filter upvars that cause trait obligation
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csmoe
parent
d4bdcfd3cf
commit
382a963c17
1 changed files with 134 additions and 120 deletions
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@ -125,11 +125,8 @@ pub trait InferCtxtExt<'tcx> {
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fn note_obligation_cause_for_async_await(
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&self,
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err: &mut DiagnosticBuilder<'_>,
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target_span: Span,
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scope_span: &Option<Span>,
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yield_span: Option<Span>,
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expr: Option<hir::HirId>,
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snippet: String,
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interior: Option<(Span, Option<Span>, Option<Span>, Option<hir::HirId>, Option<Span>)>,
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upvar: Option<(Ty<'tcx>, Span)>,
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inner_generator_body: Option<&hir::Body<'_>>,
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outer_generator: Option<DefId>,
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trait_ref: ty::TraitRef<'_>,
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@ -137,7 +134,6 @@ pub trait InferCtxtExt<'tcx> {
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tables: &ty::TypeckTables<'_>,
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obligation: &PredicateObligation<'tcx>,
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next_code: Option<&ObligationCauseCode<'tcx>>,
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from_awaited_ty: Option<Span>,
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);
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fn note_obligation_cause_code<T>(
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@ -1136,7 +1132,6 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
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obligation.cause.span={:?}",
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obligation.predicate, obligation.cause.span
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);
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let source_map = self.tcx.sess.source_map();
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let hir = self.tcx.hir();
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// Attempt to detect an async-await error by looking at the obligation causes, looking
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@ -1173,6 +1168,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
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};
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let mut generator = None;
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let mut outer_generator = None;
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let mut generator_substs = None;
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let mut next_code = Some(&obligation.cause.code);
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while let Some(code) = next_code {
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debug!("maybe_note_obligation_cause_for_async_await: code={:?}", code);
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@ -1188,8 +1184,9 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
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);
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match ty.kind {
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ty::Generator(did, ..) => {
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ty::Generator(did, substs, ..) => {
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generator = generator.or(Some(did));
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generator_substs = generator_substs.or(Some(substs));
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outer_generator = Some(did);
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}
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ty::GeneratorWitness(..) => {}
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@ -1212,12 +1209,13 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
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target_ty={:?}",
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generator, trait_ref, target_ty
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);
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let (generator_did, trait_ref, target_ty) = match (generator, trait_ref, target_ty) {
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(Some(generator_did), Some(trait_ref), Some(target_ty)) => {
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(generator_did, trait_ref, target_ty)
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}
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_ => return false,
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};
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let (generator_did, _generator_substs, trait_ref, target_ty) =
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match (generator, generator_substs, trait_ref, target_ty) {
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(Some(generator_did), Some(generator_substs), Some(trait_ref), Some(target_ty)) => {
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(generator_did, generator_substs, trait_ref, target_ty)
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}
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_ => return false,
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};
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let span = self.tcx.def_span(generator_did);
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@ -1285,7 +1283,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
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);
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eq
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};
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let target_span = tables
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let interior = tables
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.generator_interior_types
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.iter()
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.find(|ty::GeneratorInteriorTypeCause { ty, .. }| ty_matches(ty))
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@ -1306,31 +1304,29 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
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.map(|expr| expr.span);
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let ty::GeneratorInteriorTypeCause { span, scope_span, yield_span, expr, .. } =
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cause;
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(
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span,
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source_map.span_to_snippet(*span),
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scope_span,
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yield_span,
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expr,
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from_awaited_ty,
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)
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(*span, *scope_span, *yield_span, *expr, from_awaited_ty)
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});
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let upvar = if let Some(upvars) = self.tcx.upvars(generator_did) {
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upvars.iter().find_map(|(upvar_id, upvar)| {
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let upvar_ty = tables.node_type(*upvar_id);
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let upvar_ty = self.resolve_vars_if_possible(&upvar_ty);
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if ty_matches(&upvar_ty) { Some((upvar_ty, upvar.span)) } else { None }
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})
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} else {
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None
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};
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debug!(
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"maybe_note_obligation_cause_for_async_await: target_ty={:?} \
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generator_interior_types={:?} target_span={:?}",
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target_ty, tables.generator_interior_types, target_span
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"maybe_note_obligation_cause_for_async_await: interior={:?} \
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generator_interior_types={:?} upvar: {:?}",
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interior, tables.generator_interior_types, upvar
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);
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if let Some((target_span, Ok(snippet), scope_span, yield_span, expr, from_awaited_ty)) =
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target_span
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{
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if interior.is_some() || upvar.is_some() {
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self.note_obligation_cause_for_async_await(
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err,
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*target_span,
