| use std::cmp::Reverse; |
| |
| use errors::{Applicability, DiagnosticBuilder, DiagnosticId}; |
| use log::debug; |
| use rustc::bug; |
| use rustc::hir::def::{self, DefKind, NonMacroAttrKind}; |
| use rustc::hir::def::Namespace::{self, *}; |
| use rustc::hir::def_id::{CRATE_DEF_INDEX, DefId}; |
| use rustc::session::Session; |
| use rustc::ty::{self, DefIdTree}; |
| use rustc::util::nodemap::FxHashSet; |
| use syntax::ast::{self, Ident, Path}; |
| use syntax::ext::base::MacroKind; |
| use syntax::feature_gate::BUILTIN_ATTRIBUTES; |
| use syntax::source_map::SourceMap; |
| use syntax::struct_span_err; |
| use syntax::symbol::{Symbol, kw}; |
| use syntax::util::lev_distance::find_best_match_for_name; |
| use syntax_pos::{BytePos, Span, MultiSpan}; |
| |
| use crate::resolve_imports::{ImportDirective, ImportDirectiveSubclass, ImportResolver}; |
| use crate::{path_names_to_string, KNOWN_TOOLS}; |
| use crate::{BindingError, CrateLint, LegacyScope, Module, ModuleOrUniformRoot}; |
| use crate::{PathResult, ParentScope, ResolutionError, Resolver, Scope, ScopeSet, Segment}; |
| |
| type Res = def::Res<ast::NodeId>; |
| |
| /// A vector of spans and replacements, a message and applicability. |
| crate type Suggestion = (Vec<(Span, String)>, String, Applicability); |
| |
| crate struct TypoSuggestion { |
| pub candidate: Symbol, |
| pub res: Res, |
| } |
| |
| impl TypoSuggestion { |
| crate fn from_res(candidate: Symbol, res: Res) -> TypoSuggestion { |
| TypoSuggestion { candidate, res } |
| } |
| } |
| |
| /// A free importable items suggested in case of resolution failure. |
| crate struct ImportSuggestion { |
| pub did: Option<DefId>, |
| pub path: Path, |
| } |
| |
| /// Adjust the impl span so that just the `impl` keyword is taken by removing |
| /// everything after `<` (`"impl<T> Iterator for A<T> {}" -> "impl"`) and |
| /// everything after the first whitespace (`"impl Iterator for A" -> "impl"`). |
| /// |
| /// *Attention*: the method used is very fragile since it essentially duplicates the work of the |
| /// parser. If you need to use this function or something similar, please consider updating the |
| /// `source_map` functions and this function to something more robust. |
| fn reduce_impl_span_to_impl_keyword(cm: &SourceMap, impl_span: Span) -> Span { |
| let impl_span = cm.span_until_char(impl_span, '<'); |
| let impl_span = cm.span_until_whitespace(impl_span); |
| impl_span |
| } |
| |
| crate fn add_typo_suggestion( |
| err: &mut DiagnosticBuilder<'_>, suggestion: Option<TypoSuggestion>, span: Span |
| ) -> bool { |
| if let Some(suggestion) = suggestion { |
| let msg = format!( |
| "{} {} with a similar name exists", suggestion.res.article(), suggestion.res.descr() |
| ); |
| err.span_suggestion( |
| span, &msg, suggestion.candidate.to_string(), Applicability::MaybeIncorrect |
| ); |
| return true; |
| } |
| false |
| } |
| |
| crate fn add_module_candidates( |
| module: Module<'_>, names: &mut Vec<TypoSuggestion>, filter_fn: &impl Fn(Res) -> bool |
| ) { |
| for (&(ident, _), resolution) in module.resolutions.borrow().iter() { |
| if let Some(binding) = resolution.borrow().binding { |
| let res = binding.res(); |
| if filter_fn(res) { |
| names.push(TypoSuggestion::from_res(ident.name, res)); |
| } |
| } |
| } |
| } |
| |
| impl<'a> Resolver<'a> { |
| /// Combines an error with provided span and emits it. |
| /// |
| /// This takes the error provided, combines it with the span and any additional spans inside the |
| /// error and emits it. |
| crate fn report_error(&self, span: Span, resolution_error: ResolutionError<'_>) { |
| self.into_struct_error(span, resolution_error).emit(); |
| } |
| |
| crate fn into_struct_error( |
| &self, span: Span, resolution_error: ResolutionError<'_> |
| ) -> DiagnosticBuilder<'_> { |
| match resolution_error { |
| ResolutionError::GenericParamsFromOuterFunction(outer_res) => { |
| let mut err = struct_span_err!(self.session, |
| span, |
| E0401, |
| "can't use generic parameters from outer function", |
| ); |
| err.span_label(span, format!("use of generic parameter from outer function")); |
| |
| let cm = self.session.source_map(); |
| match outer_res { |
| Res::SelfTy(maybe_trait_defid, maybe_impl_defid) => { |
| if let Some(impl_span) = maybe_impl_defid.and_then(|def_id| { |
| self.definitions.opt_span(def_id) |
| }) { |
| err.span_label( |
| reduce_impl_span_to_impl_keyword(cm, impl_span), |
| "`Self` type implicitly declared here, by this `impl`", |
| ); |
| } |
| match (maybe_trait_defid, maybe_impl_defid) { |
| (Some(_), None) => { |
| err.span_label(span, "can't use `Self` here"); |
| } |
| (_, Some(_)) => { |
| err.span_label(span, "use a type here instead"); |
| } |
| (None, None) => bug!("`impl` without trait nor type?"), |
| } |
| return err; |
| }, |
