| use crate::diagnostics::{ImportSuggestion, LabelSuggestion, TypoSuggestion}; |
| use crate::late::lifetimes::{ElisionFailureInfo, LifetimeContext}; |
| use crate::late::{AliasPossibility, LateResolutionVisitor, RibKind}; |
| use crate::path_names_to_string; |
| use crate::{Finalize, Module, ModuleKind, ModuleOrUniformRoot}; |
| use crate::{PathResult, PathSource, Segment}; |
| |
| use rustc_ast::visit::FnKind; |
| use rustc_ast::{ |
| self as ast, AssocItemKind, Expr, ExprKind, GenericParam, GenericParamKind, Item, ItemKind, |
| NodeId, Path, Ty, TyKind, |
| }; |
| use rustc_ast_pretty::pprust::path_segment_to_string; |
| use rustc_data_structures::fx::FxHashSet; |
| use rustc_errors::{ |
| pluralize, struct_span_err, Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed, |
| }; |
| use rustc_hir as hir; |
| use rustc_hir::def::Namespace::{self, *}; |
| use rustc_hir::def::{self, CtorKind, CtorOf, DefKind}; |
| use rustc_hir::def_id::{DefId, CRATE_DEF_INDEX, LOCAL_CRATE}; |
| use rustc_hir::PrimTy; |
| use rustc_session::parse::feature_err; |
| use rustc_span::edition::Edition; |
| use rustc_span::hygiene::MacroKind; |
| use rustc_span::lev_distance::find_best_match_for_name; |
| use rustc_span::symbol::{kw, sym, Ident, Symbol}; |
| use rustc_span::{BytePos, MultiSpan, Span, DUMMY_SP}; |
| |
| use std::iter; |
| use std::ops::Deref; |
| |
| use tracing::debug; |
| |
| type Res = def::Res<ast::NodeId>; |
| |
| /// A field or associated item from self type suggested in case of resolution failure. |
| enum AssocSuggestion { |
| Field, |
| MethodWithSelf, |
| AssocFn, |
| AssocType, |
| AssocConst, |
| } |
| |
| impl AssocSuggestion { |
| fn action(&self) -> &'static str { |
| match self { |
| AssocSuggestion::Field => "use the available field", |
| AssocSuggestion::MethodWithSelf => "call the method with the fully-qualified path", |
| AssocSuggestion::AssocFn => "call the associated function", |
| AssocSuggestion::AssocConst => "use the associated `const`", |
| AssocSuggestion::AssocType => "use the associated type", |
| } |
| } |
| } |
| |
| crate enum MissingLifetimeSpot<'tcx> { |
| Generics(&'tcx hir::Generics<'tcx>), |
| HigherRanked { span: Span, span_type: ForLifetimeSpanType }, |
| Static, |
| } |
| |
| crate enum ForLifetimeSpanType { |
| BoundEmpty, |
| BoundTail, |
| TypeEmpty, |
| TypeTail, |
| } |
| |
| impl ForLifetimeSpanType { |
| crate fn descr(&self) -> &'static str { |
| match self { |
| Self::BoundEmpty | Self::BoundTail => "bound", |
| Self::TypeEmpty | Self::TypeTail => "type", |
| } |
| } |
| |
| crate fn suggestion(&self, sugg: &str) -> String { |
| match self { |
| Self::BoundEmpty | Self::TypeEmpty => format!("for<{}> ", sugg), |
| Self::BoundTail | Self::TypeTail => format!(", {}", sugg), |
| } |
| } |
| } |
| |
| impl<'tcx> Into<MissingLifetimeSpot<'tcx>> for &'tcx hir::Generics<'tcx> { |
| fn into(self) -> MissingLifetimeSpot<'tcx> { |
| MissingLifetimeSpot::Generics(self) |
| } |
| } |
| |
| fn is_self_type(path: &[Segment], namespace: Namespace) -> bool { |
| namespace == TypeNS && path.len() == 1 && path[0].ident.name == kw::SelfUpper |
| } |
| |
| fn is_self_value(path: &[Segment], namespace: Namespace) -> bool { |
| namespace == ValueNS && path.len() == 1 && path[0].ident.name == kw::SelfLower |
| } |
| |
| /// Gets the stringified path for an enum from an `ImportSuggestion` for an enum variant. |
| fn import_candidate_to_enum_paths(suggestion: &ImportSuggestion) -> (String, String) { |
| let variant_path = &suggestion.path; |
| let variant_path_string = path_names_to_string(variant_path); |
| |
| let path_len = suggestion.path.segments.len(); |
| let enum_path = ast::Path { |
| span: suggestion.path.span, |
| segments: suggestion.path.segments[0..path_len - 1].to_vec(), |
| tokens: None, |
| }; |
| let enum_path_string = path_names_to_string(&enum_path); |
| |
| (variant_path_string, enum_path_string) |
| } |
| |
| impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> { |
| fn def_span(&self, def_id: DefId) -> Option<Span> { |
| match def_id.krate { |
| LOCAL_CRATE => self.r.opt_span(def_id), |
| _ => Some( |
| self.r |
| .session |
| .source_map() |
| .guess_head_span(self.r.cstore().get_span_untracked(def_id, self.r.session)), |
| ), |
| } |
| } |
| |
| /// Handles error reporting for `smart_resolve_path_fragment` function. |
| /// Creates base error and amends it with one short label and possibly some longer helps/notes. |
| pub(crate) fn smart_resolve_report_errors( |
| &mut self, |
| path: &[Segment], |
| span: Span, |
| source: PathSource<'_>, |
| res: Option<Res>, |
| ) -> (DiagnosticBuilder<'a, ErrorGuaranteed>, Vec<ImportSuggestion>) { |
| let ident_span = path.last().map_or(span, |ident| ident.ident.span); |
| let ns = source.namespace(); |
| let is_expected = &|res| source.is_expected(res); |
| let is_enum_variant = &|res| matches!(res, Res::Def(DefKind::Variant, _)); |
| |
| // Make the base error. |
| let mut expected = source.descr_expected(); |
| let path_str = Segment::names_to_string(path); |
| let item_str = path.last().unwrap().ident; |
| let (base_msg, fallback_label, base_span, could_be_expr) = if let Some(res) = res { |
| ( |
| format!("expected {}, found {} `{}`", expected, res.descr(), path_str), |
| format!("not a {}", expected), |
| span, |
| match res { |
| Res::Def(DefKind::Fn, _) => { |
| // Verify whether this is a fn call or an Fn used as a type. |
| self.r |
| .session |
| .source_map() |
| .span_to_snippet(span) |
| .map(|snippet| snippet.ends_with(')')) |
| .unwrap_or(false) |
| } |
| Res::Def( |
| DefKind::Ctor(..) | DefKind::AssocFn | DefKind::Const | DefKind::AssocConst, |
| _, |
| ) |
| | Res::SelfCtor(_) |
| | Res::PrimTy(_) |
| | Res::Local(_) => true, |
| _ => false, |
| }, |
| ) |
| } else { |
| let item_span = path.last().unwrap().ident.span; |
| let (mod_prefix, mod_str) = if path.len() == 1 { |
| (String::new(), "this scope".to_string()) |
| } else if path.len() == 2 && path[0].ident.name == kw::PathRoot { |
| if self.r.session.edition() > Edition::Edition2015 { |
| // In edition 2018 onwards, the `::foo` syntax may only pull from the extern prelude |
| // which overrides all other expectations of item type |
| expected = "crate"; |
| (String::new(), "the list of imported crates".to_string()) |
| } else { |
| (String::new(), "the crate root".to_string()) |
| } |
| } else if path.len() == 2 && path[0].ident.name == kw::Crate { |
| (String::new(), "the crate root".to_string()) |
| } else { |
| let mod_path = &path[..path.len() - 1]; |
| let mod_prefix = match self.resolve_path(mod_path, Some(TypeNS), Finalize::No) { |
| PathResult::Module(ModuleOrUniformRoot::Module(module)) => module.res(), |
| _ => None, |
| } |
| .map_or_else(String::new, |res| format!("{} ", res.descr())); |
| (mod_prefix, format!("`{}`", Segment::names_to_string(mod_path))) |
| }; |
| ( |
| format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str), |
| if path_str == "async" && expected.starts_with("struct") { |
| "`async` blocks are only allowed in Rust 2018 or later".to_string() |
| } else { |
| format!("not found in {}", mod_str) |
| }, |
| item_span, |
| false, |
| ) |
| }; |
| |
| let code = source.error_code(res.is_some()); |
| let mut err = self.r.session.struct_span_err_with_code(base_span, &base_msg, code); |
| |
| if let Some(span) = self.diagnostic_metadata.current_block_could_be_bare_struct_literal { |
| err.multipart_suggestion( |
| "you might have meant to write a `struct` literal", |
| vec![ |
| (span.shrink_to_lo(), "{ SomeStruct ".to_string()), |
| (span.shrink_to_hi(), "}".to_string()), |
| ], |
| Applicability::HasPlaceholders, |
| ); |
| } |
| match (source, self.diagnostic_metadata.in_if_condition) { |
| (PathSource::Expr(_), Some(Expr { span, kind: ExprKind::Assign(..), .. })) => { |
| err.span_suggestion_verbose( |
| span.shrink_to_lo(), |
| "you might have meant to use pattern matching", |
| "let ".to_string(), |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| _ => {} |
| } |
| |
| let is_assoc_fn = self.self_type_is_available(); |
| // Emit help message for fake-self from other languages (e.g., `this` in Javascript). |
| if ["this", "my"].contains(&item_str.as_str()) && is_assoc_fn { |
| err.span_suggestion_short( |
| span, |
| "you might have meant to use `self` here instead", |
| "self".to_string(), |
| Applicability::MaybeIncorrect, |
| ); |
| if !self.self_value_is_available(path[0].ident.span) { |
| if let Some((FnKind::Fn(_, _, sig, ..), fn_span)) = |
| &self.diagnostic_metadata.current_function |
| { |
| let (span, sugg) = if let Some(param) = sig.decl.inputs.get(0) { |
| (param.span.shrink_to_lo(), "&self, ") |
| } else { |
| ( |
| self.r |
| .session |
| .source_map() |
| .span_through_char(*fn_span, '(') |
| .shrink_to_hi(), |
| "&self", |
| ) |
| }; |
| err.span_suggestion_verbose( |
| span, |
| "if you meant to use `self`, you are also missing a `self` receiver \ |
| argument", |
| sugg.to_string(), |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| } |
| } |
| |
| self.detect_assoct_type_constraint_meant_as_path(base_span, &mut err); |
| |
| // Emit special messages for unresolved `Self` and `self`. |
| if is_self_type(path, ns) { |
| err.code(rustc_errors::error_code!(E0411)); |
| err.span_label( |
| span, |
