| use crate::diagnostics::{ImportSuggestion, LabelSuggestion, TypoSuggestion}; |
| use crate::late::{AliasPossibility, LateResolutionVisitor, RibKind}; |
| use crate::late::{LifetimeBinderKind, LifetimeRes, LifetimeRibKind, LifetimeUseSet}; |
| use crate::path_names_to_string; |
| use crate::{Module, ModuleKind, ModuleOrUniformRoot}; |
| use crate::{PathResult, PathSource, Segment}; |
| |
| use rustc_ast::visit::{FnCtxt, FnKind, LifetimeCtxt}; |
| use rustc_ast::{ |
| self as ast, AssocItemKind, Expr, ExprKind, GenericParam, GenericParamKind, Item, ItemKind, |
| MethodCall, NodeId, Path, Ty, TyKind, DUMMY_NODE_ID, |
| }; |
| 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, |
| MultiSpan, |
| }; |
| 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_ID, LOCAL_CRATE}; |
| use rustc_hir::PrimTy; |
| use rustc_middle::ty::DefIdTree; |
| use rustc_session::lint; |
| use rustc_session::parse::feature_err; |
| use rustc_session::Session; |
| use rustc_span::edit_distance::find_best_match_for_name; |
| use rustc_span::edition::Edition; |
| use rustc_span::hygiene::MacroKind; |
| use rustc_span::symbol::{kw, sym, Ident, Symbol}; |
| use rustc_span::{BytePos, Span}; |
| |
| use std::iter; |
| use std::ops::Deref; |
| |
| use thin_vec::ThinVec; |
| |
| type Res = def::Res<ast::NodeId>; |
| |
| /// A field or associated item from self type suggested in case of resolution failure. |
| enum AssocSuggestion { |
| Field, |
| MethodWithSelf { called: bool }, |
| AssocFn { called: bool }, |
| AssocType, |
| AssocConst, |
| } |
| |
| impl AssocSuggestion { |
| fn action(&self) -> &'static str { |
| match self { |
| AssocSuggestion::Field => "use the available field", |
| AssocSuggestion::MethodWithSelf { called: true } => { |
| "call the method with the fully-qualified path" |
| } |
| AssocSuggestion::MethodWithSelf { called: false } => { |
| "refer to the method with the fully-qualified path" |
| } |
| AssocSuggestion::AssocFn { called: true } => "call the associated function", |
| AssocSuggestion::AssocFn { called: false } => "refer to the associated function", |
| AssocSuggestion::AssocConst => "use the associated `const`", |
| AssocSuggestion::AssocType => "use the associated type", |
| } |
| } |
| } |
| |
| 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].iter().cloned().collect(), |
| tokens: None, |
| }; |
| let enum_path_string = path_names_to_string(&enum_path); |
| |
| (variant_path_string, enum_path_string) |
| } |
| |
| /// Description of an elided lifetime. |
| #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug)] |
| pub(super) struct MissingLifetime { |
| /// Used to overwrite the resolution with the suggestion, to avoid cascasing errors. |
| pub id: NodeId, |
| /// Where to suggest adding the lifetime. |
| pub span: Span, |
| /// How the lifetime was introduced, to have the correct space and comma. |
| pub kind: MissingLifetimeKind, |
| /// Number of elided lifetimes, used for elision in path. |
| pub count: usize, |
| } |
| |
| #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug)] |
| pub(super) enum MissingLifetimeKind { |
| /// An explicit `'_`. |
| Underscore, |
| /// An elided lifetime `&' ty`. |
| Ampersand, |
| /// An elided lifetime in brackets with written brackets. |
| Comma, |
| /// An elided lifetime with elided brackets. |
| Brackets, |
| } |
| |
| /// Description of the lifetimes appearing in a function parameter. |
| /// This is used to provide a literal explanation to the elision failure. |
| #[derive(Clone, Debug)] |
| pub(super) struct ElisionFnParameter { |
| /// The index of the argument in the original definition. |
| pub index: usize, |
| /// The name of the argument if it's a simple ident. |
| pub ident: Option<Ident>, |
| /// The number of lifetimes in the parameter. |
| pub lifetime_count: usize, |
| /// The span of the parameter. |
| pub span: Span, |
| } |
| |
| /// Description of lifetimes that appear as candidates for elision. |
| /// This is used to suggest introducing an explicit lifetime. |
| #[derive(Debug)] |
| pub(super) enum LifetimeElisionCandidate { |
| /// This is not a real lifetime. |
| Ignore, |
| /// There is a named lifetime, we won't suggest anything. |
| Named, |
| Missing(MissingLifetime), |
| } |
| |
| /// Only used for diagnostics. |
| #[derive(Debug)] |
| struct BaseError { |
| msg: String, |
| fallback_label: String, |
| span: Span, |
| span_label: Option<(Span, &'static str)>, |
| could_be_expr: bool, |
| suggestion: Option<(Span, &'static str, String)>, |
| } |
| |
| #[derive(Debug)] |
| enum TypoCandidate { |
| Typo(TypoSuggestion), |
| Shadowed(Res, Option<Span>), |
| None, |
| } |
| |
| impl TypoCandidate { |
| fn to_opt_suggestion(self) -> Option<TypoSuggestion> { |
| match self { |
| TypoCandidate::Typo(sugg) => Some(sugg), |
| TypoCandidate::Shadowed(_, _) | TypoCandidate::None => None, |
| } |
| } |
| } |
| |
| impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> { |
| fn def_span(&self, def_id: DefId) -> Option<Span> { |
| match def_id.krate { |
| LOCAL_CRATE => self.r.opt_span(def_id), |
| _ => Some(self.r.cstore().get_span_untracked(def_id, self.r.tcx.sess)), |
| } |
| } |
| |
| fn make_base_error( |
| &mut self, |
| path: &[Segment], |
| span: Span, |
| source: PathSource<'_>, |
| res: Option<Res>, |
| ) -> BaseError { |
| // 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; |
| if let Some(res) = res { |
| BaseError { |
| msg: format!("expected {}, found {} `{}`", expected, res.descr(), path_str), |
| fallback_label: format!("not a {expected}"), |
| span, |
| span_label: match res { |
| Res::Def(kind, def_id) if kind == DefKind::TyParam => { |
| self.def_span(def_id).map(|span| (span, "found this type parameter")) |
| } |
| _ => None, |
| }, |
| could_be_expr: match res { |
| Res::Def(DefKind::Fn, _) => { |
| // Verify whether this is a fn call or an Fn used as a type. |
| self.r |
| .tcx |
| .sess |
| .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, |
| }, |