| Res::Def(DefKind::TyParam, def_id) => { |
| if let Some(span) = self.definitions.opt_span(def_id) { |
| err.span_label(span, "type parameter from outer function"); |
| } |
| } |
| Res::Def(DefKind::ConstParam, def_id) => { |
| if let Some(span) = self.definitions.opt_span(def_id) { |
| err.span_label(span, "const parameter from outer function"); |
| } |
| } |
| _ => { |
| bug!("GenericParamsFromOuterFunction should only be used with Res::SelfTy, \ |
| DefKind::TyParam"); |
| } |
| } |
| |
| // Try to retrieve the span of the function signature and generate a new message |
| // with a local type or const parameter. |
| let sugg_msg = &format!("try using a local generic parameter instead"); |
| if let Some((sugg_span, new_snippet)) = cm.generate_local_type_param_snippet(span) { |
| // Suggest the modification to the user |
| err.span_suggestion( |
| sugg_span, |
| sugg_msg, |
| new_snippet, |
| Applicability::MachineApplicable, |
| ); |
| } else if let Some(sp) = cm.generate_fn_name_span(span) { |
| err.span_label(sp, |
| format!("try adding a local generic parameter in this method instead")); |
| } else { |
| err.help(&format!("try using a local generic parameter instead")); |
| } |
| |
| err |
| } |
| ResolutionError::NameAlreadyUsedInParameterList(name, first_use_span) => { |
| let mut err = struct_span_err!(self.session, |
| span, |
| E0403, |
| "the name `{}` is already used for a generic \ |
| parameter in this list of generic parameters", |
| name); |
| err.span_label(span, "already used"); |
| err.span_label(first_use_span, format!("first use of `{}`", name)); |
| err |
| } |
| ResolutionError::MethodNotMemberOfTrait(method, trait_) => { |
| let mut err = struct_span_err!(self.session, |
| span, |
| E0407, |
| "method `{}` is not a member of trait `{}`", |
| method, |
| trait_); |
| err.span_label(span, format!("not a member of trait `{}`", trait_)); |
| err |
| } |
| ResolutionError::TypeNotMemberOfTrait(type_, trait_) => { |
| let mut err = struct_span_err!(self.session, |
| span, |
| E0437, |
| "type `{}` is not a member of trait `{}`", |
| type_, |
| trait_); |
| err.span_label(span, format!("not a member of trait `{}`", trait_)); |
| err |
| } |
| ResolutionError::ConstNotMemberOfTrait(const_, trait_) => { |
| let mut err = struct_span_err!(self.session, |
| span, |
| E0438, |
| "const `{}` is not a member of trait `{}`", |
| const_, |
| trait_); |
| err.span_label(span, format!("not a member of trait `{}`", trait_)); |
| err |
| } |
| ResolutionError::VariableNotBoundInPattern(binding_error) => { |
| let BindingError { name, target, origin, could_be_path } = binding_error; |
| |
| let target_sp = target.iter().copied().collect::<Vec<_>>(); |
| let origin_sp = origin.iter().copied().collect::<Vec<_>>(); |
| |
| let msp = MultiSpan::from_spans(target_sp.clone()); |
| let msg = format!("variable `{}` is not bound in all patterns", name); |
| let mut err = self.session.struct_span_err_with_code( |
| msp, |
| &msg, |
| DiagnosticId::Error("E0408".into()), |
| ); |
| for sp in target_sp { |
| err.span_label(sp, format!("pattern doesn't bind `{}`", name)); |
| } |
| for sp in origin_sp { |
| err.span_label(sp, "variable not in all patterns"); |
| } |
| if *could_be_path { |
| let help_msg = format!( |
| "if you meant to match on a variant or a `const` item, consider \ |
| making the path in the pattern qualified: `?::{}`", |
| name, |
| ); |
| err.span_help(span, &help_msg); |
| } |
| err |
| } |
| ResolutionError::VariableBoundWithDifferentMode(variable_name, |
| first_binding_span) => { |
| let mut err = struct_span_err!(self.session, |
| span, |
| E0409, |
| "variable `{}` is bound in inconsistent \ |
| ways within the same match arm", |
| variable_name); |
| err.span_label(span, "bound in different ways"); |
| err.span_label(first_binding_span, "first binding"); |
| err |
| } |
| ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => { |
| let mut err = struct_span_err!(self.session, |
| span, |
| E0415, |
| "identifier `{}` is bound more than once in this parameter list", |
| identifier); |
| err.span_label(span, "used as parameter more than once"); |
| err |
| } |
| ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => { |
| let mut err = struct_span_err!(self.session, |
| span, |
| E0416, |
| "identifier `{}` is bound more than once in the same pattern", |
| identifier); |
| err.span_label(span, "used in a pattern more than once"); |
| err |
| } |
| ResolutionError::UndeclaredLabel(name, lev_candidate) => { |
| let mut err = struct_span_err!(self.session, |
| span, |
| E0426, |
| "use of undeclared label `{}`", |
| name); |
| if let Some(lev_candidate) = lev_candidate { |
| err.span_suggestion( |
| span, |
| "a label with a similar name exists in this scope", |
| lev_candidate.to_string(), |
