diff --git a/src/librustc_trait_selection/traits/error_reporting/suggestions.rs b/src/librustc_trait_selection/traits/error_reporting/suggestions.rs index bd58e86988a..b8771d59dd4 100644 --- a/src/librustc_trait_selection/traits/error_reporting/suggestions.rs +++ b/src/librustc_trait_selection/traits/error_reporting/suggestions.rs @@ -25,6 +25,14 @@ use std::fmt; use super::InferCtxtPrivExt; use crate::traits::query::evaluate_obligation::InferCtxtExt as _; +#[derive(Debug)] +pub enum GeneratorInteriorOrUpvar { + // span of interior type + Interior(Span), + // span of upvar + Upvar(Span), +} + // This trait is public to expose the diagnostics methods to clippy. pub trait InferCtxtExt<'tcx> { fn suggest_restricting_param_bound( @@ -128,11 +136,8 @@ pub trait InferCtxtExt<'tcx> { fn note_obligation_cause_for_async_await( &self, err: &mut DiagnosticBuilder<'_>, - target_span: Span, - scope_span: &Option, - await_span: Span, - expr: Option, - snippet: String, + interior_or_upvar_span: GeneratorInteriorOrUpvar, + interior_extra_info: Option<(Option, Span, Option, Option)>, inner_generator_body: Option<&hir::Body<'_>>, outer_generator: Option, trait_ref: ty::TraitRef<'_>, @@ -140,7 +145,6 @@ pub trait InferCtxtExt<'tcx> { tables: &ty::TypeckTables<'_>, obligation: &PredicateObligation<'tcx>, next_code: Option<&ObligationCauseCode<'tcx>>, - from_awaited_ty: Option, ); fn note_obligation_cause_code( @@ -1205,7 +1209,6 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { obligation.cause.span={:?}", obligation.predicate, obligation.cause.span ); - let source_map = self.tcx.sess.source_map(); let hir = self.tcx.hir(); // Attempt to detect an async-await error by looking at the obligation causes, looking @@ -1354,7 +1357,23 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { ); eq }; - let target_span = tables + + let mut interior_or_upvar_span = None; + let mut interior_extra_info = None; + + if let Some(upvars) = self.tcx.upvars(generator_did) { + interior_or_upvar_span = upvars.iter().find_map(|(upvar_id, upvar)| { + let upvar_ty = tables.node_type(*upvar_id); + let upvar_ty = self.resolve_vars_if_possible(&upvar_ty); + if ty_matches(&upvar_ty) { + Some(GeneratorInteriorOrUpvar::Upvar(upvar.span)) + } else { + None + } + }); + }; + + tables .generator_interior_types .iter() .find(|ty::GeneratorInteriorTypeCause { ty, .. }| ty_matches(ty)) @@ -1375,31 +1394,21 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { .map(|expr| expr.span); let ty::GeneratorInteriorTypeCause { span, scope_span, yield_span, expr, .. } = cause; - ( - span, - source_map.span_to_snippet(*span), - scope_span, - yield_span, - expr, - from_awaited_ty, - ) + + interior_or_upvar_span = Some(GeneratorInteriorOrUpvar::Interior(*span)); + interior_extra_info = Some((*scope_span, *yield_span, *expr, from_awaited_ty)); }); debug!( - "maybe_note_obligation_cause_for_async_await: target_ty={:?} \ - generator_interior_types={:?} target_span={:?}", - target_ty, tables.generator_interior_types, target_span + "maybe_note_obligation_cause_for_async_await: interior_or_upvar={:?} \ + generator_interior_types={:?