| suggestion: None, |
| } |
| } else { |
| let item_span = path.last().unwrap().ident.span; |
| let (mod_prefix, mod_str, suggestion) = if path.len() == 1 { |
| debug!(?self.diagnostic_metadata.current_impl_items); |
| debug!(?self.diagnostic_metadata.current_function); |
| let suggestion = if self.current_trait_ref.is_none() |
| && let Some((fn_kind, _)) = self.diagnostic_metadata.current_function |
| && let Some(FnCtxt::Assoc(_)) = fn_kind.ctxt() |
| && let Some(items) = self.diagnostic_metadata.current_impl_items |
| && let Some(item) = items.iter().find(|i| { |
| if let AssocItemKind::Fn(..) | AssocItemKind::Const(..) = &i.kind |
| && i.ident.name == item_str.name |
| { |
| debug!(?item_str.name); |
| return true |
| } |
| false |
| }) |
| { |
| let self_sugg = match &item.kind { |
| AssocItemKind::Fn(fn_) if fn_.sig.decl.has_self() => "self.", |
| _ => "Self::", |
| }; |
| |
| Some(( |
| item_span.shrink_to_lo(), |
| match &item.kind { |
| AssocItemKind::Fn(..) => "consider using the associated function", |
| AssocItemKind::Const(..) => "consider using the associated constant", |
| _ => unreachable!("item kind was filtered above"), |
| }, |
| self_sugg.to_string() |
| )) |
| } else { |
| None |
| }; |
| (String::new(), "this scope".to_string(), suggestion) |
| } else if path.len() == 2 && path[0].ident.name == kw::PathRoot { |
| if self.r.tcx.sess.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(), None) |
| } else { |
| (String::new(), "the crate root".to_string(), None) |
| } |
| } else if path.len() == 2 && path[0].ident.name == kw::Crate { |
| (String::new(), "the crate root".to_string(), None) |
| } else { |
| let mod_path = &path[..path.len() - 1]; |
| let mod_prefix = match self.resolve_path(mod_path, Some(TypeNS), None) { |
| 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)), None) |
| }; |
| |
| let (fallback_label, suggestion) = if path_str == "async" |
| && expected.starts_with("struct") |
| { |
| ("`async` blocks are only allowed in Rust 2018 or later".to_string(), suggestion) |
| } else { |
| // check if we are in situation of typo like `True` instead of `true`. |
| let override_suggestion = |
| if ["true", "false"].contains(&item_str.to_string().to_lowercase().as_str()) { |
| let item_typo = item_str.to_string().to_lowercase(); |
| Some((item_span, "you may want to use a bool value instead", item_typo)) |
| // FIXME(vincenzopalazzo): make the check smarter, |
| // and maybe expand with levenshtein distance checks |
| } else if item_str.as_str() == "printf" { |
| Some(( |
| item_span, |
| "you may have meant to use the `print` macro", |
| "print!".to_owned(), |
| )) |
| } else { |
| suggestion |
| }; |
| (format!("not found in {mod_str}"), override_suggestion) |
| }; |
| |
| BaseError { |
| msg: format!("cannot find {expected} `{item_str}` in {mod_prefix}{mod_str}"), |
| fallback_label, |
| span: item_span, |
| span_label: None, |
| could_be_expr: false, |
| suggestion, |
| } |
| } |
| } |
| |
| /// 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<'tcx, ErrorGuaranteed>, Vec<ImportSuggestion>) { |
| debug!(?res, ?source); |
| let base_error = self.make_base_error(path, span, source, res); |
| let code = source.error_code(res.is_some()); |
| let mut err = |
| self.r.tcx.sess.struct_span_err_with_code(base_error.span, &base_error.msg, code); |
| |
| self.suggest_swapping_misplaced_self_ty_and_trait(&mut err, source, res, base_error.span); |
| |
| if let Some((span, label)) = base_error.span_label { |
| err.span_label(span, label); |
| } |
| |
| if let Some(ref sugg) = base_error.suggestion { |
| err.span_suggestion_verbose(sugg.0, sugg.1, &sugg.2, Applicability::MaybeIncorrect); |
| } |
| |
| self.suggest_bare_struct_literal(&mut err); |
| |
| if self.suggest_pattern_match_with_let(&mut err, source, span) { |
| // Fallback label. |
| err.span_label(base_error.span, &base_error.fallback_label); |
| return (err, Vec::new()); |
| } |
| |
| self.suggest_self_or_self_ref(&mut err, path, span); |
| self.detect_assoct_type_constraint_meant_as_path(&mut err, &base_error); |
| if self.suggest_self_ty(&mut err, source, path, span) |
| || self.suggest_self_value(&mut err, source, path, span) |
| { |
| return (err, Vec::new()); |
| } |
| |
| let (found, candidates) = |
| self.try_lookup_name_relaxed(&mut err, source, path, span, res, &base_error); |
| if found { |
| return (err, candidates); |
| } |
| |
| if !self.type_ascription_suggestion(&mut err, base_error.span) { |
| let mut fallback = |
| self.suggest_trait_and_bounds(&mut err, source, res, span, &base_error); |
| |
| // if we have suggested using pattern matching, then don't add needless suggestions |
| // for typos. |
| fallback |= self.suggest_typo(&mut err, source, path, span, &base_error); |
| |
| if fallback { |
| // Fallback label. |
| err.span_label(base_error.span, &base_error.fallback_label); |
| } |
| } |
| self.err_code_special_cases(&mut err, source, path, span); |
| |
| (err, candidates) |
| } |
| |
| fn detect_assoct_type_constraint_meant_as_path( |
| &self, |
| err: &mut Diagnostic, |
| base_error: &BaseError, |
| ) { |
| 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_error.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", |
| "::", |
| Applicability::MachineApplicable, |
| ); |
| } |
| } |
| } |
| } |
| } |
| |
| fn suggest_self_or_self_ref(&mut self, err: &mut Diagnostic, path: &[Segment], span: Span) { |
| if !self.self_type_is_available() { |
| return; |
| } |
| let Some(path_last_segment) = path.last() else { return }; |
| let item_str = path_last_segment.ident; |
| // Emit help message for fake-self from other languages (e.g., `this` in Javascript). |
| if ["this", "my"].contains(&item_str.as_str()) { |
| err.span_suggestion_short( |
| span, |
| "you might have meant to use `self` here instead", |
| "self", |
| 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 |
| .tcx |
| .sess |
| .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, |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| } |
