| use crate::diagnostics::{ImportSuggestion, LabelSuggestion, TypoSuggestion}; |
| use crate::late::lifetimes::{ElisionFailureInfo, LifetimeContext}; |
| use crate::late::{LateResolutionVisitor, RibKind}; |
| use crate::path_names_to_string; |
| use crate::{CrateLint, Module, ModuleKind, ModuleOrUniformRoot}; |
| use crate::{PathResult, PathSource, Segment}; |
| |
| use rustc_ast::util::lev_distance::find_best_match_for_name; |
| use rustc_ast::visit::FnKind; |
| use rustc_ast::{self as ast, Expr, ExprKind, Item, ItemKind, NodeId, Path, Ty, TyKind}; |
| use rustc_data_structures::fx::FxHashSet; |
| use rustc_errors::{pluralize, struct_span_err, Applicability, DiagnosticBuilder}; |
| use rustc_hir as hir; |
| use rustc_hir::def::Namespace::{self, *}; |
| use rustc_hir::def::{self, CtorKind, DefKind}; |
| use rustc_hir::def_id::{DefId, CRATE_DEF_INDEX, LOCAL_CRATE}; |
| use rustc_hir::PrimTy; |
| use rustc_session::config::nightly_options; |
| use rustc_span::hygiene::MacroKind; |
| use rustc_span::symbol::{kw, sym, Ident, Symbol}; |
| use rustc_span::{BytePos, Span, DUMMY_SP}; |
| |
| 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, |
| AssocItem, |
| } |
| |
| 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>, 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 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 { |
| (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), false, span, CrateLint::No) { |
| PathResult::Module(ModuleOrUniformRoot::Module(module)) => module.res(), |
| _ => None, |
| } |
| .map_or(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 the 2018 edition".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); |
| |
| 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, |
| ); |
| self.r.session.if_let_suggestions.borrow_mut().insert(*span); |
| } |
| _ => {} |
| } |
| |
| let is_assoc_fn = self.self_type_is_available(span); |
| // 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, 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, |
| ); |
| } |
| } |
| } |
| |
| // 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(|p| p.is_self()).unwrap_or(false) { |
| 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(|| { |
| ( |
| 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) |
| .drain(..) |
| .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 enum_candidates = |
| self.r.lookup_import_candidates(ident, ns, &self.parent_scope, is_enum_variant); |
| |
| 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); |
| } |
| } |
| |
| let mut enum_candidates = enum_candidates |
| .iter() |
| .map(|suggestion| import_candidate_to_enum_paths(&suggestion)) |
| .collect::<Vec<_>>(); |
| 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) |
| // Variants re-exported in prelude doesn't mean `prelude::v1` is the |
| // type name! |
| // FIXME: is there a more principled way to do this that |
| // would work for other re-exports? |
| .filter(|enum_ty_path| enum_ty_path != "std::prelude::v1") |
| // Also write `Option` rather than `std::prelude::v1::Option`. |
| .map(|enum_ty_path| { |
| // FIXME #56861: DRY-er prelude filtering. |
| enum_ty_path.trim_start_matches("std::prelude::v1::").to_owned() |
| }), |
| Applicability::MachineApplicable, |
| ); |
| } |
| } |
| if path.len() == 1 && self.self_type_is_available(span) { |
| 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, 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, |
| "try", |
| format!("self.{}", path_str), |
| Applicability::MachineApplicable, |
| ); |
| } |
| AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => { |
| err.span_suggestion( |
| span, |
| "try", |
| 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, span); |
| // 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); |
| } |
| } |
| |
| if !self.type_ascription_suggestion(&mut err, base_span) |