| "`Self` is only available in impls, traits, and type definitions".to_string(), |
| ); |
| return (err, Vec::new()); |
| } |
| if is_self_value(path, ns) { |
| debug!("smart_resolve_path_fragment: E0424, source={:?}", source); |
| |
| err.code(rustc_errors::error_code!(E0424)); |
| err.span_label(span, match source { |
| PathSource::Pat => "`self` value is a keyword and may not be bound to variables or shadowed" |
| .to_string(), |
| _ => "`self` value is a keyword only available in methods with a `self` parameter" |
| .to_string(), |
| }); |
| if let Some((fn_kind, span)) = &self.diagnostic_metadata.current_function { |
| // The current function has a `self' parameter, but we were unable to resolve |
| // a reference to `self`. This can only happen if the `self` identifier we |
| // are resolving came from a different hygiene context. |
| if fn_kind.decl().inputs.get(0).map_or(false, |p| p.is_self()) { |
| err.span_label(*span, "this function has a `self` parameter, but a macro invocation can only access identifiers it receives from parameters"); |
| } else { |
| let doesnt = if is_assoc_fn { |
| let (span, sugg) = fn_kind |
| .decl() |
| .inputs |
| .get(0) |
| .map(|p| (p.span.shrink_to_lo(), "&self, ")) |
| .unwrap_or_else(|| { |
| // Try to look for the "(" after the function name, if possible. |
| // This avoids placing the suggestion into the visibility specifier. |
| let span = fn_kind |
| .ident() |
| .map_or(*span, |ident| span.with_lo(ident.span.hi())); |
| ( |
| self.r |
| .session |
| .source_map() |
| .span_through_char(span, '(') |
| .shrink_to_hi(), |
| "&self", |
| ) |
| }); |
| err.span_suggestion_verbose( |
| span, |
| "add a `self` receiver parameter to make the associated `fn` a method", |
| sugg.to_string(), |
| Applicability::MaybeIncorrect, |
| ); |
| "doesn't" |
| } else { |
| "can't" |
| }; |
| if let Some(ident) = fn_kind.ident() { |
| err.span_label( |
| ident.span, |
| &format!("this function {} have a `self` parameter", doesnt), |
| ); |
| } |
| } |
| } |
| return (err, Vec::new()); |
| } |
| |
| // Try to lookup name in more relaxed fashion for better error reporting. |
| let ident = path.last().unwrap().ident; |
| let candidates = self |
| .r |
| .lookup_import_candidates(ident, ns, &self.parent_scope, is_expected) |
| .into_iter() |
| .filter(|ImportSuggestion { did, .. }| { |
| match (did, res.and_then(|res| res.opt_def_id())) { |
| (Some(suggestion_did), Some(actual_did)) => *suggestion_did != actual_did, |
| _ => true, |
| } |
| }) |
| .collect::<Vec<_>>(); |
| let crate_def_id = DefId::local(CRATE_DEF_INDEX); |
| if candidates.is_empty() && is_expected(Res::Def(DefKind::Enum, crate_def_id)) { |
| let mut enum_candidates: Vec<_> = self |
| .r |
| .lookup_import_candidates(ident, ns, &self.parent_scope, is_enum_variant) |
| .into_iter() |
| .map(|suggestion| import_candidate_to_enum_paths(&suggestion)) |
| .filter(|(_, enum_ty_path)| !enum_ty_path.starts_with("std::prelude::")) |
| .collect(); |
| if !enum_candidates.is_empty() { |
| if let (PathSource::Type, Some(span)) = |
| (source, self.diagnostic_metadata.current_type_ascription.last()) |
| { |
| if self |
| .r |
| .session |
| .parse_sess |
| .type_ascription_path_suggestions |
| .borrow() |
| .contains(span) |
| { |
| // Already reported this issue on the lhs of the type ascription. |
| err.delay_as_bug(); |
| return (err, candidates); |
| } |
| } |
| |
| enum_candidates.sort(); |
| |
| // Contextualize for E0412 "cannot find type", but don't belabor the point |
| // (that it's a variant) for E0573 "expected type, found variant". |
| let preamble = if res.is_none() { |
| let others = match enum_candidates.len() { |
| 1 => String::new(), |
| 2 => " and 1 other".to_owned(), |
| n => format!(" and {} others", n), |
| }; |
| format!("there is an enum variant `{}`{}; ", enum_candidates[0].0, others) |
| } else { |
| String::new() |
| }; |
| let msg = format!("{}try using the variant's enum", preamble); |
| |
| err.span_suggestions( |
| span, |
| &msg, |
| enum_candidates.into_iter().map(|(_variant_path, enum_ty_path)| enum_ty_path), |
| Applicability::MachineApplicable, |
| ); |
| } |
| } |
| if path.len() == 1 && self.self_type_is_available() { |
| if let Some(candidate) = self.lookup_assoc_candidate(ident, ns, is_expected) { |
| let self_is_available = self.self_value_is_available(path[0].ident.span); |
| match candidate { |
| AssocSuggestion::Field => { |
| if self_is_available { |
| err.span_suggestion( |
| span, |
| "you might have meant to use the available field", |
| format!("self.{}", path_str), |
| Applicability::MachineApplicable, |
| ); |
| } else { |
| err.span_label(span, "a field by this name exists in `Self`"); |
| } |
| } |
| AssocSuggestion::MethodWithSelf if self_is_available => { |
| err.span_suggestion( |
| span, |
| "you might have meant to call the method", |
| format!("self.{}", path_str), |
| Applicability::MachineApplicable, |
| ); |
| } |
| AssocSuggestion::MethodWithSelf |
| | AssocSuggestion::AssocFn |
| | AssocSuggestion::AssocConst |
| | AssocSuggestion::AssocType => { |
| err.span_suggestion( |
| span, |
| &format!("you might have meant to {}", candidate.action()), |
| format!("Self::{}", path_str), |
| Applicability::MachineApplicable, |
| ); |
| } |
| } |
| return (err, candidates); |
| } |
| |
| // If the first argument in call is `self` suggest calling a method. |
| if let Some((call_span, args_span)) = self.call_has_self_arg(source) { |
| let mut args_snippet = String::new(); |
| if let Some(args_span) = args_span { |
| if let Ok(snippet) = self.r.session.source_map().span_to_snippet(args_span) { |
| args_snippet = snippet; |
| } |
| } |
| |
| err.span_suggestion( |
| call_span, |
| &format!("try calling `{}` as a method", ident), |
| format!("self.{}({})", path_str, args_snippet), |
| Applicability::MachineApplicable, |
| ); |
| return (err, candidates); |
| } |
| } |
| |
| // Try Levenshtein algorithm. |
| let typo_sugg = self.lookup_typo_candidate(path, ns, is_expected); |
| // Try context-dependent help if relaxed lookup didn't work. |
| if let Some(res) = res { |
| if self.smart_resolve_context_dependent_help( |
| &mut err, |
| span, |
| source, |
| res, |
| &path_str, |
| &fallback_label, |
| ) { |
| // We do this to avoid losing a secondary span when we override the main error span. |
| self.r.add_typo_suggestion(&mut err, typo_sugg, ident_span); |
| return (err, candidates); |
| } |
| } |
| |
| let is_macro = base_span.from_expansion() && base_span.desugaring_kind().is_none(); |
| if !self.type_ascription_suggestion(&mut err, base_span) { |
| let mut fallback = false; |
| if let ( |
| PathSource::Trait(AliasPossibility::Maybe), |
| Some(Res::Def(DefKind::Struct | DefKind::Enum | DefKind::Union, _)), |
| false, |
| ) = (source, res, is_macro) |
| { |
| if let Some(bounds @ [_, .., _]) = self.diagnostic_metadata.current_trait_object { |
| fallback = true; |
| let spans: Vec<Span> = bounds |
| .iter() |
| .map(|bound| bound.span()) |
| .filter(|&sp| sp != base_span) |
| .collect(); |
| |
| let start_span = bounds.iter().map(|bound| bound.span()).next().unwrap(); |
| // `end_span` is the end of the poly trait ref (Foo + 'baz + Bar><) |
| let end_span = bounds.iter().map(|bound| bound.span()).last().unwrap(); |
| // `last_bound_span` is the last bound of the poly trait ref (Foo + >'baz< + Bar) |
| let last_bound_span = spans.last().cloned().unwrap(); |
| let mut multi_span: MultiSpan = spans.clone().into(); |
| for sp in spans { |
| let msg = if sp == last_bound_span { |
| format!( |
| "...because of {these} bound{s}", |
| these = pluralize!("this", bounds.len() - 1), |
| s = pluralize!(bounds.len() - 1), |
| ) |
| } else { |
| String::new() |
| }; |
| multi_span.push_span_label(sp, msg); |
| } |
| multi_span.push_span_label( |
| base_span, |
| "expected this type to be a trait...".to_string(), |
| ); |
| err.span_help( |
| multi_span, |
| "`+` is used to constrain a \"trait object\" type with lifetimes or \ |
| auto-traits; structs and enums can't be bound in that way", |
| ); |
| if bounds.iter().all(|bound| match bound { |
| ast::GenericBound::Outlives(_) => true, |
| ast::GenericBound::Trait(tr, _) => tr.span == base_span, |
| }) { |
| let mut sugg = vec![]; |
| if base_span != start_span { |
| sugg.push((start_span.until(base_span), String::new())); |
| } |
| if base_span != end_span { |
| sugg.push((base_span.shrink_to_hi().to(end_span), String::new())); |
| } |
| |
| err.multipart_suggestion( |
| "if you meant to use a type and not a trait here, remove the bounds", |
| sugg, |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| } |
| } |
| |
| fallback |= self.restrict_assoc_type_in_where_clause(span, &mut err); |
| |
| if !self.r.add_typo_suggestion(&mut err, typo_sugg, ident_span) { |
| fallback = true; |
| match self.diagnostic_metadata.current_let_binding { |
| Some((pat_sp, Some(ty_sp), None)) |
| if ty_sp.contains(base_span) && could_be_expr => |
| { |
| err.span_suggestion_short( |
| pat_sp.between(ty_sp), |
| "use `=` if you meant to assign", |
| " = ".to_string(), |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| _ => {} |
| } |
| |
| // If the trait has a single item (which wasn't matched by Levenshtein), suggest it |
| let suggestion = self.get_single_associated_item(&path, &source, is_expected); |
