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-rw-r--r--compiler/rustc_resolve/src/late/diagnostics.rs2369
1 files changed, 2369 insertions, 0 deletions
diff --git a/compiler/rustc_resolve/src/late/diagnostics.rs b/compiler/rustc_resolve/src/late/diagnostics.rs
new file mode 100644
index 000000000..2b1f2b88e
--- /dev/null
+++ b/compiler/rustc_resolve/src/late/diagnostics.rs
@@ -0,0 +1,2369 @@
+use crate::diagnostics::{ImportSuggestion, LabelSuggestion, TypoSuggestion};
+use crate::late::{AliasPossibility, LateResolutionVisitor, RibKind};
+use crate::late::{LifetimeBinderKind, LifetimeRes, LifetimeRibKind, LifetimeUseSet};
+use crate::path_names_to_string;
+use crate::{Module, ModuleKind, ModuleOrUniformRoot};
+use crate::{PathResult, PathSource, Segment};
+
+use rustc_ast::visit::{FnCtxt, FnKind, LifetimeCtxt};
+use rustc_ast::{
+ self as ast, AssocItemKind, Expr, ExprKind, GenericParam, GenericParamKind, Item, ItemKind,
+ NodeId, Path, Ty, TyKind, DUMMY_NODE_ID,
+};
+use rustc_ast_pretty::pprust::path_segment_to_string;
+use rustc_data_structures::fx::FxHashSet;
+use rustc_errors::{
+ pluralize, struct_span_err, Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed,
+ MultiSpan,
+};
+use rustc_hir as hir;
+use rustc_hir::def::Namespace::{self, *};
+use rustc_hir::def::{self, CtorKind, CtorOf, DefKind};
+use rustc_hir::def_id::{DefId, CRATE_DEF_ID, LOCAL_CRATE};
+use rustc_hir::PrimTy;
+use rustc_session::lint;
+use rustc_session::parse::feature_err;
+use rustc_session::Session;
+use rustc_span::edition::Edition;
+use rustc_span::hygiene::MacroKind;
+use rustc_span::lev_distance::find_best_match_for_name;
+use rustc_span::symbol::{kw, sym, Ident, Symbol};
+use rustc_span::{BytePos, Span};
+
+use std::iter;
+use std::ops::Deref;
+
+use tracing::debug;
+
+type Res = def::Res<ast::NodeId>;
+
+/// A field or associated item from self type suggested in case of resolution failure.
+enum AssocSuggestion {
+ Field,
+ MethodWithSelf,
+ AssocFn,
+ AssocType,
+ AssocConst,
+}
+
+impl AssocSuggestion {
+ fn action(&self) -> &'static str {
+ match self {
+ AssocSuggestion::Field => "use the available field",
+ AssocSuggestion::MethodWithSelf => "call the method with the fully-qualified path",
+ AssocSuggestion::AssocFn => "call the associated function",
+ AssocSuggestion::AssocConst => "use the associated `const`",
+ AssocSuggestion::AssocType => "use the associated type",
+ }
+ }
+}
+
+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)
+}
+
+/// Description of an elided lifetime.
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug)]
+pub(super) struct MissingLifetime {
+ /// Used to overwrite the resolution with the suggestion, to avoid cascasing errors.
+ pub id: NodeId,
+ /// Where to suggest adding the lifetime.
+ pub span: Span,
+ /// How the lifetime was introduced, to have the correct space and comma.
+ pub kind: MissingLifetimeKind,
+ /// Number of elided lifetimes, used for elision in path.
+ pub count: usize,
+}
+
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug)]
+pub(super) enum MissingLifetimeKind {
+ /// An explicit `'_`.
+ Underscore,
+ /// An elided lifetime `&' ty`.
+ Ampersand,
+ /// An elided lifetime in brackets with written brackets.
+ Comma,
+ /// An elided lifetime with elided brackets.
+ Brackets,
+}
+
+/// Description of the lifetimes appearing in a function parameter.
+/// This is used to provide a literal explanation to the elision failure.
+#[derive(Clone, Debug)]
+pub(super) struct ElisionFnParameter {
+ /// The index of the argument in the original definition.
+ pub index: usize,
+ /// The name of the argument if it's a simple ident.
+ pub ident: Option<Ident>,
+ /// The number of lifetimes in the parameter.
+ pub lifetime_count: usize,
+ /// The span of the parameter.
+ pub span: Span,
+}
+
+/// Description of lifetimes that appear as candidates for elision.
+/// This is used to suggest introducing an explicit lifetime.
+#[derive(Debug)]
+pub(super) enum LifetimeElisionCandidate {
+ /// This is not a real lifetime.
+ Ignore,
+ /// There is a named lifetime, we won't suggest anything.
+ Named,
+ Missing(MissingLifetime),
+}
+
+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.cstore().get_span_untracked(def_id, self.r.session)),
+ }
+ }
+
+ /// Handles error reporting for `smart_resolve_path_fragment` function.
+ /// Creates base error and amends it with one short label and possibly some longer helps/notes.
+ pub(crate) fn smart_resolve_report_errors(
+ &mut self,
+ path: &[Segment],
+ span: Span,
+ source: PathSource<'_>,
+ res: Option<Res>,
+ ) -> (DiagnosticBuilder<'a, ErrorGuaranteed>, Vec<ImportSuggestion>) {
+ let ident_span = path.last().map_or(span, |ident| ident.ident.span);
+ let ns = source.namespace();
+ let is_expected = &|res| source.is_expected(res);
+ let is_enum_variant = &|res| matches!(res, Res::Def(DefKind::Variant, _));
+
+ debug!(?res, ?source);
+
+ // Make the base error.
+ struct BaseError<'a> {
+ msg: String,
+ fallback_label: String,
+ span: Span,
+ could_be_expr: bool,
+ suggestion: Option<(Span, &'a str, String)>,
+ }
+ let mut expected = source.descr_expected();
+ let path_str = Segment::names_to_string(path);
+ let item_str = path.last().unwrap().ident;
+ let base_error = if let Some(res) = res {
+ BaseError {
+ msg: format!("expected {}, found {} `{}`", expected, res.descr(), path_str),
+ fallback_label: format!("not a {expected}"),
+ span,
+ could_be_expr: match res {
+ Res::Def(DefKind::Fn, _) => {
+ // Verify whether this is a fn call or an Fn used as a type.
+ self.r
+ .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,
+ },
+ suggestion: None,
+ }
+ } else {
+ let item_span = path.last().unwrap().ident.span;
+ let (mod_prefix, mod_str, suggestion) = if path.len() == 1 {
+ debug!(?self.diagnostic_metadata.current_impl_items);
+ debug!(?self.diagnostic_metadata.current_function);
+ let suggestion = if let Some(items) = self.diagnostic_metadata.current_impl_items
+ && let Some((fn_kind, _)) = self.diagnostic_metadata.current_function
+ && self.current_trait_ref.is_none()
+ && let Some(FnCtxt::Assoc(_)) = fn_kind.ctxt()
+ && let Some(item) = items.iter().find(|i| {
+ if let AssocItemKind::Fn(fn_) = &i.kind
+ && !fn_.sig.decl.has_self()
+ && i.ident.name == item_str.name
+ {
+ debug!(?item_str.name);
+ debug!(?fn_.sig.decl.inputs);
+ return true
+ }
+ false
+ })
+ {
+ Some((
+ item_span,
+ "consider using the associated function",
+ format!("Self::{}", item.ident)
+ ))
+ } else {
+ None
+ };
+ (String::new(), "this scope".to_string(), suggestion)
+ } else if path.len() == 2 && path[0].ident.name == kw::PathRoot {
+ if self.r.session.edition() > Edition::Edition2015 {
+ // In edition 2018 onwards, the `::foo` syntax may only pull from the extern prelude
+ // which overrides all other expectations of item type
+ expected = "crate";
+ (String::new(), "the list of imported crates".to_string(), None)
+ } else {
+ (String::new(), "the crate root".to_string(), None)
+ }
+ } else if path.len() == 2 && path[0].ident.name == kw::Crate {
+ (String::new(), "the crate root".to_string(), None)
+ } else {
+ let mod_path = &path[..path.len() - 1];
+ let mod_prefix = match self.resolve_path(mod_path, Some(TypeNS), None) {
+ PathResult::Module(ModuleOrUniformRoot::Module(module)) => module.res(),
+ _ => None,
+ }
+ .map_or_else(String::new, |res| format!("{} ", res.descr()));
+ (mod_prefix, format!("`{}`", Segment::names_to_string(mod_path)), None)
+ };
+ BaseError {
+ msg: format!("cannot find {expected} `{item_str}` in {mod_prefix}{mod_str}"),
+ fallback_label: if path_str == "async" && expected.starts_with("struct") {
+ "`async` blocks are only allowed in Rust 2018 or later".to_string()
+ } else {
+ format!("not found in {mod_str}")
+ },
+ span: item_span,
+ could_be_expr: false,
+ suggestion,
+ }
+ };
+
+ let code = source.error_code(res.is_some());
+ let mut err =
+ self.r.session.struct_span_err_with_code(base_error.span, &base_error.msg, code);
+
+ self.suggest_swapping_misplaced_self_ty_and_trait(&mut err, source, res, base_error.span);
+
+ if let Some(sugg) = base_error.suggestion {
+ err.span_suggestion_verbose(sugg.0, sugg.1, sugg.2, Applicability::MaybeIncorrect);
+ }
+
+ if let Some(span) = self.diagnostic_metadata.current_block_could_be_bare_struct_literal {
+ err.multipart_suggestion(
+ "you might have meant to write a `struct` literal",
+ vec![
+ (span.shrink_to_lo(), "{ SomeStruct ".to_string()),
+ (span.shrink_to_hi(), "}".to_string()),
+ ],
+ Applicability::HasPlaceholders,
+ );
+ }
+ match (source, self.diagnostic_metadata.in_if_condition) {
+ (
+ PathSource::Expr(_),
+ Some(Expr { span: expr_span, kind: ExprKind::Assign(lhs, _, _), .. }),
+ ) => {
+ // Icky heuristic so we don't suggest:
+ // `if (i + 2) = 2` => `if let (i + 2) = 2` (approximately pattern)
+ // `if 2 = i` => `if let 2 = i` (lhs needs to contain error span)
+ if lhs.is_approximately_pattern() && lhs.span.contains(span) {
+ err.span_suggestion_verbose(
+ expr_span.shrink_to_lo(),
+ "you might have meant to use pattern matching",
+ "let ",
+ Applicability::MaybeIncorrect,
+ );
+ }
+ }
+ _ => {}
+ }
+
+ let is_assoc_fn = self.self_type_is_available();
+ // Emit help message for fake-self from other languages (e.g., `this` in Javascript).
