() { + #[async_trait] + #[allow(dead_code, clippy::items_after_statements)] + pub trait Trait: Sized { + async fn f(self) { + struct Struct; + + impl Struct { + fn f(self) { + let _ = self; + } + } + } + } +} + +pub async fn test_unimplemented() { + #[async_trait] + pub trait Trait { + async fn f() { + unimplemented!() + } + } +} + +// https://github.com/dtolnay/async-trait/issues/1 +pub mod issue1 { + use async_trait::async_trait; + + #[async_trait] + trait Issue1 { + async fn f(&self); + } + + #[async_trait] + impl Issue1 for Vec { + async fn f(&self) {} + } +} + +// https://github.com/dtolnay/async-trait/issues/2 +pub mod issue2 { + use async_trait::async_trait; + use std::future::Future; + + #[async_trait] + pub trait Issue2: Future { + async fn flatten(self) -> ::Output + where + Self::Output: Future + Send, + Self: Sized, + { + let nested_future = self.await; + nested_future.await + } + } +} + +// https://github.com/dtolnay/async-trait/issues/9 +pub mod issue9 { + use async_trait::async_trait; + + #[async_trait] + pub trait Issue9: Sized + Send { + async fn f(_x: Self) {} + } +} + +// https://github.com/dtolnay/async-trait/issues/11 +pub mod issue11 { + use async_trait::async_trait; + use std::sync::Arc; + + #[async_trait] + trait Issue11 { + async fn example(self: Arc); + } + + struct Struct; + + #[async_trait] + impl Issue11 for Struct { + async fn example(self: Arc) {} + } +} + +// https://github.com/dtolnay/async-trait/issues/15 +pub mod issue15 { + use async_trait::async_trait; + use std::marker::PhantomData; + + trait Trait {} + + #[async_trait] + trait Issue15 { + async fn myfn(&self, _: PhantomData) {} + } +} + +// https://github.com/dtolnay/async-trait/issues/17 +pub mod issue17 { + use async_trait::async_trait; + + #[async_trait] + trait Issue17 { + async fn f(&self); + } + + struct Struct { + string: String, + } + + #[async_trait] + impl Issue17 for Struct { + async fn f(&self) { + println!("{}", self.string); + } + } +} + +// https://github.com/dtolnay/async-trait/issues/23 +pub mod issue23 { + use async_trait::async_trait; + + #[async_trait] + pub trait Issue23 { + async fn f(self); + + async fn g(mut self) + where + Self: Sized, + { + do_something(&mut self); + } + } + + struct S {} + + #[async_trait] + impl Issue23 for S { + async fn f(mut self) { + do_something(&mut self); + } + } + + fn do_something(_: &mut T) {} +} + +// https://github.com/dtolnay/async-trait/issues/25 +#[cfg(async_trait_nightly_testing)] +pub mod issue25 { + use crate::executor; + use async_trait::async_trait; + use std::fmt::{Display, Write}; + + #[async_trait] + trait AsyncToString { + async fn async_to_string(&self) -> String; + } + + #[async_trait] + impl AsyncToString for String { + async fn async_to_string(&self) -> String { + "special".to_owned() + } + } + + macro_rules! hide_from_stable_parser { + ($($tt:tt)*) => { + $($tt)* + }; + } + + hide_from_stable_parser! { + #[async_trait] + impl AsyncToString for T { + default async fn async_to_string(&self) -> String { + let mut buf = String::new(); + buf.write_fmt(format_args!("{}", self)).unwrap(); + buf + } + } + } + + #[test] + fn test() { + let fut = true.async_to_string(); + assert_eq!(executor::block_on_simple(fut), "true"); + + let string = String::new(); + let fut = string.async_to_string(); + assert_eq!(executor::block_on_simple(fut), "special"); + } +} + +// https://github.com/dtolnay/async-trait/issues/28 +pub mod issue28 { + use async_trait::async_trait; + + struct Str<'a>(&'a str); + + #[async_trait] + trait Trait1<'a> { + async fn f(x: Str<'a>) -> &'a str; + async fn g(x: Str<'a>) -> &'a str { + x.0 + } + } + + #[async_trait] + impl<'a> Trait1<'a> for str { + async fn f(x: Str<'a>) -> &'a str { + x.0 + } + } + + #[async_trait] + trait Trait2 { + async fn f(); + } + + #[async_trait] + impl<'a> Trait2 for &'a () { + async fn f() {} + } + + #[async_trait] + trait Trait3<'a, 'b> { + async fn f(_: &'a &'b ()); // chain 'a and 'b + async fn g(_: &'b ()); // chain 'b only + async fn h(); // do not chain + } +} + +// https://github.com/dtolnay/async-trait/issues/31 +pub mod issue31 { + use async_trait::async_trait; + + pub struct Struct<'a> { + pub name: &'a str, + } + + #[async_trait] + pub trait Trait<'a> { + async fn hello(thing: Struct<'a>) -> String; + async fn hello_twice(one: Struct<'a>, two: Struct<'a>) -> String { + let str1 = Self::hello(one).await; + let str2 = Self::hello(two).await; + str1 + &str2 + } + } +} + +// https://github.com/dtolnay/async-trait/issues/42 +pub mod issue42 { + use async_trait::async_trait; + + #[async_trait] + pub trait Context: Sized { + async fn from_parts() -> Self; + } + + pub struct TokenContext; + + #[async_trait] + impl Context for TokenContext { + async fn from_parts() -> TokenContext { + TokenContext + } + } +} + +// https://github.com/dtolnay/async-trait/issues/44 +pub mod issue44 { + use async_trait::async_trait; + + #[async_trait] + pub trait StaticWithWhereSelf + where + Box: Sized, + Self: Sized + Send, + { + async fn get_one() -> u8 { + 1 + } + } + + pub struct Struct; + + #[async_trait] + impl StaticWithWhereSelf for Struct {} +} + +// https://github.com/dtolnay/async-trait/issues/45 +pub mod issue45 { + use crate::executor; + use async_trait::async_trait; + use std::fmt::Debug; + use std::sync::atomic::{AtomicU64, Ordering}; + use std::sync::{Arc, Mutex}; + use tracing::event::Event; + use tracing::field::{Field, Visit}; + use tracing::span::{Attributes, Id, Record}; + use tracing::{info, instrument, subscriber, Metadata, Subscriber}; + + #[async_trait] + pub trait Parent { + async fn foo(&mut self, v: usize); + } + + #[async_trait] + pub trait Child { + async fn bar(&self); + } + + #[derive(Debug)] + struct Impl(usize); + + #[async_trait] + impl Parent for Impl { + #[instrument] + async fn foo(&mut self, v: usize) { + self.0 = v; + self.bar().await; + } + } + + #[async_trait] + impl Child for Impl { + // Let's check that tracing detects the renaming of the `self` variable + // too, as tracing::instrument is not going to be able to skip the + // `self` argument if it can't find it in the function signature. + #[instrument(skip(self))] + async fn bar(&self) { + info!