diff options
4 files changed, 186 insertions, 33 deletions
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs index c0881befe24..1c6e661782f 100644 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs @@ -1570,36 +1570,130 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { format!("does not implement `{}`", trait_ref.print_only_trait_path()) }; - let mut explain_yield = |interior_span: Span, - yield_span: Span, - scope_span: Option<Span>| { - let mut span = MultiSpan::from_span(yield_span); - if let Ok(snippet) = source_map.span_to_snippet(interior_span) { - span.push_span_label( - yield_span, - format!("{} occurs here, with `{}` maybe used later", await_or_yield, snippet), - ); - // If available, use the scope span to annotate the drop location. - if let Some(scope_span) = scope_span { - span.push_span_label( - source_map.end_point(scope_span), - format!("`{}` is later dropped here", snippet), - ); + let mut explain_yield = + |interior_span: Span, yield_span: Span, scope_span: Option<Span>| { + let mut span = MultiSpan::from_span(yield_span); + if let Ok(snippet) = source_map.span_to_snippet(interior_span) { + // #70935: If snippet contains newlines, display "the value" instead + // so that we do not emit complex diagnostics. + let snippet = &format!("`{}`", snippet); + let snippet = if snippet.contains('\n') { "the value" } else { snippet }; + // The multispan can be complex here, like: + // note: future is not `Send` as this value is used across an await + // --> $DIR/issue-70935-complex-spans.rs:13:9 + // | + // LL | baz(|| async{ + // | __________^___- + // | | _________| + // | || + // LL | || foo(tx.clone()); + // LL | || }).await; + // | || - ^- value is later dropped here + // | ||_________|______| + // | |__________| await occurs here, with value maybe used later + // | has type `closure` which is not `Send` + // + // So, detect it and separate into some notes, like: + // + // note: future is not `Send` as this value is used across an await + // --> $DIR/issue-70935-complex-spans.rs:13:9 + // | + // LL | / baz(|| async{ + // LL | | foo(tx.clone()); + // LL | | }).await; + // | |________________^ first, await occurs here, with the value maybe used later... + // note: the value is later dropped here + // --> $DIR/issue-70935-complex-spans.rs:15:17 + // | + // LL | }).await; + // | ^ + // + // If available, use the scope span to annotate the drop location. + if let Some(scope_span) = scope_span { + let scope_span = source_map.end_point(scope_span); + let is_overlapped = + yield_span.overlaps(scope_span) || yield_span.overlaps(interior_span); + if is_overlapped { + span.push_span_label( + yield_span, + format!( + "first, {} occurs here, with {} maybe used later...", + await_or_yield, snippet + ), + ); + err.span_note( + span, + &format!( + "{} {} as this value is used across {}", + future_or_generator, trait_explanation, an_await_or_yield + ), + ); + if source_map.is_multiline(interior_span) { + err.span_note( + scope_span, + &format!("{} is later dropped here", snippet), + ); + err.span_note( + interior_span, + &format!( + "this has type `{}` which {}", + target_ty, trait_explanation + ), + ); + } else { + let mut span = MultiSpan::from_span(scope_span); + span.push_span_label( + interior_span, + format!("has type `{}` which {}", target_ty, trait_explanation), + ); + err.span_note(span, &format!("{} is later dropped here", snippet)); + } + } else { + span.push_span_label( + yield_span, + format!( + "{} occurs here, with {} maybe used later", + await_or_yield, snippet + ), + ); + span.push_span_label( + scope_span, + format!("{} is later dropped here", snippet), + ); + span.push_span_label( + interior_span, + format!("has type `{}` which {}", target_ty, trait_explanation), + ); + err.span_note( + span, + &format!( + "{} {} as this value is used across {}", + future_or_generator, trait_explanation, an_await_or_yield + ), + ); + } + } else { + span.push_span_label( + yield_span, + format!