diff options
| -rw-r--r-- | src/test/ui/suggestions/expected-boxed-future-isnt-pinned.rs | 35 | ||||
| -rw-r--r-- | src/test/ui/suggestions/expected-boxed-future-isnt-pinned.stderr | 76 |
2 files changed, 95 insertions, 16 deletions
diff --git a/src/test/ui/suggestions/expected-boxed-future-isnt-pinned.rs b/src/test/ui/suggestions/expected-boxed-future-isnt-pinned.rs index 0a1686eac9d..5dee0f5dae0 100644 --- a/src/test/ui/suggestions/expected-boxed-future-isnt-pinned.rs +++ b/src/test/ui/suggestions/expected-boxed-future-isnt-pinned.rs @@ -11,19 +11,26 @@ fn foo<F: Future<Output=i32> + Send + 'static>(x: F) -> BoxFuture<'static, i32> x //~ ERROR mismatched types } -// FIXME: uncomment these once this commit is in Beta and we can rely on `rustc_on_unimplemented` -// having filtering for `Self` being a trait. -// -// fn bar<F: Future<Output=i32> + Send + 'static>(x: F) -> BoxFuture<'static, i32> { -// Box::new(x) -// } -// -// fn baz<F: Future<Output=i32> + Send + 'static>(x: F) -> BoxFuture<'static, i32> { -// Pin::new(x) -// } -// -// fn qux<F: Future<Output=i32> + Send + 'static>(x: F) -> BoxFuture<'static, i32> { -// Pin::new(Box::new(x)) -// } +// This case is still subpar: +// `Pin::new(x)`: store this in the heap by calling `Box::new`: `Box::new(x)` +// Should suggest changing the code from `Pin::new` to `Box::pin`. +fn bar<F: Future<Output=i32> + Send + 'static>(x: F) -> BoxFuture<'static, i32> { + Box::new(x) //~ ERROR mismatched types +} + +fn baz<F: Future<Output=i32> + Send + 'static>(x: F) -> BoxFuture<'static, i32> { + Pin::new(x) //~ ERROR mismatched types + //~^ ERROR E0277 +} + +fn qux<F: Future<Output=i32> + Send + 'static>(x: F) -> BoxFuture<'static, i32> { + Pin::new(Box::new(x)) //~ ERROR E0277 +} + +fn zap() -> BoxFuture<'static, i32> { + async { //~ ERROR mismatched types + 42 + } +} fn main() {} diff --git a/src/test/ui/suggestions/expected-boxed-future-isnt-pinned.stderr b/src/test/ui/suggestions/expected-boxed-future-isnt-pinned.stderr index 48d941283b6..ff256eb3094 100644 --- a/src/test/ui/suggestions/expected-boxed-future-isnt-pinned.stderr +++ b/src/test/ui/suggestions/expected-boxed-future-isnt-pinned.stderr @@ -15,6 +15,78 @@ LL | x = help: type parameters must be constrained to match other types = note: for more information, visit https://doc.rust-lang.org/book/ch10-02-traits.html#traits-as-parameters -error: aborting due to previous error +error[E0308]: mismatched types + --> $DIR/expected-boxed-future-isnt-pinned.rs:18:5 + | +LL | fn bar<F: Future<Output=i32> + Send + 'static>(x: F) -> BoxFuture<'static, i32> { + | ----------------------- expected `std::pin::Pin<std::boxed::Box<(dyn std::future::Future<Output = i32> + std::marker::Send + 'static)>>` because of return type +LL | Box::new(x) + | ^^^^^^^^^^^ expected struct `std::pin::Pin`, found struct `std::boxed::Box` + | + = note: expected struct `std::pin::Pin<std::boxed::Box<(dyn std::future::Future<Output = i32> + std::marker::Send + 'static)>>` + found struct `std::boxed::Box<F>` + = help: use `Box::pin` + +error[E0308]: mismatched types + --> $DIR/expected-boxed-future-isnt-pinned.rs:22:14 + | +LL | fn baz<F: Future<Output=i32> + Send + 'static>(x: F) -> BoxFuture<'static, i32> { + | - this type parameter +LL | Pin::new(x) + | ^ + | | + | expected struct `std::boxed::Box`, found type parameter `F` + | help: store this in the heap by calling `Box::new`: `Box::new(x)` + | + = note: expected struct `std::boxed::Box<dyn std::future::Future<Output = i32> + std::marker::Send>` + found type parameter `F` + = help: type parameters must be constrained to match other types + = note: for more information, visit https://doc.rust-lang.org/book/ch10-02-traits.html#traits-as-parameters + = note: for more on the distinction between the stack and the heap, read https://doc.rust-lang.org/book/ch15-01-box.html, https://doc.rust-lang.org/rust-by-example/std/box.html, and https://doc.rust-lang.org/std/boxed/index.html + +error[E0277]: `dyn std::future::Future<Output = i32> + std::marker::Send` cannot be unpinned + --> $DIR/expected-boxed-future-isnt-pinned.rs:22:5 + | +LL | Pin::new(x) + | ^^^^^^^^ the trait `std::marker::Unpin` is not implemented for `dyn std::future::Future<Output = i32> + std::marker::Send` + | + = note: consider using `Box::pin` + = note: required by `std::pin::Pin::<P>::new` + +error[E0277]: `dyn std::future::Future<Output = i32> + std::marker::Send` cannot be unpinned + --> $DIR/expected-boxed-future-isnt-pinned.rs:27:5 + | +LL | Pin::new(Box::new(x)) + | ^^^^^^^^ the trait `std::marker::Unpin` is not implemented for `dyn std::future::Future<Output = i32> + std::marker::Send` + | + = note: consider using `Box::pin` + = note: required by `std::pin::Pin::<P>::new` + +error[E0308]: mismatched types + --> $DIR/expected-boxed-future-isnt-pinned.rs:31:5 + | +LL | fn zap() -> BoxFuture<'static, i32> { + | ----------------------- expected `std::pin::Pin<std::boxed::Box<(dyn std::future::Future<Output = i32> + std::marker::Send + 'static)>>` because of return type +LL | / async { +LL | | 42 +LL | | } + | |_____^ expected struct `std::pin::Pin`, found opaque type + | + ::: $SRC_DIR/libcore/future/mod.rs:LL:COL + | +LL | pub const fn from_generator<T>(gen: T) -> impl Future<Output = T::Return> + | ------------------------------- the found opaque type + | + = note: expected struct `std::pin::Pin<std::boxed::Box<(dyn std::future::Future<Output = i32> + std::marker::Send + 'static)>>` + found opaque type `impl std::future::Future` +help: you need to pin and box this expression + | +LL | Box::pin(async { +LL | 42 +LL | }) + | + +error: aborting due to 6 previous errors -For more information about this error, try `rustc --explain E0308`. +Some errors have detailed explanations: E0277, E0308. +For more information about an error, try `rustc --explain E0277`. |