| && !self.r.add_typo_suggestion(&mut err, typo_sugg, ident_span) |
| { |
| // Fallback label. |
| err.span_label(base_span, fallback_label); |
| |
| 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, |
| ); |
| } |
| _ => {} |
| } |
| } |
| (err, candidates) |
| } |
| |
| /// 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(), |
| )) |
| } 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 = match sm.span_to_snippet(sp) { |
| Ok(ref snippet) if snippet == "{" => true, |
| _ => false, |
| }; |
| // 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 DiagnosticBuilder<'a>, |
| 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 DiagnosticBuilder<'_>, 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 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 = 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, |
| }; |
| 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!("{} {{{pad}{}{pad}}}", path_str, fields, pad = pad), |
| applicability, |
| ); |
| } |
| _ => { |
| err.span_label(span, fallback_label); |
| } |
| } |
| }; |
| |
| match (res, source) { |
| (Res::Def(DefKind::Macro(MacroKind::Bang), _), _) => { |
| 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 to be in the 2018 edition"); |
| } |
| } |
| (Res::Def(DefKind::TyAlias, def_id), PathSource::Trait(_)) => { |
| err.span_label(span, "type aliases cannot be used as traits"); |
| if nightly_options::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) { |
| 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.delay_as_bug(); |
| // We already suggested changing `:` into `::` during parsing. |
| return false; |
| } |
| if let Some(variants) = self.collect_enum_variants(def_id) { |
| if !variants.is_empty() { |
| let msg = if variants.len() == 1 { |
| "try using the enum's variant" |
| } else { |
| "try using one of the enum's variants" |
| }; |
| |
| err.span_suggestions( |
| span, |
| msg, |
| variants.iter().map(path_names_to_string), |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| } else { |
| err.note("you might have meant to use one of the enum's variants"); |
| } |
| } |
| (Res::Def(DefKind::Struct, def_id), _) if ns == ValueNS => { |
| if let Some((ctor_def, ctor_vis, fields)) = |
| self.r.struct_constructors.get(&def_id).cloned() |
| { |
| let accessible_ctor = |
| self.r.is_accessible_from(ctor_vis, self.parent_scope.module); |
| if is_expected(ctor_def) && !accessible_ctor { |
| let mut better_diag = false; |
| if let PathSource::TupleStruct(_, pattern_spans) = source { |
| if pattern_spans.len() > 0 && fields.len() == pattern_spans.len() { |
| let non_visible_spans: Vec<Span> = fields |
| .iter() |
| .zip(pattern_spans.iter()) |
| .filter_map(|(vis, span)| { |
| match self |
| .r |
| .is_accessible_from(*vis, self.parent_scope.module) |
| { |
| true => None, |
| false => Some(*span), |
| } |
| }) |
| .collect(); |
| // Extra check to be sure |
| 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", |
| ); |
| better_diag = true; |
| } |
| } |
| } |
| |
| if !better_diag { |
| err.span_label( |
| span, |
| "constructor is not visible here due to private fields".to_string(), |
| ); |
| } |
| } |
| } else { |
| bad_struct_syntax_suggestion(def_id); |
| } |
| } |
| ( |
| 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::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("/* 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 |
| } |
| |
| 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); |
| } |
| } |
| } |
| _ => {} |
| } |
| } |
| } |
| } |
| |
| for assoc_type_ident in &self.diagnostic_metadata.current_trait_assoc_types { |
| if *assoc_type_ident == ident { |
| return Some(AssocSuggestion::AssocItem); |
| } |
| } |
| |
| // 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, |
| false, |
| module.span, |
| ) { |
| let res = binding.res(); |
| if filter_fn(res) { |