| self.r.add_typo_suggestion(&mut err, suggestion, ident_span); |
| } |
| if fallback { |
| // Fallback label. |
| err.span_label(base_span, fallback_label); |
| } |
| } |
| if let Some(err_code) = &err.code { |
| if err_code == &rustc_errors::error_code!(E0425) { |
| for label_rib in &self.label_ribs { |
| for (label_ident, node_id) in &label_rib.bindings { |
| if format!("'{}", ident) == label_ident.to_string() { |
| err.span_label(label_ident.span, "a label with a similar name exists"); |
| if let PathSource::Expr(Some(Expr { |
| kind: ExprKind::Break(None, Some(_)), |
| .. |
| })) = source |
| { |
| err.span_suggestion( |
| span, |
| "use the similarly named label", |
| label_ident.name.to_string(), |
| Applicability::MaybeIncorrect, |
| ); |
| // Do not lint against unused label when we suggest them. |
| self.diagnostic_metadata.unused_labels.remove(node_id); |
| } |
| } |
| } |
| } |
| } else if err_code == &rustc_errors::error_code!(E0412) { |
| if let Some(correct) = Self::likely_rust_type(path) { |
| err.span_suggestion( |
| span, |
| "perhaps you intended to use this type", |
| correct.to_string(), |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| } |
| } |
| |
| (err, candidates) |
| } |
| |
| fn detect_assoct_type_constraint_meant_as_path(&self, base_span: Span, err: &mut Diagnostic) { |
| let Some(ty) = self.diagnostic_metadata.current_type_path else { return; }; |
| let TyKind::Path(_, path) = &ty.kind else { return; }; |
| for segment in &path.segments { |
| let Some(params) = &segment.args else { continue; }; |
| let ast::GenericArgs::AngleBracketed(ref params) = params.deref() else { continue; }; |
| for param in ¶ms.args { |
| let ast::AngleBracketedArg::Constraint(constraint) = param else { continue; }; |
| let ast::AssocConstraintKind::Bound { bounds } = &constraint.kind else { |
| continue; |
| }; |
| for bound in bounds { |
| let ast::GenericBound::Trait(trait_ref, ast::TraitBoundModifier::None) |
| = bound else |
| { |
| continue; |
| }; |
| if base_span == trait_ref.span { |
| err.span_suggestion_verbose( |
| constraint.ident.span.between(trait_ref.span), |
| "you might have meant to write a path instead of an associated type bound", |
| "::".to_string(), |
| Applicability::MachineApplicable, |
| ); |
| } |
| } |
| } |
| } |
| } |
| |
| fn get_single_associated_item( |
| &mut self, |
| path: &[Segment], |
| source: &PathSource<'_>, |
| filter_fn: &impl Fn(Res) -> bool, |
| ) -> Option<TypoSuggestion> { |
| if let crate::PathSource::TraitItem(_) = source { |
| let mod_path = &path[..path.len() - 1]; |
| if let PathResult::Module(ModuleOrUniformRoot::Module(module)) = |
| self.resolve_path(mod_path, None, Finalize::No) |
| { |
| let resolutions = self.r.resolutions(module).borrow(); |
| let targets: Vec<_> = |
| resolutions |
| .iter() |
| .filter_map(|(key, resolution)| { |
| resolution.borrow().binding.map(|binding| binding.res()).and_then( |
| |res| if filter_fn(res) { Some((key, res)) } else { None }, |
| ) |
| }) |
| .collect(); |
| if targets.len() == 1 { |
| let target = targets[0]; |
| return Some(TypoSuggestion::single_item_from_res( |
| target.0.ident.name, |
| target.1, |
| )); |
| } |
| } |
| } |
| None |
| } |
| |
| /// Given `where <T as Bar>::Baz: String`, suggest `where T: Bar<Baz = String>`. |
| fn restrict_assoc_type_in_where_clause(&mut self, span: Span, err: &mut Diagnostic) -> bool { |
| // Detect that we are actually in a `where` predicate. |
| let (bounded_ty, bounds, where_span) = |
| if let Some(ast::WherePredicate::BoundPredicate(ast::WhereBoundPredicate { |
| bounded_ty, |
| bound_generic_params, |
| bounds, |
| span, |
| })) = self.diagnostic_metadata.current_where_predicate |
| { |
| if !bound_generic_params.is_empty() { |
| return false; |
| } |
| (bounded_ty, bounds, span) |
| } else { |
| return false; |
| }; |
| |
| // Confirm that the target is an associated type. |
| let (ty, position, path) = if let ast::TyKind::Path( |
| Some(ast::QSelf { ty, position, .. }), |
| path, |
| ) = &bounded_ty.kind |
| { |
| // use this to verify that ident is a type param. |
| let Some(partial_res) = self.r.partial_res_map.get(&bounded_ty.id) else { |
| return false; |
| }; |
| if !(matches!( |
| partial_res.base_res(), |
| hir::def::Res::Def(hir::def::DefKind::AssocTy, _) |
| ) && partial_res.unresolved_segments() == 0) |
| { |
| return false; |
| } |
| (ty, position, path) |
| } else { |
| return false; |
| }; |
| |
| let peeled_ty = ty.peel_refs(); |
| if let ast::TyKind::Path(None, type_param_path) = &peeled_ty.kind { |
| // Confirm that the `SelfTy` is a type parameter. |
| let Some(partial_res) = self.r.partial_res_map.get(&peeled_ty.id) else { |
| return false; |
| }; |
| if !(matches!( |
| partial_res.base_res(), |
| hir::def::Res::Def(hir::def::DefKind::TyParam, _) |
| ) && partial_res.unresolved_segments() == 0) |
| { |
| return false; |
| } |
| if let ( |
| [ast::PathSegment { ident: constrain_ident, args: None, .. }], |
| [ast::GenericBound::Trait(poly_trait_ref, ast::TraitBoundModifier::None)], |
| ) = (&type_param_path.segments[..], &bounds[..]) |
| { |
| if let [ast::PathSegment { ident, args: None, .. }] = |
| &poly_trait_ref.trait_ref.path.segments[..] |
| { |
| if ident.span == span { |
| err.span_suggestion_verbose( |
| *where_span, |
| &format!("constrain the associated type to `{}`", ident), |
| format!( |
| "{}: {}<{} = {}>", |
| self.r |
| .session |
| .source_map() |
| .span_to_snippet(ty.span) // Account for `<&'a T as Foo>::Bar`. |
| .unwrap_or_else(|_| constrain_ident.to_string()), |
| path.segments[..*position] |
| .iter() |
| .map(|segment| path_segment_to_string(segment)) |
| .collect::<Vec<_>>() |
| .join("::"), |
| path.segments[*position..] |
| .iter() |
| .map(|segment| path_segment_to_string(segment)) |
| .collect::<Vec<_>>() |
| .join("::"), |
| ident, |
| ), |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| return true; |
| } |
| } |
| } |
| false |
| } |
| |
| /// Check if the source is call expression and the first argument is `self`. If true, |
| /// return the span of whole call and the span for all arguments expect the first one (`self`). |
| fn call_has_self_arg(&self, source: PathSource<'_>) -> Option<(Span, Option<Span>)> { |
| let mut has_self_arg = None; |
| if let PathSource::Expr(Some(parent)) = source { |
| match &parent.kind { |
| ExprKind::Call(_, args) if !args.is_empty() => { |
| let mut expr_kind = &args[0].kind; |
| loop { |
| match expr_kind { |
| ExprKind::Path(_, arg_name) if arg_name.segments.len() == 1 => { |
| if arg_name.segments[0].ident.name == kw::SelfLower { |
| let call_span = parent.span; |
| let tail_args_span = if args.len() > 1 { |
| Some(Span::new( |
| args[1].span.lo(), |
| args.last().unwrap().span.hi(), |
| call_span.ctxt(), |
| None, |
| )) |
| } else { |
| None |
| }; |
| has_self_arg = Some((call_span, tail_args_span)); |
| } |
| break; |
| } |
| ExprKind::AddrOf(_, _, expr) => expr_kind = &expr.kind, |
| _ => break, |
| } |
| } |
| } |
| _ => (), |
| } |
| }; |
| has_self_arg |
| } |
| |
| fn followed_by_brace(&self, span: Span) -> (bool, Option<Span>) { |
| // HACK(estebank): find a better way to figure out that this was a |
| // parser issue where a struct literal is being used on an expression |
| // where a brace being opened means a block is being started. Look |
| // ahead for the next text to see if `span` is followed by a `{`. |
| let sm = self.r.session.source_map(); |
| let mut sp = span; |
| loop { |
| sp = sm.next_point(sp); |
| match sm.span_to_snippet(sp) { |
| Ok(ref snippet) => { |
| if snippet.chars().any(|c| !c.is_whitespace()) { |
| break; |
| } |
| } |
| _ => break, |
| } |
| } |
| let followed_by_brace = matches!(sm.span_to_snippet(sp), Ok(ref snippet) if snippet == "{"); |
| // In case this could be a struct literal that needs to be surrounded |
| // by parentheses, find the appropriate span. |
| let mut i = 0; |
| let mut closing_brace = None; |
| loop { |
| sp = sm.next_point(sp); |
| match sm.span_to_snippet(sp) { |
| Ok(ref snippet) => { |
| if snippet == "}" { |
| closing_brace = Some(span.to(sp)); |
| break; |
| } |
| } |
| _ => break, |
| } |
| i += 1; |
| // The bigger the span, the more likely we're incorrect -- |
| // bound it to 100 chars long. |
| if i > 100 { |
| break; |
| } |
| } |
| (followed_by_brace, closing_brace) |
| } |
| |
| /// Provides context-dependent help for errors reported by the `smart_resolve_path_fragment` |
| /// function. |
| /// Returns `true` if able to provide context-dependent help. |
| fn smart_resolve_context_dependent_help( |
| &mut self, |
| err: &mut Diagnostic, |
| span: Span, |
| source: PathSource<'_>, |
| res: Res, |
| path_str: &str, |
| fallback_label: &str, |
| ) -> bool { |
| let ns = source.namespace(); |
| let is_expected = &|res| source.is_expected(res); |
| |
| let path_sep = |err: &mut Diagnostic, expr: &Expr| match expr.kind { |
| ExprKind::Field(_, ident) => { |
| err.span_suggestion( |
| expr.span, |
| "use the path separator to refer to an item", |
| format!("{}::{}", path_str, ident), |
| Applicability::MaybeIncorrect, |
| ); |
| true |
| } |
| ExprKind::MethodCall(ref segment, ..) => { |
| let span = expr.span.with_hi(segment.ident.span.hi()); |
| err.span_suggestion( |
| span, |
| "use the path separator to refer to an item", |