( + "{} occurs here, with {} maybe used later", + await_or_yield, snippet + ), + ); + span.push_span_label( + interior_span, + format!("has type `{}` which {}", target_ty, trait_explanation), + ); + err.span_note( + span, + &format!( + "{} {} as this value is used across {}", + future_or_generator, trait_explanation, an_await_or_yield + ), + ); + } } - } - span.push_span_label( - interior_span, - format!("has type `{}` which {}", target_ty, trait_explanation), - ); - - err.span_note( - span, - &format!( - "{} {} as this value is used across {}", - future_or_generator, trait_explanation, an_await_or_yield - ), - ); - }; + }; match interior_or_upvar_span { GeneratorInteriorOrUpvar::Interior(interior_span) => { if let Some((scope_span, yield_span, expr, from_awaited_ty)) = interior_extra_info { diff --git a/src/test/ui/async-await/issue-70935-complex-spans.rs b/src/test/ui/async-await/issue-70935-complex-spans.rs new file mode 100644 index 00000000000..2965a7e0654 --- /dev/null +++ b/src/test/ui/async-await/issue-70935-complex-spans.rs @@ -0,0 +1,25 @@ +// edition:2018 +// #70935: Check if we do not emit snippet +// with newlines which lead complex diagnostics. + +use std::future::Future; + +async fn baz<T>(_c: impl FnMut() -> T) where T: Future<Output=()> { +} + +fn foo(tx: std::sync::mpsc::Sender<i32>) -> impl Future + Send { + //~^ ERROR: future cannot be sent between threads safely + async move { + baz(|| async{ + foo(tx.clone()); + }).await; + } +} + +fn bar(_s: impl Future + Send) { +} + +fn main() { + let (tx, _rx) = std::sync::mpsc::channel(); + bar(foo(tx)); +} diff --git a/src/test/ui/async-await/issue-70935-complex-spans.stderr b/src/test/ui/async-await/issue-70935-complex-spans.stderr new file mode 100644 index 00000000000..8451fb84099 --- /dev/null +++ b/src/test/ui/async-await/issue-70935-complex-spans.stderr @@ -0,0 +1,30 @@ +error: future cannot be sent between threads safely + --> $DIR/issue-70935-complex-spans.rs:10:45 + | +LL | fn foo(tx: std::sync::mpsc::Sender<i32>) -> impl Future + Send { + | ^^^^^^^^^^^^^^^^^^ future created by async block is not `Send` + | + = help: the trait `Sync` is not implemented for `Sender<i32>` +note: future is not `Send` as this value is used across an await + --> $DIR/issue-70935-complex-spans.rs:13:9 + | +LL | / baz(|| async{ +LL | | foo(tx.clone()); +LL | | }).await; + | |________________^ first, await occurs here, with the value maybe used later... +note: the value is later dropped here + --> $DIR/issue-70935-complex-spans.rs:15:17 + | +LL | }).await; + | ^ +note: this has type `[closure@$DIR/issue-70935-complex-spans.rs:13:13: 15:10]` which is not `Send` + --> $DIR/issue-70935-complex-spans.rs:13:13 + | +LL | baz(|| async{ + | _____________^ +LL | | foo(tx.clone()); +LL | | }).await; + | |_________^ + +error: aborting due to previous error + diff --git a/src/test/ui/async-await/issues/issue-65436-raw-ptr-not-send.stderr b/src/test/ui/async-await/issues/issue-65436-raw-ptr-not-send.stderr index e4b2725686a..5568dab8655 100644 --- a/src/test/ui/async-await/issues/issue-65436-raw-ptr-not-send.stderr +++ b/src/test/ui/async-await/issues/issue-65436-raw-ptr-not-send.stderr @@ -12,10 +12,14 @@ note: future is not `Send` as this value is used across an await --> $DIR/issue-65436-raw-ptr-not-send.rs:14:9 | LL | bar(Foo(std::ptr::null())).await; - | ^^^^^^^^----------------^^^^^^^^- `std::ptr::null()` is later dropped here - | | | - | | has type `*const u8` which is not `Send` - | await occurs here, with `std::ptr::null()` maybe used later + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ first, await occurs here, with `std::ptr::null()` maybe used later... +note: `std::ptr::null()` is later dropped here + --> $DIR/issue-65436-raw-ptr-not-send.rs:14:41 + | +LL | bar(Foo(std::ptr::null())).await; + | ---------------- ^ + | | + | has type `*const u8` which is not `Send` help: consider moving this into a `let` binding to create a shorter lived borrow --> $DIR/issue-65436-raw-ptr-not-send.rs:14:13 | |