}", + interior_or_upvar_span, tables.generator_interior_types ); - if let Some((target_span, Ok(snippet), scope_span, yield_span, expr, from_awaited_ty)) = - target_span - { + if let Some(interior_or_upvar_span) = interior_or_upvar_span { self.note_obligation_cause_for_async_await( err, - *target_span, - scope_span, - *yield_span, - *expr, - snippet, + interior_or_upvar_span, + interior_extra_info, generator_body, outer_generator, trait_ref, @@ -1407,7 +1416,6 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { tables, obligation, next_code, - from_awaited_ty, ); true } else { @@ -1420,11 +1428,8 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { fn note_obligation_cause_for_async_await( &self, err: &mut DiagnosticBuilder<'_>, - target_span: Span, - scope_span: &Option, - yield_span: Span, - expr: Option, - snippet: String, + interior_or_upvar_span: GeneratorInteriorOrUpvar, + interior_extra_info: Option<(Option, Span, Option, Option)>, inner_generator_body: Option<&hir::Body<'_>>, outer_generator: Option, trait_ref: ty::TraitRef<'_>, @@ -1432,7 +1437,6 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { tables: &ty::TypeckTables<'_>, obligation: &PredicateObligation<'tcx>, next_code: Option<&ObligationCauseCode<'tcx>>, - from_awaited_ty: Option, ) { let source_map = self.tcx.sess.source_map(); @@ -1493,47 +1497,28 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { format!("does not implement `{}`", trait_ref.print_only_trait_path()) }; - if let Some(await_span) = from_awaited_ty { - // The type causing this obligation is one being awaited at await_span. - let mut span = MultiSpan::from_span(await_span); - - span.push_span_label( - await_span, - format!("await occurs here on type `{}`, which {}", target_ty, trait_explanation), - ); - - err.span_note( - span, - &format!( - "future {not_trait} as it awaits another future which {not_trait}", - not_trait = trait_explanation - ), - ); - } else { - // Look at the last interior type to get a span for the `.await`. - debug!( - "note_obligation_cause_for_async_await generator_interior_types: {:#?}", - tables.generator_interior_types - ); + let mut explain_yield = |interior_span: Span, + yield_span: Span, + scope_span: Option| { 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), + ); + } + } span.push_span_label( - yield_span, - format!("{} occurs here, with `{}` maybe used later", await_or_yield, snippet), - ); - - span.push_span_label( - target_span, + interior_span, format!("has type `{}` which {}", target_ty, trait_explanation), ); - // 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), - ); - } - err.span_note( span, &format!( @@ -1541,48 +1526,90 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { 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 { + if let Some(await_span) = from_awaited_ty { + // The type causing this obligation is one being awaited at await_span. + let mut span = MultiSpan::from_span(await_span); + span.push_span_label( + await_span, + format!( + "await occurs here on type `{}`, which {}", + target_ty, trait_explanation + ), + ); + err.span_note( + span, + &format!( + "future {not_trait} as it awaits another future which {not_trait}", + not_trait = trait_explanation + ), + ); + } else { + // Look at the last interior type to get a span for the `.await`. + debug!( + "note_obligation_cause_for_async_await generator_interior_types: {:#?}", + tables.generator_interior_types + ); + explain_yield(interior_span, yield_span, scope_span); + } - if let Some(expr_id) = expr { - let expr = hir.expect_expr(expr_id); - debug!("target_ty evaluated from {:?}", expr); + if let Some(expr_id) = expr { + let expr = hir.expect_expr(expr_id); + debug!("target_ty evaluated from {:?