| format!("{}::{}", path_str, segment.ident), |
| Applicability::MaybeIncorrect, |
| ); |
| true |
| } |
| _ => false, |
| }; |
| |
| let find_span = |source: &PathSource<'_>, err: &mut Diagnostic| { |
| match source { |
| PathSource::Expr(Some(Expr { span, kind: ExprKind::Call(_, _), .. })) |
| | PathSource::TupleStruct(span, _) => { |
| // We want the main underline to cover the suggested code as well for |
| // cleaner output. |
| err.set_span(*span); |
| *span |
| } |
| _ => span, |
| } |
| }; |
| |
| let mut bad_struct_syntax_suggestion = |def_id: DefId| { |
| let (followed_by_brace, closing_brace) = self.followed_by_brace(span); |
| |
| match source { |
| PathSource::Expr(Some( |
| parent @ Expr { kind: ExprKind::Field(..) | ExprKind::MethodCall(..), .. }, |
| )) if path_sep(err, &parent) => {} |
| PathSource::Expr( |
| None |
| | Some(Expr { |
| kind: |
| ExprKind::Path(..) |
| | ExprKind::Binary(..) |
| | ExprKind::Unary(..) |
| | ExprKind::If(..) |
| | ExprKind::While(..) |
| | ExprKind::ForLoop(..) |
| | ExprKind::Match(..), |
| .. |
| }), |
| ) if followed_by_brace => { |
| if let Some(sp) = closing_brace { |
| err.span_label(span, fallback_label); |
| err.multipart_suggestion( |
| "surround the struct literal with parentheses", |
| vec![ |
| (sp.shrink_to_lo(), "(".to_string()), |
| (sp.shrink_to_hi(), ")".to_string()), |
| ], |
| Applicability::MaybeIncorrect, |
| ); |
| } else { |
| err.span_label( |
| span, // Note the parentheses surrounding the suggestion below |
| format!( |
| "you might want to surround a struct literal with parentheses: \ |
| `({} {{ /* fields */ }})`?", |
| path_str |
| ), |
| ); |
| } |
| } |
| PathSource::Expr(_) | PathSource::TupleStruct(..) | PathSource::Pat => { |
| let span = find_span(&source, err); |
| if let Some(span) = self.def_span(def_id) { |
| err.span_label(span, &format!("`{}` defined here", path_str)); |
| } |
| let (tail, descr, applicability) = match source { |
| PathSource::Pat | PathSource::TupleStruct(..) => { |
| ("", "pattern", Applicability::MachineApplicable) |
| } |
| _ => (": val", "literal", Applicability::HasPlaceholders), |
| }; |
| let (fields, applicability) = match self.r.field_names.get(&def_id) { |
| Some(fields) => ( |
| fields |
| .iter() |
| .map(|f| format!("{}{}", f.node, tail)) |
| .collect::<Vec<String>>() |
| .join(", "), |
| applicability, |
| ), |
| None => ("/* fields */".to_string(), Applicability::HasPlaceholders), |
| }; |
| let pad = match self.r.field_names.get(&def_id) { |
| Some(fields) if fields.is_empty() => "", |
| _ => " ", |
| }; |
| err.span_suggestion( |
| span, |
| &format!("use struct {} syntax instead", descr), |
| format!("{path_str} {{{pad}{fields}{pad}}}"), |
| applicability, |
| ); |
| } |
| _ => { |
| err.span_label(span, fallback_label); |
| } |
| } |
| }; |
| |
| match (res, source) { |
| ( |
| Res::Def(DefKind::Macro(MacroKind::Bang), _), |
| PathSource::Expr(Some(Expr { |
| kind: ExprKind::Index(..) | ExprKind::Call(..), .. |
| })) |
| | PathSource::Struct, |
| ) => { |
| err.span_label(span, fallback_label); |
| err.span_suggestion_verbose( |
| span.shrink_to_hi(), |
| "use `!` to invoke the macro", |
| "!".to_string(), |
| Applicability::MaybeIncorrect, |
| ); |
| if path_str == "try" && span.rust_2015() { |
| err.note("if you want the `try` keyword, you need Rust 2018 or later"); |
| } |
| } |
| (Res::Def(DefKind::Macro(MacroKind::Bang), _), _) => { |
| err.span_label(span, fallback_label); |
| } |
| (Res::Def(DefKind::TyAlias, def_id), PathSource::Trait(_)) => { |
| err.span_label(span, "type aliases cannot be used as traits"); |
| if self.r.session.is_nightly_build() { |
| let msg = "you might have meant to use `#![feature(trait_alias)]` instead of a \ |
| `type` alias"; |
| if let Some(span) = self.def_span(def_id) { |
| if let Ok(snip) = self.r.session.source_map().span_to_snippet(span) { |
| // The span contains a type alias so we should be able to |
| // replace `type` with `trait`. |
| let snip = snip.replacen("type", "trait", 1); |
| err.span_suggestion(span, msg, snip, Applicability::MaybeIncorrect); |
| } else { |
| err.span_help(span, msg); |
| } |
| } else { |
| err.help(msg); |
| } |
| } |
| } |
| (Res::Def(DefKind::Mod, _), PathSource::Expr(Some(parent))) => { |
| if !path_sep(err, &parent) { |
| return false; |
| } |
| } |
| ( |
| Res::Def(DefKind::Enum, def_id), |
| PathSource::TupleStruct(..) | PathSource::Expr(..), |
| ) => { |
| if self |
| .diagnostic_metadata |
| .current_type_ascription |
| .last() |
| .map(|sp| { |
| self.r |
| .session |
| .parse_sess |
| .type_ascription_path_suggestions |
| .borrow() |
| .contains(&sp) |
| }) |
| .unwrap_or(false) |
| { |
| err.downgrade_to_delayed_bug(); |
| // We already suggested changing `:` into `::` during parsing. |
| return false; |
| } |
| |
| self.suggest_using_enum_variant(err, source, def_id, span); |
| } |
| (Res::Def(DefKind::Struct, def_id), source) if ns == ValueNS => { |
| let (ctor_def, ctor_vis, fields) = |
| if let Some(struct_ctor) = self.r.struct_constructors.get(&def_id).cloned() { |
| if let PathSource::Expr(Some(parent)) = source { |
| if let ExprKind::Field(..) | ExprKind::MethodCall(..) = parent.kind { |
| bad_struct_syntax_suggestion(def_id); |
| return true; |
| } |
| } |
| struct_ctor |
| } else { |
| bad_struct_syntax_suggestion(def_id); |
| return true; |
| }; |
| |
| let is_accessible = self.r.is_accessible_from(ctor_vis, self.parent_scope.module); |
| if !is_expected(ctor_def) || is_accessible { |
| return true; |
| } |
| |
| let field_spans = match source { |
| // e.g. `if let Enum::TupleVariant(field1, field2) = _` |
| PathSource::TupleStruct(_, pattern_spans) => { |
| err.set_primary_message( |
| "cannot match against a tuple struct which contains private fields", |
| ); |
| |
| // Use spans of the tuple struct pattern. |
| Some(Vec::from(pattern_spans)) |
| } |
| // e.g. `let _ = Enum::TupleVariant(field1, field2);` |
| _ if source.is_call() => { |
| err.set_primary_message( |
| "cannot initialize a tuple struct which contains private fields", |
| ); |
| |
| // Use spans of the tuple struct definition. |
| self.r |
| .field_names |
| .get(&def_id) |
| .map(|fields| fields.iter().map(|f| f.span).collect::<Vec<_>>()) |
| } |
| _ => None, |
| }; |
| |
| if let Some(spans) = |
| field_spans.filter(|spans| spans.len() > 0 && fields.len() == spans.len()) |
| { |
| let non_visible_spans: Vec<Span> = iter::zip(&fields, &spans) |
| .filter(|(vis, _)| { |
| !self.r.is_accessible_from(**vis, self.parent_scope.module) |
| }) |
| .map(|(_, span)| *span) |
| .collect(); |
| |
| if non_visible_spans.len() > 0 { |
| let mut m: rustc_span::MultiSpan = non_visible_spans.clone().into(); |
| non_visible_spans |
| .into_iter() |
| .for_each(|s| m.push_span_label(s, "private field".to_string())); |
| err.span_note(m, "constructor is not visible here due to private fields"); |
| } |
| |
| return true; |
| } |
| |
| err.span_label( |
| span, |
| "constructor is not visible here due to private fields".to_string(), |
| ); |
| } |
| ( |
| Res::Def( |
| DefKind::Union | DefKind::Variant | DefKind::Ctor(_, CtorKind::Fictive), |
| def_id, |
| ), |
| _, |
| ) if ns == ValueNS => { |
| bad_struct_syntax_suggestion(def_id); |
| } |
| (Res::Def(DefKind::Ctor(_, CtorKind::Const), def_id), _) if ns == ValueNS => { |
| match source { |
| PathSource::Expr(_) | PathSource::TupleStruct(..) | PathSource::Pat => { |
| let span = find_span(&source, err); |
| if let Some(span) = self.def_span(def_id) { |
| err.span_label(span, &format!("`{}` defined here", path_str)); |
| } |
| err.span_suggestion( |
| span, |
| &"use this syntax instead", |
| path_str.to_string(), |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| _ => return false, |
| } |
| } |
| (Res::Def(DefKind::Ctor(_, CtorKind::Fn), def_id), _) if ns == ValueNS => { |
| if let Some(span) = self.def_span(def_id) { |
| err.span_label(span, &format!("`{}` defined here", path_str)); |
| } |
| let fields = self.r.field_names.get(&def_id).map_or_else( |
| || "/* fields */".to_string(), |
| |fields| vec!["_"; fields.len()].join(", "), |
| ); |
| err.span_suggestion( |
| span, |
| "use the tuple variant pattern syntax instead", |
| format!("{}({})", path_str, fields), |
| Applicability::HasPlaceholders, |
| ); |
| } |
| (Res::SelfTy { .. }, _) if ns == ValueNS => { |
| err.span_label(span, fallback_label); |
| err.note("can't use `Self` as a constructor, you must use the implemented struct"); |
| } |
| (Res::Def(DefKind::TyAlias | DefKind::AssocTy, _), _) if ns == ValueNS => { |
| err.note("can't use a type alias as a constructor"); |
| } |
| _ => return false, |
| } |
| true |
| } |
| |
| /// Given the target `ident` and `kind`, search for the similarly named associated item |
| /// in `self.current_trait_ref`. |
| crate fn find_similarly_named_assoc_item( |
| &mut self, |
| ident: Symbol, |
| kind: &AssocItemKind, |
| ) -> Option<Symbol> { |
| let Some((module, _)) = &self.current_trait_ref else { |
| return None; |
| }; |
| if ident == kw::Underscore { |
| // We do nothing for `_`. |
| return None; |
| } |
| |
| let resolutions = self.r.resolutions(module); |
| let targets = resolutions |
| .borrow() |
| .iter() |
| .filter_map(|(key, res)| res.borrow().binding.map(|binding| (key, binding.res()))) |
| .filter(|(_, res)| match (kind, res) { |
