diff options
Diffstat (limited to 'compiler')
3 files changed, 82 insertions, 9 deletions
diff --git a/compiler/rustc_borrowck/src/diagnostics/region_errors.rs b/compiler/rustc_borrowck/src/diagnostics/region_errors.rs index 567a9814fcc..cc33ef14756 100644 --- a/compiler/rustc_borrowck/src/diagnostics/region_errors.rs +++ b/compiler/rustc_borrowck/src/diagnostics/region_errors.rs @@ -192,6 +192,8 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> { // buffered in the `MirBorrowckCtxt`. let mut outlives_suggestion = OutlivesSuggestionBuilder::default(); + let mut last_unexpected_hidden_region: Option<(Span, Ty<'_>, ty::OpaqueTypeKey<'tcx>)> = + None; for nll_error in nll_errors.into_iter() { match nll_error { @@ -234,13 +236,19 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> { let named_ty = self.regioncx.name_regions(self.infcx.tcx, hidden_ty); let named_key = self.regioncx.name_regions(self.infcx.tcx, key); let named_region = self.regioncx.name_regions(self.infcx.tcx, member_region); - self.buffer_error(unexpected_hidden_region_diagnostic( + let mut diag = unexpected_hidden_region_diagnostic( self.infcx.tcx, span, named_ty, named_region, named_key, - )); + ); + if last_unexpected_hidden_region != Some((span, named_ty, named_key)) { + self.buffer_error(diag); + last_unexpected_hidden_region = Some((span, named_ty, named_key)); + } else { + diag.delay_as_bug(); + } } RegionErrorKind::BoundUniversalRegionError { @@ -730,6 +738,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> { Some(arg), captures, Some((param.param_ty_span, param.param_ty.to_string())), + self.infcx.tcx.is_suitable_region(f).map(|r| r.def_id), ); } } diff --git a/compiler/rustc_infer/src/infer/error_reporting/mod.rs b/compiler/rustc_infer/src/infer/error_reporting/mod.rs index 7222eb77682..0644c7ada10 100644 --- a/compiler/rustc_infer/src/infer/error_reporting/mod.rs +++ b/compiler/rustc_infer/src/infer/error_reporting/mod.rs @@ -303,6 +303,7 @@ pub fn unexpected_hidden_region_diagnostic<'tcx>( None, format!("captures `{}`", hidden_region), None, + Some(reg_info.def_id), ) } } diff --git a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/static_impl_trait.rs b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/static_impl_trait.rs index d9cdfa9dd4f..94662780c36 100644 --- a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/static_impl_trait.rs +++ b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/static_impl_trait.rs @@ -8,13 +8,17 @@ use rustc_data_structures::fx::FxIndexSet; use rustc_errors::{struct_span_err, Applicability, Diagnostic, ErrorGuaranteed, MultiSpan}; use rustc_hir::def_id::DefId; use rustc_hir::intravisit::{walk_ty, Visitor}; -use rustc_hir::{self as hir, GenericBound, Item, ItemKind, Lifetime, LifetimeName, Node, TyKind}; +use rustc_hir::{ + self as hir, GenericBound, GenericParamKind, Item, ItemKind, Lifetime, LifetimeName, Node, + TyKind, +}; use rustc_middle::ty::{ self, AssocItemContainer, StaticLifetimeVisitor, Ty, TyCtxt, TypeSuperVisitable, TypeVisitor, }; use rustc_span::symbol::Ident; use rustc_span::Span; +use rustc_span::def_id::LocalDefId; use std::ops::ControlFlow; impl<'a, 'tcx> NiceRegionError<'a, 'tcx> { @@ -268,6 +272,7 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> { Some(arg), captures, Some((param.param_ty_span, param.param_ty.to_string())), + Some(anon_reg_sup.def_id), ); let reported = err.emit(); @@ -283,6 +288,7 @@ pub fn suggest_new_region_bound( arg: Option<String>, captures: String, param: Option<(Span, String)>, + scope_def_id: Option<LocalDefId>, ) { debug!("try_report_static_impl_trait: fn_return={:?}", fn_returns); // FIXME: account for the need of parens in `&(dyn Trait + '_)` @@ -340,12 +346,69 @@ pub fn suggest_new_region_bound( _ => false, }) { } else { - err.span_suggestion_verbose( - fn_return.span.shrink_to_hi(), - &format!("{declare} `{ty}` {captures}, {explicit}",), - &plus_lt, - Applicability::MaybeIncorrect, - ); + // get a lifetime name of existing named lifetimes if any + let existing_lt_name = if let Some(id) = scope_def_id + && let Some(generics) = tcx.hir().get_generics(id) + && let named_lifetimes = generics + .params + .iter() + .filter(|p| matches!(p.kind, GenericParamKind::Lifetime { kind: hir::LifetimeParamKind::Explicit })) + .map(|p| { if let hir::ParamName::Plain(name) = p.name {Some(name.to_string())} else {None}}) + .filter(|n| ! matches!(n, None)) + .collect::<Vec<_>>() + && named_lifetimes.len() > 0 { + named_lifetimes[0].clone() + } else { + None + }; + let name = if let Some(name) = &existing_lt_name { + format!("{}", name) + } else { + format!("'a") + }; + // if there are more than one elided lifetimes in inputs, the explicit `'_` lifetime cannot be used. + // introducing a new lifetime `'a` or making use of one from existing named lifetimes if any + if let Some(id) = scope_def_id + && let Some(generics) = tcx.hir().get_generics(id) + && let mut spans_suggs = generics + .params + .iter() + .filter(|p| p.is_elided_lifetime()) + .map(|p| + if p.span.hi() - p.span.lo() == rustc_span::BytePos(1) { // Ampersand (elided without '_) + (p.span.shrink_to_hi(),format!("{name} ")) + } else { // Underscore (elided with '_) + (p.span, format!("{name}")) + } + ) + .collect::<Vec<_>>() + && spans_suggs.len() > 1 + { + let use_lt = + if existing_lt_name == None { + spans_suggs.push((generics.span.shrink_to_hi(), format!("<{name}>"))); + format!("you can introduce a named lifetime parameter `{name}`") + } else { + // make use the existing named lifetime + format!("you can use the named lifetime parameter `{name}`") + }; + spans_suggs + .push((fn_return.span.shrink_to_hi(), format!(" + {name} "))); + err.multipart_suggestion_verbose( + &format!( + "{declare} `{ty}` {captures}, {use_lt}", + ), + spans_suggs, + Applicability::MaybeIncorrect, + ); + } else { + err.span_suggestion_verbose( + fn_return.span.shrink_to_hi(), + &format!("{declare} `{ty}` {captures}, {explicit}",), + &plus_lt, + Applicability::MaybeIncorrect, + ); + } } } TyKind::TraitObject(_, lt, _) => { |