(val = self.0); + } + } + + // A simple subscriber implementation to test the behavior of async-trait + // with tokio-rs/tracing. This implementation is not robust against race + // conditions, but it's not an issue here as we are only polling on a single + // future at a time. + #[derive(Debug)] + struct SubscriberInner { + current_depth: AtomicU64, + // We assert that nested functions work. If the fix were to break, we + // would see two top-level functions instead of `bar` nested in `foo`. + max_depth: AtomicU64, + max_span_id: AtomicU64, + // Name of the variable / value / depth when the event was recorded. + value: Mutex>, + } + + #[derive(Debug, Clone)] + struct TestSubscriber { + inner: Arc, + } + + impl TestSubscriber { + fn new() -> Self { + TestSubscriber { + inner: Arc::new(SubscriberInner { + current_depth: AtomicU64::new(0), + max_depth: AtomicU64::new(0), + max_span_id: AtomicU64::new(1), + value: Mutex::new(None), + }), + } + } + } + + struct U64Visitor(Option<(&'static str, u64)>); + + impl Visit for U64Visitor { + fn record_debug(&mut self, _field: &Field, _value: &dyn Debug) {} + + fn record_u64(&mut self, field: &Field, value: u64) { + self.0 = Some((field.name(), value)); + } + } + + impl Subscriber for TestSubscriber { + fn enabled(&self, _metadata: &Metadata) -> bool { + true + } + fn new_span(&self, _span: &Attributes) -> Id { + Id::from_u64(self.inner.max_span_id.fetch_add(1, Ordering::AcqRel)) + } + fn record(&self, _span: &Id, _values: &Record) {} + fn record_follows_from(&self, _span: &Id, _follows: &Id) {} + fn event(&self, event: &Event) { + let mut visitor = U64Visitor(None); + event.record(&mut visitor); + if let Some((s, v)) = visitor.0 { + let current_depth = self.inner.current_depth.load(Ordering::Acquire); + *self.inner.value.lock().unwrap() = Some((s, v, current_depth)); + } + } + fn enter(&self, _span: &Id) { + let old_depth = self.inner.current_depth.fetch_add(1, Ordering::AcqRel); + if old_depth + 1 > self.inner.max_depth.load(Ordering::Acquire) { + self.inner.max_depth.fetch_add(1, Ordering::AcqRel); + } + } + fn exit(&self, _span: &Id) { + self.inner.current_depth.fetch_sub(1, Ordering::AcqRel); + } + } + + #[test] + #[cfg_attr(miri, ignore)] // https://github.com/matklad/once_cell/pull/185 + fn tracing() { + // Create the future outside of the subscriber, as no call to tracing + // should be made until the future is polled. + let mut struct_impl = Impl(0); + let fut = struct_impl.foo(5); + let subscriber = TestSubscriber::new(); + subscriber::with_default(subscriber.clone(), || executor::block_on_simple(fut)); + // Did we enter bar inside of foo? + assert_eq!(subscriber.inner.max_depth.load(Ordering::Acquire), 2); + // Have we exited all spans? + assert_eq!(subscriber.inner.current_depth.load(Ordering::Acquire), 0); + // Did we create only two spans? Note: spans start at 1, hence the -1. + assert_eq!(subscriber.inner.max_span_id.load(Ordering::Acquire) - 1, 2); + // Was the value recorded at the right depth i.e. in the right function? + // If so, was it the expected value? + assert_eq!(*subscriber.inner.value.lock().unwrap(), Some(("val", 5, 2))); + } +} + +// https://github.com/dtolnay/async-trait/issues/46 +pub mod issue46 { + use async_trait::async_trait; + + macro_rules! implement_commands_workaround { + ($tyargs:tt : $ty:tt) => { + #[async_trait] + pub trait AsyncCommands1: Sized { + async fn f<$tyargs: $ty>(&mut self, x: $tyargs) { + self.f(x).await + } + } + }; + } + + implement_commands_workaround!(K: Send); + + macro_rules! implement_commands { + ($tyargs:ident : $ty:ident) => { + #[async_trait] + pub trait AsyncCommands2: Sized { + async fn f<$tyargs: $ty>(&mut self, x: $tyargs) { + self.f(x).await + } + } + }; + } + + implement_commands!(K: Send); +} + +// https://github.com/dtolnay/async-trait/issues/53 +pub mod issue53 { + use async_trait::async_trait; + + pub struct Unit; + pub struct Tuple(u8); + pub struct Struct { + pub x: u8, + } + + #[async_trait] + pub trait Trait { + async fn method(); + } + + #[async_trait] + impl Trait for Unit { + async fn method() { + let _ = Self; + } + } + + #[async_trait] + impl Trait for Tuple { + async fn method() { + let _ = Self(0); + } + } + + #[async_trait] + impl Trait for Struct { + async fn method() { + let _ = Self { x: 0 }; + } + } + + #[async_trait] + impl Trait for std::marker::PhantomData { + async fn method() { + let _ = Self; + } + } +} + +// https://github.com/dtolnay/async-trait/issues/57 +#[cfg(async_trait_nightly_testing)] +pub mod issue57 { + use crate::executor; + use async_trait::async_trait; + + #[async_trait] + trait Trait { + async fn const_generic(_: [T; C]) {} + } + + struct Struct; + + #[async_trait] + impl Trait for Struct { + async fn const_generic(_: [T; C]) {} + } + + #[test] + fn test() { + let fut = Struct::const_generic([0; 10]); + executor::block_on_simple(fut); + } +} + +// https://github.com/dtolnay/async-trait/issues/68 +pub mod issue68 { + #[rustversion::since(1.40)] // procedural macros cannot expand to macro definitions in 1.39. + #[async_trait::async_trait] + pub trait Example { + async fn method(&self) { + macro_rules! t { + () => {{ + let _: &Self = self; + }}; + } + t!