| (AssocItemKind::Const(..), Res::Def(DefKind::AssocConst, _)) => true, |
| (AssocItemKind::Fn(_), Res::Def(DefKind::AssocFn, _)) => true, |
| (AssocItemKind::TyAlias(..), Res::Def(DefKind::AssocTy, _)) => true, |
| _ => false, |
| }) |
| .map(|(key, _)| key.ident.name) |
| .collect::<Vec<_>>(); |
| |
| find_best_match_for_name(&targets, ident, None) |
| } |
| |
| fn lookup_assoc_candidate<FilterFn>( |
| &mut self, |
| ident: Ident, |
| ns: Namespace, |
| filter_fn: FilterFn, |
| ) -> Option<AssocSuggestion> |
| where |
| FilterFn: Fn(Res) -> bool, |
| { |
| fn extract_node_id(t: &Ty) -> Option<NodeId> { |
| match t.kind { |
| TyKind::Path(None, _) => Some(t.id), |
| TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty), |
| // This doesn't handle the remaining `Ty` variants as they are not |
| // that commonly the self_type, it might be interesting to provide |
| // support for those in future. |
| _ => None, |
| } |
| } |
| |
| // Fields are generally expected in the same contexts as locals. |
| if filter_fn(Res::Local(ast::DUMMY_NODE_ID)) { |
| if let Some(node_id) = |
| self.diagnostic_metadata.current_self_type.as_ref().and_then(extract_node_id) |
| { |
| // Look for a field with the same name in the current self_type. |
| if let Some(resolution) = self.r.partial_res_map.get(&node_id) { |
| match resolution.base_res() { |
| Res::Def(DefKind::Struct | DefKind::Union, did) |
| if resolution.unresolved_segments() == 0 => |
| { |
| if let Some(field_names) = self.r.field_names.get(&did) { |
| if field_names |
| .iter() |
| .any(|&field_name| ident.name == field_name.node) |
| { |
| return Some(AssocSuggestion::Field); |
| } |
| } |
| } |
| _ => {} |
| } |
| } |
| } |
| } |
| |
| if let Some(items) = self.diagnostic_metadata.current_trait_assoc_items { |
| for assoc_item in items { |
| if assoc_item.ident == ident { |
| return Some(match &assoc_item.kind { |
| ast::AssocItemKind::Const(..) => AssocSuggestion::AssocConst, |
| ast::AssocItemKind::Fn(box ast::Fn { sig, .. }) if sig.decl.has_self() => { |
| AssocSuggestion::MethodWithSelf |
| } |
| ast::AssocItemKind::Fn(..) => AssocSuggestion::AssocFn, |
| ast::AssocItemKind::TyAlias(..) => AssocSuggestion::AssocType, |
| ast::AssocItemKind::MacCall(_) => continue, |
| }); |
| } |
| } |
| } |
| |
| // Look for associated items in the current trait. |
| if let Some((module, _)) = self.current_trait_ref { |
| if let Ok(binding) = self.r.resolve_ident_in_module( |
| ModuleOrUniformRoot::Module(module), |
| ident, |
| ns, |
| &self.parent_scope, |
| None, |
| ) { |
| let res = binding.res(); |
| if filter_fn(res) { |
| if self.r.has_self.contains(&res.def_id()) { |
| return Some(AssocSuggestion::MethodWithSelf); |
| } else { |
| match res { |
| Res::Def(DefKind::AssocFn, _) => return Some(AssocSuggestion::AssocFn), |
| Res::Def(DefKind::AssocConst, _) => { |
| return Some(AssocSuggestion::AssocConst); |
| } |
| Res::Def(DefKind::AssocTy, _) => { |
| return Some(AssocSuggestion::AssocType); |
| } |
| _ => {} |
| } |
| } |
| } |
| } |
| } |
| |
| None |
| } |
| |
| fn lookup_typo_candidate( |
| &mut self, |
| path: &[Segment], |
| ns: Namespace, |
| filter_fn: &impl Fn(Res) -> bool, |
| ) -> Option<TypoSuggestion> { |
| let mut names = Vec::new(); |
| if path.len() == 1 { |
| // Search in lexical scope. |
| // Walk backwards up the ribs in scope and collect candidates. |
| for rib in self.ribs[ns].iter().rev() { |
| // Locals and type parameters |
| for (ident, &res) in &rib.bindings { |
| if filter_fn(res) { |
| names.push(TypoSuggestion::typo_from_res(ident.name, res)); |
| } |
| } |
| // Items in scope |
| if let RibKind::ModuleRibKind(module) = rib.kind { |
| // Items from this module |
| self.r.add_module_candidates(module, &mut names, &filter_fn); |
| |
| if let ModuleKind::Block(..) = module.kind { |
| // We can see through blocks |
| } else { |
| // Items from the prelude |
| if !module.no_implicit_prelude { |
| let extern_prelude = self.r.extern_prelude.clone(); |
| names.extend(extern_prelude.iter().flat_map(|(ident, _)| { |
| self.r.crate_loader.maybe_process_path_extern(ident.name).and_then( |
| |crate_id| { |
| let crate_mod = Res::Def( |
| DefKind::Mod, |
| DefId { krate: crate_id, index: CRATE_DEF_INDEX }, |
| ); |
| |
| if filter_fn(crate_mod) { |
| Some(TypoSuggestion::typo_from_res( |
| ident.name, crate_mod, |
| )) |
| } else { |
| None |
| } |
| }, |
| ) |
| })); |
| |
| if let Some(prelude) = self.r.prelude { |
| self.r.add_module_candidates(prelude, &mut names, &filter_fn); |
| } |
| } |
| break; |
| } |
| } |
| } |
| // Add primitive types to the mix |
| if filter_fn(Res::PrimTy(PrimTy::Bool)) { |
| names.extend(PrimTy::ALL.iter().map(|prim_ty| { |
| TypoSuggestion::typo_from_res(prim_ty.name(), Res::PrimTy(*prim_ty)) |
| })) |
| } |
| } else { |
| // Search in module. |
| let mod_path = &path[..path.len() - 1]; |
| if let PathResult::Module(ModuleOrUniformRoot::Module(module)) = |
| self.resolve_path(mod_path, Some(TypeNS), Finalize::No) |
| { |
| self.r.add_module_candidates(module, &mut names, &filter_fn); |
| } |
| } |
| |
| let name = path[path.len() - 1].ident.name; |
| // Make sure error reporting is deterministic. |
| names.sort_by(|a, b| a.candidate.as_str().partial_cmp(b.candidate.as_str()).unwrap()); |
| |
| match find_best_match_for_name( |
| &names.iter().map(|suggestion| suggestion.candidate).collect::<Vec<Symbol>>(), |
| name, |
| None, |
| ) { |
| Some(found) if found != name => { |
| names.into_iter().find(|suggestion| suggestion.candidate == found) |
| } |
| _ => None, |
| } |
| } |
| |
| // Returns the name of the Rust type approximately corresponding to |
| // a type name in another programming language. |
| fn likely_rust_type(path: &[Segment]) -> Option<Symbol> { |
| let name = path[path.len() - 1].ident.as_str(); |
| // Common Java types |
| Some(match name { |
| "byte" => sym::u8, // In Java, bytes are signed, but in practice one almost always wants unsigned bytes. |
| "short" => sym::i16, |
| "boolean" => sym::bool, |
| "int" => sym::i32, |
| "long" => sym::i64, |
| "float" => sym::f32, |
| "double" => sym::f64, |
| _ => return None, |
| }) |
| } |
| |
| /// Only used in a specific case of type ascription suggestions |
| fn get_colon_suggestion_span(&self, start: Span) -> Span { |
| let sm = self.r.session.source_map(); |
| start.to(sm.next_point(start)) |
| } |
| |
| fn type_ascription_suggestion(&self, err: &mut Diagnostic, base_span: Span) -> bool { |
| let sm = self.r.session.source_map(); |
| let base_snippet = sm.span_to_snippet(base_span); |
| if let Some(&sp) = self.diagnostic_metadata.current_type_ascription.last() { |
| if let Ok(snippet) = sm.span_to_snippet(sp) { |
| let len = snippet.trim_end().len() as u32; |
| if snippet.trim() == ":" { |
| let colon_sp = |
| sp.with_lo(sp.lo() + BytePos(len - 1)).with_hi(sp.lo() + BytePos(len)); |
| let mut show_label = true; |
| if sm.is_multiline(sp) { |
| err.span_suggestion_short( |
| colon_sp, |
| "maybe you meant to write `;` here", |
| ";".to_string(), |
| Applicability::MaybeIncorrect, |
| ); |
| } else { |
| let after_colon_sp = |
| self.get_colon_suggestion_span(colon_sp.shrink_to_hi()); |
| if snippet.len() == 1 { |
| // `foo:bar` |
| err.span_suggestion( |
| colon_sp, |
| "maybe you meant to write a path separator here", |
| "::".to_string(), |
| Applicability::MaybeIncorrect, |
| ); |
| show_label = false; |
| if !self |
| .r |
| .session |
| .parse_sess |
| .type_ascription_path_suggestions |
| .borrow_mut() |
| .insert(colon_sp) |
| { |
| err.downgrade_to_delayed_bug(); |
| } |
| } |
| if let Ok(base_snippet) = base_snippet { |
| let mut sp = after_colon_sp; |
| for _ in 0..100 { |
| // Try to find an assignment |
| sp = sm.next_point(sp); |
| let snippet = sm.span_to_snippet(sp.to(sm.next_point(sp))); |
| match snippet { |
| Ok(ref x) if x.as_str() == "=" => { |
| err.span_suggestion( |
| base_span, |
| "maybe you meant to write an assignment here", |
| format!("let {}", base_snippet), |
| Applicability::MaybeIncorrect, |
| ); |
| show_label = false; |
| break; |
| } |
| Ok(ref x) if x.as_str() == "\n" => break, |
| Err(_) => break, |
| Ok(_) => {} |
| } |
| } |
| } |
| } |
| if show_label { |
| err.span_label( |
| base_span, |
| "expecting a type here because of type ascription", |
| ); |
| } |
| return show_label; |
| } |
| } |
| } |
| false |
| } |
| |
| fn find_module(&mut self, def_id: DefId) -> Option<(Module<'a>, ImportSuggestion)> { |
| let mut result = None; |
| let mut seen_modules = FxHashSet::default(); |
| let mut worklist = vec![(self.r.graph_root, Vec::new())]; |
| |
| while let Some((in_module, path_segments)) = worklist.pop() { |
| // abort if the module is already found |
| if result.is_some() { |
| break; |
| } |
| |
| in_module.for_each_child(self.r, |_, ident, _, name_binding| { |
| // abort if the module is already found or if name_binding is private external |
| if result.is_some() || !name_binding.vis.is_visible_locally() { |
| return; |
| } |
| if let Some(module) = name_binding.module() { |
| // form the path |
| let mut path_segments = path_segments.clone(); |
| path_segments.push(ast::PathSegment::from_ident(ident)); |
| let module_def_id = module.def_id(); |
| if module_def_id == def_id { |
| let path = |
| Path { span: name_binding.span, segments: path_segments, tokens: None }; |