| } |
| } |
| |
| fn try_lookup_name_relaxed( |
| &mut self, |
| err: &mut Diagnostic, |
| source: PathSource<'_>, |
| path: &[Segment], |
| span: Span, |
| res: Option<Res>, |
| base_error: &BaseError, |
| ) -> (bool, Vec<ImportSuggestion>) { |
| // Try to lookup name in more relaxed fashion for better error reporting. |
| let ident = path.last().unwrap().ident; |
| let is_expected = &|res| source.is_expected(res); |
| let ns = source.namespace(); |
| let is_enum_variant = &|res| matches!(res, Res::Def(DefKind::Variant, _)); |
| let path_str = Segment::names_to_string(path); |
| let ident_span = path.last().map_or(span, |ident| ident.ident.span); |
| let mut 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 = CRATE_DEF_ID.to_def_id(); |
| // Try to filter out intrinsics candidates, as long as we have |
| // some other candidates to suggest. |
| let intrinsic_candidates: Vec<_> = candidates |
| .drain_filter(|sugg| { |
| let path = path_names_to_string(&sugg.path); |
| path.starts_with("core::intrinsics::") || path.starts_with("std::intrinsics::") |
| }) |
| .collect(); |
| if candidates.is_empty() { |
| // Put them back if we have no more candidates to suggest... |
| candidates.extend(intrinsic_candidates); |
| } |
| 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 |
| .tcx |
| .sess |
| .parse_sess |
| .type_ascription_path_suggestions |
| .borrow() |
| .contains(span) |
| { |
| // Already reported this issue on the lhs of the type ascription. |
| err.downgrade_to_delayed_bug(); |
| return (true, 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, |
| ); |
| } |
| } |
| |
| // Try finding a suitable replacement. |
| let typo_sugg = |
| self.lookup_typo_candidate(path, source.namespace(), is_expected).to_opt_suggestion(); |
| if path.len() == 1 && self.self_type_is_available() { |
| if let Some(candidate) = |
| self.lookup_assoc_candidate(ident, ns, is_expected, source.is_call()) |
| { |
| 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 { called } if self_is_available => { |
| let msg = if called { |
| "you might have meant to call the method" |
| } else { |
| "you might have meant to refer to the method" |
| }; |
| err.span_suggestion( |
| span, |
| msg, |
| 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, |
| ); |
| } |
| } |
| self.r.add_typo_suggestion(err, typo_sugg, ident_span); |
| return (true, 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.tcx.sess.source_map().span_to_snippet(args_span) { |
| args_snippet = snippet; |
| } |
| } |
| |
| err.span_suggestion( |
| call_span, |
| &format!("try calling `{ident}` as a method"), |
| format!("self.{path_str}({args_snippet})"), |
| Applicability::MachineApplicable, |
| ); |
| return (true, candidates); |
| } |
| } |
| |
| // Try context-dependent help if relaxed lookup didn't work. |
| if let Some(res) = res { |
| if self.smart_resolve_context_dependent_help( |
| err, |
| span, |
| source, |
| res, |
| &path_str, |
| &base_error.fallback_label, |
| ) { |
| // We do this to avoid losing a secondary span when we override the main error span. |
| self.r.add_typo_suggestion(err, typo_sugg, ident_span); |
| return (true, candidates); |
| } |
| } |
| |
| // Try to find in last block rib |
| if let Some(rib) = &self.last_block_rib && let RibKind::NormalRibKind = rib.kind { |
| for (ident, &res) in &rib.bindings { |
| if let Res::Local(_) = res && path.len() == 1 && |
| ident.span.eq_ctxt(path[0].ident.span) && |
| ident.name == path[0].ident.name { |
| err.span_help( |
| ident.span, |
| &format!("the binding `{}` is available in a different scope in the same function", path_str), |
| ); |
| return (true, candidates); |
| } |
| } |
| } |
| |
| return (false, candidates); |
| } |
| |
| fn suggest_trait_and_bounds( |
| &mut self, |
| err: &mut Diagnostic, |
| source: PathSource<'_>, |
| res: Option<Res>, |
| span: Span, |
| base_error: &BaseError, |
| ) -> bool { |
| let is_macro = |
| base_error.span.from_expansion() && base_error.span.desugaring_kind().is_none(); |
| 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_error.span) |
| .collect(); |
| |
| let start_span = bounds[0].span(); |
| // `end_span` is the end of the poly trait ref (Foo + 'baz + Bar><) |
| let end_span = bounds.last().unwrap().span(); |
| // `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_error.span, "expected this type to be a trait..."); |
| 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_error.span, |
| }) { |
| let mut sugg = vec![]; |
| if base_error.span != start_span { |
| sugg.push((start_span.until(base_error.span), String::new())); |
| } |
| if base_error.span != end_span { |
| sugg.push((base_error.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, err); |
| fallback |
| } |
| |
| fn suggest_typo( |
| &mut self, |
| err: &mut Diagnostic, |
| source: PathSource<'_>, |
| path: &[Segment], |
| span: Span, |
| base_error: &BaseError, |
| ) -> bool { |
| let is_expected = &|res| source.is_expected(res); |
| let ident_span = path.last().map_or(span, |ident| ident.ident.span); |
| let typo_sugg = self.lookup_typo_candidate(path, source.namespace(), is_expected); |
| let is_in_same_file = &|sp1, sp2| { |
| let source_map = self.r.tcx.sess.source_map(); |
| let file1 = source_map.span_to_filename(sp1); |
| let file2 = source_map.span_to_filename(sp2); |
| file1 == file2 |
| }; |
| // print 'you might have meant' if the candidate is (1) is a shadowed name with |
| // accessible definition and (2) either defined in the same crate as the typo |
| // (could be in a different file) or introduced in the same file as the typo |
| // (could belong to a different crate) |
| if let TypoCandidate::Shadowed(res, Some(sugg_span)) = typo_sugg |
| && res |
| .opt_def_id() |
| .map_or(false, |id| id.is_local() || is_in_same_file(span, sugg_span)) |
| { |
| err.span_label( |
| sugg_span, |
| format!("you might have meant to refer to this {}", res.descr()), |
| ); |
