| use std::cmp::Reverse; |
| |
| use errors::{Applicability, DiagnosticBuilder, DiagnosticId}; |
| use log::debug; |
| use rustc::hir::def::*; |
| use rustc::hir::def::Namespace::*; |
| use rustc::hir::def_id::{CRATE_DEF_INDEX, DefId}; |
| use rustc::session::config::nightly_options; |
| use syntax::ast::{ExprKind}; |
| use syntax::symbol::keywords; |
| use syntax_pos::Span; |
| |
| use crate::macros::ParentScope; |
| use crate::resolve_imports::ImportResolver; |
| use crate::{import_candidate_to_enum_paths, is_self_type, is_self_value, path_names_to_string}; |
| use crate::{AssocSuggestion, CrateLint, ImportSuggestion, ModuleOrUniformRoot, PathResult, |
| PathSource, Resolver, Segment}; |
| |
| impl<'a> Resolver<'a> { |
| /// 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<'_>, |
| def: Option<Def>, |
| ) -> (DiagnosticBuilder<'a>, Vec<ImportSuggestion>) { |
| let ident_span = path.last().map_or(span, |ident| ident.ident.span); |
| let ns = source.namespace(); |
| let is_expected = &|def| source.is_expected(def); |
| let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false }; |
| |
| // 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 code = source.error_code(def.is_some()); |
| let (base_msg, fallback_label, base_span) = if let Some(def) = def { |
| (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str), |
| format!("not a {}", expected), |
| span) |
| } 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 == keywords::PathRoot.name() { |
| (String::new(), "the crate root".to_string()) |
| } else { |
| let mod_path = &path[..path.len() - 1]; |
| let mod_prefix = match self.resolve_path_without_parent_scope( |
| mod_path, Some(TypeNS), false, span, CrateLint::No |
| ) { |
| PathResult::Module(ModuleOrUniformRoot::Module(module)) => |
| module.def(), |
| _ => None, |
| }.map_or(String::new(), |def| format!("{} ", def.kind_name())); |
| (mod_prefix, format!("`{}`", Segment::names_to_string(mod_path))) |
| }; |
| (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str), |
| format!("not found in {}", mod_str), |
| item_span) |
| }; |
| |
| let code = DiagnosticId::Error(code.into()); |
| let mut err = self.session.struct_span_err_with_code(base_span, &base_msg, code); |
| |
| // Emit help message for fake-self from other languages (e.g., `this` in Javascript). |
| if ["this", "my"].contains(&&*item_str.as_str()) |
| && self.self_value_is_available(path[0].ident.span, span) { |
| err.span_suggestion( |
| span, |
| "did you mean", |
| "self".to_string(), |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| |
| // Emit special messages for unresolved `Self` and `self`. |
| if is_self_type(path, ns) { |
| __diagnostic_used!(E0411); |
| err.code(DiagnosticId::Error("E0411".into())); |
| err.span_label(span, format!("`Self` is only available in impls, traits, \ |
| and type definitions")); |
| return (err, Vec::new()); |
| } |
| if is_self_value(path, ns) { |
| debug!("smart_resolve_path_fragment: E0424, source={:?}", source); |
| |
| __diagnostic_used!(E0424); |
| err.code(DiagnosticId::Error("E0424".into())); |
| err.span_label(span, match source { |
| PathSource::Pat => { |
| format!("`self` value is a keyword \ |
| and may not be bound to \ |
| variables or shadowed") |
| } |
| _ => { |
| format!("`self` value is a keyword \ |
| only available in methods \ |
| with `self` parameter") |
| } |
| }); |
| 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.lookup_import_candidates(ident, ns, is_expected) |
| .drain(..) |
| .filter(|ImportSuggestion { did, .. }| { |
| match (did, def.and_then(|def| def.opt_def_id())) { |
| (Some(suggestion_did), Some(actual_did)) => *suggestion_did != actual_did, |
| _ => true, |
| } |
| }) |
| .collect::<Vec<_>>(); |
| if candidates.is_empty() && is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) { |
| let enum_candidates = |
| self.lookup_import_candidates(ident, ns, is_enum_variant); |
| let mut enum_candidates = enum_candidates.iter() |
| .map(|suggestion| { |
| import_candidate_to_enum_paths(&suggestion) |
| }).collect::<Vec<_>>(); |
| enum_candidates.sort(); |
| |
| if !enum_candidates.is_empty() { |
| // 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 def.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 => { |
| err.span_suggestion( |
| span, |
| "try", |
| format!("self.{}", path_str), |
| Applicability::MachineApplicable, |
| ); |
| if !self_is_available { |
| err.span_label(span, format!("`self` value is a keyword \ |
| only available in \ |
| methods with `self` parameter")); |
| } |
| } |
| 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); |
| } |
| } |
| |
| let mut levenshtein_worked = false; |
| |
| // Try Levenshtein algorithm. |
| let suggestion = self.lookup_typo_candidate(path, ns, is_expected, span); |
| if let Some(suggestion) = suggestion { |
| let msg = format!( |
| "{} {} with a similar name exists", |
| suggestion.article, suggestion.kind |
| ); |
| err.span_suggestion( |
| ident_span, |
| &msg, |
| suggestion.candidate.to_string(), |
| Applicability::MaybeIncorrect, |
| ); |
| |
| levenshtein_worked = true; |
| } |
| |
| // Try context-dependent help if relaxed lookup didn't work. |
| if let Some(def) = def { |
| if self.smart_resolve_context_dependent_help(&mut err, |
| span, |
| source, |
| def, |
| &path_str, |
| &fallback_label) { |
| return (err, candidates); |
| } |
| } |
| |
| // Fallback label. |