| result = Some(( |
| module, |
| ImportSuggestion { |
| did: Some(def_id), |
| descr: "module", |
| path, |
| accessible: true, |
| note: None, |
| }, |
| )); |
| } else { |
| // add the module to the lookup |
| if seen_modules.insert(module_def_id) { |
| worklist.push((module, path_segments)); |
| } |
| } |
| } |
| }); |
| } |
| |
| result |
| } |
| |
| fn collect_enum_ctors(&mut self, def_id: DefId) -> Option<Vec<(Path, DefId, CtorKind)>> { |
| self.find_module(def_id).map(|(enum_module, enum_import_suggestion)| { |
| let mut variants = Vec::new(); |
| enum_module.for_each_child(self.r, |_, ident, _, name_binding| { |
| if let Res::Def(DefKind::Ctor(CtorOf::Variant, kind), def_id) = name_binding.res() { |
| let mut segms = enum_import_suggestion.path.segments.clone(); |
| segms.push(ast::PathSegment::from_ident(ident)); |
| let path = Path { span: name_binding.span, segments: segms, tokens: None }; |
| variants.push((path, def_id, kind)); |
| } |
| }); |
| variants |
| }) |
| } |
| |
| /// Adds a suggestion for using an enum's variant when an enum is used instead. |
| fn suggest_using_enum_variant( |
| &mut self, |
| err: &mut Diagnostic, |
| source: PathSource<'_>, |
| def_id: DefId, |
| span: Span, |
| ) { |
| let Some(variants) = self.collect_enum_ctors(def_id) else { |
| err.note("you might have meant to use one of the enum's variants"); |
| return; |
| }; |
| |
| let suggest_only_tuple_variants = |
| matches!(source, PathSource::TupleStruct(..)) || source.is_call(); |
| if suggest_only_tuple_variants { |
| // Suggest only tuple variants regardless of whether they have fields and do not |
| // suggest path with added parentheses. |
| let suggestable_variants = variants |
| .iter() |
| .filter(|(.., kind)| *kind == CtorKind::Fn) |
| .map(|(variant, ..)| path_names_to_string(variant)) |
| .collect::<Vec<_>>(); |
| |
| let non_suggestable_variant_count = variants.len() - suggestable_variants.len(); |
| |
| let source_msg = if source.is_call() { |
| "to construct" |
| } else if matches!(source, PathSource::TupleStruct(..)) { |
| "to match against" |
| } else { |
| unreachable!() |
| }; |
| |
| if !suggestable_variants.is_empty() { |
| let msg = if non_suggestable_variant_count == 0 && suggestable_variants.len() == 1 { |
| format!("try {} the enum's variant", source_msg) |
| } else { |
| format!("try {} one of the enum's variants", source_msg) |
| }; |
| |
| err.span_suggestions( |
| span, |
| &msg, |
| suggestable_variants.into_iter(), |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| |
| // If the enum has no tuple variants.. |
| if non_suggestable_variant_count == variants.len() { |
| err.help(&format!("the enum has no tuple variants {}", source_msg)); |
| } |
| |
| // If there are also non-tuple variants.. |
| if non_suggestable_variant_count == 1 { |
| err.help(&format!( |
| "you might have meant {} the enum's non-tuple variant", |
| source_msg |
| )); |
| } else if non_suggestable_variant_count >= 1 { |
| err.help(&format!( |
| "you might have meant {} one of the enum's non-tuple variants", |
| source_msg |
| )); |
| } |
| } else { |
| let needs_placeholder = |def_id: DefId, kind: CtorKind| { |
| let has_no_fields = self.r.field_names.get(&def_id).map_or(false, |f| f.is_empty()); |
| match kind { |
| CtorKind::Const => false, |
| CtorKind::Fn | CtorKind::Fictive if has_no_fields => false, |
| _ => true, |
| } |
| }; |
| |
| let mut suggestable_variants = variants |
| .iter() |
| .filter(|(_, def_id, kind)| !needs_placeholder(*def_id, *kind)) |
| .map(|(variant, _, kind)| (path_names_to_string(variant), kind)) |
| .map(|(variant, kind)| match kind { |
| CtorKind::Const => variant, |
| CtorKind::Fn => format!("({}())", variant), |
| CtorKind::Fictive => format!("({} {{}})", variant), |
| }) |
| .collect::<Vec<_>>(); |
| |
| if !suggestable_variants.is_empty() { |
| let msg = if suggestable_variants.len() == 1 { |
| "you might have meant to use the following enum variant" |
| } else { |
| "you might have meant to use one of the following enum variants" |
| }; |
| |
| err.span_suggestions( |
| span, |
| msg, |
| suggestable_variants.drain(..), |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| |
| let suggestable_variants_with_placeholders = variants |
| .iter() |
| .filter(|(_, def_id, kind)| needs_placeholder(*def_id, *kind)) |
| .map(|(variant, _, kind)| (path_names_to_string(variant), kind)) |
| .filter_map(|(variant, kind)| match kind { |
| CtorKind::Fn => Some(format!("({}(/* fields */))", variant)), |
| CtorKind::Fictive => Some(format!("({} {{ /* fields */ }})", variant)), |
| _ => None, |
| }) |
| .collect::<Vec<_>>(); |
| |
| if !suggestable_variants_with_placeholders.is_empty() { |
| let msg = match ( |
| suggestable_variants.is_empty(), |
| suggestable_variants_with_placeholders.len(), |
| ) { |
| (true, 1) => "the following enum variant is available", |
| (true, _) => "the following enum variants are available", |
| (false, 1) => "alternatively, the following enum variant is available", |
| (false, _) => "alternatively, the following enum variants are also available", |
| }; |
| |
| err.span_suggestions( |
| span, |
| msg, |
| suggestable_variants_with_placeholders.into_iter(), |
| Applicability::HasPlaceholders, |
| ); |
| } |
| }; |
| |
| if def_id.is_local() { |
| if let Some(span) = self.def_span(def_id) { |
| err.span_note(span, "the enum is defined here"); |
| } |
| } |
| } |
| |
| crate fn report_missing_type_error( |
| &self, |
| path: &[Segment], |
| ) -> Option<(Span, &'static str, String, Applicability)> { |
| let (ident, span) = match path { |
| [segment] if !segment.has_generic_args => { |
| (segment.ident.to_string(), segment.ident.span) |
| } |
| _ => return None, |
| }; |
| let mut iter = ident.chars().map(|c| c.is_uppercase()); |
| let single_uppercase_char = |
| matches!(iter.next(), Some(true)) && matches!(iter.next(), None); |
| if !self.diagnostic_metadata.currently_processing_generics && !single_uppercase_char { |
| return None; |
| } |
| match (self.diagnostic_metadata.current_item, single_uppercase_char, self.diagnostic_metadata.currently_processing_generics) { |
| (Some(Item { kind: ItemKind::Fn(..), ident, .. }), _, _) if ident.name == sym::main => { |
| // Ignore `fn main()` as we don't want to suggest `fn main<T>()` |
| } |
| ( |
| Some(Item { |
| kind: |
| kind @ ItemKind::Fn(..) |
| | kind @ ItemKind::Enum(..) |
| | kind @ ItemKind::Struct(..) |
| | kind @ ItemKind::Union(..), |
| .. |
| }), |
| true, _ |
| ) |
| // Without the 2nd `true`, we'd suggest `impl <T>` for `impl T` when a type `T` isn't found |
| | (Some(Item { kind: kind @ ItemKind::Impl(..), .. }), true, true) |
| | (Some(Item { kind, .. }), false, _) => { |
| // Likely missing type parameter. |
| if let Some(generics) = kind.generics() { |
| if span.overlaps(generics.span) { |
| // Avoid the following: |
| // error[E0405]: cannot find trait `A` in this scope |
| // --> $DIR/typo-suggestion-named-underscore.rs:CC:LL |
| // | |
| // L | fn foo<T: A>(x: T) {} // Shouldn't suggest underscore |
| // | ^- help: you might be missing a type parameter: `, A` |
| // | | |
| // | not found in this scope |
| return None; |
| } |
| let msg = "you might be missing a type parameter"; |
| let (span, sugg) = if let [.., param] = &generics.params[..] { |
| let span = if let [.., bound] = ¶m.bounds[..] { |
| bound.span() |
| } else if let GenericParam { |
| kind: GenericParamKind::Const { ty, kw_span: _, default }, .. |
| } = param { |
| default.as_ref().map(|def| def.value.span).unwrap_or(ty.span) |
| } else { |
| param.ident.span |
| }; |
| (span, format!(", {}", ident)) |
| } else { |
| (generics.span, format!("<{}>", ident)) |
| }; |
| // Do not suggest if this is coming from macro expansion. |
| if span.can_be_used_for_suggestions() { |
| return Some(( |
| span.shrink_to_hi(), |
| msg, |
| sugg, |
| Applicability::MaybeIncorrect, |
| )); |
| } |
| } |
| } |
| _ => {} |
| } |
| None |
| } |
| |
| /// Given the target `label`, search the `rib_index`th label rib for similarly named labels, |
| /// optionally returning the closest match and whether it is reachable. |
| crate fn suggestion_for_label_in_rib( |
| &self, |
| rib_index: usize, |
| label: Ident, |
| ) -> Option<LabelSuggestion> { |
| // Are ribs from this `rib_index` within scope? |
| let within_scope = self.is_label_valid_from_rib(rib_index); |
| |
| let rib = &self.label_ribs[rib_index]; |
| let names = rib |
| .bindings |
| .iter() |
| .filter(|(id, _)| id.span.ctxt() == label.span.ctxt()) |
| .map(|(id, _)| id.name) |
| .collect::<Vec<Symbol>>(); |
| |
| find_best_match_for_name(&names, label.name, None).map(|symbol| { |
| // Upon finding a similar name, get the ident that it was from - the span |
| // contained within helps make a useful diagnostic. In addition, determine |
| // whether this candidate is within scope. |
| let (ident, _) = rib.bindings.iter().find(|(ident, _)| ident.name == symbol).unwrap(); |
| (*ident, within_scope) |
| }) |
| } |
| } |
| |
| impl<'tcx> LifetimeContext<'_, 'tcx> { |
| crate fn report_missing_lifetime_specifiers( |
| &self, |
| spans: Vec<Span>, |
| count: usize, |
| ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> { |
| struct_span_err!( |
| self.tcx.sess, |
| spans, |
| E0106, |
| "missing lifetime specifier{}", |