| Applicability::MaybeIncorrect, |
| ); |
| } else { |
| err.span_label(span, format!("undeclared label `{}`", name)); |
| } |
| err |
| } |
| ResolutionError::SelfImportsOnlyAllowedWithin => { |
| struct_span_err!(self.session, |
| span, |
| E0429, |
| "{}", |
| "`self` imports are only allowed within a { } list") |
| } |
| ResolutionError::SelfImportCanOnlyAppearOnceInTheList => { |
| let mut err = struct_span_err!(self.session, span, E0430, |
| "`self` import can only appear once in an import list"); |
| err.span_label(span, "can only appear once in an import list"); |
| err |
| } |
| ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => { |
| let mut err = struct_span_err!(self.session, span, E0431, |
| "`self` import can only appear in an import list with \ |
| a non-empty prefix"); |
| err.span_label(span, "can only appear in an import list with a non-empty prefix"); |
| err |
| } |
| ResolutionError::FailedToResolve { label, suggestion } => { |
| let mut err = struct_span_err!(self.session, span, E0433, |
| "failed to resolve: {}", &label); |
| err.span_label(span, label); |
| |
| if let Some((suggestions, msg, applicability)) = suggestion { |
| err.multipart_suggestion(&msg, suggestions, applicability); |
| } |
| |
| err |
| } |
| ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => { |
| let mut err = struct_span_err!(self.session, |
| span, |
| E0434, |
| "{}", |
| "can't capture dynamic environment in a fn item"); |
| err.help("use the `|| { ... }` closure form instead"); |
| err |
| } |
| ResolutionError::AttemptToUseNonConstantValueInConstant => { |
| let mut err = struct_span_err!(self.session, span, E0435, |
| "attempt to use a non-constant value in a constant"); |
| err.span_label(span, "non-constant value"); |
| err |
| } |
| ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => { |
| let res = binding.res(); |
| let shadows_what = res.descr(); |
| let mut err = struct_span_err!(self.session, span, E0530, "{}s cannot shadow {}s", |
| what_binding, shadows_what); |
| err.span_label(span, format!("cannot be named the same as {} {}", |
| res.article(), shadows_what)); |
| let participle = if binding.is_import() { "imported" } else { "defined" }; |
| let msg = format!("the {} `{}` is {} here", shadows_what, name, participle); |
| err.span_label(binding.span, msg); |
| err |
| } |
| ResolutionError::ForwardDeclaredTyParam => { |
| let mut err = struct_span_err!(self.session, span, E0128, |
| "type parameters with a default cannot use \ |
| forward declared identifiers"); |
| err.span_label( |
| span, "defaulted type parameters cannot be forward declared".to_string()); |
| err |
| } |
| ResolutionError::ConstParamDependentOnTypeParam => { |
| let mut err = struct_span_err!( |
| self.session, |
| span, |
| E0671, |
| "const parameters cannot depend on type parameters" |
| ); |
| err.span_label(span, format!("const parameter depends on type parameter")); |
| err |
| } |
| } |
| } |
| |
| /// Lookup typo candidate in scope for a macro or import. |
| fn early_lookup_typo_candidate( |
| &mut self, |
| scope_set: ScopeSet, |
| parent_scope: &ParentScope<'a>, |
| ident: Ident, |
| filter_fn: &impl Fn(Res) -> bool, |
| ) -> Option<TypoSuggestion> { |
| let mut suggestions = Vec::new(); |
| self.visit_scopes(scope_set, parent_scope, ident, |this, scope, use_prelude, _| { |
| match scope { |
| Scope::DeriveHelpers => { |
| let res = Res::NonMacroAttr(NonMacroAttrKind::DeriveHelper); |
| if filter_fn(res) { |
| for derive in parent_scope.derives { |
| let parent_scope = |
| &ParentScope { derives: &[], ..*parent_scope }; |
| if let Ok((Some(ext), _)) = this.resolve_macro_path( |
| derive, Some(MacroKind::Derive), parent_scope, false, false |
| ) { |
| suggestions.extend(ext.helper_attrs.iter().map(|name| { |
| TypoSuggestion::from_res(*name, res) |
| })); |
| } |
| } |
| } |
| } |
| Scope::MacroRules(legacy_scope) => { |
| if let LegacyScope::Binding(legacy_binding) = legacy_scope { |
| let res = legacy_binding.binding.res(); |
| if filter_fn(res) { |
| suggestions.push( |
| TypoSuggestion::from_res(legacy_binding.ident.name, res) |
| ) |
| } |
| } |
| } |
| Scope::CrateRoot => { |
| let root_ident = Ident::new(kw::PathRoot, ident.span); |
| let root_module = this.resolve_crate_root(root_ident); |
| add_module_candidates(root_module, &mut suggestions, filter_fn); |
| } |
| Scope::Module(module) => { |
| add_module_candidates(module, &mut suggestions, filter_fn); |
| } |
| Scope::MacroUsePrelude => { |
| suggestions.extend(this.macro_use_prelude.iter().filter_map(|(name, binding)| { |
| let res = binding.res(); |
| if filter_fn(res) { |
| Some(TypoSuggestion::from_res(*name, res)) |
| } else { |
| None |
| } |
| })); |
| } |
| Scope::BuiltinAttrs => { |
| let res = Res::NonMacroAttr(NonMacroAttrKind::Builtin); |