| return true; |
| } |
| let mut fallback = false; |
| let typo_sugg = typo_sugg.to_opt_suggestion(); |
| if !self.r.add_typo_suggestion(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_error.span) && base_error.could_be_expr => |
| { |
| err.span_suggestion_short( |
| pat_sp.between(ty_sp), |
| "use `=` if you meant to assign", |
| " = ", |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| _ => {} |
| } |
| |
| // If the trait has a single item (which wasn't matched by the algorithm), suggest it |
| let suggestion = self.get_single_associated_item(&path, &source, is_expected); |
| if !self.r.add_typo_suggestion(err, suggestion, ident_span) { |
| fallback = !self.let_binding_suggestion(err, ident_span); |
| } |
| } |
| fallback |
| } |
| |
| fn err_code_special_cases( |
| &mut self, |
| err: &mut Diagnostic, |
| source: PathSource<'_>, |
| path: &[Segment], |
| span: Span, |
| ) { |
| 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 { |
| let ident = path.last().unwrap().ident; |
| 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, |
| 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, |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| } |
| } |
| } |
| |
| /// Emit special messages for unresolved `Self` and `self`. |
| fn suggest_self_ty( |
| &mut self, |
| err: &mut Diagnostic, |
| source: PathSource<'_>, |
| path: &[Segment], |
| span: Span, |
| ) -> bool { |
| if !is_self_type(path, source.namespace()) { |
| return false; |
| } |
| err.code(rustc_errors::error_code!(E0411)); |
| err.span_label(span, "`Self` is only available in impls, traits, and type definitions"); |
| if let Some(item_kind) = self.diagnostic_metadata.current_item { |
| if !item_kind.ident.span.is_dummy() { |
| err.span_label( |
| item_kind.ident.span, |
| format!( |
| "`Self` not allowed in {} {}", |
| item_kind.kind.article(), |
| item_kind.kind.descr() |
| ), |
| ); |
| } |
| } |
| true |
| } |
| |
| fn suggest_self_value( |
| &mut self, |
| err: &mut Diagnostic, |
| source: PathSource<'_>, |
| path: &[Segment], |
| span: Span, |
| ) -> bool { |
| if !is_self_value(path, source.namespace()) { |
| return false; |
| } |
| |
| 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" |
| } |
| _ => "`self` value is a keyword only available in methods with a `self` parameter", |
| }, |
| ); |
| let is_assoc_fn = self.self_type_is_available(); |
| 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 |
| .tcx |
| .sess |
| .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, |
| 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), |
| ); |
| } |
| } |
| } else if let Some(item_kind) = self.diagnostic_metadata.current_item { |
| err.span_label( |
| item_kind.ident.span, |
| format!( |
| "`self` not allowed in {} {}", |
| item_kind.kind.article(), |
| item_kind.kind.descr() |
| ), |
| ); |
| } |
| true |
| } |
| |
| fn suggest_swapping_misplaced_self_ty_and_trait( |
| &mut self, |
| err: &mut Diagnostic, |
| source: PathSource<'_>, |
| res: Option<Res>, |
| span: Span, |
| ) { |
| if let Some((trait_ref, self_ty)) = |
| self.diagnostic_metadata.currently_processing_impl_trait.clone() |
| && let TyKind::Path(_, self_ty_path) = &self_ty.kind |
| && let PathResult::Module(ModuleOrUniformRoot::Module(module)) = |
| self.resolve_path(&Segment::from_path(self_ty_path), Some(TypeNS), None) |
| && let ModuleKind::Def(DefKind::Trait, ..) = module.kind |
| && trait_ref.path.span == span |
| && let PathSource::Trait(_) = source |
| && let Some(Res::Def(DefKind::Struct | DefKind::Enum | DefKind::Union, _)) = res |
| && let Ok(self_ty_str) = |
| self.r.tcx.sess.source_map().span_to_snippet(self_ty.span) |
| && let Ok(trait_ref_str) = |
| self.r.tcx.sess.source_map().span_to_snippet(trait_ref.path.span) |
| { |
| err.multipart_suggestion( |
| "`impl` items mention the trait being implemented first and the type it is being implemented for second", |
| vec![(trait_ref.path.span, self_ty_str), (self_ty.span, trait_ref_str)], |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| } |
| |
| fn suggest_bare_struct_literal(&mut self, err: &mut Diagnostic) { |
| 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, |
| ); |
| } |
| } |
| |
| fn suggest_pattern_match_with_let( |
| &mut self, |
| err: &mut Diagnostic, |
| source: PathSource<'_>, |
| span: Span, |
| ) -> bool { |
| if let PathSource::Expr(_) = source && |
| let Some(Expr { |
| span: expr_span, |
| kind: ExprKind::Assign(lhs, _, _), |
| .. |
| }) = self.diagnostic_metadata.in_if_condition { |
| // Icky heuristic so we don't suggest: |
| // `if (i + 2) = 2` => `if let (i + 2) = 2` (approximately pattern) |
| // `if 2 = i` => `if let 2 = i` (lhs needs to contain error span) |
| if lhs.is_approximately_pattern() && lhs.span.contains(span) { |
| err.span_suggestion_verbose( |
| expr_span.shrink_to_lo(), |
| "you might have meant to use pattern matching", |
| "let ", |
| Applicability::MaybeIncorrect, |
| ); |
| return true; |
| } |
| } |
| false |
| } |
| |
| 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, None) |
| { |
| 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_ident(target.0.ident, 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(qself), 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.full_res(), |
| Some(hir::def::Res::Def(hir::def::DefKind::AssocTy, _)) |
| ) { |
| return false; |
| } |
| (&qself.ty, qself.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.full_res(), |
| Some(hir::def::Res::Def(hir::def::DefKind::TyParam, _)) |
| ) { |
| 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 |
| .tcx |
| .sess |
| .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.tcx.sess.source_map(); |
| let sp = sm.span_look_ahead(span, None, Some(50)); |
| 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 closing_span = sm.span_look_ahead(span, Some("}"), Some(50)); |
| let closing_brace: Option<Span> = sm |
| .span_to_snippet(closing_span) |
| .map_or(None, |s| if s == "}" { Some(span.to(closing_span)) } else { None }); |