| pluralize!(count) |
| ) |
| } |
| |
| crate fn emit_undeclared_lifetime_error(&self, lifetime_ref: &hir::Lifetime) { |
| let mut err = struct_span_err!( |
| self.tcx.sess, |
| lifetime_ref.span, |
| E0261, |
| "use of undeclared lifetime name `{}`", |
| lifetime_ref |
| ); |
| err.span_label(lifetime_ref.span, "undeclared lifetime"); |
| let mut suggested_spans = vec![]; |
| for missing in &self.missing_named_lifetime_spots { |
| match missing { |
| MissingLifetimeSpot::Generics(generics) => { |
| let (span, sugg) = if let Some(param) = generics.params.iter().find(|p| { |
| !matches!( |
| p.kind, |
| hir::GenericParamKind::Type { synthetic: true, .. } |
| | hir::GenericParamKind::Lifetime { |
| kind: hir::LifetimeParamKind::Elided, |
| } |
| ) |
| }) { |
| (param.span.shrink_to_lo(), format!("{}, ", lifetime_ref)) |
| } else { |
| (generics.span, format!("<{}>", lifetime_ref)) |
| }; |
| if suggested_spans.contains(&span) { |
| continue; |
| } |
| suggested_spans.push(span); |
| if span.can_be_used_for_suggestions() { |
| err.span_suggestion( |
| span, |
| &format!("consider introducing lifetime `{}` here", lifetime_ref), |
| sugg, |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| } |
| MissingLifetimeSpot::HigherRanked { span, span_type } => { |
| err.span_suggestion( |
| *span, |
| &format!( |
| "consider making the {} lifetime-generic with a new `{}` lifetime", |
| span_type.descr(), |
| lifetime_ref |
| ), |
| span_type.suggestion(&lifetime_ref.to_string()), |
| Applicability::MaybeIncorrect, |
| ); |
| err.note( |
| "for more information on higher-ranked polymorphism, visit \ |
| https://doc.rust-lang.org/nomicon/hrtb.html", |
| ); |
| } |
| _ => {} |
| } |
| } |
| err.emit(); |
| } |
| |
| /// Returns whether to add `'static` lifetime to the suggested lifetime list. |
| crate fn report_elision_failure( |
| &mut self, |
| // FIXME(eddyb) rename this since it's no longer a `DiagnosticBuilder`. |
| db: &mut Diagnostic, |
| params: &[ElisionFailureInfo], |
| ) -> bool { |
| let mut m = String::new(); |
| let len = params.len(); |
| |
| let elided_params: Vec<_> = |
| params.iter().cloned().filter(|info| info.lifetime_count > 0).collect(); |
| |
| let elided_len = elided_params.len(); |
| |
| for (i, info) in elided_params.into_iter().enumerate() { |
| let ElisionFailureInfo { parent, index, lifetime_count: n, have_bound_regions, span } = |
| info; |
| |
| db.span_label(span, ""); |
| let help_name = if let Some(ident) = |
| parent.and_then(|body| self.tcx.hir().body(body).params[index].pat.simple_ident()) |
| { |
| format!("`{}`", ident) |
| } else { |
| format!("argument {}", index + 1) |
| }; |
| |
| m.push_str( |
| &(if n == 1 { |
| help_name |
| } else { |
| format!( |
| "one of {}'s {} {}lifetimes", |
| help_name, |
| n, |
| if have_bound_regions { "free " } else { "" } |
| ) |
| })[..], |
| ); |
| |
| if elided_len == 2 && i == 0 { |
| m.push_str(" or "); |
| } else if i + 2 == elided_len { |
| m.push_str(", or "); |
| } else if i != elided_len - 1 { |
| m.push_str(", "); |
| } |
| } |
| |
| if len == 0 { |
| db.help( |
| "this function's return type contains a borrowed value, \ |
| but there is no value for it to be borrowed from", |
| ); |
| true |
| } else if elided_len == 0 { |
| db.help( |
| "this function's return type contains a borrowed value with \ |
| an elided lifetime, but the lifetime cannot be derived from \ |
| the arguments", |
| ); |
| true |
| } else if elided_len == 1 { |
| db.help(&format!( |
| "this function's return type contains a borrowed value, \ |
| but the signature does not say which {} it is borrowed from", |
| m |
| )); |
| false |
| } else { |
| db.help(&format!( |
| "this function's return type contains a borrowed value, \ |
| but the signature does not say whether it is borrowed from {}", |
| m |
| )); |
| false |
| } |
| } |
| |
| crate fn report_elided_lifetime_in_ty(&self, lifetime_refs: &[&hir::Lifetime]) { |
| let Some(missing_lifetime) = lifetime_refs.iter().find(|lt| { |
| lt.name == hir::LifetimeName::Implicit(true) |
| }) else { return }; |
| |
| let mut spans: Vec<_> = lifetime_refs.iter().map(|lt| lt.span).collect(); |
| spans.sort(); |
| let mut spans_dedup = spans.clone(); |
| spans_dedup.dedup(); |
| let spans_with_counts: Vec<_> = spans_dedup |
| .into_iter() |
| .map(|sp| (sp, spans.iter().filter(|nsp| *nsp == &sp).count())) |
| .collect(); |
| |
| self.tcx.struct_span_lint_hir( |
| rustc_session::lint::builtin::ELIDED_LIFETIMES_IN_PATHS, |
| missing_lifetime.hir_id, |
| spans, |
| |lint| { |
| let mut db = lint.build("hidden lifetime parameters in types are deprecated"); |
| self.add_missing_lifetime_specifiers_label( |
| &mut db, |
| spans_with_counts, |
| &FxHashSet::from_iter([kw::UnderscoreLifetime]), |
| Vec::new(), |
| &[], |
| ); |
| db.emit(); |
| }, |
| ); |
| } |
| |
| // FIXME(const_generics): This patches over an ICE caused by non-'static lifetimes in const |
| // generics. We are disallowing this until we can decide on how we want to handle non-'static |
| // lifetimes in const generics. See issue #74052 for discussion. |
| crate fn emit_non_static_lt_in_const_generic_error(&self, lifetime_ref: &hir::Lifetime) { |
| let mut err = struct_span_err!( |
| self.tcx.sess, |
| lifetime_ref.span, |
| E0771, |
| "use of non-static lifetime `{}` in const generic", |
| lifetime_ref |
| ); |
| err.note( |
| "for more information, see issue #74052 \ |
| <https://github.com/rust-lang/rust/issues/74052>", |
| ); |
| err.emit(); |
| } |
| |
| crate fn is_trait_ref_fn_scope(&mut self, trait_ref: &'tcx hir::PolyTraitRef<'tcx>) -> bool { |
| if let def::Res::Def(_, did) = trait_ref.trait_ref.path.res { |
| if [ |
| self.tcx.lang_items().fn_once_trait(), |
| self.tcx.lang_items().fn_trait(), |
| self.tcx.lang_items().fn_mut_trait(), |
| ] |
| .contains(&Some(did)) |
| { |
| let (span, span_type) = match &trait_ref.bound_generic_params { |
| [] => (trait_ref.span.shrink_to_lo(), ForLifetimeSpanType::BoundEmpty), |
| [.., bound] => (bound.span.shrink_to_hi(), ForLifetimeSpanType::BoundTail), |
| }; |
| self.missing_named_lifetime_spots |
| .push(MissingLifetimeSpot::HigherRanked { span, span_type }); |
| return true; |
| } |
| }; |
| false |
| } |
| |
| crate fn add_missing_lifetime_specifiers_label( |
| &self, |
| err: &mut Diagnostic, |
| mut spans_with_counts: Vec<(Span, usize)>, |
| lifetime_names: &FxHashSet<Symbol>, |
| lifetime_spans: Vec<Span>, |
| params: &[ElisionFailureInfo], |
| ) { |
| let snippets: Vec<Option<String>> = spans_with_counts |
| .iter() |
| .map(|(span, _)| self.tcx.sess.source_map().span_to_snippet(*span).ok()) |
| .collect(); |
| |
| // Empty generics are marked with a span of "<", but since from now on |
| // that information is in the snippets it can be removed from the spans. |
| for ((span, _), snippet) in spans_with_counts.iter_mut().zip(&snippets) { |
| if snippet.as_deref() == Some("<") { |
| *span = span.shrink_to_hi(); |
| } |
| } |
| |
| for &(span, count) in &spans_with_counts { |
| err.span_label( |
| span, |
| format!( |
| "expected {} lifetime parameter{}", |
| if count == 1 { "named".to_string() } else { count.to_string() }, |
| pluralize!(count), |
| ), |
| ); |
| } |
| |
| let suggest_existing = |
| |err: &mut Diagnostic, |
| name: &str, |
| formatters: Vec<Option<Box<dyn Fn(&str) -> String>>>| { |
| if let Some(MissingLifetimeSpot::HigherRanked { span: for_span, span_type }) = |
| self.missing_named_lifetime_spots.iter().rev().next() |
| { |
| // When we have `struct S<'a>(&'a dyn Fn(&X) -> &X);` we want to not only suggest |
| // using `'a`, but also introduce the concept of HRLTs by suggesting |
| // `struct S<'a>(&'a dyn for<'b> Fn(&X) -> &'b X);`. (#72404) |
| let mut introduce_suggestion = vec![]; |
| |
| let a_to_z_repeat_n = |n| { |
| (b'a'..=b'z').map(move |c| { |
| let mut s = '\''.to_string(); |
| s.extend(std::iter::repeat(char::from(c)).take(n)); |
| s |
| }) |
| }; |
| |
| // If all single char lifetime names are present, we wrap around and double the chars. |
| let lt_name = (1..) |
| .flat_map(a_to_z_repeat_n) |
| .find(|lt| !lifetime_names.contains(&Symbol::intern(<))) |
| .unwrap(); |
| let msg = format!( |
| "consider making the {} lifetime-generic with a new `{}` lifetime", |
| span_type.descr(), |
| lt_name, |
| ); |
| err.note( |
| "for more information on higher-ranked polymorphism, visit \ |
| https://doc.rust-lang.org/nomicon/hrtb.html", |
| ); |
| let for_sugg = span_type.suggestion(<_name); |
| for param in params { |
| if let Ok(snippet) = self.tcx.sess.source_map().span_to_snippet(param.span) |
| { |
| if snippet.starts_with('&') && !snippet.starts_with("&'") { |
| introduce_suggestion |
| .push((param.span, format!("&{} {}", lt_name, &snippet[1..]))); |
| } else if let Some(stripped) = snippet.strip_prefix("&'_ ") { |
| introduce_suggestion |
| .push((param.span, format!("&{} {}", lt_name, stripped))); |
| } |
| } |
| } |
| introduce_suggestion.push((*for_span, for_sugg)); |
| for ((span, _), formatter) in spans_with_counts.iter().zip(formatters.iter()) { |
| if let Some(formatter) = formatter { |
| introduce_suggestion.push((*span, formatter(<_name))); |
| } |
| } |
| err.multipart_suggestion_verbose( |
| &msg, |
| introduce_suggestion, |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| |