| if filter_fn(res) { |
| suggestions.extend(BUILTIN_ATTRIBUTES.iter().map(|(name, ..)| { |
| TypoSuggestion::from_res(*name, res) |
| })); |
| } |
| } |
| Scope::LegacyPluginHelpers => { |
| let res = Res::NonMacroAttr(NonMacroAttrKind::LegacyPluginHelper); |
| if filter_fn(res) { |
| let plugin_attributes = this.session.plugin_attributes.borrow(); |
| suggestions.extend(plugin_attributes.iter().map(|(name, _)| { |
| TypoSuggestion::from_res(*name, res) |
| })); |
| } |
| } |
| Scope::ExternPrelude => { |
| suggestions.extend(this.extern_prelude.iter().filter_map(|(ident, _)| { |
| let res = Res::Def(DefKind::Mod, DefId::local(CRATE_DEF_INDEX)); |
| if filter_fn(res) { |
| Some(TypoSuggestion::from_res(ident.name, res)) |
| } else { |
| None |
| } |
| })); |
| } |
| Scope::ToolPrelude => { |
| let res = Res::NonMacroAttr(NonMacroAttrKind::Tool); |
| suggestions.extend(KNOWN_TOOLS.iter().map(|name| { |
| TypoSuggestion::from_res(*name, res) |
| })); |
| } |
| Scope::StdLibPrelude => { |
| if let Some(prelude) = this.prelude { |
| let mut tmp_suggestions = Vec::new(); |
| add_module_candidates(prelude, &mut tmp_suggestions, filter_fn); |
| suggestions.extend(tmp_suggestions.into_iter().filter(|s| { |
| use_prelude || this.is_builtin_macro(s.res) |
| })); |
| } |
| } |
| Scope::BuiltinTypes => { |
| let primitive_types = &this.primitive_type_table.primitive_types; |
| suggestions.extend( |
| primitive_types.iter().flat_map(|(name, prim_ty)| { |
| let res = Res::PrimTy(*prim_ty); |
| if filter_fn(res) { |
| Some(TypoSuggestion::from_res(*name, res)) |
| } else { |
| None |
| } |
| }) |
| ) |
| } |
| } |
| |
| None::<()> |
| }); |
| |
| // Make sure error reporting is deterministic. |
| suggestions.sort_by_cached_key(|suggestion| suggestion.candidate.as_str()); |
| |
| match find_best_match_for_name( |
| suggestions.iter().map(|suggestion| &suggestion.candidate), |
| &ident.as_str(), |
| None, |
| ) { |
| Some(found) if found != ident.name => suggestions |
| .into_iter() |
| .find(|suggestion| suggestion.candidate == found), |
| _ => None, |
| } |
| } |
| |
| fn lookup_import_candidates_from_module<FilterFn>(&mut self, |
| lookup_ident: Ident, |
| namespace: Namespace, |
| start_module: Module<'a>, |
| crate_name: Ident, |
| filter_fn: FilterFn) |
| -> Vec<ImportSuggestion> |
| where FilterFn: Fn(Res) -> bool |
| { |
| let mut candidates = Vec::new(); |
| let mut seen_modules = FxHashSet::default(); |
| let not_local_module = crate_name.name != kw::Crate; |
| let mut worklist = vec![(start_module, Vec::<ast::PathSegment>::new(), not_local_module)]; |
| |
| while let Some((in_module, |
| path_segments, |
| in_module_is_extern)) = worklist.pop() { |
| self.populate_module_if_necessary(in_module); |
| |
| // We have to visit module children in deterministic order to avoid |
| // instabilities in reported imports (#43552). |
| in_module.for_each_child_stable(|ident, ns, name_binding| { |
| // avoid imports entirely |
| if name_binding.is_import() && !name_binding.is_extern_crate() { return; } |
| // avoid non-importable candidates as well |
| if !name_binding.is_importable() { return; } |
| |
| // collect results based on the filter function |
| if ident.name == lookup_ident.name && ns == namespace { |
| let res = name_binding.res(); |
| if filter_fn(res) { |
| // create the path |
| let mut segms = path_segments.clone(); |
| if lookup_ident.span.rust_2018() { |
| // crate-local absolute paths start with `crate::` in edition 2018 |
| // FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660) |
| segms.insert( |
| 0, ast::PathSegment::from_ident(crate_name) |
| ); |
| } |
| |
| segms.push(ast::PathSegment::from_ident(ident)); |
| let path = Path { |
| span: name_binding.span, |
| segments: segms, |
| }; |
| // the entity is accessible in the following cases: |
| // 1. if it's defined in the same crate, it's always |
| // accessible (since private entities can be made public) |
| // 2. if it's defined in another crate, it's accessible |
| // only if both the module is public and the entity is |
| // declared as public (due to pruning, we don't explore |
| // outside crate private modules => no need to check this) |
| if !in_module_is_extern || name_binding.vis == ty::Visibility::Public { |
| let did = match res { |
| Res::Def(DefKind::Ctor(..), did) => self.parent(did), |
| _ => res.opt_def_id(), |
| }; |
| candidates.push(ImportSuggestion { did, path }); |
| } |
| } |
| } |
| |
| // collect submodules to explore |
| 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 is_extern_crate_that_also_appears_in_prelude = |
| name_binding.is_extern_crate() && |
| lookup_ident.span.rust_2018(); |
| |
| let is_visible_to_user = |
| !in_module_is_extern || name_binding.vis == ty::Visibility::Public; |
| |
