diff options
3 files changed, 41 insertions, 1 deletions
diff --git a/src/librustc_mir/borrow_check/conflict_errors.rs b/src/librustc_mir/borrow_check/conflict_errors.rs index 4217a29bc66..247783c420e 100644 --- a/src/librustc_mir/borrow_check/conflict_errors.rs +++ b/src/librustc_mir/borrow_check/conflict_errors.rs @@ -1190,7 +1190,16 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> { ); let suggestion = match tcx.sess.source_map().span_to_snippet(args_span) { - Ok(string) => format!("move {}", string), + Ok(mut string) => { + if string.starts_with("async ") { + string.insert_str(6, "move "); + } else if string.starts_with("async|") { + string.insert_str(5, " move"); + } else { + string.insert_str(0, "move "); + }; + string + }, Err(_) => "move |<args>| <body>".to_string() }; diff --git a/src/test/ui/async-await/async-borrowck-escaping-closure-error.rs b/src/test/ui/async-await/async-borrowck-escaping-closure-error.rs new file mode 100644 index 00000000000..d2fa5d0a3d0 --- /dev/null +++ b/src/test/ui/async-await/async-borrowck-escaping-closure-error.rs @@ -0,0 +1,10 @@ +// edition:2018 +#![feature(async_closure,async_await)] +fn foo() -> Box<dyn std::future::Future<Output = u32>> { + let x = 0u32; + Box::new((async || x)()) + //~^ ERROR E0373 +} + +fn main() { +} diff --git a/src/test/ui/async-await/async-borrowck-escaping-closure-error.stderr b/src/test/ui/async-await/async-borrowck-escaping-closure-error.stderr new file mode 100644 index 00000000000..8bcfcf98920 --- /dev/null +++ b/src/test/ui/async-await/async-borrowck-escaping-closure-error.stderr @@ -0,0 +1,21 @@ +error[E0373]: closure may outlive the current function, but it borrows `x`, which is owned by the current function + --> $DIR/async-borrowck-escaping-closure-error.rs:5:15 + | +LL | Box::new((async || x)()) + | ^^^^^^^^ - `x` is borrowed here + | | + | may outlive borrowed value `x` + | +note: closure is returned here + --> $DIR/async-borrowck-escaping-closure-error.rs:5:5 + | +LL | Box::new((async || x)()) + | ^^^^^^^^^^^^^^^^^^^^^^^^ +help: to force the closure to take ownership of `x` (and any other referenced variables), use the `move` keyword + | +LL | Box::new((async move || x)()) + | ^^^^^^^^^^^^^ + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0373`. |