+ if ["this", "my"].contains(&item_str.as_str()) && is_assoc_fn {
+ err.span_suggestion_short(
+ span,
+ "you might have meant to use `self` here instead",
+ "self",
+ Applicability::MaybeIncorrect,
+ );
+ if !self.self_value_is_available(path[0].ident.span) {
+ if let Some((FnKind::Fn(_, _, sig, ..), fn_span)) =
+ &self.diagnostic_metadata.current_function
+ {
+ let (span, sugg) = if let Some(param) = sig.decl.inputs.get(0) {
+ (param.span.shrink_to_lo(), "&self, ")
+ } else {
+ (
+ self.r
+ .session
+ .source_map()
+ .span_through_char(*fn_span, '(')
+ .shrink_to_hi(),
+ "&self",
+ )
+ };
+ err.span_suggestion_verbose(
+ span,
+ "if you meant to use `self`, you are also missing a `self` receiver \
+ argument",
+ sugg,
+ Applicability::MaybeIncorrect,
+ );
+ }
+ }
+ }
+
+ self.detect_assoct_type_constraint_meant_as_path(base_error.span, &mut err);
+
+ // Emit special messages for unresolved `Self` and `self`.
+ if is_self_type(path, ns) {
+ err.code(rustc_errors::error_code!(E0411));
+ err.span_label(
+ span,
+ "`Self` is only available in impls, traits, and type definitions".to_string(),
+ );
+ if let Some(item_kind) = self.diagnostic_metadata.current_item {
+ err.span_label(
+ item_kind.ident.span,
+ format!(
+ "`Self` not allowed in {} {}",
+ item_kind.kind.article(),
+ item_kind.kind.descr()
+ ),
+ );
+ }
+ 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",
+ _ => "`self` value is a keyword only available in methods with a `self` parameter",
+ });
+ if let Some((fn_kind, span)) = &self.diagnostic_metadata.current_function {
+ // The current function has a `self' parameter, but we were unable to resolve
+ // a reference to `self`. This can only happen if the `self` identifier we
+ // are resolving came from a different hygiene context.
+ if fn_kind.decl().inputs.get(0).map_or(false, |p| p.is_self()) {
+ err.span_label(*span, "this function has a `self` parameter, but a macro invocation can only access identifiers it receives from parameters");
+ } else {
+ let doesnt = if is_assoc_fn {
+ let (span, sugg) = fn_kind
+ .decl()
+ .inputs
+ .get(0)
+ .map(|p| (p.span.shrink_to_lo(), "&self, "))
+ .unwrap_or_else(|| {
+ // Try to look for the "(" after the function name, if possible.
+ // This avoids placing the suggestion into the visibility specifier.
+ let span = fn_kind
+ .ident()
+ .map_or(*span, |ident| span.with_lo(ident.span.hi()));
+ (
+ self.r
+ .session
+ .source_map()
+ .span_through_char(span, '(')
+ .shrink_to_hi(),
+ "&self",
+ )
+ });
+ err.span_suggestion_verbose(
+ span,
+ "add a `self` receiver parameter to make the associated `fn` a method",
+ sugg,
+ Applicability::MaybeIncorrect,
+ );
+ "doesn't"
+ } else {
+ "can't"
+ };
+ if let Some(ident) = fn_kind.ident() {
+ err.span_label(
+ ident.span,
+ &format!("this function {} have a `self` parameter", doesnt),
+ );
+ }
+ }
+ } else if let Some(item_kind) = self.diagnostic_metadata.current_item {
+ err.span_label(
+ item_kind.ident.span,
+ format!(
+ "`self` not allowed in {} {}",
+ item_kind.kind.article(),
+ item_kind.kind.descr()
+ ),
+ );
+ }
+ return (err, Vec::new());
+ }
+
+ // Try to lookup name in more relaxed fashion for better error reporting.
+ let ident = path.last().unwrap().ident;
+ let mut candidates = self
+ .r
+ .lookup_import_candidates(ident, ns, &self.parent_scope, is_expected)
+ .into_iter()
+ .filter(|ImportSuggestion { did, .. }| {
+ match (did, res.and_then(|res| res.opt_def_id())) {
+ (Some(suggestion_did), Some(actual_did)) => *suggestion_did != actual_did,
+ _ => true,
+ }
+ })
+ .collect::<Vec<_>>();
+ let crate_def_id = CRATE_DEF_ID.to_def_id();
+ // Try to filter out intrinsics candidates, as long as we have
+ // some other candidates to suggest.
+ let intrinsic_candidates: Vec<_> = candidates
+ .drain_filter(|sugg| {
+ let path = path_names_to_string(&sugg.path);
+ path.starts_with("core::intrinsics::") || path.starts_with("std::intrinsics::")
+ })
+ .collect();
+ if candidates.is_empty() {
+ // Put them back if we have no more candidates to suggest...
+ candidates.extend(intrinsic_candidates);
+ }
+ if candidates.is_empty() && is_expected(Res::Def(DefKind::Enum, crate_def_id)) {
+ let mut enum_candidates: Vec<_> = self
+ .r
+ .lookup_import_candidates(ident, ns, &self.parent_scope, is_enum_variant)
+ .into_iter()
+ .map(|suggestion| import_candidate_to_enum_paths(&suggestion))
+ .filter(|(_, enum_ty_path)| !enum_ty_path.starts_with("std::prelude::"))
+ .collect();
+ if !enum_candidates.is_empty() {
+ if let (PathSource::Type, Some(span)) =
+ (source, self.diagnostic_metadata.current_type_ascription.last())
+ {
+ if self
+ .r
+ .session
+ .parse_sess
+ .type_ascription_path_suggestions
+ .borrow()
+ .contains(span)
+ {
+ // Already reported this issue on the lhs of the type ascription.
+ err.delay_as_bug();
+ return (err, candidates);
+ }
+ }
+
+ enum_candidates.sort();
+
+ // Contextualize for E0412 "cannot find type", but don't belabor the point
+ // (that it's a variant) for E0573 "expected type, found variant".
+ let preamble = if res.is_none() {
+ let others = match enum_candidates.len() {
+ 1 => String::new(),
+ 2 => " and 1 other".to_owned(),
+ n => format!(" and {} others", n),
+ };
+ format!("there is an enum variant `{}`{}; ", enum_candidates[0].0, others)
+ } else {
+ String::new()
+ };
+ let msg = format!("{}try using the variant's enum", preamble);
+
+ err.span_suggestions(
+ span,
+ &msg,
+ enum_candidates.into_iter().map(|(_variant_path, enum_ty_path)| enum_ty_path),
+ Applicability::MachineApplicable,
+ );
+ }
+ }
+ // Try Levenshtein algorithm.
+ let typo_sugg = self.lookup_typo_candidate(path, ns, is_expected);
+ if path.len() == 1 && self.self_type_is_available() {
+ if let Some(candidate) = self.lookup_assoc_candidate(ident, ns, is_expected) {
+ let self_is_available = self.self_value_is_available(path[0].ident.span);
+ match candidate {
+ AssocSuggestion::Field => {
+ if self_is_available {
+ err.span_suggestion(
+ span,
+ "you might have meant to use the available field",
+ format!("self.{path_str}"),
+ Applicability::MachineApplicable,
+ );
+ } else {
+ err.span_label(span, "a field by this name exists in `Self`");
+ }
+ }
+ AssocSuggestion::MethodWithSelf if self_is_available => {
+ err.span_suggestion(
+ span,
+ "you might have meant to call the method",
+ format!("self.{path_str}"),
+ Applicability::MachineApplicable,
+ );
+ }
+ AssocSuggestion::MethodWithSelf
+ | AssocSuggestion::AssocFn
+ | AssocSuggestion::AssocConst
+ | AssocSuggestion::AssocType => {
+ err.span_suggestion(
+ span,
+ &format!("you might have meant to {}", candidate.action()),
+ format!("Self::{path_str}"),
+ Applicability::MachineApplicable,
+ );
+ }
+ }
+ self.r.add_typo_suggestion(&mut err, typo_sugg, ident_span);
+ 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 `{ident}` as a method"),
+ format!("self.{path_str}({args_snippet})"),
+ Applicability::MachineApplicable,
+ );
+ return (err, candidates);
+ }
+ }
+
+ // 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,
+ &base_error.fallback_label,
+ ) {
+ // We do this to avoid losing a secondary span when we override the main error span.