}", expr); - let parent = hir.get_parent_node(expr_id); - if let Some(hir::Node::Expr(e)) = hir.find(parent) { - let parent_span = hir.span(parent); - let parent_did = parent.owner.to_def_id(); - // ```rust - // impl T { - // fn foo(&self) -> i32 {} - // } - // T.foo(); - // ^^^^^^^ a temporary `&T` created inside this method call due to `&self` - // ``` - // - let is_region_borrow = - tables.expr_adjustments(expr).iter().any(|adj| adj.is_region_borrow()); + let parent = hir.get_parent_node(expr_id); + if let Some(hir::Node::Expr(e)) = hir.find(parent) { + let parent_span = hir.span(parent); + let parent_did = parent.owner.to_def_id(); + // ```rust + // impl T { + // fn foo(&self) -> i32 {} + // } + // T.foo(); + // ^^^^^^^ a temporary `&T` created inside this method call due to `&self` + // ``` + // + let is_region_borrow = tables + .expr_adjustments(expr) + .iter() + .any(|adj| adj.is_region_borrow()); - // ```rust - // struct Foo(*const u8); - // bar(Foo(std::ptr::null())).await; - // ^^^^^^^^^^^^^^^^^^^^^ raw-ptr `*T` created inside this struct ctor. - // ``` - debug!("parent_def_kind: {:?}", self.tcx.def_kind(parent_did)); - let is_raw_borrow_inside_fn_like_call = match self.tcx.def_kind(parent_did) { - DefKind::Fn | DefKind::Ctor(..) => target_ty.is_unsafe_ptr(), - _ => false, - }; + // ```rust + // struct Foo(*const u8); + // bar(Foo(std::ptr::null())).await; + // ^^^^^^^^^^^^^^^^^^^^^ raw-ptr `*T` created inside this struct ctor. + // ``` + debug!("parent_def_kind: {:?}", self.tcx.def_kind(parent_did)); + let is_raw_borrow_inside_fn_like_call = + match self.tcx.def_kind(parent_did) { + DefKind::Fn | DefKind::Ctor(..) => target_ty.is_unsafe_ptr(), + _ => false, + }; - if (tables.is_method_call(e) && is_region_borrow) - || is_raw_borrow_inside_fn_like_call - { - err.span_help( - parent_span, - "consider moving this into a `let` \ + if (tables.is_method_call(e) && is_region_borrow) + || is_raw_borrow_inside_fn_like_call + { + err.span_help( + parent_span, + "consider moving this into a `let` \ binding to create a shorter lived borrow", - ); + ); + } + } + } } } + GeneratorInteriorOrUpvar::Upvar(upvar_span) => { + let mut span = MultiSpan::from_span(upvar_span); + span.push_span_label( + upvar_span, + format!("has type `{}` which {}", target_ty, trait_explanation), + ); + err.span_note(span, &format!("captured value {}", trait_explanation)); + } } // Add a note for the item obligation that remains - normally a note pointing to the diff --git a/src/test/ui/async-await/issue-70818.rs b/src/test/ui/async-await/issue-70818.rs new file mode 100644 index 00000000000..0609e4fc081 --- /dev/null +++ b/src/test/ui/async-await/issue-70818.rs @@ -0,0 +1,9 @@ +// edition:2018 + +use std::future::Future; +fn foo(ty: T, ty1: U) -> impl Future + Send { +//~^ Error future cannot be sent between threads safely + async { (ty, ty1) } +} + +fn main() {} diff --git a/src/test/ui/async-await/issue-70818.stderr b/src/test/ui/async-await/issue-70818.stderr new file mode 100644 index 00000000000..5fb772fa10a --- /dev/null +++ b/src/test/ui/async-await/issue-70818.stderr @@ -0,0 +1,23 @@ +error: future cannot be sent between threads safely + --> $DIR/issue-70818.rs:4:38 + | +LL | fn foo(ty: T, ty1: U) -> impl Future + Send { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ future created by async block is not `Send` +LL | +LL | async { (ty, ty1) } + | ------------------- this returned value is of type `impl std::future::Future` + | + = help: within `impl std::future::Future`, the trait `std::marker::Send` is not implemented for `U` +note: captured value is not `Send` + --> $DIR/issue-70818.rs:6:18 + | +LL | async { (ty, ty1) } + | ^^^ has type `U` which is not `Send` + = note: the return type of a function must have a statically known size +help: consider restricting type parameter `U` + | +LL | fn foo(ty: T, ty1: U) -> impl Future + Send { + | ^^^^^^^^^^^^^^^^^^^ + +error: aborting due to previous error +