| if !is_extern_crate_that_also_appears_in_prelude && is_visible_to_user { |
| // add the module to the lookup |
| let is_extern = in_module_is_extern || name_binding.is_extern_crate(); |
| if seen_modules.insert(module.def_id().unwrap()) { |
| worklist.push((module, path_segments, is_extern)); |
| } |
| } |
| } |
| }) |
| } |
| |
| candidates |
| } |
| |
| /// When name resolution fails, this method can be used to look up candidate |
| /// entities with the expected name. It allows filtering them using the |
| /// supplied predicate (which should be used to only accept the types of |
| /// definitions expected, e.g., traits). The lookup spans across all crates. |
| /// |
| /// N.B., the method does not look into imports, but this is not a problem, |
| /// since we report the definitions (thus, the de-aliased imports). |
| crate fn lookup_import_candidates<FilterFn>( |
| &mut self, lookup_ident: Ident, namespace: Namespace, filter_fn: FilterFn |
| ) -> Vec<ImportSuggestion> |
| where FilterFn: Fn(Res) -> bool |
| { |
| let mut suggestions = self.lookup_import_candidates_from_module( |
| lookup_ident, namespace, self.graph_root, Ident::with_dummy_span(kw::Crate), &filter_fn |
| ); |
| |
| if lookup_ident.span.rust_2018() { |
| let extern_prelude_names = self.extern_prelude.clone(); |
| for (ident, _) in extern_prelude_names.into_iter() { |
| if let Some(crate_id) = self.crate_loader.maybe_process_path_extern(ident.name, |
| ident.span) { |
| let crate_root = self.get_module(DefId { |
| krate: crate_id, |
| index: CRATE_DEF_INDEX, |
| }); |
| self.populate_module_if_necessary(&crate_root); |
| |
| suggestions.extend(self.lookup_import_candidates_from_module( |
| lookup_ident, namespace, crate_root, ident, &filter_fn)); |
| } |
| } |
| } |
| |
| suggestions |
| } |
| |
| crate fn unresolved_macro_suggestions( |
| &mut self, |
| err: &mut DiagnosticBuilder<'a>, |
| macro_kind: MacroKind, |
| parent_scope: &ParentScope<'a>, |
| ident: Ident, |
| ) { |
| let is_expected = &|res: Res| res.macro_kind() == Some(macro_kind); |
| let suggestion = self.early_lookup_typo_candidate( |
| ScopeSet::Macro(macro_kind), parent_scope, ident, is_expected |
| ); |
| add_typo_suggestion(err, suggestion, ident.span); |
| |
| if macro_kind == MacroKind::Derive && |
| (ident.as_str() == "Send" || ident.as_str() == "Sync") { |
| let msg = format!("unsafe traits like `{}` should be implemented explicitly", ident); |
| err.span_note(ident.span, &msg); |
| } |
| if self.macro_names.contains(&ident.modern()) { |
| err.help("have you added the `#[macro_use]` on the module/import?"); |
| } |
| } |
| } |
| |
| impl<'a, 'b> ImportResolver<'a, 'b> { |
| /// Adds suggestions for a path that cannot be resolved. |
| pub(crate) fn make_path_suggestion( |
| &mut self, |
| span: Span, |
| mut path: Vec<Segment>, |
| parent_scope: &ParentScope<'b>, |
| ) -> Option<(Vec<Segment>, Vec<String>)> { |
| debug!("make_path_suggestion: span={:?} path={:?}", span, path); |
| |
| match (path.get(0), path.get(1)) { |
| // `{{root}}::ident::...` on both editions. |
| // On 2015 `{{root}}` is usually added implicitly. |
| (Some(fst), Some(snd)) if fst.ident.name == kw::PathRoot && |
| !snd.ident.is_path_segment_keyword() => {} |
| // `ident::...` on 2018. |
| (Some(fst), _) if fst.ident.span.rust_2018() && |
| !fst.ident.is_path_segment_keyword() => { |
| // Insert a placeholder that's later replaced by `self`/`super`/etc. |
| path.insert(0, Segment::from_ident(Ident::invalid())); |
| } |
| _ => return None, |
| } |
| |
| self.make_missing_self_suggestion(span, path.clone(), parent_scope) |
| .or_else(|| self.make_missing_crate_suggestion(span, path.clone(), parent_scope)) |
| .or_else(|| self.make_missing_super_suggestion(span, path.clone(), parent_scope)) |
| .or_else(|| self.make_external_crate_suggestion(span, path, parent_scope)) |
| } |
| |
| /// Suggest a missing `self::` if that resolves to an correct module. |
| /// |
| /// ``` |
| /// | |
| /// LL | use foo::Bar; |
| /// | ^^^ did you mean `self::foo`? |
| /// ``` |
| fn make_missing_self_suggestion( |
| &mut self, |
| span: Span, |
| mut path: Vec<Segment>, |
| parent_scope: &ParentScope<'b>, |
| ) -> Option<(Vec<Segment>, Vec<String>)> { |
| // Replace first ident with `self` and check if that is valid. |
| path[0].ident.name = kw::SelfLower; |
| let result = self.r.resolve_path(&path, None, parent_scope, false, span, CrateLint::No); |
| debug!("make_missing_self_suggestion: path={:?} result={:?}", path, result); |
| if let PathResult::Module(..) = result { |
| Some((path, Vec::new())) |
| } else { |
| None |
| } |
| } |
| |
| /// Suggests a missing `crate::` if that resolves to an correct module. |
| /// |
| /// ``` |
| /// | |
| /// LL | use foo::Bar; |
| /// | ^^^ did you mean `crate::foo`? |
| /// ``` |