(); + } + } +} + +// https://github.com/dtolnay/async-trait/issues/73 +pub mod issue73 { + use async_trait::async_trait; + + #[async_trait] + pub trait Example { + const ASSOCIATED: &'static str; + + async fn associated(&self) { + println!("Associated:{}", Self::ASSOCIATED); + } + } +} + +// https://github.com/dtolnay/async-trait/issues/81 +pub mod issue81 { + use async_trait::async_trait; + + #[async_trait] + pub trait Trait { + async fn handle(&self); + } + + pub enum Enum { + Variant, + } + + #[async_trait] + impl Trait for Enum { + async fn handle(&self) { + let Enum::Variant = self; + let Self::Variant = self; + } + } +} + +// https://github.com/dtolnay/async-trait/issues/83 +pub mod issue83 { + #![allow(clippy::needless_arbitrary_self_type)] + + use async_trait::async_trait; + + #[async_trait] + pub trait Trait { + async fn f(&self) {} + async fn g(self: &Self) {} + } +} + +// https://github.com/dtolnay/async-trait/issues/85 +pub mod issue85 { + #![deny(non_snake_case)] + + use async_trait::async_trait; + + #[async_trait] + pub trait Trait { + #[allow(non_snake_case)] + async fn camelCase(); + } + + pub struct Struct; + + #[async_trait] + impl Trait for Struct { + async fn camelCase() {} + } +} + +// https://github.com/dtolnay/async-trait/issues/87 +pub mod issue87 { + use async_trait::async_trait; + + #[async_trait] + pub trait Trait { + async fn f(&self); + } + + pub enum Tuple { + V(), + } + + pub enum Struct { + V {}, + } + + #[async_trait] + impl Trait for Tuple { + async fn f(&self) { + let Tuple::V() = self; + let Self::V() = self; + let _ = Self::V; + let _ = Self::V(); + } + } + + #[async_trait] + impl Trait for Struct { + async fn f(&self) { + let Struct::V {} = self; + let Self::V {} = self; + let _ = Self::V {}; + } + } +} + +// https://github.com/dtolnay/async-trait/issues/89 +pub mod issue89 { + #![allow(bare_trait_objects)] + + use async_trait::async_trait; + + #[async_trait] + trait Trait { + async fn f(&self); + } + + #[async_trait] + impl Trait for Send + Sync { + async fn f(&self) {} + } + + #[async_trait] + impl Trait for dyn Fn(i8) + Send + Sync { + async fn f(&self) {} + } + + #[async_trait] + impl Trait for (dyn Fn(u8) + Send + Sync) { + async fn f(&self) {} + } +} + +// https://github.com/dtolnay/async-trait/issues/92 +pub mod issue92 { + use async_trait::async_trait; + + macro_rules! mac { + ($($tt:tt)*) => { + $($tt)* + }; + } + + pub struct Struct { + _x: T, + } + + impl Struct { + const ASSOCIATED1: &'static str = "1"; + async fn associated1() {} + } + + #[async_trait] + pub trait Trait + where + mac!(Self): Send, + { + const ASSOCIATED2: &'static str; + type Associated2; + + #[allow(path_statements, clippy::let_underscore_future, clippy::no_effect)] + async fn associated2(&self) { + // trait items + mac!(let _: Self::Associated2;); + mac!(let _: ::Associated2;); + mac!(let _: ::Associated2;); + mac!(Self::ASSOCIATED2;); + mac!(::ASSOCIATED2;); + mac!(::ASSOCIATED2;); + mac!(let _ = Self::associated2(self);); + mac!(let _ = ::associated2(self);); + mac!(let _ = ::associated2(self);); + } + } + + #[async_trait] + impl Trait for Struct + where + mac!(Self): Send, + { + const ASSOCIATED2: &'static str = "2"; + type Associated2 = (); + + #[allow(path_statements, clippy::let_underscore_future, clippy::no_effect)] + async fn associated2(&self) { + // inherent items + mac!(Self::ASSOCIATED1;); + mac!(::ASSOCIATED1;); + mac!(let _ = Self::associated1();); + mac!(let _ = ::associated1();); + + // trait items + mac!(let _: ::Associated2;); + mac!(Self::ASSOCIATED2;); + mac!(::ASSOCIATED2;); + mac!(::ASSOCIATED2;); + mac!(let _ = Self::associated2(self);); + mac!(let _ = ::associated2(self);); + mac!(let _ = ::associated2(self);); + } + } + + pub struct Unit; + + #[async_trait] + impl Trait for Unit { + const ASSOCIATED2: &'static str = "2"; + type Associated2 = (); + + async fn associated2(&self) { + mac!(let Self: Self = *self;); + } + } +} + +// https://github.com/dtolnay/async-trait/issues/92#issuecomment-683370136 +pub mod issue92_2 { + use async_trait::async_trait; + + macro_rules! mac { + ($($tt:tt)*) => { + $($tt)* + }; + } + + pub trait Trait1 { + fn func1(); + } + + #[async_trait] + pub trait Trait2: Trait1 { + async fn func2() { + mac!(Self::func1()); + + macro_rules! mac2 { + ($($tt:tt)*) => { + Self::func1(); + }; + } + mac2!(); + } + } +} + +// https://github.com/dtolnay/async-trait/issues/104 +pub mod issue104 { + use async_trait::async_trait; + + #[async_trait] + trait T1 { + async fn id(&self) -> i32; + } + + macro_rules! impl_t1 { + ($ty:ty, $id:expr) => { + #[async_trait] + impl T1 for $ty { + async fn id(&self) -> i32 { + $id + } + } + }; + } + + struct Foo; + + impl_t1!(Foo, 1); +} + +// https://github.com/dtolnay/async-trait/issues/106 +pub mod issue106 { + use async_trait::async_trait; + use std::future::Future; + + #[async_trait] + pub trait ProcessPool: Send + Sync { + type ThreadPool; + + async fn spawn(&self, work: F) -> T + where + F: FnOnce(&Self::ThreadPool) -> Fut + Send, + Fut: Future + 'static; + } + + #[async_trait] + impl