+ self.r.add_typo_suggestion(&mut err, typo_sugg, ident_span);
+ return (err, candidates);
+ }
+ }
+
+ let is_macro =
+ base_error.span.from_expansion() && base_error.span.desugaring_kind().is_none();
+ if !self.type_ascription_suggestion(&mut err, base_error.span) {
+ let mut fallback = false;
+ if let (
+ PathSource::Trait(AliasPossibility::Maybe),
+ Some(Res::Def(DefKind::Struct | DefKind::Enum | DefKind::Union, _)),
+ false,
+ ) = (source, res, is_macro)
+ {
+ if let Some(bounds @ [_, .., _]) = self.diagnostic_metadata.current_trait_object {
+ fallback = true;
+ let spans: Vec<Span> = bounds
+ .iter()
+ .map(|bound| bound.span())
+ .filter(|&sp| sp != base_error.span)
+ .collect();
+
+ let start_span = bounds.iter().map(|bound| bound.span()).next().unwrap();
+ // `end_span` is the end of the poly trait ref (Foo + 'baz + Bar><)
+ let end_span = bounds.iter().map(|bound| bound.span()).last().unwrap();
+ // `last_bound_span` is the last bound of the poly trait ref (Foo + >'baz< + Bar)
+ let last_bound_span = spans.last().cloned().unwrap();
+ let mut multi_span: MultiSpan = spans.clone().into();
+ for sp in spans {
+ let msg = if sp == last_bound_span {
+ format!(
+ "...because of {these} bound{s}",
+ these = pluralize!("this", bounds.len() - 1),
+ s = pluralize!(bounds.len() - 1),
+ )
+ } else {
+ String::new()
+ };
+ multi_span.push_span_label(sp, msg);
+ }
+ multi_span
+ .push_span_label(base_error.span, "expected this type to be a trait...");
+ err.span_help(
+ multi_span,
+ "`+` is used to constrain a \"trait object\" type with lifetimes or \
+ auto-traits; structs and enums can't be bound in that way",
+ );
+ if bounds.iter().all(|bound| match bound {
+ ast::GenericBound::Outlives(_) => true,
+ ast::GenericBound::Trait(tr, _) => tr.span == base_error.span,
+ }) {
+ let mut sugg = vec![];
+ if base_error.span != start_span {
+ sugg.push((start_span.until(base_error.span), String::new()));
+ }
+ if base_error.span != end_span {
+ sugg.push((base_error.span.shrink_to_hi().to(end_span), String::new()));
+ }
+
+ err.multipart_suggestion(
+ "if you meant to use a type and not a trait here, remove the bounds",
+ sugg,
+ Applicability::MaybeIncorrect,
+ );
+ }
+ }
+ }
+
+ fallback |= self.restrict_assoc_type_in_where_clause(span, &mut err);
+
+ if !self.r.add_typo_suggestion(&mut err, typo_sugg, ident_span) {
+ fallback = true;
+ match self.diagnostic_metadata.current_let_binding {
+ Some((pat_sp, Some(ty_sp), None))
+ if ty_sp.contains(base_error.span) && base_error.could_be_expr =>
+ {
+ err.span_suggestion_short(
+ pat_sp.between(ty_sp),
+ "use `=` if you meant to assign",
+ " = ",
+ Applicability::MaybeIncorrect,
+ );
+ }
+ _ => {}
+ }
+
+ // If the trait has a single item (which wasn't matched by Levenshtein), suggest it
+ let suggestion = self.get_single_associated_item(&path, &source, is_expected);
+ self.r.add_typo_suggestion(&mut err, suggestion, ident_span);
+ }
+ if fallback {
+ // Fallback label.
+ err.span_label(base_error.span, base_error.fallback_label);
+ }
+ }
+ if let Some(err_code) = &err.code {
+ if err_code == &rustc_errors::error_code!(E0425) {
+ for label_rib in &self.label_ribs {
+ for (label_ident, node_id) in &label_rib.bindings {
+ if format!("'{}", ident) == label_ident.to_string() {
+ err.span_label(label_ident.span, "a label with a similar name exists");
+ if let PathSource::Expr(Some(Expr {
+ kind: ExprKind::Break(None, Some(_)),
+ ..
+ })) = source
+ {
+ err.span_suggestion(
+ span,
+ "use the similarly named label",
+ label_ident.name,
+ Applicability::MaybeIncorrect,
+ );
+ // Do not lint against unused label when we suggest them.
+ self.diagnostic_metadata.unused_labels.remove(node_id);
+ }
+ }
+ }
+ }
+ } else if err_code == &rustc_errors::error_code!(E0412) {
+ if let Some(correct) = Self::likely_rust_type(path) {
+ err.span_suggestion(
+ span,
+ "perhaps you intended to use this type",
+ correct,
+ Applicability::MaybeIncorrect,
+ );
+ }
+ }
+ }
+
+ (err, candidates)
+ }
+
+ fn detect_assoct_type_constraint_meant_as_path(&self, base_span: Span, err: &mut Diagnostic) {
+ let Some(ty) = self.diagnostic_metadata.current_type_path else { return; };
+ let TyKind::Path(_, path) = &ty.kind else { return; };
+ for segment in &path.segments {
+ let Some(params) = &segment.args else { continue; };
+ let ast::GenericArgs::AngleBracketed(ref params) = params.deref() else { continue; };
+ for param in &params.args {
+ let ast::AngleBracketedArg::Constraint(constraint) = param else { continue; };
+ let ast::AssocConstraintKind::Bound { bounds } = &constraint.kind else {
+ continue;
+ };
+ for bound in bounds {
+ let ast::GenericBound::Trait(trait_ref, ast::TraitBoundModifier::None)
+ = bound else
+ {
+ continue;
+ };
+ if base_span == trait_ref.span {
+ err.span_suggestion_verbose(
+ constraint.ident.span.between(trait_ref.span),
+ "you might have meant to write a path instead of an associated type bound",
+ "::",
+ Applicability::MachineApplicable,
+ );
+ }
+ }
+ }
+ }
+ }
+
+ fn suggest_swapping_misplaced_self_ty_and_trait(
+ &mut self,
+ err: &mut Diagnostic,
+ source: PathSource<'_>,
+ res: Option<Res>,
+ span: Span,
+ ) {
+ if let Some((trait_ref, self_ty)) =
+ self.diagnostic_metadata.currently_processing_impl_trait.clone()
+ && let TyKind::Path(_, self_ty_path) = &self_ty.kind
+ && let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
+ self.resolve_path(&Segment::from_path(self_ty_path), Some(TypeNS), None)
+ && let ModuleKind::Def(DefKind::Trait, ..) = module.kind
+ && trait_ref.path.span == span
+ && let PathSource::Trait(_) = source
+ && let Some(Res::Def(DefKind::Struct | DefKind::Enum | DefKind::Union, _)) = res
+ && let Ok(self_ty_str) =
+ self.r.session.source_map().span_to_snippet(self_ty.span)
+ && let Ok(trait_ref_str) =
+ self.r.session.source_map().span_to_snippet(trait_ref.path.span)
+ {
+ err.multipart_suggestion(
+ "`impl` items mention the trait being implemented first and the type it is being implemented for second",
+ vec![(trait_ref.path.span, self_ty_str), (self_ty.span, trait_ref_str)],
+ Applicability::MaybeIncorrect,
+ );
+ }
+ }
+
+ fn get_single_associated_item(
+ &mut self,
+ path: &[Segment],
+ source: &PathSource<'_>,
+ filter_fn: &impl Fn(Res) -> bool,
+ ) -> Option<TypoSuggestion> {
+ if let crate::PathSource::TraitItem(_) = source {
+ let mod_path = &path[..path.len() - 1];
+ if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
+ self.resolve_path(mod_path, None, None)
+ {
+ let resolutions = self.r.resolutions(module).borrow();
+ let targets: Vec<_> =
+ resolutions
+ .iter()
+ .filter_map(|(key, resolution)| {
+ resolution.borrow().binding.map(|binding| binding.res()).and_then(
+ |res| if filter_fn(res) { Some((key, res)) } else { None },
+ )
+ })
+ .collect();
+ if targets.len() == 1 {
+ let target = targets[0];
+ return Some(TypoSuggestion::single_item_from_res(
+ target.0.ident.name,
+ target.1,
+ ));
+ }
+ }
+ }
+ None
+ }
+
+ /// Given `where <T as Bar>::Baz: String`, suggest `where T: Bar<Baz = String>`.
+ fn restrict_assoc_type_in_where_clause(&mut self, span: Span, err: &mut Diagnostic) -> bool {
+ // Detect that we are actually in a `where` predicate.
+ let (bounded_ty, bounds, where_span) =
+ if let Some(ast::WherePredicate::BoundPredicate(ast::WhereBoundPredicate {
+ bounded_ty,
+ bound_generic_params,
+ bounds,
+ span,
+ })) = self.diagnostic_metadata.current_where_predicate
+ {
+ if !bound_generic_params.is_empty() {
+ return false;
+ }
+ (bounded_ty, bounds, span)
+ } else {
+ return false;
+ };
+
+ // Confirm that the target is an associated type.
+ let (ty, position, path) = if let ast::TyKind::Path(
+ Some(ast::QSelf { ty, position, .. }),
+ path,
+ ) = &bounded_ty.kind
+ {
+ // use this to verify that ident is a type param.
+ let Some(partial_res) = self.r.partial_res_map.get(&bounded_ty.id) else {
+ return false;
+ };
+ if !(matches!(
+ partial_res.base_res(),
+ hir::def::Res::Def(hir::def::DefKind::AssocTy, _)
+ ) && partial_res.unresolved_segments() == 0)
+ {
+ return false;
+ }
+ (ty, position, path)
+ } else {
+ return false;
+ };
+
+ let peeled_ty = ty.peel_refs();
+ if let ast::TyKind::Path(None, type_param_path) = &peeled_ty.kind {
+ // Confirm that the `SelfTy` is a type parameter.
+ let Some(partial_res) = self.r.partial_res_map.get(&peeled_ty.id) else {
+ return false;
+ };
+ if !(matches!(
+ partial_res.base_res(),
+ hir::def::Res::Def(hir::def::DefKind::TyParam, _)
+ ) && partial_res.unresolved_segments() == 0)
+ {
+ return false;
+ }
+ if let (
+ [ast::PathSegment { ident: constrain_ident, args: None, .. }],
+ [ast::GenericBound::Trait(poly_trait_ref, ast::TraitBoundModifier::None)],
+ ) = (&type_param_path.segments[..], &bounds[..])