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scope_span,
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*yield_span,
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*expr,
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snippet,
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interior,
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upvar,
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generator_body,
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outer_generator,
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trait_ref,
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@ -1338,7 +1334,6 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
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tables,
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obligation,
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next_code,
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from_awaited_ty,
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);
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true
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} else {
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@ -1351,11 +1346,8 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
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fn note_obligation_cause_for_async_await(
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&self,
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err: &mut DiagnosticBuilder<'_>,
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target_span: Span,
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scope_span: &Option<Span>,
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yield_span: Option<Span>,
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expr: Option<hir::HirId>,
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snippet: String,
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interior: Option<(Span, Option<Span>, Option<Span>, Option<hir::HirId>, Option<Span>)>,
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upvar: Option<(Ty<'tcx>, Span)>,
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inner_generator_body: Option<&hir::Body<'_>>,
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outer_generator: Option<DefId>,
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trait_ref: ty::TraitRef<'_>,
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@ -1363,7 +1355,6 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
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tables: &ty::TypeckTables<'_>,
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obligation: &PredicateObligation<'tcx>,
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next_code: Option<&ObligationCauseCode<'tcx>>,
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from_awaited_ty: Option<Span>,
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) {
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let source_map = self.tcx.sess.source_map();
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@ -1424,99 +1415,122 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
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format!("does not implement `{}`", trait_ref.print_only_trait_path())
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};
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if let Some(await_span) = from_awaited_ty {
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// The type causing this obligation is one being awaited at await_span.
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let mut span = MultiSpan::from_span(await_span);
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span.push_span_label(
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await_span,
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format!("await occurs here on type `{}`, which {}", target_ty, trait_explanation),
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);
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err.span_note(
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span,
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&format!(
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"future {not_trait} as it awaits another future which {not_trait}",
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not_trait = trait_explanation
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),
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);
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} else {
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// Look at the last interior type to get a span for the `.await`.
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debug!(
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"note_obligation_cause_for_async_await generator_interior_types: {:#?}",
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tables.generator_interior_types
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);
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if let Some(yield_span) = yield_span {
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let mut span = MultiSpan::from_span(yield_span);
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span.push_span_label(
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yield_span,
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format!("{} occurs here, with `{}` maybe used later", await_or_yield, snippet),
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);
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if let Some((target_span, scope_span, yield_span, expr, from_awaited_ty)) = interior {
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if let Some(await_span) = from_awaited_ty {
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// The type causing this obligation is one being awaited at await_span.
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let mut span = MultiSpan::from_span(await_span);
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span.push_span_label(
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target_span,
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format!("has type `{}` which {}", target_ty, trait_explanation),
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await_span,
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format!(
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"await occurs here on type `{}`, which {}",
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target_ty, trait_explanation
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),
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);
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// If available, use the scope span to annotate the drop location.
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if let Some(scope_span) = scope_span {
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span.push_span_label(
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source_map.end_point(*scope_span),
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format!("`{}` is later dropped here", snippet),
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);
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}
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err.span_note(
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span,
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&format!(
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"{} {} as this value is used across {}",
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future_or_generator, trait_explanation, an_await_or_yield
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"future {not_trait} as it awaits another future which {not_trait}",
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not_trait = trait_explanation
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),
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);
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}
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}
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} else {
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// Look at the last interior type to get a span for the `.await`.
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debug!(
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"note_obligation_cause_for_async_await generator_interior_types: {:#?}",
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tables.generator_interior_types
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);
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if let Some(expr_id) = expr {
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let expr = hir.expect_expr(expr_id);
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debug!("target_ty evaluated from {:?}", expr);
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if let Some(yield_span) = yield_span {
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let mut span = MultiSpan::from_span(yield_span);
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if let Ok(snippet) = source_map.span_to_snippet(target_span) {
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span.push_span_label(
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yield_span,
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format!(
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"{} occurs here, with `{}` maybe used later",
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await_or_yield, snippet
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),
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);
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// If available, use the scope span to annotate the drop location.