ProcessPool for &P + where + P: ?Sized + ProcessPool, + { + type ThreadPool = P::ThreadPool; + + async fn spawn(&self, work: F) -> T + where + F: FnOnce(&Self::ThreadPool) -> Fut + Send, + Fut: Future + 'static, + { + (**self).spawn(work).await + } + } +} + +// https://github.com/dtolnay/async-trait/issues/110 +pub mod issue110 { + use async_trait::async_trait; + use std::marker::PhantomData; + + #[async_trait] + pub trait Loader { + async fn load(&self, key: &str); + } + + pub struct AwsEc2MetadataLoader<'a> { + marker: PhantomData<&'a ()>, + } + + #[async_trait] + impl Loader for AwsEc2MetadataLoader<'_> { + async fn load(&self, _key: &str) {} + } +} + +// https://github.com/dtolnay/async-trait/issues/120 +pub mod issue120 { + #![deny(clippy::trivially_copy_pass_by_ref)] + + use async_trait::async_trait; + + #[async_trait] + trait Trait { + async fn f(&self); + } + + #[async_trait] + impl Trait for () { + async fn f(&self) {} + } +} + +// https://github.com/dtolnay/async-trait/issues/123 +pub mod issue123 { + use async_trait::async_trait; + + #[async_trait] + trait Trait { + async fn f(&self) -> &str + where + T: 'async_trait, + { + "default" + } + } + + #[async_trait] + impl Trait for () {} +} + +// https://github.com/dtolnay/async-trait/issues/129 +pub mod issue129 { + use async_trait::async_trait; + + #[async_trait] + pub trait TestTrait { + async fn a(_b: u8, c: u8) -> u8 { + c + } + } + + pub struct TestStruct; + + #[async_trait] + impl TestTrait for TestStruct { + async fn a(_b: u8, c: u8) -> u8 { + c + } + } +} + +// https://github.com/dtolnay/async-trait/issues/134 +#[cfg(async_trait_nightly_testing)] +pub mod issue134 { + use async_trait::async_trait; + + #[async_trait] + trait TestTrait { + async fn run(self) + where + Self: Sized, + { + } + } + + pub struct TestStruct; + + #[async_trait] + impl TestTrait for TestStruct { + async fn run(self) + where + Self: Sized, + { + } + } +} + +// https://github.com/dtolnay/async-trait/pull/125#pullrequestreview-491880881 +pub mod drop_order { + use crate::executor; + use async_trait::async_trait; + use std::sync::atomic::{AtomicBool, Ordering}; + + struct Flagger<'a>(&'a AtomicBool); + + impl Drop for Flagger<'_> { + fn drop(&mut self) { + self.0.fetch_xor(true, Ordering::AcqRel); + } + } + + #[async_trait] + trait Trait { + async fn async_trait(_: Flagger<'_>, flag: &AtomicBool); + } + + struct Struct; + + #[async_trait] + impl Trait for Struct { + async fn async_trait(_: Flagger<'_>, flag: &AtomicBool) { + flag.fetch_or(true, Ordering::AcqRel); + } + } + + async fn standalone(_: Flagger<'_>, flag: &AtomicBool) { + flag.fetch_or(true, Ordering::AcqRel); + } + + #[async_trait] + trait SelfTrait { + async fn async_trait(self, flag: &AtomicBool); + } + + #[async_trait] + impl SelfTrait for Flagger<'_> { + async fn async_trait(self, flag: &AtomicBool) { + flag.fetch_or(true, Ordering::AcqRel); + } + } + + #[test] + fn test_drop_order() { + // 0 : 0 ^ 1 = 1 | 1 = 1 (if flagger then block) + // 0 : 0 | 1 = 1 ^ 1 = 0 (if block then flagger) + + let flag = AtomicBool::new(false); + executor::block_on_simple(standalone(Flagger(&flag), &flag)); + assert!(!flag.load(Ordering::Acquire)); + + executor::block_on_simple(Struct::async_trait(Flagger(&flag), &flag)); + assert!(!flag.load(Ordering::Acquire)); + + executor::block_on_simple(Flagger(&flag).async_trait(&flag)); + assert!(!flag.load(Ordering::Acquire)); + } +} + +// https://github.com/dtolnay/async-trait/issues/145 +pub mod issue145 { + #![deny(clippy::type_complexity)] + + use async_trait::async_trait; + + #[async_trait] + pub trait ManageConnection: Sized + Send + Sync + 'static { + type Connection: Send + 'static; + type Error: Send + 'static; + + async fn connect(&self) -> Result; + } +} + +// https://github.com/dtolnay/async-trait/issues/147 +pub mod issue147 { + #![deny(clippy::let_unit_value)] + + use async_trait::async_trait; + + pub struct MyType; + + #[async_trait] + pub trait MyTrait { + async fn x(); + async fn y() -> (); + async fn z(); + } + + #[async_trait] + impl MyTrait for MyType { + async fn x() {} + async fn y() -> () {} + async fn z() { + unimplemented!() + } + } +} + +// https://github.com/dtolnay/async-trait/issues/149 +pub mod issue149 { + use async_trait::async_trait; + + pub struct Thing; + pub trait Ret {} + impl Ret for Thing {} + + pub async fn ok() -> &'static dyn Ret { + return &Thing; + } + + #[async_trait] + pub trait Trait { + async fn fail() -> &'static dyn Ret { + return &Thing; + } + } +} + +// https://github.com/dtolnay/async-trait/issues/152 +#[cfg(async_trait_nightly_testing)] +pub mod issue152 { + use async_trait::async_trait; + + #[async_trait] + trait Trait { + type Assoc; + + async fn f(&self) -> Self::Assoc; + } + + struct Struct; + + #[async_trait] + impl Trait for Struct { + type Assoc = impl Sized; + + async fn f(&self) -> Self::Assoc {} + } +} + +// https://github.com/dtolnay/async-trait/issues/154 +pub mod issue154 { + #![deny(clippy::items_after_statements)] + + use async_trait::async_trait; + + #[async_trait] + pub trait MyTrait { + async fn f(&self); + } + + pub struct Struct; + + #[async_trait] + impl MyTrait for Struct { + async fn f(&self) { + const MAX: u16 = 128; + println!("{}", MAX); + } + } +} + +// https://github.com/dtolnay/async-trait/issues/158 +pub mod issue158 { + use async_trait::async_trait; + + fn f() {} + + #[async_trait] + pub trait Trait { + async fn f(&self) { + self::f(); + } + } +} + +// https://github.com/dtolnay/async-trait/issues/161 +#[allow(clippy::mut_mut)] +pub mod issue161 { + use async_trait::async_trait; + use futures::future::FutureExt; + use std::sync::Arc; + + #[async_trait] + pub trait Trait { + async fn f(self: Arc); + } + + pub struct MyStruct(bool); + + #[async_trait] + impl Trait for MyStruct { + async fn f(self: Arc) { + futures::select! { + _ = async { + println!