+ {
+ if let [ast::PathSegment { ident, args: None, .. }] =
+ &poly_trait_ref.trait_ref.path.segments[..]
+ {
+ if ident.span == span {
+ err.span_suggestion_verbose(
+ *where_span,
+ &format!("constrain the associated type to `{}`", ident),
+ format!(
+ "{}: {}<{} = {}>",
+ self.r
+ .session
+ .source_map()
+ .span_to_snippet(ty.span) // Account for `<&'a T as Foo>::Bar`.
+ .unwrap_or_else(|_| constrain_ident.to_string()),
+ path.segments[..*position]
+ .iter()
+ .map(|segment| path_segment_to_string(segment))
+ .collect::<Vec<_>>()
+ .join("::"),
+ path.segments[*position..]
+ .iter()
+ .map(|segment| path_segment_to_string(segment))
+ .collect::<Vec<_>>()
+ .join("::"),
+ ident,
+ ),
+ Applicability::MaybeIncorrect,
+ );
+ }
+ return true;
+ }
+ }
+ }
+ false
+ }
+
+ /// Check if the source is call expression and the first argument is `self`. If true,
+ /// return the span of whole call and the span for all arguments expect the first one (`self`).
+ fn call_has_self_arg(&self, source: PathSource<'_>) -> Option<(Span, Option<Span>)> {
+ let mut has_self_arg = None;
+ if let PathSource::Expr(Some(parent)) = source {
+ match &parent.kind {
+ ExprKind::Call(_, args) if !args.is_empty() => {
+ let mut expr_kind = &args[0].kind;
+ loop {
+ match expr_kind {
+ ExprKind::Path(_, arg_name) if arg_name.segments.len() == 1 => {
+ if arg_name.segments[0].ident.name == kw::SelfLower {
+ let call_span = parent.span;
+ let tail_args_span = if args.len() > 1 {
+ Some(Span::new(
+ args[1].span.lo(),
+ args.last().unwrap().span.hi(),
+ call_span.ctxt(),
+ None,
+ ))
+ } else {
+ None
+ };
+ has_self_arg = Some((call_span, tail_args_span));
+ }
+ break;
+ }
+ ExprKind::AddrOf(_, _, expr) => expr_kind = &expr.kind,
+ _ => break,
+ }
+ }
+ }
+ _ => (),
+ }
+ };
+ has_self_arg
+ }
+
+ fn followed_by_brace(&self, span: Span) -> (bool, Option<Span>) {
+ // HACK(estebank): find a better way to figure out that this was a
+ // parser issue where a struct literal is being used on an expression
+ // where a brace being opened means a block is being started. Look
+ // ahead for the next text to see if `span` is followed by a `{`.
+ let sm = self.r.session.source_map();
+ let mut sp = span;
+ loop {
+ sp = sm.next_point(sp);
+ match sm.span_to_snippet(sp) {
+ Ok(ref snippet) => {
+ if snippet.chars().any(|c| !c.is_whitespace()) {
+ break;
+ }
+ }
+ _ => break,
+ }
+ }
+ let followed_by_brace = matches!(sm.span_to_snippet(sp), Ok(ref snippet) if snippet == "{");
+ // In case this could be a struct literal that needs to be surrounded
+ // by parentheses, find the appropriate span.
+ let mut i = 0;
+ let mut closing_brace = None;
+ loop {
+ sp = sm.next_point(sp);
+ match sm.span_to_snippet(sp) {
+ Ok(ref snippet) => {
+ if snippet == "}" {
+ closing_brace = Some(span.to(sp));
+ break;
+ }
+ }
+ _ => break,
+ }
+ i += 1;
+ // The bigger the span, the more likely we're incorrect --
+ // bound it to 100 chars long.
+ if i > 100 {
+ break;
+ }
+ }
+ (followed_by_brace, closing_brace)
+ }
+
+ /// Provides context-dependent help for errors reported by the `smart_resolve_path_fragment`
+ /// function.
+ /// Returns `true` if able to provide context-dependent help.
+ fn smart_resolve_context_dependent_help(
+ &mut self,
+ err: &mut Diagnostic,
+ span: Span,
+ source: PathSource<'_>,
+ res: Res,
+ path_str: &str,
+ fallback_label: &str,
+ ) -> bool {
+ let ns = source.namespace();
+ let is_expected = &|res| source.is_expected(res);
+
+ let path_sep = |err: &mut Diagnostic, expr: &Expr| match expr.kind {
+ ExprKind::Field(_, ident) => {
+ err.span_suggestion(
+ expr.span,
+ "use the path separator to refer to an item",
+ format!("{}::{}", path_str, ident),
+ Applicability::MaybeIncorrect,
+ );
+ true
+ }
+ ExprKind::MethodCall(ref segment, ..) => {
+ let span = expr.span.with_hi(segment.ident.span.hi());
+ err.span_suggestion(
+ span,
+ "use the path separator to refer to an item",
+ format!("{}::{}", path_str, segment.ident),
+ Applicability::MaybeIncorrect,
+ );
+ true
+ }
+ _ => false,
+ };
+
+ let find_span = |source: &PathSource<'_>, err: &mut Diagnostic| {
+ match source {
+ PathSource::Expr(Some(Expr { span, kind: ExprKind::Call(_, _), .. }))
+ | PathSource::TupleStruct(span, _) => {
+ // We want the main underline to cover the suggested code as well for
+ // cleaner output.
+ err.set_span(*span);
+ *span
+ }
+ _ => span,
+ }
+ };
+
+ let mut bad_struct_syntax_suggestion = |def_id: DefId| {
+ let (followed_by_brace, closing_brace) = self.followed_by_brace(span);
+
+ match source {
+ PathSource::Expr(Some(
+ parent @ Expr { kind: ExprKind::Field(..) | ExprKind::MethodCall(..), .. },
+ )) if path_sep(err, &parent) => {}
+ PathSource::Expr(
+ None
+ | Some(Expr {
+ kind:
+ ExprKind::Path(..)
+ | ExprKind::Binary(..)
+ | ExprKind::Unary(..)
+ | ExprKind::If(..)
+ | ExprKind::While(..)
+ | ExprKind::ForLoop(..)
+ | ExprKind::Match(..),
+ ..
+ }),
+ ) if followed_by_brace => {
+ if let Some(sp) = closing_brace {
+ err.span_label(span, fallback_label);
+ err.multipart_suggestion(
+ "surround the struct literal with parentheses",
+ vec![
+ (sp.shrink_to_lo(), "(".to_string()),
+ (sp.shrink_to_hi(), ")".to_string()),
+ ],
+ Applicability::MaybeIncorrect,
+ );
+ } else {
+ err.span_label(
+ span, // Note the parentheses surrounding the suggestion below
+ format!(
+ "you might want to surround a struct literal with parentheses: \
+ `({} {{ /* fields */ }})`?",
+ path_str
+ ),
+ );
+ }
+ }
+ PathSource::Expr(_) | PathSource::TupleStruct(..) | PathSource::Pat => {
+ let span = find_span(&source, err);
+ if let Some(span) = self.def_span(def_id) {
+ err.span_label(span, &format!("`{}` defined here", path_str));
+ }
+ let (tail, descr, applicability) = match source {
+ PathSource::Pat | PathSource::TupleStruct(..) => {
+ ("", "pattern", Applicability::MachineApplicable)
+ }
+ _ => (": val", "literal", Applicability::HasPlaceholders),
+ };
+ let (fields, applicability) = match self.r.field_names.get(&def_id) {
+ Some(fields) => (
+ fields
+ .iter()
+ .map(|f| format!("{}{}", f.node, tail))
+ .collect::<Vec<String>>()
+ .join(", "),
+ applicability,
+ ),
+ None => ("/* fields */".to_string(), Applicability::HasPlaceholders),
+ };
+ let pad = match self.r.field_names.get(&def_id) {
+ Some(fields) if fields.is_empty() => "",
+ _ => " ",
+ };
+ err.span_suggestion(
+ span,
+ &format!("use struct {} syntax instead", descr),
+ format!("{path_str} {{{pad}{fields}{pad}}}"),
+ applicability,
+ );
+ }
+ _ => {
+ err.span_label(span, fallback_label);
+ }
+ }
+ };
+
+ match (res, source) {
+ (
+ Res::Def(DefKind::Macro(MacroKind::Bang), _),
+ PathSource::Expr(Some(Expr {
+ kind: ExprKind::Index(..) | ExprKind::Call(..), ..
+ }))
+ | PathSource::Struct,
+ ) => {
+ err.span_label(span, fallback_label);
+ err.span_suggestion_verbose(
+ span.shrink_to_hi(),
+ "use `!` to invoke the macro",
+ "!",
+ Applicability::MaybeIncorrect,
+ );
+ if path_str == "try" && span.rust_2015() {
+ err.note("if you want the `try` keyword, you need Rust 2018 or later");
+ }
+ }
+ (Res::Def(DefKind::Macro(MacroKind::Bang), _), _) => {
+ err.span_label(span, fallback_label);
+ }
+ (Res::Def(DefKind::TyAlias, def_id), PathSource::Trait(_)) => {
+ err.span_label(span, "type aliases cannot be used as traits");
+ if self.r.session.is_nightly_build() {
+ let msg = "you might have meant to use `#![feature(trait_alias)]` instead of a \
+ `type` alias";
+ if let Some(span) = self.def_span(def_id) {
+ if let Ok(snip) = self.r.session.source_map().span_to_snippet(span) {
+ // The span contains a type alias so we should be able to
+ // replace `type` with `trait`.