| let spans_suggs: Vec<_> = formatters |
| .into_iter() |
| .zip(spans_with_counts.iter()) |
| .filter_map(|(formatter, (span, _))| { |
| if let Some(formatter) = formatter { |
| Some((*span, formatter(name))) |
| } else { |
| None |
| } |
| }) |
| .collect(); |
| if spans_suggs.is_empty() { |
| // If all the spans come from macros, we cannot extract snippets and then |
| // `formatters` only contains None and `spans_suggs` is empty. |
| return; |
| } |
| err.multipart_suggestion_verbose( |
| &format!( |
| "consider using the `{}` lifetime", |
| lifetime_names.iter().next().unwrap() |
| ), |
| spans_suggs, |
| Applicability::MaybeIncorrect, |
| ); |
| }; |
| let suggest_new = |err: &mut Diagnostic, suggs: Vec<Option<String>>| { |
| for missing in self.missing_named_lifetime_spots.iter().rev() { |
| let mut introduce_suggestion = vec![]; |
| let msg; |
| let should_break; |
| introduce_suggestion.push(match missing { |
| MissingLifetimeSpot::Generics(generics) => { |
| if generics.span == DUMMY_SP { |
| // Account for malformed generics in the HIR. This shouldn't happen, |
| // but if we make a mistake elsewhere, mainly by keeping something in |
| // `missing_named_lifetime_spots` that we shouldn't, like associated |
| // `const`s or making a mistake in the AST lowering we would provide |
| // non-sensical suggestions. Guard against that by skipping these. |
| // (#74264) |
| continue; |
| } |
| msg = "consider introducing a named lifetime parameter".to_string(); |
| should_break = true; |
| if let Some(param) = generics.params.iter().find(|p| { |
| !matches!( |
| p.kind, |
| hir::GenericParamKind::Type { synthetic: true, .. } |
| | hir::GenericParamKind::Lifetime { |
| kind: hir::LifetimeParamKind::Elided |
| } |
| ) |
| }) { |
| (param.span.shrink_to_lo(), "'a, ".to_string()) |
| } else { |
| (generics.span, "<'a>".to_string()) |
| } |
| } |
| MissingLifetimeSpot::HigherRanked { span, span_type } => { |
| msg = format!( |
| "consider making the {} lifetime-generic with a new `'a` lifetime", |
| span_type.descr(), |
| ); |
| should_break = false; |
| err.note( |
| "for more information on higher-ranked polymorphism, visit \ |
| https://doc.rust-lang.org/nomicon/hrtb.html", |
| ); |
| (*span, span_type.suggestion("'a")) |
| } |
| MissingLifetimeSpot::Static => { |
| let mut spans_suggs = Vec::new(); |
| for ((span, count), snippet) in |
| spans_with_counts.iter().copied().zip(snippets.iter()) |
| { |
| let (span, sugg) = match snippet.as_deref() { |
| Some("&") => (span.shrink_to_hi(), "'static ".to_owned()), |
| Some("'_") => (span, "'static".to_owned()), |
| Some(snippet) if !snippet.ends_with('>') => { |
| if snippet == "" { |
| ( |
| span, |
| std::iter::repeat("'static") |
| .take(count) |
| .collect::<Vec<_>>() |
| .join(", "), |
| ) |
| } else if snippet == "<" || snippet == "(" { |
| ( |
| span.shrink_to_hi(), |
| std::iter::repeat("'static") |
| .take(count) |
| .collect::<Vec<_>>() |
| .join(", "), |
| ) |
| } else { |
| ( |
| span.shrink_to_hi(), |
| format!( |
| "<{}>", |
| std::iter::repeat("'static") |
| .take(count) |
| .collect::<Vec<_>>() |
| .join(", "), |
| ), |
| ) |
| } |
| } |
| _ => continue, |
| }; |
| spans_suggs.push((span, sugg.to_string())); |
| } |
| err.multipart_suggestion_verbose( |
| "consider using the `'static` lifetime", |
| spans_suggs, |
| Applicability::MaybeIncorrect, |
| ); |
| continue; |
| } |
| }); |
| |
| struct Lifetime(Span, String); |
| impl Lifetime { |
| fn is_unnamed(&self) -> bool { |
| self.1.starts_with('&') && !self.1.starts_with("&'") |
| } |
| fn is_underscore(&self) -> bool { |
| self.1.starts_with("&'_ ") |
| } |
| fn is_named(&self) -> bool { |
| self.1.starts_with("&'") |
| } |
| fn suggestion(&self, sugg: String) -> Option<(Span, String)> { |
| Some( |
| match ( |
| self.is_unnamed(), |
| self.is_underscore(), |
| self.is_named(), |
| sugg.starts_with('&'), |
| ) { |
| (true, _, _, false) => (self.span_unnamed_borrow(), sugg), |
| (true, _, _, true) => { |
| (self.span_unnamed_borrow(), sugg[1..].to_string()) |
| } |
| (_, true, _, false) => { |
| (self.span_underscore_borrow(), sugg.trim().to_string()) |
| } |
| (_, true, _, true) => { |
| (self.span_underscore_borrow(), sugg[1..].trim().to_string()) |
| } |
| (_, _, true, false) => { |
| (self.span_named_borrow(), sugg.trim().to_string()) |
| } |
| (_, _, true, true) => { |
| (self.span_named_borrow(), sugg[1..].trim().to_string()) |
| } |
| _ => return None, |
| }, |
| ) |
| } |
| fn span_unnamed_borrow(&self) -> Span { |
| let lo = self.0.lo() + BytePos(1); |
| self.0.with_lo(lo).with_hi(lo) |
| } |
| fn span_named_borrow(&self) -> Span { |
| let lo = self.0.lo() + BytePos(1); |
| self.0.with_lo(lo) |
| } |
| fn span_underscore_borrow(&self) -> Span { |
| let lo = self.0.lo() + BytePos(1); |
| let hi = lo + BytePos(2); |
| self.0.with_lo(lo).with_hi(hi) |
| } |
| } |
| |
| for param in params { |
| if let Ok(snippet) = self.tcx.sess.source_map().span_to_snippet(param.span) { |
| if let Some((span, sugg)) = |
| Lifetime(param.span, snippet).suggestion("'a ".to_string()) |
| { |
| introduce_suggestion.push((span, sugg)); |
| } |
| } |
| } |
| for (span, sugg) in spans_with_counts.iter().copied().zip(suggs.iter()).filter_map( |
| |((span, _), sugg)| match &sugg { |
| Some(sugg) => Some((span, sugg.to_string())), |
| _ => None, |
| }, |
| ) { |
| let (span, sugg) = self |
| .tcx |
| .sess |
| .source_map() |
| .span_to_snippet(span) |
| .ok() |
| .and_then(|snippet| Lifetime(span, snippet).suggestion(sugg.clone())) |
| .unwrap_or((span, sugg)); |
| introduce_suggestion.push((span, sugg.to_string())); |
| } |
| err.multipart_suggestion_verbose( |
| &msg, |
| introduce_suggestion, |
| Applicability::MaybeIncorrect, |
| ); |
| if should_break { |
| break; |
| } |
| } |
| }; |
| |
| let lifetime_names: Vec<_> = lifetime_names.iter().collect(); |
| match &lifetime_names[..] { |
| [name] => { |
| let mut suggs: Vec<Option<Box<dyn Fn(&str) -> String>>> = Vec::new(); |
| for (snippet, (_, count)) in snippets.iter().zip(spans_with_counts.iter().copied()) |
| { |
| suggs.push(match snippet.as_deref() { |
| Some("&") => Some(Box::new(|name| format!("&{} ", name))), |
| Some("'_") => Some(Box::new(|n| n.to_string())), |
| Some("") => Some(Box::new(move |n| format!("{}, ", n).repeat(count))), |
| Some("<") => Some(Box::new(move |n| { |
| std::iter::repeat(n).take(count).collect::<Vec<_>>().join(", ") |
| })), |
| Some(snippet) if !snippet.ends_with('>') => Some(Box::new(move |name| { |
| format!( |
| "{}<{}>", |
| snippet, |
| std::iter::repeat(name.to_string()) |
| .take(count) |
| .collect::<Vec<_>>() |
| .join(", ") |
| ) |
| })), |
| _ => None, |
| }); |
| } |
| suggest_existing(err, name.as_str(), suggs); |
| } |
| [] => { |
| let mut suggs = Vec::new(); |
| for (snippet, (_, count)) in |
| snippets.iter().cloned().zip(spans_with_counts.iter().copied()) |
| { |
| suggs.push(match snippet.as_deref() { |
| Some("&") => Some("&'a ".to_string()), |
| Some("'_") => Some("'a".to_string()), |
| Some("") => { |
| Some(std::iter::repeat("'a, ").take(count).collect::<Vec<_>>().join("")) |
| } |
| Some("<") => { |
| Some(std::iter::repeat("'a").take(count).collect::<Vec<_>>().join(", ")) |
| } |
| Some(snippet) => Some(format!( |
| "{}<{}>", |
| snippet, |
| std::iter::repeat("'a").take(count).collect::<Vec<_>>().join(", "), |
| )), |
| None => None, |
| }); |
| } |
| suggest_new(err, suggs); |
| } |
| lts if lts.len() > 1 => { |
| err.span_note(lifetime_spans, "these named lifetimes are available to use"); |
| |
| let mut spans_suggs: Vec<_> = Vec::new(); |
| for ((span, _), snippet) in spans_with_counts.iter().copied().zip(snippets.iter()) { |
| match snippet.as_deref() { |
| Some("") => spans_suggs.push((span, "'lifetime, ".to_string())), |
| Some("&") => spans_suggs |
| .push((span.with_lo(span.lo() + BytePos(1)), "'lifetime ".to_string())), |
| _ => {} |
| } |
| } |
| |
| if spans_suggs.len() > 0 { |
| // This happens when we have `Foo<T>` where we point at the space before `T`, |
| // but this can be confusing so we give a suggestion with placeholders. |
| err.multipart_suggestion_verbose( |
| "consider using one of the available lifetimes here", |
| spans_suggs, |
| Applicability::HasPlaceholders, |
| ); |
| } |
| } |
| _ => unreachable!(), |
| } |
| } |
| |
| /// Non-static lifetimes are prohibited in anonymous constants under `min_const_generics`. |
| /// This function will emit an error if `generic_const_exprs` is not enabled, the body identified by |
| /// `body_id` is an anonymous constant and `lifetime_ref` is non-static. |
| crate fn maybe_emit_forbidden_non_static_lifetime_error( |
| &self, |
| body_id: hir::BodyId, |
| lifetime_ref: &'tcx hir::Lifetime, |
| ) { |
| let is_anon_const = matches!( |
| self.tcx.def_kind(self.tcx.hir().body_owner_def_id(body_id)), |
| hir::def::DefKind::AnonConst |
| ); |
| let is_allowed_lifetime = matches!( |
| lifetime_ref.name, |
| hir::LifetimeName::Implicit(_) |
| | hir::LifetimeName::Static |
| | hir::LifetimeName::Underscore |
| ); |
| |
| if !self.tcx.lazy_normalization() && is_anon_const && !is_allowed_lifetime { |
| feature_err( |
| &self.tcx.sess.parse_sess, |
| sym::generic_const_exprs, |
| lifetime_ref.span, |
| "a non-static lifetime is not allowed in a `const`", |
| ) |
| .emit(); |
| } |
| } |
| } |