| fn make_missing_crate_suggestion( |
| &mut self, |
| span: Span, |
| mut path: Vec<Segment>, |
| parent_scope: &ParentScope<'b>, |
| ) -> Option<(Vec<Segment>, Vec<String>)> { |
| // Replace first ident with `crate` and check if that is valid. |
| path[0].ident.name = kw::Crate; |
| let result = self.r.resolve_path(&path, None, parent_scope, false, span, CrateLint::No); |
| debug!("make_missing_crate_suggestion: path={:?} result={:?}", path, result); |
| if let PathResult::Module(..) = result { |
| Some(( |
| path, |
| vec![ |
| "`use` statements changed in Rust 2018; read more at \ |
| <https://doc.rust-lang.org/edition-guide/rust-2018/module-system/path-\ |
| clarity.html>".to_string() |
| ], |
| )) |
| } else { |
| None |
| } |
| } |
| |
| /// Suggests a missing `super::` if that resolves to an correct module. |
| /// |
| /// ``` |
| /// | |
| /// LL | use foo::Bar; |
| /// | ^^^ did you mean `super::foo`? |
| /// ``` |
| fn make_missing_super_suggestion( |
| &mut self, |
| span: Span, |
| mut path: Vec<Segment>, |
| parent_scope: &ParentScope<'b>, |
| ) -> Option<(Vec<Segment>, Vec<String>)> { |
| // Replace first ident with `crate` and check if that is valid. |
| path[0].ident.name = kw::Super; |
| let result = self.r.resolve_path(&path, None, parent_scope, false, span, CrateLint::No); |
| debug!("make_missing_super_suggestion: path={:?} result={:?}", path, result); |
| if let PathResult::Module(..) = result { |
| Some((path, Vec::new())) |
| } else { |
| None |
| } |
| } |
| |
| /// Suggests a missing external crate name if that resolves to an correct module. |
| /// |
| /// ``` |
| /// | |
| /// LL | use foobar::Baz; |
| /// | ^^^^^^ did you mean `baz::foobar`? |
| /// ``` |
| /// |
| /// Used when importing a submodule of an external crate but missing that crate's |
| /// name as the first part of path. |
| fn make_external_crate_suggestion( |
| &mut self, |
| span: Span, |
| mut path: Vec<Segment>, |
| parent_scope: &ParentScope<'b>, |
| ) -> Option<(Vec<Segment>, Vec<String>)> { |
| if path[1].ident.span.rust_2015() { |
| return None; |
| } |
| |
| // Sort extern crate names in reverse order to get |
| // 1) some consistent ordering for emitted dignostics, and |
| // 2) `std` suggestions before `core` suggestions. |
| let mut extern_crate_names = |
| self.r.extern_prelude.iter().map(|(ident, _)| ident.name).collect::<Vec<_>>(); |
| extern_crate_names.sort_by_key(|name| Reverse(name.as_str())); |
| |
| for name in extern_crate_names.into_iter() { |
| // Replace first ident with a crate name and check if that is valid. |
| path[0].ident.name = name; |
| let result = self.r.resolve_path(&path, None, parent_scope, false, span, CrateLint::No); |
| debug!("make_external_crate_suggestion: name={:?} path={:?} result={:?}", |
| name, path, result); |
| if let PathResult::Module(..) = result { |
| return Some((path, Vec::new())); |
| } |
| } |
| |
| None |
| } |
| |
| /// Suggests importing a macro from the root of the crate rather than a module within |
| /// the crate. |
| /// |
| /// ``` |
| /// help: a macro with this name exists at the root of the crate |
| /// | |
| /// LL | use issue_59764::makro; |
| /// | ^^^^^^^^^^^^^^^^^^ |
| /// | |
| /// = note: this could be because a macro annotated with `#[macro_export]` will be exported |
| /// at the root of the crate instead of the module where it is defined |
| /// ``` |
| pub(crate) fn check_for_module_export_macro( |
| &self, |
| directive: &'b ImportDirective<'b>, |
| module: ModuleOrUniformRoot<'b>, |
| ident: Ident, |
| ) -> Option<(Option<Suggestion>, Vec<String>)> { |
| let mut crate_module = if let ModuleOrUniformRoot::Module(module) = module { |
| module |
| } else { |
| return None; |
| }; |
| |
| while let Some(parent) = crate_module.parent { |
| crate_module = parent; |
| } |
| |
| if ModuleOrUniformRoot::same_def(ModuleOrUniformRoot::Module(crate_module), module) { |
| // Don't make a suggestion if the import was already from the root of the |
| // crate. |
| return None; |
| } |
| |
| let resolutions = crate_module.resolutions.borrow(); |
| let resolution = resolutions.get(&(ident, MacroNS))?; |
| let binding = resolution.borrow().binding()?; |
| if let Res::Def(DefKind::Macro(MacroKind::Bang), _) = binding.res() { |
| let module_name = crate_module.kind.name().unwrap(); |
| let import = match directive.subclass { |
| ImportDirectiveSubclass::SingleImport { source, target, .. } if source != target => |
| format!("{} as {}", source, target), |
| _ => format!("{}", ident), |
| }; |
| |
| let mut corrections: Vec<(Span, String)> = Vec::new(); |
| if !directive.is_nested() { |
| // Assume this is the easy case of `use issue_59764::foo::makro;` and just remove |
| // intermediate segments. |
| corrections.push((directive.span, format!("{}::{}", module_name, import))); |