+ let snip = snip.replacen("type", "trait", 1);
+ err.span_suggestion(span, msg, snip, Applicability::MaybeIncorrect);
+ } else {
+ err.span_help(span, msg);
+ }
+ } else {
+ err.help(msg);
+ }
+ }
+ }
+ (Res::Def(DefKind::Mod, _), PathSource::Expr(Some(parent))) => {
+ if !path_sep(err, &parent) {
+ return false;
+ }
+ }
+ (
+ Res::Def(DefKind::Enum, def_id),
+ PathSource::TupleStruct(..) | PathSource::Expr(..),
+ ) => {
+ if self
+ .diagnostic_metadata
+ .current_type_ascription
+ .last()
+ .map(|sp| {
+ self.r
+ .session
+ .parse_sess
+ .type_ascription_path_suggestions
+ .borrow()
+ .contains(&sp)
+ })
+ .unwrap_or(false)
+ {
+ err.downgrade_to_delayed_bug();
+ // We already suggested changing `:` into `::` during parsing.
+ return false;
+ }
+
+ self.suggest_using_enum_variant(err, source, def_id, span);
+ }
+ (Res::Def(DefKind::Struct, def_id), source) if ns == ValueNS => {
+ let (ctor_def, ctor_vis, fields) =
+ if let Some(struct_ctor) = self.r.struct_constructors.get(&def_id).cloned() {
+ if let PathSource::Expr(Some(parent)) = source {
+ if let ExprKind::Field(..) | ExprKind::MethodCall(..) = parent.kind {
+ bad_struct_syntax_suggestion(def_id);
+ return true;
+ }
+ }
+ struct_ctor
+ } else {
+ bad_struct_syntax_suggestion(def_id);
+ return true;
+ };
+
+ let is_accessible = self.r.is_accessible_from(ctor_vis, self.parent_scope.module);
+ if !is_expected(ctor_def) || is_accessible {
+ return true;
+ }
+
+ let field_spans = match source {
+ // e.g. `if let Enum::TupleVariant(field1, field2) = _`
+ PathSource::TupleStruct(_, pattern_spans) => {
+ err.set_primary_message(
+ "cannot match against a tuple struct which contains private fields",
+ );
+
+ // Use spans of the tuple struct pattern.
+ Some(Vec::from(pattern_spans))
+ }
+ // e.g. `let _ = Enum::TupleVariant(field1, field2);`
+ _ if source.is_call() => {
+ err.set_primary_message(
+ "cannot initialize a tuple struct which contains private fields",
+ );
+
+ // Use spans of the tuple struct definition.
+ self.r
+ .field_names
+ .get(&def_id)
+ .map(|fields| fields.iter().map(|f| f.span).collect::<Vec<_>>())
+ }
+ _ => None,
+ };
+
+ if let Some(spans) =
+ field_spans.filter(|spans| spans.len() > 0 && fields.len() == spans.len())
+ {
+ let non_visible_spans: Vec<Span> = iter::zip(&fields, &spans)
+ .filter(|(vis, _)| {
+ !self.r.is_accessible_from(**vis, self.parent_scope.module)
+ })
+ .map(|(_, span)| *span)
+ .collect();
+
+ if non_visible_spans.len() > 0 {
+ let mut m: MultiSpan = non_visible_spans.clone().into();
+ non_visible_spans
+ .into_iter()
+ .for_each(|s| m.push_span_label(s, "private field"));
+ err.span_note(m, "constructor is not visible here due to private fields");
+ }
+
+ return true;
+ }
+
+ err.span_label(span, "constructor is not visible here due to private fields");
+ }
+ (
+ Res::Def(
+ DefKind::Union | DefKind::Variant | DefKind::Ctor(_, CtorKind::Fictive),
+ def_id,
+ ),
+ _,
+ ) if ns == ValueNS => {
+ bad_struct_syntax_suggestion(def_id);
+ }
+ (Res::Def(DefKind::Ctor(_, CtorKind::Const), def_id), _) if ns == ValueNS => {
+ match source {
+ PathSource::Expr(_) | PathSource::TupleStruct(..) | PathSource::Pat => {
+ let span = find_span(&source, err);
+ if let Some(span) = self.def_span(def_id) {
+ err.span_label(span, &format!("`{}` defined here", path_str));
+ }
+ err.span_suggestion(
+ span,
+ "use this syntax instead",
+ path_str,
+ Applicability::MaybeIncorrect,
+ );
+ }
+ _ => return false,
+ }
+ }
+ (Res::Def(DefKind::Ctor(_, CtorKind::Fn), def_id), _) if ns == ValueNS => {
+ if let Some(span) = self.def_span(def_id) {
+ err.span_label(span, &format!("`{}` defined here", path_str));
+ }
+ let fields = self.r.field_names.get(&def_id).map_or_else(
+ || "/* fields */".to_string(),
+ |fields| vec!["_"; fields.len()].join(", "),
+ );
+ err.span_suggestion(
+ span,
+ "use the tuple variant pattern syntax instead",
+ format!("{}({})", path_str, fields),
+ Applicability::HasPlaceholders,
+ );
+ }
+ (Res::SelfTy { .. }, _) if ns == ValueNS => {
+ err.span_label(span, fallback_label);
+ err.note("can't use `Self` as a constructor, you must use the implemented struct");
+ }
+ (Res::Def(DefKind::TyAlias | DefKind::AssocTy, _), _) if ns == ValueNS => {
+ err.note("can't use a type alias as a constructor");
+ }
+ _ => return false,
+ }
+ true
+ }
+
+ /// Given the target `ident` and `kind`, search for the similarly named associated item
+ /// in `self.current_trait_ref`.
+ pub(crate) fn find_similarly_named_assoc_item(
+ &mut self,
+ ident: Symbol,
+ kind: &AssocItemKind,
+ ) -> Option<Symbol> {
+ let (module, _) = self.current_trait_ref.as_ref()?;
+ if ident == kw::Underscore {
+ // We do nothing for `_`.
+ return None;
+ }
+
+ let resolutions = self.r.resolutions(module);
+ let targets = resolutions
+ .borrow()
+ .iter()
+ .filter_map(|(key, res)| res.borrow().binding.map(|binding| (key, binding.res())))
+ .filter(|(_, res)| match (kind, res) {
+ (AssocItemKind::Const(..), Res::Def(DefKind::AssocConst, _)) => true,
+ (AssocItemKind::Fn(_), Res::Def(DefKind::AssocFn, _)) => true,
+ (AssocItemKind::TyAlias(..), Res::Def(DefKind::AssocTy, _)) => true,
+ _ => false,
+ })
+ .map(|(key, _)| key.ident.name)
+ .collect::<Vec<_>>();
+
+ find_best_match_for_name(&targets, ident, None)
+ }
+
+ fn lookup_assoc_candidate<FilterFn>(
+ &mut self,
+ ident: Ident,
+ ns: Namespace,
+ filter_fn: FilterFn,
+ ) -> Option<AssocSuggestion>
+ where
+ FilterFn: Fn(Res) -> bool,
+ {
+ fn extract_node_id(t: &Ty) -> Option<NodeId> {
+ match t.kind {
+ TyKind::Path(None, _) => Some(t.id),
+ TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
+ // This doesn't handle the remaining `Ty` variants as they are not
+ // that commonly the self_type, it might be interesting to provide
+ // support for those in future.
+ _ => None,
+ }
+ }
+
+ // Fields are generally expected in the same contexts as locals.
+ if filter_fn(Res::Local(ast::DUMMY_NODE_ID)) {
+ if let Some(node_id) =
+ self.diagnostic_metadata.current_self_type.as_ref().and_then(extract_node_id)
+ {
+ // Look for a field with the same name in the current self_type.
+ if let Some(resolution) = self.r.partial_res_map.get(&node_id) {
+ match resolution.base_res() {
+ Res::Def(DefKind::Struct | DefKind::Union, did)
+ if resolution.unresolved_segments() == 0 =>
+ {
+ if let Some(field_names) = self.r.field_names.get(&did) {
+ if field_names
+ .iter()
+ .any(|&field_name| ident.name == field_name.node)
+ {
+ return Some(AssocSuggestion::Field);
+ }
+ }
+ }
+ _ => {}
+ }
+ }
+ }
+ }
+
+ if let Some(items) = self.diagnostic_metadata.current_trait_assoc_items {
+ for assoc_item in items {
+ if assoc_item.ident == ident {
+ return Some(match &assoc_item.kind {
+ ast::AssocItemKind::Const(..) => AssocSuggestion::AssocConst,
+ ast::AssocItemKind::Fn(box ast::Fn { sig, .. }) if sig.decl.has_self() => {
+ AssocSuggestion::MethodWithSelf
+ }
+ ast::AssocItemKind::Fn(..) => AssocSuggestion::AssocFn,
+ ast::AssocItemKind::TyAlias(..) => AssocSuggestion::AssocType,
+ ast::AssocItemKind::MacCall(_) => continue,
+ });
+ }
+ }
+ }
+
+ // Look for associated items in the current trait.
+ if let Some((module, _)) = self.current_trait_ref {
+ if let Ok(binding) = self.r.maybe_resolve_ident_in_module(
+ ModuleOrUniformRoot::Module(module),
+ ident,
+ ns,
+ &self.parent_scope,
+ ) {
+ let res = binding.res();
+ if filter_fn(res) {
+ if self.r.has_self.contains(&res.def_id()) {
+ return Some(AssocSuggestion::MethodWithSelf);
+ } else {
+ match res {
+ Res::Def(DefKind::AssocFn, _) => return Some(AssocSuggestion::AssocFn),
+ Res::Def(DefKind::AssocConst, _) => {
+ return Some(AssocSuggestion::AssocConst);
+ }
+ Res::Def(DefKind::AssocTy, _) => {
+ return Some(AssocSuggestion::AssocType);
+ }
+ _ => {}
+ }
+ }
+ }
+ }
+ }
+
+ None
+ }
+
+ fn lookup_typo_candidate(
+ &mut self,
+ path: &[Segment],
+ ns: Namespace,
+ filter_fn: &impl Fn(Res) -> bool,
+ ) -> Option<TypoSuggestion> {
+ let mut names = Vec::new();
+ if path.len() == 1 {
+ // Search in lexical scope.