("{}", self.0); + }.fuse() => {} + } + } + } +} + +// https://github.com/dtolnay/async-trait/issues/169 +#[deny(where_clauses_object_safety)] +pub mod issue169 { + use async_trait::async_trait; + + #[async_trait] + pub trait Trait: ::core::marker::Sync { + async fn f(&self) {} + } + + pub fn test(_t: &dyn Trait) {} +} + +// https://github.com/dtolnay/async-trait/issues/177 +pub mod issue177 { + use async_trait::async_trait; + + #[async_trait] + pub trait Trait { + async fn foo(&self, _callback: impl FnMut(&str) + Send) {} + } + + pub struct Struct; + + #[async_trait] + impl Trait for Struct { + async fn foo(&self, _callback: impl FnMut(&str) + Send) {} + } +} + +// https://github.com/dtolnay/async-trait/issues/183 +pub mod issue183 { + #![deny(clippy::shadow_same)] + + use async_trait::async_trait; + + #[async_trait] + trait Foo { + async fn foo(_n: i32) {} + } +} + +// https://github.com/dtolnay/async-trait/issues/199 +pub mod issue199 { + use async_trait::async_trait; + use std::cell::Cell; + + struct IncrementOnDrop<'a>(&'a Cell); + + impl<'a> Drop for IncrementOnDrop<'a> { + fn drop(&mut self) { + self.0.set(self.0.get() + 1); + } + } + + #[async_trait(?Send)] + trait Trait { + async fn f(counter: &Cell, arg: IncrementOnDrop<'_>); + } + + struct Struct; + + #[async_trait(?Send)] + impl Trait for Struct { + async fn f(counter: &Cell, _: IncrementOnDrop<'_>) { + assert_eq!(counter.get(), 0); // second arg not dropped yet + } + } + + #[test] + fn test() { + let counter = Cell::new(0); + let future = Struct::f(&counter, IncrementOnDrop(&counter)); + assert_eq!(counter.get(), 0); + drop(future); + assert_eq!(counter.get(), 1); + } +} + +// https://github.com/dtolnay/async-trait/issues/204 +pub mod issue204 { + use async_trait::async_trait; + + #[async_trait] + pub trait Trait { + async fn f(arg: &impl Trait); + async fn g(arg: *const impl Trait); + } +} + +// https://github.com/dtolnay/async-trait/issues/210 +pub mod issue210 { + use async_trait::async_trait; + use std::sync::Arc; + + #[async_trait] + pub trait Trait { + async fn f(self: Arc) {} + } +} + +// https://github.com/dtolnay/async-trait/issues/226 +pub mod issue226 { + use async_trait::async_trait; + + #[async_trait] + pub trait Trait { + async fn cfg_param(&self, param: u8); + async fn cfg_param_wildcard(&self, _: u8); + async fn cfg_param_tuple(&self, (left, right): (u8, u8)); + } + + struct Struct; + + #[async_trait] + impl Trait for Struct { + async fn cfg_param(&self, #[cfg(any())] param: u8, #[cfg(all())] _unused: u8) {} + + async fn cfg_param_wildcard(&self, #[cfg(any())] _: u8, #[cfg(all())] _: u8) {} + + async fn cfg_param_tuple( + &self, + #[cfg(any())] (left, right): (u8, u8), + #[cfg(all())] (_left, _right): (u8, u8), + ) { + } + } +} + +// https://github.com/dtolnay/async-trait/issues/232 +pub mod issue232 { + use async_trait::async_trait; + + #[async_trait] + pub trait Generic { + async fn take_ref(&self, thing: &T); + } + + pub struct One; + + #[async_trait] + impl Generic for One { + async fn take_ref(&self, _: &T) {} + } + + pub struct Two; + + #[async_trait] + impl Generic<(T, T)> for Two { + async fn take_ref(&self, (a, b): &(T, T)) { + let _ = a; + let _ = b; + } + } + + pub struct Three; + + #[async_trait] + impl Generic<(T, T, T)> for Three { + async fn take_ref(&self, (_a, _b, _c): &(T, T, T)) {} + } +} + +// https://github.com/dtolnay/async-trait/issues/234 +pub mod issue234 { + use async_trait::async_trait; + + pub struct Droppable; + + impl Drop for Droppable { + fn drop(&mut self) {} + } + + pub struct Tuple(T, U); + + #[async_trait] + pub trait Trait { + async fn f(arg: Tuple); + } + + pub struct UnderscorePattern; + + #[async_trait] + impl Trait for UnderscorePattern { + async fn f(Tuple(_, _int): Tuple) {} + } + + pub struct DotDotPattern; + + #[async_trait] + impl Trait for DotDotPattern { + async fn f(Tuple { 1: _int, .. }: Tuple) {} + } +} + +// https://github.com/dtolnay/async-trait/issues/236 +pub mod issue236 { + #![deny(clippy::async_yields_async)] + #![allow(clippy::manual_async_fn)] + + use async_trait::async_trait; + use std::future::{self, Future, Ready}; + + // Does not trigger the lint. + pub async fn async_fn() -> Ready<()> { + future::ready(()) + } + + #[allow(clippy::async_yields_async)] + pub fn impl_future_fn() -> impl Future> { + async { future::ready(()) } + } + + // The async_trait attribute turns the former into the latter, so we make it + // put its own allow(async_yeilds_async) to remain consistent with async fn. + #[async_trait] + pub trait Trait { + async fn f() -> Ready<()> { + future::ready(()) + } + } +} + +// https://github.com/dtolnay/async-trait/issues/238 +pub mod issue238 { + #![deny(single_use_lifetimes)] + + use async_trait::async_trait; + + #[async_trait] + pub trait Trait { + async fn f(); + } + + pub struct Struct; + + #[async_trait] + impl Trait for &Struct { + async fn f() {} + } +} diff --git a/tests/ui/arg-implementation-detail.rs b/tests/ui/arg-implementation-detail.rs new file mode 100644 index 0000000..b83aa72 --- /dev/null +++ b/tests/ui/arg-implementation-detail.rs @@ -0,0 +1,22 @@ +use async_trait::async_trait; + +pub struct Struct; + +#[async_trait] +pub trait Trait { + async fn f((_a, _b): (Struct, Struct)) { + // Expands to something like: + // + // fn f(__arg0: (Struct, Struct)) -> … { + // Box::pin(async move { + // let (_a, _b) = __arg0; + // … + // }) + // } + // + // but user's code must not be allowed to name that temporary argument: + let _ = __arg0; + } +} + +fn main() {} diff --git a/tests/ui/arg-implementation-detail.stderr b/tests/ui/arg-implementation-detail.stderr new file mode 100644 index 0000000..e742688 --- /dev/null +++ b/tests/ui/arg-implementation-detail.stderr @@ -0,0 +1,5 @@ +error[E0425]: cannot find value `__arg0` in this scope + --> tests/ui/arg-implementation-detail.rs:18:17 + | +18 | let _ = __arg0; + | ^^^^^^ not found in this scope diff --git a/tests/ui/bare-trait-object.rs b/tests/ui/bare-trait-object.rs new file mode 100644 index 0000000..afcd6b4 --- /dev/null +++ b/tests/ui/bare-trait-object.rs @@ -0,0 +1,15 @@ +#![deny(bare_trait_objects)] + +use async_trait::async_trait; + +#[async_trait] +trait Trait { + async fn f(&self); +} + +#[async_trait] +impl Trait for Send + Sync { + async fn f(&self) {} +} + +fn main() {} diff --git a/tests/ui/bare-trait-object.stderr b/tests/ui/bare-trait-object.stderr new file mode 100644 index 0000000..50b2048 --- /dev/null +++ b/tests/ui/bare-trait-object.stderr @@ -0,0 +1,21 @@ +error: trait objects without an explicit `dyn` are deprecated + --> tests/ui/bare-trait-object.rs:11:16 + | +11 | impl Trait for Send + Sync { + | ^^^^^^^^^^^ + | + = warning: this is accepted in the current edition (Rust 2018) but is a hard error in Rust 2021! + = note: for more information, see +note: the lint level is defined here + --> tests/ui/bare-trait-object.rs:1:9 + | +1 | #![deny(bare_trait_objects)] + | ^^^^^^^^^^^^^^^^^^ +help: use `dyn` + | +11 | impl Trait for dyn Send + Sync { + | +++ +help: alternatively use a blanket implementation to implement `Trait` for all types that also implement `Send + Sync` + | +11 | impl Trait for T { + | ++++++++++++++++ ~ diff --git a/tests/ui/consider-restricting.rs b/tests/ui/consider-restricting.rs new file mode 100644 index 0000000..e23c8b1 --- /dev/null +++ b/tests/ui/consider-restricting.rs @@ -0,0 +1,26 @@ +// https://github.com/rust-lang/rust/issues/93828 + +use async_trait::async_trait; + +pub trait IntoUrl {} + +#[async_trait] +pub trait ClientExt { + async fn publish(&self, url: T); +} + +struct Client; + +#[async_trait] +impl ClientExt for Client { + async fn publish(&self, url: T) {} +} + +struct Client2; + +#[async_trait] +impl ClientExt for Client2 { + async fn publish(&self, url: T) {} +} + +fn main() {} diff --git a/tests/ui/consider-restricting.stderr b/tests/ui/consider-restricting.stderr new file mode 100644 index 0000000..62ff894 --- /dev/null +++ b/tests/ui/consider-restricting.stderr @@ -0,0 +1,33 @@ +error: future cannot be sent between threads safely + --> tests/ui/consider-restricting.rs:16:49 + | +16 | async fn publish(&self, url: T) {} + | ^^ future created by async block is not `Send` + | +note: captured value is not `Send` + --> tests/ui/consider-restricting.rs:16:41 + | +16 | async fn publish(&self, url: T) {} + | ^^^ has type `T` which is not `Send` + = note: required for the cast from `[async block@$DIR/tests/ui/consider-restricting.rs:16:49: 16:51]` to the object type `dyn Future + Send` +help: consider further restricting this bound + | +16 | async fn publish(&self, url: T) {} + | +++++++++++++++++++ + +error: future cannot be sent between threads safely + --> tests/ui/consider-restricting.rs:23:40 + | +23 | async fn publish(&self, url: T) {} + | ^^ future created by async block is not `Send` + | +note: captured value is not `Send` + --> tests/ui/consider-restricting.rs:23:32 + | +23 | async fn publish(&self, url: T) {} + | ^^^ has type `T` which is not `Send` + = note: required for the cast from `[async block@$DIR/tests/ui/consider-restricting.rs:23:40: 23:42]` to the object type `dyn Future + Send` +help: consider further restricting this bound + | +23 | async fn publish(&self, url: T) {} + | +++++++++++++++++++ diff --git a/tests/ui/delimiter-span.rs b/tests/ui/delimiter-span.rs new file mode 100644 index 0000000..51a44a2 --- /dev/null +++ b/tests/ui/delimiter-span.rs @@ -0,0 +1,24 @@ +#![allow(unused_macro_rules)] + +use async_trait::async_trait; + +macro_rules! picky { + ($(t:tt)*) => {}; +} + +#[async_trait] +trait Trait { + async fn method(); +} + +struct Struct; + +#[async_trait] +impl Trait for Struct { + async fn method() { + picky!({ 123, self }); + picky!({ 123 }); + } +} + +fn main() {} diff --git a/tests/ui/delimiter-span.stderr b/tests/ui/delimiter-span.stderr new file mode 100644 index 0000000..f03da4c --- /dev/null +++ b/tests/ui/delimiter-span.stderr @@ -0,0 +1,21 @@ +error: no rules expected the token `{` + --> tests/ui/delimiter-span.rs:19:16 + | +5 | macro_rules! picky { + | ------------------ when calling this macro +... +19 | picky!({ 123, self }); + | ^ no rules expected this token in macro call + | + = note: while trying to match sequence start + +error: no rules expected the token `{` + --> tests/ui/delimiter-span.rs:20:16 + | +5 | macro_rules! picky { + | ------------------ when calling this macro +... +20 | picky!({ 123 }); + | ^ no rules expected this token in macro call + | + = note: while trying to match sequence start diff --git a/tests/ui/lifetime-defined-here.rs b/tests/ui/lifetime-defined-here.rs new file mode 100644 index 0000000..237cf66 --- /dev/null +++ b/tests/ui/lifetime-defined-here.rs @@ -0,0 +1,23 @@ +use async_trait::async_trait; + +#[async_trait] +trait Foo { + async fn bar(&self, x: &str, y: &'_ str) -> &'static str; +} + +struct S(String); + +#[async_trait] +impl Foo for S { + async fn bar(&self, x: &str, y: &'_ str) -> &'static str { + if false { + &self.0 + } else if false { + x + } else { + y + } + } +} + +fn main() {} diff --git a/tests/ui/lifetime-defined-here.stderr b/tests/ui/lifetime-defined-here.stderr new file mode 100644 index 0000000..9ffef5b --- /dev/null +++ b/tests/ui/lifetime-defined-here.stderr @@ -0,0 +1,29 @@ +error: lifetime may not live long enough + --> tests/ui/lifetime-defined-here.rs:12:49 + | +12 | async fn bar(&self, x: &str, y: &'_ str) -> &'static str { + | - ^^^^^^^^^^^^ type annotation requires that `'life0` must outlive `'static` + | | + | lifetime `'life0` defined here + +error: lifetime may not live long enough + --> tests/ui/lifetime-defined-here.rs:12:49 + | +12 | async fn bar(&self, x: &str, y: &'_ str) -> &'static str { + | - ^^^^^^^^^^^^ type annotation requires that `'life1` must