| return Some(if self.r.has_self.contains(&res.def_id()) { |
| AssocSuggestion::MethodWithSelf |
| } else { |
| AssocSuggestion::AssocItem |
| }); |
| } |
| } |
| } |
| |
| None |
| } |
| |
| fn lookup_typo_candidate( |
| &mut self, |
| path: &[Segment], |
| ns: Namespace, |
| filter_fn: &impl Fn(Res) -> bool, |
| span: Span, |
| ) -> 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::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::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( |
| self.r.primitive_type_table.primitive_types.iter().map(|(name, prim_ty)| { |
| TypoSuggestion::from_res(*name, Res::PrimTy(*prim_ty)) |
| }), |
| ) |
| } |
| } else { |
| // Search in module. |
| let mod_path = &path[..path.len() - 1]; |
| if let PathResult::Module(module) = |
| self.resolve_path(mod_path, Some(TypeNS), false, span, CrateLint::No) |
| { |
| if let ModuleOrUniformRoot::Module(module) = module { |
| 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_cached_key(|suggestion| suggestion.candidate.as_str()); |
| |
| match find_best_match_for_name( |
| names.iter().map(|suggestion| &suggestion.candidate), |
| name, |
| None, |
| ) { |
| Some(found) if found != name => { |
| names.into_iter().find(|suggestion| suggestion.candidate == found) |
| } |
| _ => 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 DiagnosticBuilder<'_>, 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.delay_as_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().unwrap(); |
| 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, |
| }, |
| )); |
| } else { |
| // add the module to the lookup |
| if seen_modules.insert(module_def_id) { |
| worklist.push((module, path_segments)); |
| } |
| } |
| } |
| }); |
| } |
| |
| result |
| } |
| |
| fn collect_enum_variants(&mut self, def_id: DefId) -> Option<Vec<Path>> { |
| 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::Variant, _) = name_binding.res() { |
| let mut segms = enum_import_suggestion.path.segments.clone(); |
| segms.push(ast::PathSegment::from_ident(ident)); |
| variants.push(Path { span: name_binding.span, segments: segms, tokens: None }); |
| } |
| }); |
| variants |
| }) |
| } |
| |
| 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) { |
| (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, |
| ) |
| | (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 { |
| param.ident.span |
| }; |
| (span, format!(", {}", ident)) |
| } else { |
| (generics.span, format!("<{}>", ident)) |
| }; |
| // Do not suggest if this is coming from macro expansion. |
| if !span.from_expansion() { |
| 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); |
| |
| 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, |
| span: Span, |
| count: usize, |
| ) -> DiagnosticBuilder<'tcx> { |
| struct_span_err!( |
| self.tcx.sess, |
| span, |
| 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 suggests_in_band = false; |
| 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| match p.kind { |
| hir::GenericParamKind::Type { |
| synthetic: Some(hir::SyntheticTyParamKind::ImplTrait), |
| .. |
| } => false, |
| hir::GenericParamKind::Lifetime { |
| kind: hir::LifetimeParamKind::Elided, |
| } => false, |
| _ => true, |
| }) { |
| (param.span.shrink_to_lo(), format!("{}, ", lifetime_ref)) |
| } else { |
| suggests_in_band = true; |
| (generics.span, format!("<{}>", lifetime_ref)) |
| }; |
| 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", |
| ); |
| } |
| _ => {} |
| } |
| } |
| if nightly_options::is_nightly_build() |
| && !self.tcx.features().in_band_lifetimes |
| && suggests_in_band |
| { |
| err.help( |
| "if you want to experiment with in-band lifetime bindings, \ |
| add `#![feature(in_band_lifetimes)]` to the crate attributes", |
| ); |
| } |
| err.emit(); |
| } |
| |
| // FIXME(const_generics): This patches over a 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 DiagnosticBuilder<'_>, |