+ // Walk backwards up the ribs in scope and collect candidates.
+ for rib in self.ribs[ns].iter().rev() {
+ // Locals and type parameters
+ for (ident, &res) in &rib.bindings {
+ if filter_fn(res) {
+ names.push(TypoSuggestion::typo_from_res(ident.name, res));
+ }
+ }
+ // Items in scope
+ if let RibKind::ModuleRibKind(module) = rib.kind {
+ // Items from this module
+ self.r.add_module_candidates(module, &mut names, &filter_fn);
+
+ if let ModuleKind::Block = module.kind {
+ // We can see through blocks
+ } else {
+ // Items from the prelude
+ if !module.no_implicit_prelude {
+ let extern_prelude = self.r.extern_prelude.clone();
+ names.extend(extern_prelude.iter().flat_map(|(ident, _)| {
+ self.r.crate_loader.maybe_process_path_extern(ident.name).and_then(
+ |crate_id| {
+ let crate_mod =
+ Res::Def(DefKind::Mod, crate_id.as_def_id());
+
+ if filter_fn(crate_mod) {
+ Some(TypoSuggestion::typo_from_res(
+ ident.name, crate_mod,
+ ))
+ } else {
+ None
+ }
+ },
+ )
+ }));
+
+ if let Some(prelude) = self.r.prelude {
+ self.r.add_module_candidates(prelude, &mut names, &filter_fn);
+ }
+ }
+ break;
+ }
+ }
+ }
+ // Add primitive types to the mix
+ if filter_fn(Res::PrimTy(PrimTy::Bool)) {
+ names.extend(PrimTy::ALL.iter().map(|prim_ty| {
+ TypoSuggestion::typo_from_res(prim_ty.name(), Res::PrimTy(*prim_ty))
+ }))
+ }
+ } else {
+ // Search in module.
+ let mod_path = &path[..path.len() - 1];
+ if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
+ self.resolve_path(mod_path, Some(TypeNS), None)
+ {
+ self.r.add_module_candidates(module, &mut names, &filter_fn);
+ }
+ }
+
+ let name = path[path.len() - 1].ident.name;
+ // Make sure error reporting is deterministic.
+ names.sort_by(|a, b| a.candidate.as_str().partial_cmp(b.candidate.as_str()).unwrap());
+
+ match find_best_match_for_name(
+ &names.iter().map(|suggestion| suggestion.candidate).collect::<Vec<Symbol>>(),
+ name,
+ None,
+ ) {
+ Some(found) if found != name => {
+ names.into_iter().find(|suggestion| suggestion.candidate == found)
+ }
+ _ => None,
+ }
+ }
+
+ // Returns the name of the Rust type approximately corresponding to
+ // a type name in another programming language.
+ fn likely_rust_type(path: &[Segment]) -> Option<Symbol> {
+ let name = path[path.len() - 1].ident.as_str();
+ // Common Java types
+ Some(match name {
+ "byte" => sym::u8, // In Java, bytes are signed, but in practice one almost always wants unsigned bytes.
+ "short" => sym::i16,
+ "Bool" => sym::bool,
+ "Boolean" => sym::bool,
+ "boolean" => sym::bool,
+ "int" => sym::i32,
+ "long" => sym::i64,
+ "float" => sym::f32,
+ "double" => sym::f64,
+ _ => return None,
+ })
+ }
+
+ /// Only used in a specific case of type ascription suggestions
+ fn get_colon_suggestion_span(&self, start: Span) -> Span {
+ let sm = self.r.session.source_map();
+ start.to(sm.next_point(start))
+ }
+
+ fn type_ascription_suggestion(&self, err: &mut Diagnostic, base_span: Span) -> bool {
+ let sm = self.r.session.source_map();
+ let base_snippet = sm.span_to_snippet(base_span);
+ if let Some(&sp) = self.diagnostic_metadata.current_type_ascription.last() {
+ if let Ok(snippet) = sm.span_to_snippet(sp) {
+ let len = snippet.trim_end().len() as u32;
+ if snippet.trim() == ":" {
+ let colon_sp =
+ sp.with_lo(sp.lo() + BytePos(len - 1)).with_hi(sp.lo() + BytePos(len));
+ let mut show_label = true;
+ if sm.is_multiline(sp) {
+ err.span_suggestion_short(
+ colon_sp,
+ "maybe you meant to write `;` here",
+ ";",
+ Applicability::MaybeIncorrect,
+ );
+ } else {
+ let after_colon_sp =
+ self.get_colon_suggestion_span(colon_sp.shrink_to_hi());
+ if snippet.len() == 1 {
+ // `foo:bar`
+ err.span_suggestion(
+ colon_sp,
+ "maybe you meant to write a path separator here",
+ "::",
+ Applicability::MaybeIncorrect,
+ );
+ show_label = false;
+ if !self
+ .r
+ .session
+ .parse_sess
+ .type_ascription_path_suggestions
+ .borrow_mut()
+ .insert(colon_sp)
+ {
+ err.downgrade_to_delayed_bug();
+ }
+ }
+ if let Ok(base_snippet) = base_snippet {
+ let mut sp = after_colon_sp;
+ for _ in 0..100 {
+ // Try to find an assignment
+ sp = sm.next_point(sp);
+ let snippet = sm.span_to_snippet(sp.to(sm.next_point(sp)));
+ match snippet {
+ Ok(ref x) if x.as_str() == "=" => {
+ err.span_suggestion(
+ base_span,
+ "maybe you meant to write an assignment here",
+ format!("let {}", base_snippet),
+ Applicability::MaybeIncorrect,
+ );
+ show_label = false;
+ break;
+ }
+ Ok(ref x) if x.as_str() == "\n" => break,
+ Err(_) => break,
+ Ok(_) => {}
+ }
+ }
+ }
+ }
+ if show_label {
+ err.span_label(
+ base_span,
+ "expecting a type here because of type ascription",
+ );
+ }
+ return show_label;
+ }
+ }
+ }
+ false
+ }
+
+ fn find_module(&mut self, def_id: DefId) -> Option<(Module<'a>, ImportSuggestion)> {
+ let mut result = None;
+ let mut seen_modules = FxHashSet::default();
+ let mut worklist = vec![(self.r.graph_root, Vec::new())];
+
+ while let Some((in_module, path_segments)) = worklist.pop() {
+ // abort if the module is already found
+ if result.is_some() {
+ break;
+ }
+
+ in_module.for_each_child(self.r, |_, ident, _, name_binding| {
+ // abort if the module is already found or if name_binding is private external
+ if result.is_some() || !name_binding.vis.is_visible_locally() {
+ return;
+ }
+ if let Some(module) = name_binding.module() {
+ // form the path
+ let mut path_segments = path_segments.clone();
+ path_segments.push(ast::PathSegment::from_ident(ident));
+ let module_def_id = module.def_id();
+ if module_def_id == def_id {
+ let path =
+ Path { span: name_binding.span, segments: path_segments, tokens: None };
+ result = Some((
+ module,
+ ImportSuggestion {
+ did: Some(def_id),
+ descr: "module",
+ path,
+ accessible: true,
+ note: None,
+ },
+ ));
+ } else {
+ // add the module to the lookup
+ if seen_modules.insert(module_def_id) {
+ worklist.push((module, path_segments));
+ }
+ }
+ }
+ });
+ }
+
+ result
+ }
+
+ fn collect_enum_ctors(&mut self, def_id: DefId) -> Option<Vec<(Path, DefId, CtorKind)>> {
+ self.find_module(def_id).map(|(enum_module, enum_import_suggestion)| {
+ let mut variants = Vec::new();
+ enum_module.for_each_child(self.r, |_, ident, _, name_binding| {
+ if let Res::Def(DefKind::Ctor(CtorOf::Variant, kind), def_id) = name_binding.res() {
+ let mut segms = enum_import_suggestion.path.segments.clone();
+ segms.push(ast::PathSegment::from_ident(ident));
+ let path = Path { span: name_binding.span, segments: segms, tokens: None };
+ variants.push((path, def_id, kind));
+ }
+ });
+ variants
+ })
+ }
+
+ /// Adds a suggestion for using an enum's variant when an enum is used instead.
+ fn suggest_using_enum_variant(
+ &mut self,
+ err: &mut Diagnostic,
+ source: PathSource<'_>,
+ def_id: DefId,
+ span: Span,
+ ) {
+ let Some(variants) = self.collect_enum_ctors(def_id) else {
+ err.note("you might have meant to use one of the enum's variants");
+ return;
+ };
+
+ let suggest_only_tuple_variants =
+ matches!(source, PathSource::TupleStruct(..)) || source.is_call();
+ if suggest_only_tuple_variants {
+ // Suggest only tuple variants regardless of whether they have fields and do not
+ // suggest path with added parentheses.
+ let suggestable_variants = variants
+ .iter()
+ .filter(|(.., kind)| *kind == CtorKind::Fn)
+ .map(|(variant, ..)| path_names_to_string(variant))
+ .collect::<Vec<_>>();
+
+ let non_suggestable_variant_count = variants.len() - suggestable_variants.len();
+
+ let source_msg = if source.is_call() {
+ "to construct"
+ } else if matches!(source, PathSource::TupleStruct(..)) {
+ "to match against"
+ } else {
+ unreachable!()
+ };
+
+ if !suggestable_variants.is_empty() {
+ let msg = if non_suggestable_variant_count == 0 && suggestable_variants.len() == 1 {
+ format!("try {} the enum's variant", source_msg)
+ } else {
+ format!("try {} one of the enum's variants", source_msg)
+ };
+
+ err.span_suggestions(
+ span,
+ &msg,
+ suggestable_variants.into_iter(),
+ Applicability::MaybeIncorrect,
+ );
+ }
+
+ // If the enum has no tuple variants..