| (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, kind: DefKind| { |
| const MESSAGE: &str = "use the path separator to refer to an item"; |
| |
| let (lhs_span, rhs_span) = match &expr.kind { |
| ExprKind::Field(base, ident) => (base.span, ident.span), |
| ExprKind::MethodCall(box MethodCall { receiver, span, .. }) => { |
| (receiver.span, *span) |
| } |
| _ => return false, |
| }; |
| |
| if lhs_span.eq_ctxt(rhs_span) { |
| err.span_suggestion( |
| lhs_span.between(rhs_span), |
| MESSAGE, |
| "::", |
| Applicability::MaybeIncorrect, |
| ); |
| true |
| } else if kind == DefKind::Struct |
| && let Some(lhs_source_span) = lhs_span.find_ancestor_inside(expr.span) |
| && let Ok(snippet) = self.r.tcx.sess.source_map().span_to_snippet(lhs_source_span) |
| { |
| // The LHS is a type that originates from a macro call. |
| // We have to add angle brackets around it. |
| |
| err.span_suggestion_verbose( |
| lhs_source_span.until(rhs_span), |
| MESSAGE, |
| format!("<{snippet}>::"), |
| Applicability::MaybeIncorrect, |
| ); |
| true |
| } else { |
| // Either we were unable to obtain the source span / the snippet or |
| // the LHS originates from a macro call and it is not a type and thus |
| // there is no way to replace `.` with `::` and still somehow suggest |
| // valid Rust code. |
| |
| 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, DefKind::Struct) => {} |
| 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", |
| "!", |
| Applicability::MaybeIncorrect, |
| ); |
| if path_str == "try" && span.is_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.tcx.sess.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.tcx.sess.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(kind @ (DefKind::Mod | DefKind::Trait), _), |
| PathSource::Expr(Some(parent)), |
| ) => { |
| if !path_sep(err, &parent, kind) { |
| return false; |
| } |
| } |
| ( |
| Res::Def(DefKind::Enum, def_id), |
| PathSource::TupleStruct(..) | PathSource::Expr(..), |
| ) => { |
| if self |
| .diagnostic_metadata |
| .current_type_ascription |
| .last() |
| .map(|sp| { |
| self.r |
| .tcx |
| .sess |
| .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 { |
| if let Some(fields) = self.r.field_visibility_spans.get(&def_id) { |
| err.multipart_suggestion_verbose( |
| &format!( |
| "consider making the field{} publicly accessible", |
| pluralize!(fields.len()) |
| ), |
| fields.iter().map(|span| (*span, "pub ".to_string())).collect(), |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| |
| let mut m: MultiSpan = non_visible_spans.clone().into(); |
| non_visible_spans |
| .into_iter() |
| .for_each(|s| m.push_span_label(s, "private field")); |
| 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"); |
| } |
| (Res::Def(DefKind::Union | DefKind::Variant, 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, |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| _ => return false, |
| } |
| } |
| (Res::Def(DefKind::Ctor(_, CtorKind::Fn), ctor_def_id), _) if ns == ValueNS => { |
| let def_id = self.r.parent(ctor_def_id); |
| 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::SelfTyParam { .. } | Res::SelfTyAlias { .. }, _) 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`. |
| pub(crate) fn find_similarly_named_assoc_item( |
| &mut self, |
| ident: Symbol, |
| kind: &AssocItemKind, |
| ) -> Option<Symbol> { |
| let (module, _) = self.current_trait_ref.as_ref()?; |
| 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::Type(..), 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, |
| called: bool, |
| ) -> 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::Ref(_, 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) { |
| if let Some(Res::Def(DefKind::Struct | DefKind::Union, did)) = |
| resolution.full_res() |
| { |
| 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 { called } |
| } |
| ast::AssocItemKind::Fn(..) => AssocSuggestion::AssocFn { called }, |
| ast::AssocItemKind::Type(..) => 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.maybe_resolve_ident_in_module( |
| ModuleOrUniformRoot::Module(module), |
| ident, |
| ns, |
| &self.parent_scope, |
| ) { |
| let res = binding.res(); |
| if filter_fn(res) { |
| if self.r.has_self.contains(&res.def_id()) { |
| return Some(AssocSuggestion::MethodWithSelf { called }); |
| } else { |
| match res { |
| Res::Def(DefKind::AssocFn, _) => { |
| return Some(AssocSuggestion::AssocFn { called }); |
| } |
| 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, |
| ) -> TypoCandidate { |
| let mut names = Vec::new(); |
| if path.len() == 1 { |
| let mut ctxt = path.last().unwrap().ident.span.ctxt(); |
| |
| // Search in lexical scope. |
| // Walk backwards up the ribs in scope and collect candidates. |
| for rib in self.ribs[ns].iter().rev() { |
| let rib_ctxt = if rib.kind.contains_params() { |
| ctxt.normalize_to_macros_2_0() |
| } else { |
| ctxt.normalize_to_macro_rules() |
| }; |
| |
| // Locals and type parameters |
| for (ident, &res) in &rib.bindings { |
| if filter_fn(res) && ident.span.ctxt() == rib_ctxt { |
| names.push(TypoSuggestion::typo_from_ident(*ident, res)); |
| } |
| } |
| |
| if let RibKind::MacroDefinition(def) = rib.kind && def == self.r.macro_def(ctxt) { |
| // If an invocation of this macro created `ident`, give up on `ident` |
| // and switch to `ident`'s source from the macro definition. |
| ctxt.remove_mark(); |
| continue; |
| } |
| |
| // Items in scope |
| if let RibKind::ModuleRibKind(module) = rib.kind { |
| // Items from this module |
| self.r.add_module_candidates(module, &mut names, &filter_fn, Some(ctxt)); |
| |
| 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(|c| c.maybe_process_path_extern(ident.name)) |
| .and_then(|crate_id| { |
| let crate_mod = |
| Res::Def(DefKind::Mod, crate_id.as_def_id()); |
| |
| filter_fn(crate_mod).then(|| { |
| TypoSuggestion::typo_from_ident(*ident, crate_mod) |
| }) |
| }) |
| })); |
| |