| span: Span, |
| count: usize, |
| lifetime_names: &FxHashSet<Symbol>, |
| lifetime_spans: Vec<Span>, |
| params: &[ElisionFailureInfo], |
| ) { |
| let snippet = self.tcx.sess.source_map().span_to_snippet(span).ok(); |
| |
| 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 DiagnosticBuilder<'_>, |
| name: &str, |
| formatter: &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)); |
| introduce_suggestion.push((span, formatter(<_name))); |
| err.multipart_suggestion(&msg, introduce_suggestion, Applicability::MaybeIncorrect); |
| } |
| |
| err.span_suggestion_verbose( |
| span, |
| &format!("consider using the `{}` lifetime", lifetime_names.iter().next().unwrap()), |
| formatter(name), |
| Applicability::MaybeIncorrect, |
| ); |
| }; |
| let suggest_new = |err: &mut DiagnosticBuilder<'_>, sugg: &str| { |
| 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| match p.kind { |
| hir::GenericParamKind::Type { |
| synthetic: Some(hir::SyntheticTyParamKind::ImplTrait), |
| .. |
| } => false, |
| _ => true, |
| }) { |
| (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 (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 { |
| ( |
| span.shrink_to_hi(), |
| format!( |
| "<{}>", |
| std::iter::repeat("'static") |
| .take(count) |
| .collect::<Vec<_>>() |
| .join(", ") |
| ), |
| ) |
| } |
| } |
| _ => continue, |
| }; |
| err.span_suggestion_verbose( |
| span, |
| "consider using the `'static` lifetime", |
| sugg.to_string(), |
| Applicability::MaybeIncorrect, |
| ); |
| continue; |
| } |
| }); |
| 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!("&'a {}", &snippet[1..]))); |
| } else if snippet.starts_with("&'_ ") { |
| introduce_suggestion |
| .push((param.span, format!("&'a {}", &snippet[4..]))); |
| } |
| } |
| } |
| introduce_suggestion.push((span, sugg.to_string())); |
| err.multipart_suggestion(&msg, introduce_suggestion, Applicability::MaybeIncorrect); |
| if should_break { |
| break; |
| } |
| } |
| }; |
| |
| let lifetime_names: Vec<_> = lifetime_names.iter().collect(); |
| match (&lifetime_names[..], snippet.as_deref()) { |
| ([name], Some("&")) => { |
| suggest_existing(err, &name.as_str()[..], &|name| format!("&{} ", name)); |
| } |
| ([name], Some("'_")) => { |
| suggest_existing(err, &name.as_str()[..], &|n| n.to_string()); |
| } |
| ([name], Some("")) => { |
| suggest_existing(err, &name.as_str()[..], &|n| format!("{}, ", n).repeat(count)); |
| } |
| ([name], Some(snippet)) if !snippet.ends_with('>') => { |
| let f = |name: &str| { |
| format!( |
| "{}<{}>", |
| snippet, |
| std::iter::repeat(name.to_string()) |
| .take(count) |
| .collect::<Vec<_>>() |
| .join(", ") |
| ) |
| }; |
| suggest_existing(err, &name.as_str()[..], &f); |
| } |
| ([], Some("&")) if count == 1 => { |
| suggest_new(err, "&'a "); |
| } |
| ([], Some("'_")) if count == 1 => { |
| suggest_new(err, "'a"); |
| } |
| ([], Some(snippet)) if !snippet.ends_with('>') => { |
| if snippet == "" { |
| // This happens when we have `type Bar<'a> = Foo<T>` where we point at the space |
| // before `T`. We will suggest `type Bar<'a> = Foo<'a, T>`. |
| suggest_new( |
| err, |
| &std::iter::repeat("'a, ").take(count).collect::<Vec<_>>().join(""), |
| ); |
| } else { |
| suggest_new( |
| err, |
| &format!( |
| "{}<{}>", |
| snippet, |
| std::iter::repeat("'a").take(count).collect::<Vec<_>>().join(", ") |
| ), |
| ); |
| } |
| } |
| (lts, ..) if lts.len() > 1 => { |
| err.span_note(lifetime_spans, "these named lifetimes are available to use"); |
| if Some("") == snippet.as_deref() { |
| // 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.span_suggestion_verbose( |
| span, |
| "consider using one of the available lifetimes here", |
| "'lifetime, ".repeat(count), |
| Applicability::HasPlaceholders, |
| ); |
| } |
| } |
| _ => {} |
| } |
| } |
| } |