+ if non_suggestable_variant_count == variants.len() {
+ err.help(&format!("the enum has no tuple variants {}", source_msg));
+ }
+
+ // If there are also non-tuple variants..
+ if non_suggestable_variant_count == 1 {
+ err.help(&format!(
+ "you might have meant {} the enum's non-tuple variant",
+ source_msg
+ ));
+ } else if non_suggestable_variant_count >= 1 {
+ err.help(&format!(
+ "you might have meant {} one of the enum's non-tuple variants",
+ source_msg
+ ));
+ }
+ } else {
+ let needs_placeholder = |def_id: DefId, kind: CtorKind| {
+ let has_no_fields = self.r.field_names.get(&def_id).map_or(false, |f| f.is_empty());
+ match kind {
+ CtorKind::Const => false,
+ CtorKind::Fn | CtorKind::Fictive if has_no_fields => false,
+ _ => true,
+ }
+ };
+
+ let mut suggestable_variants = variants
+ .iter()
+ .filter(|(_, def_id, kind)| !needs_placeholder(*def_id, *kind))
+ .map(|(variant, _, kind)| (path_names_to_string(variant), kind))
+ .map(|(variant, kind)| match kind {
+ CtorKind::Const => variant,
+ CtorKind::Fn => format!("({}())", variant),
+ CtorKind::Fictive => format!("({} {{}})", variant),
+ })
+ .collect::<Vec<_>>();
+
+ if !suggestable_variants.is_empty() {
+ let msg = if suggestable_variants.len() == 1 {
+ "you might have meant to use the following enum variant"
+ } else {
+ "you might have meant to use one of the following enum variants"
+ };
+
+ err.span_suggestions(
+ span,
+ msg,
+ suggestable_variants.drain(..),
+ Applicability::MaybeIncorrect,
+ );
+ }
+
+ let suggestable_variants_with_placeholders = variants
+ .iter()
+ .filter(|(_, def_id, kind)| needs_placeholder(*def_id, *kind))
+ .map(|(variant, _, kind)| (path_names_to_string(variant), kind))
+ .filter_map(|(variant, kind)| match kind {
+ CtorKind::Fn => Some(format!("({}(/* fields */))", variant)),
+ CtorKind::Fictive => Some(format!("({} {{ /* fields */ }})", variant)),
+ _ => None,
+ })
+ .collect::<Vec<_>>();
+
+ if !suggestable_variants_with_placeholders.is_empty() {
+ let msg = match (
+ suggestable_variants.is_empty(),
+ suggestable_variants_with_placeholders.len(),
+ ) {
+ (true, 1) => "the following enum variant is available",
+ (true, _) => "the following enum variants are available",
+ (false, 1) => "alternatively, the following enum variant is available",
+ (false, _) => "alternatively, the following enum variants are also available",
+ };
+
+ err.span_suggestions(
+ span,
+ msg,
+ suggestable_variants_with_placeholders.into_iter(),
+ Applicability::HasPlaceholders,
+ );
+ }
+ };
+
+ if def_id.is_local() {
+ if let Some(span) = self.def_span(def_id) {
+ err.span_note(span, "the enum is defined here");
+ }
+ }
+ }
+
+ pub(crate) fn report_missing_type_error(
+ &self,
+ path: &[Segment],
+ ) -> Option<(Span, &'static str, String, Applicability)> {
+ let (ident, span) = match path {
+ [segment] if !segment.has_generic_args && segment.ident.name != kw::SelfUpper => {
+ (segment.ident.to_string(), segment.ident.span)
+ }
+ _ => return None,
+ };
+ let mut iter = ident.chars().map(|c| c.is_uppercase());
+ let single_uppercase_char =
+ matches!(iter.next(), Some(true)) && matches!(iter.next(), None);
+ if !self.diagnostic_metadata.currently_processing_generics && !single_uppercase_char {
+ return None;
+ }
+ match (self.diagnostic_metadata.current_item, single_uppercase_char, self.diagnostic_metadata.currently_processing_generics) {
+ (Some(Item { kind: ItemKind::Fn(..), ident, .. }), _, _) if ident.name == sym::main => {
+ // Ignore `fn main()` as we don't want to suggest `fn main<T>()`
+ }
+ (
+ Some(Item {
+ kind:
+ kind @ ItemKind::Fn(..)
+ | kind @ ItemKind::Enum(..)
+ | kind @ ItemKind::Struct(..)
+ | kind @ ItemKind::Union(..),
+ ..
+ }),
+ true, _
+ )
+ // Without the 2nd `true`, we'd suggest `impl <T>` for `impl T` when a type `T` isn't found
+ | (Some(Item { kind: kind @ ItemKind::Impl(..), .. }), true, true)
+ | (Some(Item { kind, .. }), false, _) => {
+ // Likely missing type parameter.
+ if let Some(generics) = kind.generics() {
+ if span.overlaps(generics.span) {
+ // Avoid the following:
+ // error[E0405]: cannot find trait `A` in this scope
+ // --> $DIR/typo-suggestion-named-underscore.rs:CC:LL
+ // |
+ // L | fn foo<T: A>(x: T) {} // Shouldn't suggest underscore
+ // | ^- help: you might be missing a type parameter: `, A`
+ // | |
+ // | not found in this scope
+ return None;
+ }
+ let msg = "you might be missing a type parameter";
+ let (span, sugg) = if let [.., param] = &generics.params[..] {
+ let span = if let [.., bound] = &param.bounds[..] {
+ bound.span()
+ } else if let GenericParam {
+ kind: GenericParamKind::Const { ty, kw_span: _, default }, ..
+ } = param {
+ default.as_ref().map(|def| def.value.span).unwrap_or(ty.span)
+ } else {
+ param.ident.span
+ };
+ (span, format!(", {}", ident))
+ } else {
+ (generics.span, format!("<{}>", ident))
+ };
+ // Do not suggest if this is coming from macro expansion.
+ if span.can_be_used_for_suggestions() {
+ return Some((
+ span.shrink_to_hi(),
+ msg,
+ sugg,
+ Applicability::MaybeIncorrect,
+ ));
+ }
+ }
+ }
+ _ => {}
+ }
+ None
+ }
+
+ /// Given the target `label`, search the `rib_index`th label rib for similarly named labels,
+ /// optionally returning the closest match and whether it is reachable.
+ pub(crate) fn suggestion_for_label_in_rib(
+ &self,
+ rib_index: usize,
+ label: Ident,
+ ) -> Option<LabelSuggestion> {
+ // Are ribs from this `rib_index` within scope?
+ let within_scope = self.is_label_valid_from_rib(rib_index);
+
+ let rib = &self.label_ribs[rib_index];
+ let names = rib
+ .bindings
+ .iter()
+ .filter(|(id, _)| id.span.eq_ctxt(label.span))
+ .map(|(id, _)| id.name)
+ .collect::<Vec<Symbol>>();
+
+ find_best_match_for_name(&names, label.name, None).map(|symbol| {
+ // Upon finding a similar name, get the ident that it was from - the span
+ // contained within helps make a useful diagnostic. In addition, determine
+ // whether this candidate is within scope.
+ let (ident, _) = rib.bindings.iter().find(|(ident, _)| ident.name == symbol).unwrap();
+ (*ident, within_scope)
+ })
+ }
+
+ pub(crate) fn maybe_report_lifetime_uses(
+ &mut self,
+ generics_span: Span,
+ params: &[ast::GenericParam],
+ ) {
+ for (param_index, param) in params.iter().enumerate() {
+ let GenericParamKind::Lifetime = param.kind else { continue };
+
+ let def_id = self.r.local_def_id(param.id);
+
+ let use_set = self.lifetime_uses.remove(&def_id);
+ debug!(
+ "Use set for {:?}({:?} at {:?}) is {:?}",
+ def_id, param.ident, param.ident.span, use_set
+ );
+
+ let deletion_span = || {
+ if params.len() == 1 {
+ // if sole lifetime, remove the entire `<>` brackets
+ generics_span
+ } else if param_index == 0 {
+ // if removing within `<>` brackets, we also want to
+ // delete a leading or trailing comma as appropriate
+ param.span().to(params[param_index + 1].span().shrink_to_lo())
+ } else {
+ // if removing within `<>` brackets, we also want to
+ // delete a leading or trailing comma as appropriate
+ params[param_index - 1].span().shrink_to_hi().to(param.span())
+ }
+ };
+ match use_set {
+ Some(LifetimeUseSet::Many) => {}
+ Some(LifetimeUseSet::One { use_span, use_ctxt }) => {
+ debug!(?param.ident, ?param.ident.span, ?use_span);
+
+ let elidable = matches!(use_ctxt, LifetimeCtxt::Rptr);
+
+ let deletion_span = deletion_span();
+ self.r.lint_buffer.buffer_lint_with_diagnostic(
+ lint::builtin::SINGLE_USE_LIFETIMES,
+ param.id,
+ param.ident.span,
+ &format!("lifetime parameter `{}` only used once", param.ident),
+ lint::BuiltinLintDiagnostics::SingleUseLifetime {
+ param_span: param.ident.span,
+ use_span: Some((use_span, elidable)),
+ deletion_span,
+ },
+ );
+ }
+ None => {
+ debug!(?param.ident, ?param.ident.span);
+
+ let deletion_span = deletion_span();
+ self.r.lint_buffer.buffer_lint_with_diagnostic(
+ lint::builtin::UNUSED_LIFETIMES,
+ param.id,
+ param.ident.span,
+ &format!("lifetime parameter `{}` never used", param.ident),
+ lint::BuiltinLintDiagnostics::SingleUseLifetime {
+ param_span: param.ident.span,
+ use_span: None,
+ deletion_span,
+ },
+ );
+ }
+ }
+ }
+ }
+
+ pub(crate) fn emit_undeclared_lifetime_error(
+ &self,
+ lifetime_ref: &ast::Lifetime,
+ outer_lifetime_ref: Option<Ident>,
+ ) {
+ debug_assert_ne!(lifetime_ref.ident.name, kw::UnderscoreLifetime);
+ let mut err = if let Some(outer) = outer_lifetime_ref {
+ let mut err = struct_span_err!(
+ self.r.session,
+ lifetime_ref.ident.span,
+ E0401,
+ "can't use generic parameters from outer item",
+ );
+ err.span_label(lifetime_ref.ident.span, "use of generic parameter from outer item");
+ err.span_label(outer.span, "lifetime parameter from outer item");
+ err
+ } else {
+ let mut err = struct_span_err!(
+ self.r.session,
+ lifetime_ref.ident.span,
+ E0261,
+ "use of undeclared lifetime name `{}`",
+ lifetime_ref.ident
+ );
+ err.span_label(lifetime_ref.ident.span, "undeclared lifetime");
+ err
+ };
+ self.suggest_introducing_lifetime(
+ &mut err,
+ Some(lifetime_ref.ident.name.as_str()),
+ |err, _, span, message, suggestion| {
+ err.span_suggestion(span, message, suggestion, Applicability::MaybeIncorrect);
+ true
+ },
+ );
+ err.emit();
+ }
+
+ fn suggest_introducing_lifetime(
+ &self,
+ err: &mut DiagnosticBuilder<'_, ErrorGuaranteed>,
+ name: Option<&str>,
+ suggest: impl Fn(&mut DiagnosticBuilder<'_, ErrorGuaranteed>, bool, Span, &str, String) -> bool,
+ ) {
+ let mut suggest_note = true;
+ for rib in self.lifetime_ribs.iter().rev() {
+ let mut should_continue = true;
+ match rib.kind {
+ LifetimeRibKind::Generics { binder: _, span, kind } => {
+ if !span.can_be_used_for_suggestions() && suggest_note && let Some(name) = name {
+ suggest_note = false; // Avoid displaying the same help multiple times.