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if let Some(scope_span) = scope_span {
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span.push_span_label(
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source_map.end_point(scope_span),
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format!("`{}` is later dropped here", snippet),
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);
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}
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}
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span.push_span_label(
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target_span,
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format!("has type `{}` which {}", target_ty, trait_explanation),
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);
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let parent = hir.get_parent_node(expr_id);
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if let Some(hir::Node::Expr(e)) = hir.find(parent) {
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let parent_span = hir.span(parent);
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let parent_did = parent.owner.to_def_id();
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// ```rust
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// impl T {
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// fn foo(&self) -> i32 {}
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// }
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// T.foo();
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// ^^^^^^^ a temporary `&T` created inside this method call due to `&self`
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// ```
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//
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let is_region_borrow =
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tables.expr_adjustments(expr).iter().any(|adj| adj.is_region_borrow());
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// ```rust
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// struct Foo(*const u8);
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// bar(Foo(std::ptr::null())).await;
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// ^^^^^^^^^^^^^^^^^^^^^ raw-ptr `*T` created inside this struct ctor.
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// ```
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debug!("parent_def_kind: {:?}", self.tcx.def_kind(parent_did));
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let is_raw_borrow_inside_fn_like_call = match self.tcx.def_kind(parent_did) {
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DefKind::Fn | DefKind::Ctor(..) => target_ty.is_unsafe_ptr(),
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_ => false,
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};
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if (tables.is_method_call(e) && is_region_borrow)
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|| is_raw_borrow_inside_fn_like_call
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{
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err.span_help(
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parent_span,
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"consider moving this into a `let` \
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binding to create a shorter lived borrow",
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err.span_note(
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span,
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&format!(
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"{} {} as this value is used across {}",
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future_or_generator, trait_explanation, an_await_or_yield
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),
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);
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}
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}
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if let Some((_, upvar_span)) = upvar {
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let mut span = MultiSpan::from_span(upvar_span);
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span.push_span_label(
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upvar_span,
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format!("has type `{}` which {}", target_ty, trait_explanation),
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);
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}
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if let Some(expr_id) = expr {
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let expr = hir.expect_expr(expr_id);
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debug!("target_ty evaluated from {:?}", expr);
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let parent = hir.get_parent_node(expr_id);
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if let Some(hir::Node::Expr(e)) = hir.find(parent) {
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let parent_span = hir.span(parent);
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let parent_did = parent.owner.to_def_id();
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// ```rust
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// impl T {
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// fn foo(&self) -> i32 {}
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// }
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// T.foo();
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// ^^^^^^^ a temporary `&T` created inside this method call due to `&self`
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// ```
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//
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let is_region_borrow =
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tables.expr_adjustments(expr).iter().any(|adj| adj.is_region_borrow());
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// ```rust
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// struct Foo(*const u8);
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// bar(Foo(std::ptr::null())).await;
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// ^^^^^^^^^^^^^^^^^^^^^ raw-ptr `*T` created inside this struct ctor.
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// ```
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debug!("parent_def_kind: {:?}", self.tcx.def_kind(parent_did));
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let is_raw_borrow_inside_fn_like_call = match self.tcx.def_kind(parent_did) {
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DefKind::Fn | DefKind::Ctor(..) => target_ty.is_unsafe_ptr(),
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_ => false,
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};
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if (tables.is_method_call(e) && is_region_borrow)
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|| is_raw_borrow_inside_fn_like_call
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{
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err.span_help(
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parent_span,
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"consider moving this into a `let` \
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binding to create a shorter lived borrow",
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);
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}
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}
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}
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} else {
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if let Some((_, upvar_span)) = upvar {
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let mut span = MultiSpan::from_span(upvar_span);
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span.push_span_label(
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upvar_span,
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format!("has type `{}` which {}", target_ty, trait_explanation),
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);
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err.span_note(span, &format!("captured outer value {}", trait_explanation));
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}
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}
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// Add a note for the item obligation that remains - normally a note pointing to the
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