| if let Some(prelude) = self.r.prelude { |
| self.r.add_module_candidates(prelude, &mut names, &filter_fn, None); |
| } |
| } |
| 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_name(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), None) |
| { |
| self.r.add_module_candidates(module, &mut names, &filter_fn, None); |
| } |
| } |
| |
| 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) => { |
| let Some(sugg) = names.into_iter().find(|suggestion| suggestion.candidate == found) else { |
| return TypoCandidate::None; |
| }; |
| if found == name { |
| TypoCandidate::Shadowed(sugg.res, sugg.span) |
| } else { |
| TypoCandidate::Typo(sugg) |
| } |
| } |
| _ => TypoCandidate::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, |
| "Bool" => sym::bool, |
| "Boolean" => sym::bool, |
| "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.tcx.sess.source_map(); |
| start.to(sm.next_point(start)) |
| } |
| |
| fn type_ascription_suggestion(&self, err: &mut Diagnostic, base_span: Span) -> bool { |
| let sm = self.r.tcx.sess.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", |
| ";", |
| 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", |
| "::", |
| Applicability::MaybeIncorrect, |
| ); |
| show_label = false; |
| if !self |
| .r |
| .tcx |
| .sess |
| .parse_sess |
| .type_ascription_path_suggestions |
| .borrow_mut() |
| .insert(colon_sp) |
| { |
| err.downgrade_to_delayed_bug(); |
| } |
| } |
| if let Ok(base_snippet) = base_snippet { |
| // Try to find an assignment |
| let eq_span = sm.span_look_ahead(after_colon_sp, Some("="), Some(50)); |
| if let Ok(ref snippet) = sm.span_to_snippet(eq_span) && snippet == "=" { |
| err.span_suggestion( |
| base_span, |
| "maybe you meant to write an assignment here", |
| format!("let {}", base_snippet), |
| Applicability::MaybeIncorrect, |
| ); |
| show_label = false; |
| } |
| } |
| } |
| if show_label { |
| err.span_label( |
| base_span, |
| "expecting a type here because of type ascription", |
| ); |
| } |
| return show_label; |
| } |
| } |
| } |
| false |
| } |
| |
| // try to give a suggestion for this pattern: `name = blah`, which is common in other languages |
| // suggest `let name = blah` to introduce a new binding |
| fn let_binding_suggestion(&mut self, err: &mut Diagnostic, ident_span: Span) -> bool { |
| if let Some(Expr { kind: ExprKind::Assign(lhs, .. ), .. }) = self.diagnostic_metadata.in_assignment && |
| let ast::ExprKind::Path(None, _) = lhs.kind { |
| if !ident_span.from_expansion() { |
| err.span_suggestion_verbose( |
| ident_span.shrink_to_lo(), |
| "you might have meant to introduce a new binding", |
| "let ".to_string(), |
| Applicability::MaybeIncorrect, |
| ); |
| return true; |
| } |
| } |
| 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, ThinVec::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, |
| 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 = |ctor_def_id: DefId, kind: CtorKind| { |
| let def_id = self.r.parent(ctor_def_id); |
| 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 if has_no_fields => false, |
| _ => true, |
| } |
| }; |
| |
| let 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), |
| }) |
| .collect::<Vec<_>>(); |
| let no_suggestable_variant = suggestable_variants.is_empty(); |
| |
| if !no_suggestable_variant { |
| 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, |
| 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)), |
| _ => None, |
| }) |
| .collect::<Vec<_>>(); |
| |
| if !suggestable_variants_with_placeholders.is_empty() { |
| let msg = |
| match (no_suggestable_variant, 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, |
| 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"); |
| } |
| } |
| } |
| |
| pub(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.name != kw::SelfUpper |
| && segment.ident.name != kw::Dyn => |
| { |
| (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. |
| pub(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.eq_ctxt(label.span)) |
| .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) |
| }) |
| } |
| |
| pub(crate) fn maybe_report_lifetime_uses( |
| &mut self, |
| generics_span: Span, |
| params: &[ast::GenericParam], |
| ) { |
| for (param_index, param) in params.iter().enumerate() { |
| let GenericParamKind::Lifetime = param.kind else { continue }; |
| |
| let def_id = self.r.local_def_id(param.id); |
| |
| let use_set = self.lifetime_uses.remove(&def_id); |
| debug!( |
| "Use set for {:?}({:?} at {:?}) is {:?}", |
| def_id, param.ident, param.ident.span, use_set |
| ); |
| |
| let deletion_span = || { |
| if params.len() == 1 { |
| // if sole lifetime, remove the entire `<>` brackets |
| Some(generics_span) |
| } else if param_index == 0 { |
| // if removing within `<>` brackets, we also want to |
| // delete a leading or trailing comma as appropriate |
| match ( |
| param.span().find_ancestor_inside(generics_span), |
| params[param_index + 1].span().find_ancestor_inside(generics_span), |
| ) { |
| (Some(param_span), Some(next_param_span)) => { |
| Some(param_span.to(next_param_span.shrink_to_lo())) |
| } |
| _ => None, |
| } |
| } else { |
| // if removing within `<>` brackets, we also want to |
| // delete a leading or trailing comma as appropriate |
| match ( |
| param.span().find_ancestor_inside(generics_span), |
| params[param_index - 1].span().find_ancestor_inside(generics_span), |
| ) { |
| (Some(param_span), Some(prev_param_span)) => { |
| Some(prev_param_span.shrink_to_hi().to(param_span)) |
| } |
| _ => None, |
| } |
| } |
| }; |
| match use_set { |
| Some(LifetimeUseSet::Many) => {} |
| Some(LifetimeUseSet::One { use_span, use_ctxt }) => { |
| debug!(?param.ident, ?param.ident.span, ?use_span); |
| |
| let elidable = matches!(use_ctxt, LifetimeCtxt::Ref); |
| |
| let deletion_span = deletion_span(); |
| self.r.lint_buffer.buffer_lint_with_diagnostic( |
| lint::builtin::SINGLE_USE_LIFETIMES, |
| param.id, |
| param.ident.span, |
| &format!("lifetime parameter `{}` only used once", param.ident), |