| } else { |
| // Find the binding span (and any trailing commas and spaces). |
| // ie. `use a::b::{c, d, e};` |
| // ^^^ |
| let (found_closing_brace, binding_span) = find_span_of_binding_until_next_binding( |
| self.r.session, directive.span, directive.use_span, |
| ); |
| debug!("check_for_module_export_macro: found_closing_brace={:?} binding_span={:?}", |
| found_closing_brace, binding_span); |
| |
| let mut removal_span = binding_span; |
| if found_closing_brace { |
| // If the binding span ended with a closing brace, as in the below example: |
| // ie. `use a::b::{c, d};` |
| // ^ |
| // Then expand the span of characters to remove to include the previous |
| // binding's trailing comma. |
| // ie. `use a::b::{c, d};` |
| // ^^^ |
| if let Some(previous_span) = extend_span_to_previous_binding( |
| self.r.session, binding_span, |
| ) { |
| debug!("check_for_module_export_macro: previous_span={:?}", previous_span); |
| removal_span = removal_span.with_lo(previous_span.lo()); |
| } |
| } |
| debug!("check_for_module_export_macro: removal_span={:?}", removal_span); |
| |
| // Remove the `removal_span`. |
| corrections.push((removal_span, "".to_string())); |
| |
| // Find the span after the crate name and if it has nested imports immediatately |
| // after the crate name already. |
| // ie. `use a::b::{c, d};` |
| // ^^^^^^^^^ |
| // or `use a::{b, c, d}};` |
| // ^^^^^^^^^^^ |
| let (has_nested, after_crate_name) = find_span_immediately_after_crate_name( |
| self.r.session, module_name, directive.use_span, |
| ); |
| debug!("check_for_module_export_macro: has_nested={:?} after_crate_name={:?}", |
| has_nested, after_crate_name); |
| |
| let source_map = self.r.session.source_map(); |
| |
| // Add the import to the start, with a `{` if required. |
| let start_point = source_map.start_point(after_crate_name); |
| if let Ok(start_snippet) = source_map.span_to_snippet(start_point) { |
| corrections.push(( |
| start_point, |
| if has_nested { |
| // In this case, `start_snippet` must equal '{'. |
| format!("{}{}, ", start_snippet, import) |
| } else { |
| // In this case, add a `{`, then the moved import, then whatever |
| // was there before. |
| format!("{{{}, {}", import, start_snippet) |
| } |
| )); |
| } |
| |
| // Add a `};` to the end if nested, matching the `{` added at the start. |
| if !has_nested { |
| corrections.push((source_map.end_point(after_crate_name), |
| "};".to_string())); |
| } |
| } |
| |
| let suggestion = Some(( |
| corrections, |
| String::from("a macro with this name exists at the root of the crate"), |
| Applicability::MaybeIncorrect, |
| )); |
| let note = vec![ |
| "this could be because a macro annotated with `#[macro_export]` will be exported \ |
| at the root of the crate instead of the module where it is defined".to_string(), |
| ]; |
| Some((suggestion, note)) |
| } else { |
| None |
| } |
| } |
| } |
| |
| /// Given a `binding_span` of a binding within a use statement: |
| /// |
| /// ``` |
| /// use foo::{a, b, c}; |
| /// ^ |
| /// ``` |
| /// |
| /// then return the span until the next binding or the end of the statement: |
| /// |
| /// ``` |
| /// use foo::{a, b, c}; |
| /// ^^^ |
| /// ``` |
| pub(crate) fn find_span_of_binding_until_next_binding( |
| sess: &Session, |
| binding_span: Span, |
| use_span: Span, |
| ) -> (bool, Span) { |
| let source_map = sess.source_map(); |
| |
| // Find the span of everything after the binding. |
| // ie. `a, e};` or `a};` |
| let binding_until_end = binding_span.with_hi(use_span.hi()); |
| |
| // Find everything after the binding but not including the binding. |
| // ie. `, e};` or `};` |
| let after_binding_until_end = binding_until_end.with_lo(binding_span.hi()); |
| |
| // Keep characters in the span until we encounter something that isn't a comma or |
| // whitespace. |
| // ie. `, ` or ``. |
| // |
| // Also note whether a closing brace character was encountered. If there |
| // was, then later go backwards to remove any trailing commas that are left. |
| let mut found_closing_brace = false; |
| let after_binding_until_next_binding = source_map.span_take_while( |
| after_binding_until_end, |
| |&ch| { |
| if ch == '}' { found_closing_brace = true; } |
| ch == ' ' || ch == ',' |
| } |
| ); |
| |
| // Combine the two spans. |
| // ie. `a, ` or `a`. |
| // |
| // Removing these would leave `issue_52891::{d, e};` or `issue_52891::{d, e, };` |
| let span = binding_span.with_hi(after_binding_until_next_binding.hi()); |
| |
| (found_closing_brace, span) |
| } |
| |
| /// Given a `binding_span`, return the span through to the comma or opening brace of the previous |
| /// binding. |
| /// |
| /// ``` |
| /// use foo::a::{a, b, c}; |
| /// ^^--- binding span |
| /// | |
| /// returned span |
| /// |