outlive `'static` + | | + | lifetime `'life1` defined here + +error: lifetime may not live long enough + --> tests/ui/lifetime-defined-here.rs:12:49 + | +12 | async fn bar(&self, x: &str, y: &'_ str) -> &'static str { + | -- ^^^^^^^^^^^^ type annotation requires that `'life2` must outlive `'static` + | | + | lifetime `'life2` defined here + +help: the following changes may resolve your lifetime errors + | + = help: replace `'life0` with `'static` + = help: replace `'life1` with `'static` + = help: replace `'life2` with `'static` diff --git a/tests/ui/lifetime-span.rs b/tests/ui/lifetime-span.rs new file mode 100644 index 0000000..01981e6 --- /dev/null +++ b/tests/ui/lifetime-span.rs @@ -0,0 +1,36 @@ +use async_trait::async_trait; + +struct A; +struct B; + +#[async_trait] +pub trait Trait<'r> { + async fn method(&'r self); +} + +#[async_trait] +impl Trait for A { + async fn method(&self) {} +} + +#[async_trait] +impl<'r> Trait<'r> for B { + async fn method(&self) {} +} + +#[async_trait] +pub trait Trait2 { + async fn method<'r>(&'r self); +} + +#[async_trait] +impl Trait2 for A { + async fn method(&self) {} +} + +#[async_trait] +impl<'r> Trait2<'r> for B { + async fn method(&'r self) {} +} + +fn main() {} diff --git a/tests/ui/lifetime-span.stderr b/tests/ui/lifetime-span.stderr new file mode 100644 index 0000000..fa16ac7 --- /dev/null +++ b/tests/ui/lifetime-span.stderr @@ -0,0 +1,24 @@ +error[E0726]: implicit elided lifetime not allowed here + --> tests/ui/lifetime-span.rs:12:6 + | +12 | impl Trait for A { + | ^^^^^ expected lifetime parameter + | +help: indicate the anonymous lifetime + | +12 | impl Trait<'_> for A { + | ++++ + +error[E0107]: trait takes 0 lifetime arguments but 1 lifetime argument was supplied + --> tests/ui/lifetime-span.rs:32:10 + | +32 | impl<'r> Trait2<'r> for B { + | ^^^^^^---- help: remove these generics + | | + | expected 0 lifetime arguments + | +note: trait defined here, with 0 lifetime parameters + --> tests/ui/lifetime-span.rs:22:11 + | +22 | pub trait Trait2 { + | ^^^^^^ diff --git a/tests/ui/missing-async-in-impl.rs b/tests/ui/missing-async-in-impl.rs new file mode 100644 index 0000000..3a5f58c --- /dev/null +++ b/tests/ui/missing-async-in-impl.rs @@ -0,0 +1,15 @@ +use async_trait::async_trait; + +#[async_trait] +pub trait Trait { + async fn method(); +} + +pub struct Struct; + +#[async_trait] +impl Trait for Struct { + fn method() {} +} + +fn main() {} diff --git a/tests/ui/missing-async-in-impl.stderr b/tests/ui/missing-async-in-impl.stderr new file mode 100644 index 0000000..e461c85 --- /dev/null +++ b/tests/ui/missing-async-in-impl.stderr @@ -0,0 +1,8 @@ +error[E0195]: lifetime parameters or bounds on method `method` do not match the trait declaration + --> tests/ui/missing-async-in-impl.rs:12:14 + | +5 | async fn method(); + | -------- lifetimes in impl do not match this method in trait +... +12 | fn method() {} + | ^ lifetimes do not match method in trait diff --git a/tests/ui/missing-async-in-trait.rs b/tests/ui/missing-async-in-trait.rs new file mode 100644 index 0000000..56fea7a --- /dev/null +++ b/tests/ui/missing-async-in-trait.rs @@ -0,0 +1,15 @@ +use async_trait::async_trait; + +#[async_trait] +pub trait Trait { + fn method(); +} + +pub struct Struct; + +#[async_trait] +impl Trait for Struct { + async fn method() {} +} + +fn main() {} diff --git a/tests/ui/missing-async-in-trait.stderr b/tests/ui/missing-async-in-trait.stderr new file mode 100644 index 0000000..c92c38d --- /dev/null +++ b/tests/ui/missing-async-in-trait.stderr @@ -0,0 +1,8 @@ +error[E0195]: lifetime parameters or bounds on method `method` do not match the trait declaration + --> tests/ui/missing-async-in-trait.rs:12:14 + | +5 | fn method(); + | - lifetimes in impl do not match this method in trait +... +12 | async fn method() {} + | ^^^^^^^^ lifetimes do not match method in trait diff --git a/tests/ui/missing-body.rs b/tests/ui/missing-body.rs new file mode 100644 index 0000000..f3e1126 --- /dev/null +++ b/tests/ui/missing-body.rs @@ -0,0 +1,15 @@ +use async_trait::async_trait; + +#[async_trait] +trait Trait { + async fn f(&self); +} + +struct Thing; + +#[async_trait] +impl Trait for Thing { + async fn f(&self); +} + +fn main() {} diff --git a/tests/ui/missing-body.stderr b/tests/ui/missing-body.stderr new file mode 100644 index 0000000..e6ddb42 --- /dev/null +++ b/tests/ui/missing-body.stderr @@ -0,0 +1,7 @@ +error: associated function in `impl` without body + --> tests/ui/missing-body.rs:12:5 + | +12 | async fn f(&self); + | ^^^^^^^^^^^^^^^^^- + | | + | help: provide a definition for the function: `{ }` diff --git a/tests/ui/must-use.rs b/tests/ui/must-use.rs new file mode 100644 index 0000000..7ad0d9b --- /dev/null +++ b/tests/ui/must-use.rs @@ -0,0 +1,21 @@ +#![deny(unused_must_use)] + +use async_trait::async_trait; + +#[async_trait] +trait Interface { + async fn f(&self); +} + +struct Thing; + +#[async_trait] +impl Interface for Thing { + async fn f(&self) {} +} + +pub async fn f() { + Thing.f(); +} + +fn main() {} diff --git a/tests/ui/must-use.stderr b/tests/ui/must-use.stderr new file mode 100644 index 0000000..fd6fc31 --- /dev/null +++ b/tests/ui/must-use.stderr @@ -0,0 +1,11 @@ +error: unused return value of `Interface::f` that must be used + --> tests/ui/must-use.rs:18:5 + | +18 | Thing.f(); + | ^^^^^^^^^ + | +note: the lint level is defined here + --> tests/ui/must-use.rs:1:9 + | +1 | #![deny(unused_must_use)] + | ^^^^^^^^^^^^^^^ diff --git a/tests/ui/self-span.rs b/tests/ui/self-span.rs new file mode 100644 index 0000000..b01f247 --- /dev/null +++ b/tests/ui/self-span.rs @@ -0,0 +1,30 @@ +use async_trait::async_trait; + +pub struct S {} + +pub enum