| lint::BuiltinLintDiagnostics::SingleUseLifetime { |
| param_span: param.ident.span, |
| use_span: Some((use_span, elidable)), |
| deletion_span, |
| }, |
| ); |
| } |
| None => { |
| debug!(?param.ident, ?param.ident.span); |
| let deletion_span = deletion_span(); |
| // the give lifetime originates from expanded code so we won't be able to remove it #104432 |
| let lifetime_only_in_expanded_code = |
| deletion_span.map(|sp| sp.in_derive_expansion()).unwrap_or(true); |
| if !lifetime_only_in_expanded_code { |
| self.r.lint_buffer.buffer_lint_with_diagnostic( |
| lint::builtin::UNUSED_LIFETIMES, |
| param.id, |
| param.ident.span, |
| &format!("lifetime parameter `{}` never used", param.ident), |
| lint::BuiltinLintDiagnostics::SingleUseLifetime { |
| param_span: param.ident.span, |
| use_span: None, |
| deletion_span, |
| }, |
| ); |
| } |
| } |
| } |
| } |
| } |
| |
| pub(crate) fn emit_undeclared_lifetime_error( |
| &self, |
| lifetime_ref: &ast::Lifetime, |
| outer_lifetime_ref: Option<Ident>, |
| ) { |
| debug_assert_ne!(lifetime_ref.ident.name, kw::UnderscoreLifetime); |
| let mut err = if let Some(outer) = outer_lifetime_ref { |
| let mut err = struct_span_err!( |
| self.r.tcx.sess, |
| lifetime_ref.ident.span, |
| E0401, |
| "can't use generic parameters from outer item", |
| ); |
| err.span_label(lifetime_ref.ident.span, "use of generic parameter from outer item"); |
| err.span_label(outer.span, "lifetime parameter from outer item"); |
| err |
| } else { |
| let mut err = struct_span_err!( |
| self.r.tcx.sess, |
| lifetime_ref.ident.span, |
| E0261, |
| "use of undeclared lifetime name `{}`", |
| lifetime_ref.ident |
| ); |
| err.span_label(lifetime_ref.ident.span, "undeclared lifetime"); |
| err |
| }; |
| self.suggest_introducing_lifetime( |
| &mut err, |
| Some(lifetime_ref.ident.name.as_str()), |
| |err, _, span, message, suggestion| { |
| err.span_suggestion(span, message, suggestion, Applicability::MaybeIncorrect); |
| true |
| }, |
| ); |
| err.emit(); |
| } |
| |
| fn suggest_introducing_lifetime( |
| &self, |
| err: &mut Diagnostic, |
| name: Option<&str>, |
| suggest: impl Fn(&mut Diagnostic, bool, Span, &str, String) -> bool, |
| ) { |
| let mut suggest_note = true; |
| for rib in self.lifetime_ribs.iter().rev() { |
| let mut should_continue = true; |
| match rib.kind { |
| LifetimeRibKind::Generics { binder: _, span, kind } => { |
| if !span.can_be_used_for_suggestions() && suggest_note && let Some(name) = name { |
| suggest_note = false; // Avoid displaying the same help multiple times. |
| err.span_label( |
| span, |
| &format!( |
| "lifetime `{}` is missing in item created through this procedural macro", |
| name, |
| ), |
| ); |
| continue; |
| } |
| |
| let higher_ranked = matches!( |
| kind, |
| LifetimeBinderKind::BareFnType |
| | LifetimeBinderKind::PolyTrait |
| | LifetimeBinderKind::WhereBound |
| ); |
| let (span, sugg) = if span.is_empty() { |
| let sugg = format!( |
| "{}<{}>{}", |
| if higher_ranked { "for" } else { "" }, |
| name.unwrap_or("'a"), |
| if higher_ranked { " " } else { "" }, |
| ); |
| (span, sugg) |
| } else { |
| let span = self |
| .r |
| .tcx |
| .sess |
| .source_map() |
| .span_through_char(span, '<') |
| .shrink_to_hi(); |
| let sugg = format!("{}, ", name.unwrap_or("'a")); |
| (span, sugg) |
| }; |
| if higher_ranked { |
| let message = format!( |
| "consider making the {} lifetime-generic with a new `{}` lifetime", |
| kind.descr(), |
| name.unwrap_or("'a"), |
| ); |
| should_continue = suggest(err, true, span, &message, sugg); |
| err.note_once( |
| "for more information on higher-ranked polymorphism, visit \ |
| https://doc.rust-lang.org/nomicon/hrtb.html", |
| ); |
| } else if let Some(name) = name { |
| let message = format!("consider introducing lifetime `{}` here", name); |
| should_continue = suggest(err, false, span, &message, sugg); |
| } else { |
| let message = "consider introducing a named lifetime parameter"; |
| should_continue = suggest(err, false, span, &message, sugg); |
| } |
| } |
| LifetimeRibKind::Item => break, |
| _ => {} |
| } |
| if !should_continue { |
| break; |
| } |
| } |
| } |
| |
| pub(crate) fn emit_non_static_lt_in_const_generic_error(&self, lifetime_ref: &ast::Lifetime) { |
| struct_span_err!( |
| self.r.tcx.sess, |
| lifetime_ref.ident.span, |
| E0771, |
| "use of non-static lifetime `{}` in const generic", |
| lifetime_ref.ident |
| ) |
| .note( |
| "for more information, see issue #74052 \ |
| <https://github.com/rust-lang/rust/issues/74052>", |
| ) |
| .emit(); |
| } |
| |
| /// 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. |
| pub(crate) fn maybe_emit_forbidden_non_static_lifetime_error( |
| &self, |
| lifetime_ref: &ast::Lifetime, |
| ) { |
| let feature_active = self.r.tcx.sess.features_untracked().generic_const_exprs; |
| if !feature_active { |
| feature_err( |
| &self.r.tcx.sess.parse_sess, |
| sym::generic_const_exprs, |
| lifetime_ref.ident.span, |
| "a non-static lifetime is not allowed in a `const`", |
| ) |
| .emit(); |
| } |
| } |
| |
| pub(crate) fn report_missing_lifetime_specifiers( |
| &mut self, |
| lifetime_refs: Vec<MissingLifetime>, |
| function_param_lifetimes: Option<(Vec<MissingLifetime>, Vec<ElisionFnParameter>)>, |
| ) -> ErrorGuaranteed { |
| let num_lifetimes: usize = lifetime_refs.iter().map(|lt| lt.count).sum(); |
| let spans: Vec<_> = lifetime_refs.iter().map(|lt| lt.span).collect(); |
| |
| let mut err = struct_span_err!( |
| self.r.tcx.sess, |
| spans, |
| E0106, |
| "missing lifetime specifier{}", |
| pluralize!(num_lifetimes) |
| ); |
| self.add_missing_lifetime_specifiers_label( |
| &mut err, |
| lifetime_refs, |
| function_param_lifetimes, |
| ); |
| err.emit() |
| } |
| |
| fn add_missing_lifetime_specifiers_label( |
| &mut self, |
| err: &mut Diagnostic, |
| lifetime_refs: Vec<MissingLifetime>, |
| function_param_lifetimes: Option<(Vec<MissingLifetime>, Vec<ElisionFnParameter>)>, |
| ) { |