| if !levenshtein_worked { |
| err.span_label(base_span, fallback_label); |
| self.type_ascription_suggestion(&mut err, base_span); |
| } |
| (err, candidates) |
| } |
| |
| /// 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<'_>, |
| def: Def, |
| path_str: &str, |
| fallback_label: &str, |
| ) -> bool { |
| let ns = source.namespace(); |
| let is_expected = &|def| source.is_expected(def); |
| |
| match (def, source) { |
| (Def::Macro(..), _) => { |
| err.span_suggestion( |
| span, |
| "use `!` to invoke the macro", |
| format!("{}!", path_str), |
| 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"); |
| } |
| } |
| (Def::TyAlias(..), PathSource::Trait(_)) => { |
| err.span_label(span, "type aliases cannot be used as traits"); |
| if nightly_options::is_nightly_build() { |
| err.note("did you mean to use a trait alias?"); |
| } |
| } |
| (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node { |
| ExprKind::Field(_, ident) => { |
| err.span_suggestion( |
| parent.span, |
| "use the path separator to refer to an item", |
| format!("{}::{}", path_str, ident), |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| ExprKind::MethodCall(ref segment, ..) => { |
| let span = parent.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, |
| ); |
| } |
| _ => return false, |
| }, |
| (Def::Enum(..), PathSource::TupleStruct) |
| | (Def::Enum(..), PathSource::Expr(..)) => { |
| if let Some(variants) = self.collect_enum_variants(def) { |
| 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("did you mean to use one of the enum's variants?"); |
| } |
| }, |
| (Def::Struct(def_id), _) if ns == ValueNS => { |
| if let Some((ctor_def, ctor_vis)) |
| = self.struct_constructors.get(&def_id).cloned() { |
| let accessible_ctor = self.is_accessible(ctor_vis); |
| if is_expected(ctor_def) && !accessible_ctor { |
| err.span_label(span, format!("constructor is not visible \ |
| here due to private fields")); |
| } |
| } else { |
| // 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.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 parenthesis, 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 == "}" { |
| let sp = span.to(sp); |
| if let Ok(snippet) = sm.span_to_snippet(sp) { |
| closing_brace = Some((sp, snippet)); |
| } |
| break; |
| } |
| } |
| _ => break, |
| } |
| i += 1; |
| // The bigger the span, the more likely we're incorrect -- |
| // bound it to 100 chars long. |
| if i > 100 { |
| break; |
| } |
| } |
| match source { |
| PathSource::Expr(Some(parent)) => { |
| match parent.node { |
| ExprKind::MethodCall(ref path_assignment, _) => { |
| err.span_suggestion( |
| sm.start_point(parent.span) |
| .to(path_assignment.ident.span), |
| "use `::` to access an associated function", |
| format!("{}::{}", |
| path_str, |
| path_assignment.ident), |
| Applicability::MaybeIncorrect |
| ); |
| }, |
| _ => { |
| err.span_label( |
| span, |
| format!("did you mean `{} {{ /* fields */ }}`?", |
| path_str), |
| ); |
| }, |
| } |
| }, |
| PathSource::Expr(None) if followed_by_brace == true => { |
| if let Some((sp, snippet)) = closing_brace { |
| err.span_suggestion( |
| sp, |
| "surround the struct literal with parenthesis", |
| format!("({})", snippet), |
| Applicability::MaybeIncorrect, |
| ); |
| } else { |
| err.span_label( |
| span, |
| format!("did you mean `({} {{ /* fields */ }})`?", |
| path_str), |
| ); |
| } |
| }, |
| _ => { |
| err.span_label( |
| span, |
| format!("did you mean `{} {{ /* fields */ }}`?", |
| path_str), |
| ); |
| }, |
| } |
| } |
| } |
| (Def::Union(..), _) | |
| (Def::Variant(..), _) | |
| (Def::VariantCtor(_, CtorKind::Fictive), _) if ns == ValueNS => { |
| err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?", |
| path_str)); |
| } |
| (Def::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"); |
| } |
| (Def::TyAlias(_), _) | (Def::AssociatedTy(..), _) if ns == ValueNS => { |
| err.note("can't use a type alias as a constructor"); |
| } |
| _ => return false, |
| } |
| true |
| } |
| } |
| |
| impl<'a, 'b:'a> 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>, Option<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 == keywords::PathRoot.name() && |
| !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(keywords::Invalid.ident())); |
| } |
| _ => 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>, Option<String>)> { |
| // Replace first ident with `self` and check if that is valid. |
| path[0].ident.name = keywords::SelfLower.name(); |
| let result = self.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, None)) |
| } 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>, Option<String>)> { |
| // Replace first ident with `crate` and check if that is valid. |
| path[0].ident.name = keywords::Crate.name(); |
| let result = self.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, |
| Some( |
| "`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>, Option<String>)> { |
| // Replace first ident with `crate` and check if that is valid. |
| path[0].ident.name = keywords::Super.name(); |
| let result = self.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, None)) |
| } 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>, Option<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.resolver.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.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, None)); |
| } |
| } |
| |
| None |
| } |
| } |
