diff options
Diffstat (limited to 'src/librustc')
| -rw-r--r-- | src/librustc/traits/error_reporting.rs | 32 | ||||
| -rw-r--r-- | src/librustc/ty/adjustment.rs | 9 | ||||
| -rw-r--r-- | src/librustc/ty/context.rs | 7 |
3 files changed, 39 insertions, 9 deletions
diff --git a/src/librustc/traits/error_reporting.rs b/src/librustc/traits/error_reporting.rs index 0c9a73d78a5..c1df1149bbd 100644 --- a/src/librustc/traits/error_reporting.rs +++ b/src/librustc/traits/error_reporting.rs @@ -2479,19 +2479,21 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> { ); eq }) - .map(|ty::GeneratorInteriorTypeCause { span, scope_span, .. }| { - (span, source_map.span_to_snippet(*span), scope_span) + .map(|ty::GeneratorInteriorTypeCause { span, scope_span, expr, .. }| { + (span, source_map.span_to_snippet(*span), scope_span, expr) }); + debug!( "maybe_note_obligation_cause_for_async_await: target_ty={:?} \ generator_interior_types={:?} target_span={:?}", target_ty, tables.generator_interior_types, target_span ); - if let Some((target_span, Ok(snippet), scope_span)) = target_span { + if let Some((target_span, Ok(snippet), scope_span, expr)) = target_span { self.note_obligation_cause_for_async_await( err, *target_span, scope_span, + *expr, snippet, generator_did, last_generator, @@ -2514,6 +2516,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> { err: &mut DiagnosticBuilder<'_>, target_span: Span, scope_span: &Option<Span>, + expr: Option<hir::HirId>, snippet: String, first_generator: DefId, last_generator: Option<DefId>, @@ -2549,6 +2552,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> { // not implemented. let is_send = self.tcx.is_diagnostic_item(sym::send_trait, trait_ref.def_id); let is_sync = self.tcx.is_diagnostic_item(sym::sync_trait, trait_ref.def_id); + let hir = self.tcx.hir(); let trait_explanation = if is_send || is_sync { let (trait_name, trait_verb) = if is_send { ("`Send`", "sent") } else { ("`Sync`", "shared") }; @@ -2564,8 +2568,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> { let message = if let Some(name) = last_generator .and_then(|generator_did| self.tcx.parent(generator_did)) - .and_then(|parent_did| self.tcx.hir().as_local_hir_id(parent_did)) - .and_then(|parent_hir_id| self.tcx.hir().opt_name(parent_hir_id)) + .and_then(|parent_did| hir.as_local_hir_id(parent_did)) + .and_then(|parent_hir_id| hir.opt_name(parent_hir_id)) { format!("future returned by `{}` is not {}", name, trait_name) } else { @@ -2581,7 +2585,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> { }; // Look at the last interior type to get a span for the `.await`. - let await_span = tables.generator_interior_types.iter().map(|i| i.span).last().unwrap(); + let await_span = tables.generator_interior_types.iter().map(|t| t.span).last().unwrap(); let mut span = MultiSpan::from_span(await_span); span.push_span_label( await_span, @@ -2606,6 +2610,22 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> { ), ); + if let Some(expr_id) = expr { + let expr = hir.expect_expr(expr_id); + let is_ref = 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 method_span = hir.span(parent); + if tables.is_method_call(e) && is_ref { + err.span_help( + method_span, + "consider moving this method call into a `let` \ + binding to create a shorter lived borrow", + ); + } + } + } + // Add a note for the item obligation that remains - normally a note pointing to the // bound that introduced the obligation (e.g. `T: Send`). debug!("note_obligation_cause_for_async_await: next_code={:?}", next_code); diff --git a/src/librustc/ty/adjustment.rs b/src/librustc/ty/adjustment.rs index ebefb03b813..db034d1618c 100644 --- a/src/librustc/ty/adjustment.rs +++ b/src/librustc/ty/adjustment.rs @@ -81,6 +81,15 @@ pub struct Adjustment<'tcx> { pub target: Ty<'tcx>, } +impl Adjustment<'tcx> { + pub fn is_region_borrow(&self) -> bool { + match self.kind { + Adjust::Borrow(AutoBorrow::Ref(..)) => true, + _ => false, + } + } +} + #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)] pub enum Adjust<'tcx> { /// Go from ! to any type. diff --git a/src/librustc/ty/context.rs b/src/librustc/ty/context.rs index 6b98fddb22e..ef776c88a8f 100644 --- a/src/librustc/ty/context.rs +++ b/src/librustc/ty/context.rs @@ -315,8 +315,7 @@ pub struct ResolvedOpaqueTy<'tcx> { /// /// Here, we would store the type `T`, the span of the value `x`, and the "scope-span" for /// the scope that contains `x`. -#[derive(RustcEncodable, RustcDecodable, Clone, Debug, Eq, Hash, PartialEq)] -#[derive(HashStable, TypeFoldable)] +#[derive(RustcEncodable, RustcDecodable, Clone, Debug, Eq, Hash, PartialEq, HashStable)] pub struct GeneratorInteriorTypeCause<'tcx> { /// Type of the captured binding. pub ty: Ty<'tcx>, @@ -324,6 +323,8 @@ pub struct GeneratorInteriorTypeCause<'tcx> { pub span: Span, /// Span of the scope of the captured binding. pub scope_span: Option<Span>, + /// Expr which the type evaluated from. + pub expr: Option<hir::HirId>, } #[derive(RustcEncodable, RustcDecodable, Debug)] @@ -436,7 +437,7 @@ pub struct TypeckTables<'tcx> { /// entire variable. pub upvar_list: ty::UpvarListMap, - /// Stores the type, span and optional scope span of all types + /// Stores the type, expression, span and optional scope span of all types /// that are live across the yield of this generator (if a generator). pub generator_interior_types: Vec<GeneratorInteriorTypeCause<'tcx>>, } |