| for < in &lifetime_refs { |
| err.span_label( |
| lt.span, |
| format!( |
| "expected {} lifetime parameter{}", |
| if lt.count == 1 { "named".to_string() } else { lt.count.to_string() }, |
| pluralize!(lt.count), |
| ), |
| ); |
| } |
| |
| let mut in_scope_lifetimes: Vec<_> = self |
| .lifetime_ribs |
| .iter() |
| .rev() |
| .take_while(|rib| !matches!(rib.kind, LifetimeRibKind::Item)) |
| .flat_map(|rib| rib.bindings.iter()) |
| .map(|(&ident, &res)| (ident, res)) |
| .filter(|(ident, _)| ident.name != kw::UnderscoreLifetime) |
| .collect(); |
| debug!(?in_scope_lifetimes); |
| |
| debug!(?function_param_lifetimes); |
| if let Some((param_lifetimes, params)) = &function_param_lifetimes { |
| let elided_len = param_lifetimes.len(); |
| let num_params = params.len(); |
| |
| let mut m = String::new(); |
| |
| for (i, info) in params.iter().enumerate() { |
| let ElisionFnParameter { ident, index, lifetime_count, span } = *info; |
| debug_assert_ne!(lifetime_count, 0); |
| |
| err.span_label(span, ""); |
| |
| if i != 0 { |
| if i + 1 < num_params { |
| m.push_str(", "); |
| } else if num_params == 2 { |
| m.push_str(" or "); |
| } else { |
| m.push_str(", or "); |
| } |
| } |
| |
| let help_name = if let Some(ident) = ident { |
| format!("`{}`", ident) |
| } else { |
| format!("argument {}", index + 1) |
| }; |
| |
| if lifetime_count == 1 { |
| m.push_str(&help_name[..]) |
| } else { |
| m.push_str(&format!("one of {}'s {} lifetimes", help_name, lifetime_count)[..]) |
| } |
| } |
| |
| if num_params == 0 { |
| err.help( |
| "this function's return type contains a borrowed value, \ |
| but there is no value for it to be borrowed from", |
| ); |
| if in_scope_lifetimes.is_empty() { |
| in_scope_lifetimes = vec![( |
| Ident::with_dummy_span(kw::StaticLifetime), |
| (DUMMY_NODE_ID, LifetimeRes::Static), |
| )]; |
| } |
| } else if elided_len == 0 { |
| err.help( |
| "this function's return type contains a borrowed value with \ |
| an elided lifetime, but the lifetime cannot be derived from \ |
| the arguments", |
| ); |
| if in_scope_lifetimes.is_empty() { |
| in_scope_lifetimes = vec![( |
| Ident::with_dummy_span(kw::StaticLifetime), |
| (DUMMY_NODE_ID, LifetimeRes::Static), |
| )]; |
| } |
| } else if num_params == 1 { |
| err.help(&format!( |
| "this function's return type contains a borrowed value, \ |
| but the signature does not say which {} it is borrowed from", |
| m |
| )); |
| } else { |
| err.help(&format!( |
| "this function's return type contains a borrowed value, \ |
| but the signature does not say whether it is borrowed from {}", |
| m |
| )); |
| } |
| } |
| |
| let existing_name = match &in_scope_lifetimes[..] { |
| [] => Symbol::intern("'a"), |
| [(existing, _)] => existing.name, |
| _ => Symbol::intern("'lifetime"), |
| }; |
| |
| let mut spans_suggs: Vec<_> = Vec::new(); |
| let build_sugg = |lt: MissingLifetime| match lt.kind { |
| MissingLifetimeKind::Underscore => { |
| debug_assert_eq!(lt.count, 1); |
| (lt.span, existing_name.to_string()) |
| } |
| MissingLifetimeKind::Ampersand => { |
| debug_assert_eq!(lt.count, 1); |
| (lt.span.shrink_to_hi(), format!("{} ", existing_name)) |
| } |
| MissingLifetimeKind::Comma => { |
| let sugg: String = std::iter::repeat([existing_name.as_str(), ", "]) |
| .take(lt.count) |
| .flatten() |
| .collect(); |
| (lt.span.shrink_to_hi(), sugg) |
| } |
| MissingLifetimeKind::Brackets => { |
| let sugg: String = std::iter::once("<") |
| .chain( |
| std::iter::repeat(existing_name.as_str()).take(lt.count).intersperse(", "), |
| ) |
| .chain([">"]) |
| .collect(); |
| (lt.span.shrink_to_hi(), sugg) |
| } |
| }; |
| for < in &lifetime_refs { |
| spans_suggs.push(build_sugg(lt)); |
| } |
| debug!(?spans_suggs); |
| match in_scope_lifetimes.len() { |
| 0 => { |
| if let Some((param_lifetimes, _)) = function_param_lifetimes { |
| for lt in param_lifetimes { |
| spans_suggs.push(build_sugg(lt)) |
| } |
| } |
| self.suggest_introducing_lifetime( |
| err, |
| None, |
| |err, higher_ranked, span, message, intro_sugg| { |
| err.multipart_suggestion_verbose( |
| message, |
| std::iter::once((span, intro_sugg)) |
| .chain(spans_suggs.iter().cloned()) |
| .collect(), |
| Applicability::MaybeIncorrect, |
| ); |
| higher_ranked |
| }, |
| ); |
| } |
| 1 => { |
| err.multipart_suggestion_verbose( |
| &format!("consider using the `{}` lifetime", existing_name), |
| spans_suggs, |
| Applicability::MaybeIncorrect, |
| ); |
| |
| // Record as using the suggested resolution. |
| let (_, (_, res)) = in_scope_lifetimes[0]; |
| for < in &lifetime_refs { |
| self.r.lifetimes_res_map.insert(lt.id, res); |
| } |
| } |
| _ => { |
| let lifetime_spans: Vec<_> = |
| in_scope_lifetimes.iter().map(|(ident, _)| ident.span).collect(); |
| err.span_note(lifetime_spans, "these named lifetimes are available to use"); |
| |
| 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, |
| ); |
| } |
| } |
| } |
| } |
| } |
| |
| /// Report lifetime/lifetime shadowing as an error. |
| pub(super) fn signal_lifetime_shadowing(sess: &Session, orig: Ident, shadower: Ident) { |
| let mut err = struct_span_err!( |
| sess, |
| shadower.span, |
| E0496, |
| "lifetime name `{}` shadows a lifetime name that is already in scope", |
| orig.name, |
| ); |
| err.span_label(orig.span, "first declared here"); |
| err.span_label(shadower.span, format!("lifetime `{}` already in scope", orig.name)); |
| err.emit(); |
| } |
| |
| /// Shadowing involving a label is only a warning for historical reasons. |
| //FIXME: make this a proper lint. |
| pub(super) fn signal_label_shadowing(sess: &Session, orig: Span, shadower: Ident) { |
| let name = shadower.name; |
| let shadower = shadower.span; |
| let mut err = sess.struct_span_warn( |
| shadower, |
| &format!("label name `{}` shadows a label name that is already in scope", name), |
| ); |
| err.span_label(orig, "first declared here"); |
| err.span_label(shadower, format!("label `{}` already in scope", name)); |
| err.emit(); |
| } |