E { + V {}, +} + +#[async_trait] +pub trait Trait { + async fn method(self); +} + +#[async_trait] +impl Trait for S { + async fn method(self) { + let _: () = self; + let _: Self = Self; + } +} + +#[async_trait] +impl Trait for E { + async fn method(self) { + let _: () = self; + let _: Self = Self::V; + } +} + +fn main() {} diff --git a/tests/ui/self-span.stderr b/tests/ui/self-span.stderr new file mode 100644 index 0000000..04493f8 --- /dev/null +++ b/tests/ui/self-span.stderr @@ -0,0 +1,27 @@ +error[E0308]: mismatched types + --> tests/ui/self-span.rs:17:21 + | +17 | let _: () = self; + | -- ^^^^ expected `()`, found `S` + | | + | expected due to this + +error: the `Self` constructor can only be used with tuple or unit structs + --> tests/ui/self-span.rs:18:23 + | +18 | let _: Self = Self; + | ^^^^ help: use curly brackets: `Self { /* fields */ }` + +error[E0308]: mismatched types + --> tests/ui/self-span.rs:25:21 + | +25 | let _: () = self; + | -- ^^^^ expected `()`, found `E` + | | + | expected due to this + +error[E0533]: expected value, found struct variant `Self::V` + --> tests/ui/self-span.rs:26:23 + | +26 | let _: Self = Self::V; + | ^^^^^^^ not a value diff --git a/tests/ui/send-not-implemented.rs b/tests/ui/send-not-implemented.rs new file mode 100644 index 0000000..d8883fb --- /dev/null +++ b/tests/ui/send-not-implemented.rs @@ -0,0 +1,22 @@ +use async_trait::async_trait; +use std::sync::Mutex; + +async fn f() {} + +#[async_trait] +trait Test { + async fn test(&self) { + let mutex = Mutex::new(()); + let _guard = mutex.lock().unwrap(); + f().await; + } + + async fn test_ret(&self) -> bool { + let mutex = Mutex::new(()); + let _guard = mutex.lock().unwrap(); + f().await; + true + } +} + +fn main() {} diff --git a/tests/ui/send-not-implemented.stderr b/tests/ui/send-not-implemented.stderr new file mode 100644 index 0000000..d68fc43 --- /dev/null +++ b/tests/ui/send-not-implemented.stderr @@ -0,0 +1,47 @@ +error: future cannot be sent between threads safely + --> tests/ui/send-not-implemented.rs:8:26 + | +8 | async fn test(&self) { + | __________________________^ +9 | | let mutex = Mutex::new(()); +10 | | let _guard = mutex.lock().unwrap(); +11 | | f().await; +12 | | } + | |_____^ future created by async block is not `Send` + | + = help: within `[async block@$DIR/tests/ui/send-not-implemented.rs:8:26: 12:6]`, the trait `Send` is not implemented for `MutexGuard<'_, ()>` +note: future is not `Send` as this value is used across an await + --> tests/ui/send-not-implemented.rs:11:12 + | +10 | let _guard = mutex.lock().unwrap(); + | ------ has type `MutexGuard<'_, ()>` which is not `Send` +11 | f().await; + | ^^^^^^ await occurs here, with `_guard` maybe used later +12 | } + | - `_guard` is later dropped here + = note: required for the cast from `[async block@$DIR/tests/ui/send-not-implemented.rs:8:26: 12:6]` to the object type `dyn Future + Send` + +error: future cannot be sent between threads safely + --> tests/ui/send-not-implemented.rs:14:38 + | +14 | async fn test_ret(&self) -> bool { + | ______________________________________^ +15 | | let mutex = Mutex::new(()); +16 | | let _guard = mutex.lock().unwrap(); +17 | | f().await; +18 | | true +19 | | } + | |_____^ future created by async block is not `Send` + | + = help: within `[async block@$DIR/tests/ui/send-not-implemented.rs:14:38: 19:6]`, the trait `Send` is not implemented for `MutexGuard<'_, ()>` +note: future is not `Send` as this value is used across an await + --> tests/ui/send-not-implemented.rs:17:12 + | +16 | let _guard = mutex.lock().unwrap(); + | ------ has type `MutexGuard<'_, ()>` which is not `Send` +17 | f().await; + | ^^^^^^ await occurs here, with `_guard` maybe used later +18 | true +19 | } + | - `_guard` is later dropped here + = note: required for the cast from `[async block@$DIR/tests/ui/send-not-implemented.rs:14:38: 19:6]` to the object type `dyn Future + Send` diff --git a/tests/ui/unreachable.rs b/tests/ui/unreachable.rs new file mode 100644 index 0000000..cac2826 --- /dev/null +++ b/tests/ui/unreachable.rs @@ -0,0 +1,20 @@ +#![deny(warnings)] + +use async_trait::async_trait; + +#[async_trait] +pub trait Trait { + async fn f() { + unimplemented!() + } +} + +#[async_trait] +pub trait TraitFoo { + async fn f() { + let _y = unimplemented!(); + let _z = _y; + } +} + +fn main() {} diff --git a/tests/ui/unreachable.stderr b/tests/ui/unreachable.stderr new file mode 100644 index 0000000..08595e5 --- /dev/null +++ b/tests/ui/unreachable.stderr @@ -0,0 +1,14 @@ +error: unreachable statement + --> tests/ui/unreachable.rs:16:9 + | +15 | let _y = unimplemented!(); + | ---------------- any code following this expression is unreachable +16 | let _z = _y; + | ^^^^^^^^^^^^ unreachable statement + | +note: the lint level is defined here + --> tests/ui/unreachable.rs:1:9 + | +1 | #![deny(warnings)] + | ^^^^^^^^ + = note: `#[deny(unreachable_code)]` implied by `#[deny(warnings)]` diff --git a/tests/ui/unsupported-self.rs b/tests/ui/unsupported-self.rs new file mode 100644 index 0000000..5868c61 --- /dev/null +++ b/tests/ui/unsupported-self.rs @@ -0,0 +1,15 @@ +use async_trait::async_trait; + +#[async_trait] +pub trait Trait { + async fn method(); +} + +#[async_trait] +impl Trait for &'static str { + async fn method() { + let _ = Self; + } +} + +fn main() {} diff --git a/tests/ui/unsupported-self.stderr b/tests/ui/unsupported-self.stderr new file mode 100644 index 0000000..1493945 --- /dev/null +++ b/tests/ui/unsupported-self.stderr @@ -0,0 +1,5 @@ +error: the `Self` constructor can only be used with tuple or unit structs + --> tests/ui/unsupported-self.rs:11:17 + | +11 | let _ = Self; + | ^^^^ -- cgit v1.2.3