| /// use foo::{a, b, c}; |
| /// --- binding span |
| /// ``` |
| pub(crate) fn extend_span_to_previous_binding( |
| sess: &Session, |
| binding_span: Span, |
| ) -> Option<Span> { |
| let source_map = sess.source_map(); |
| |
| // `prev_source` will contain all of the source that came before the span. |
| // Then split based on a command and take the first (ie. closest to our span) |
| // snippet. In the example, this is a space. |
| let prev_source = source_map.span_to_prev_source(binding_span).ok()?; |
| |
| let prev_comma = prev_source.rsplit(',').collect::<Vec<_>>(); |
| let prev_starting_brace = prev_source.rsplit('{').collect::<Vec<_>>(); |
| if prev_comma.len() <= 1 || prev_starting_brace.len() <= 1 { |
| return None; |
| } |
| |
| let prev_comma = prev_comma.first().unwrap(); |
| let prev_starting_brace = prev_starting_brace.first().unwrap(); |
| |
| // If the amount of source code before the comma is greater than |
| // the amount of source code before the starting brace then we've only |
| // got one item in the nested item (eg. `issue_52891::{self}`). |
| if prev_comma.len() > prev_starting_brace.len() { |
| return None; |
| } |
| |
| Some(binding_span.with_lo(BytePos( |
| // Take away the number of bytes for the characters we've found and an |
| // extra for the comma. |
| binding_span.lo().0 - (prev_comma.as_bytes().len() as u32) - 1 |
| ))) |
| } |
| |
| /// Given a `use_span` of a binding within a use statement, returns the highlighted span and if |
| /// it is a nested use tree. |
| /// |
| /// ``` |
| /// use foo::a::{b, c}; |
| /// ^^^^^^^^^^ // false |
| /// |
| /// use foo::{a, b, c}; |
| /// ^^^^^^^^^^ // true |
| /// |
| /// use foo::{a, b::{c, d}}; |
| /// ^^^^^^^^^^^^^^^ // true |
| /// ``` |
| fn find_span_immediately_after_crate_name( |
| sess: &Session, |
| module_name: Symbol, |
| use_span: Span, |
| ) -> (bool, Span) { |
| debug!("find_span_immediately_after_crate_name: module_name={:?} use_span={:?}", |
| module_name, use_span); |
| let source_map = sess.source_map(); |
| |
| // Using `use issue_59764::foo::{baz, makro};` as an example throughout.. |
| let mut num_colons = 0; |
| // Find second colon.. `use issue_59764:` |
| let until_second_colon = source_map.span_take_while(use_span, |c| { |
| if *c == ':' { num_colons += 1; } |
| match c { |
| ':' if num_colons == 2 => false, |
| _ => true, |
| } |
| }); |
| // Find everything after the second colon.. `foo::{baz, makro};` |
| let from_second_colon = use_span.with_lo(until_second_colon.hi() + BytePos(1)); |
| |
| let mut found_a_non_whitespace_character = false; |
| // Find the first non-whitespace character in `from_second_colon`.. `f` |
| let after_second_colon = source_map.span_take_while(from_second_colon, |c| { |
| if found_a_non_whitespace_character { return false; } |
| if !c.is_whitespace() { found_a_non_whitespace_character = true; } |
| true |
| }); |
| |
| // Find the first `{` in from_second_colon.. `foo::{` |
| let next_left_bracket = source_map.span_through_char(from_second_colon, '{'); |
| |
| (next_left_bracket == after_second_colon, from_second_colon) |
| } |
| |
| /// When an entity with a given name is not available in scope, we search for |
| /// entities with that name in all crates. This method allows outputting the |
| /// results of this search in a programmer-friendly way |
| crate fn show_candidates( |
| err: &mut DiagnosticBuilder<'_>, |
| // This is `None` if all placement locations are inside expansions |
| span: Option<Span>, |
| candidates: &[ImportSuggestion], |
| better: bool, |
| found_use: bool, |
| ) { |
| // we want consistent results across executions, but candidates are produced |
| // by iterating through a hash map, so make sure they are ordered: |
| let mut path_strings: Vec<_> = |
| candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect(); |
| path_strings.sort(); |
| |
| let better = if better { "better " } else { "" }; |
| let msg_diff = match path_strings.len() { |
| 1 => " is found in another module, you can import it", |
| _ => "s are found in other modules, you can import them", |
| }; |
| let msg = format!("possible {}candidate{} into scope", better, msg_diff); |
| |
| if let Some(span) = span { |
| for candidate in &mut path_strings { |
| // produce an additional newline to separate the new use statement |
| // from the directly following item. |
| let additional_newline = if found_use { |
| "" |
| } else { |
| "\n" |
| }; |
| *candidate = format!("use {};\n{}", candidate, additional_newline); |
| } |
| |
| err.span_suggestions( |
| span, |
| &msg, |
| path_strings.into_iter(), |
| Applicability::Unspecified, |
| ); |
| } else { |
| let mut msg = msg; |
| msg.push(':'); |
| for candidate in path_strings { |
| msg.push('\n'); |
| msg.push_str(&candidate); |
| } |
| } |
| } |