+ err.span_label(
+ span,
+ &format!(
+ "lifetime `{}` is missing in item created through this procedural macro",
+ name,
+ ),
+ );
+ continue;
+ }
+
+ let higher_ranked = matches!(
+ kind,
+ LifetimeBinderKind::BareFnType
+ | LifetimeBinderKind::PolyTrait
+ | LifetimeBinderKind::WhereBound
+ );
+ let (span, sugg) = if span.is_empty() {
+ let sugg = format!(
+ "{}<{}>{}",
+ if higher_ranked { "for" } else { "" },
+ name.unwrap_or("'a"),
+ if higher_ranked { " " } else { "" },
+ );
+ (span, sugg)
+ } else {
+ let span =
+ self.r.session.source_map().span_through_char(span, '<').shrink_to_hi();
+ let sugg = format!("{}, ", name.unwrap_or("'a"));
+ (span, sugg)
+ };
+ if higher_ranked {
+ let message = format!(
+ "consider making the {} lifetime-generic with a new `{}` lifetime",
+ kind.descr(),
+ name.unwrap_or("'a"),
+ );
+ should_continue = suggest(err, true, span, &message, sugg);
+ err.note_once(
+ "for more information on higher-ranked polymorphism, visit \
+ https://doc.rust-lang.org/nomicon/hrtb.html",
+ );
+ } else if let Some(name) = name {
+ let message = format!("consider introducing lifetime `{}` here", name);
+ should_continue = suggest(err, false, span, &message, sugg);
+ } else {
+ let message = format!("consider introducing a named lifetime parameter");
+ should_continue = suggest(err, false, span, &message, sugg);
+ }
+ }
+ LifetimeRibKind::Item => break,
+ _ => {}
+ }
+ if !should_continue {
+ break;
+ }
+ }
+ }
+
+ pub(crate) fn emit_non_static_lt_in_const_generic_error(&self, lifetime_ref: &ast::Lifetime) {
+ struct_span_err!(
+ self.r.session,
+ lifetime_ref.ident.span,
+ E0771,
+ "use of non-static lifetime `{}` in const generic",
+ lifetime_ref.ident
+ )
+ .note(
+ "for more information, see issue #74052 \
+ <https://github.com/rust-lang/rust/issues/74052>",
+ )
+ .emit();
+ }
+
+ /// Non-static lifetimes are prohibited in anonymous constants under `min_const_generics`.
+ /// This function will emit an error if `generic_const_exprs` is not enabled, the body identified by
+ /// `body_id` is an anonymous constant and `lifetime_ref` is non-static.
+ pub(crate) fn maybe_emit_forbidden_non_static_lifetime_error(
+ &self,
+ lifetime_ref: &ast::Lifetime,
+ ) {
+ let feature_active = self.r.session.features_untracked().generic_const_exprs;
+ if !feature_active {
+ feature_err(
+ &self.r.session.parse_sess,
+ sym::generic_const_exprs,
+ lifetime_ref.ident.span,
+ "a non-static lifetime is not allowed in a `const`",
+ )
+ .emit();
+ }
+ }
+
+ pub(crate) fn report_missing_lifetime_specifiers(
+ &mut self,
+ lifetime_refs: Vec<MissingLifetime>,
+ function_param_lifetimes: Option<(Vec<MissingLifetime>, Vec<ElisionFnParameter>)>,
+ ) -> ErrorGuaranteed {
+ let num_lifetimes: usize = lifetime_refs.iter().map(|lt| lt.count).sum();
+ let spans: Vec<_> = lifetime_refs.iter().map(|lt| lt.span).collect();
+
+ let mut err = struct_span_err!(
+ self.r.session,
+ spans,
+ E0106,
+ "missing lifetime specifier{}",
+ pluralize!(num_lifetimes)
+ );
+ self.add_missing_lifetime_specifiers_label(
+ &mut err,
+ lifetime_refs,
+ function_param_lifetimes,
+ );
+ err.emit()
+ }
+
+ pub(crate) fn add_missing_lifetime_specifiers_label(
+ &mut self,
+ err: &mut DiagnosticBuilder<'_, ErrorGuaranteed>,
+ lifetime_refs: Vec<MissingLifetime>,
+ function_param_lifetimes: Option<(Vec<MissingLifetime>, Vec<ElisionFnParameter>)>,
+ ) {
+ for &lt in &lifetime_refs {
+ err.span_label(
+ lt.span,
+ format!(
+ "expected {} lifetime parameter{}",
+ if lt.count == 1 { "named".to_string() } else { lt.count.to_string() },
+ pluralize!(lt.count),
+ ),
+ );
+ }
+
+ let mut in_scope_lifetimes: Vec<_> = self
+ .lifetime_ribs
+ .iter()
+ .rev()
+ .take_while(|rib| !matches!(rib.kind, LifetimeRibKind::Item))
+ .flat_map(|rib| rib.bindings.iter())
+ .map(|(&ident, &res)| (ident, res))
+ .filter(|(ident, _)| ident.name != kw::UnderscoreLifetime)
+ .collect();
+ debug!(?in_scope_lifetimes);
+
+ debug!(?function_param_lifetimes);
+ if let Some((param_lifetimes, params)) = &function_param_lifetimes {
+ let elided_len = param_lifetimes.len();
+ let num_params = params.len();
+
+ let mut m = String::new();
+
+ for (i, info) in params.iter().enumerate() {
+ let ElisionFnParameter { ident, index, lifetime_count, span } = *info;
+ debug_assert_ne!(lifetime_count, 0);
+
+ err.span_label(span, "");
+
+ if i != 0 {
+ if i + 1 < num_params {
+ m.push_str(", ");
+ } else if num_params == 2 {
+ m.push_str(" or ");
+ } else {
+ m.push_str(", or ");
+ }
+ }
+
+ let help_name = if let Some(ident) = ident {
+ format!("`{}`", ident)
+ } else {
+ format!("argument {}", index + 1)
+ };
+
+ if lifetime_count == 1 {
+ m.push_str(&help_name[..])
+ } else {
+ m.push_str(&format!("one of {}'s {} lifetimes", help_name, lifetime_count)[..])
+ }
+ }
+
+ if num_params == 0 {
+ err.help(
+ "this function's return type contains a borrowed value, \
+ but there is no value for it to be borrowed from",
+ );
+ if in_scope_lifetimes.is_empty() {
+ in_scope_lifetimes = vec![(
+ Ident::with_dummy_span(kw::StaticLifetime),
+ (DUMMY_NODE_ID, LifetimeRes::Static),
+ )];
+ }
+ } else if elided_len == 0 {
+ err.help(
+ "this function's return type contains a borrowed value with \
+ an elided lifetime, but the lifetime cannot be derived from \
+ the arguments",
+ );
+ if in_scope_lifetimes.is_empty() {
+ in_scope_lifetimes = vec![(
+ Ident::with_dummy_span(kw::StaticLifetime),
+ (DUMMY_NODE_ID, LifetimeRes::Static),
+ )];
+ }
+ } else if num_params == 1 {
+ err.help(&format!(
+ "this function's return type contains a borrowed value, \
+ but the signature does not say which {} it is borrowed from",
+ m
+ ));
+ } else {
+ err.help(&format!(
+ "this function's return type contains a borrowed value, \
+ but the signature does not say whether it is borrowed from {}",
+ m
+ ));
+ }
+ }
+
+ let existing_name = match &in_scope_lifetimes[..] {
+ [] => Symbol::intern("'a"),
+ [(existing, _)] => existing.name,
+ _ => Symbol::intern("'lifetime"),
+ };
+
+ let mut spans_suggs: Vec<_> = Vec::new();
+ let build_sugg = |lt: MissingLifetime| match lt.kind {
+ MissingLifetimeKind::Underscore => {
+ debug_assert_eq!(lt.count, 1);
+ (lt.span, existing_name.to_string())
+ }
+ MissingLifetimeKind::Ampersand => {
+ debug_assert_eq!(lt.count, 1);
+ (lt.span.shrink_to_hi(), format!("{} ", existing_name))
+ }
+ MissingLifetimeKind::Comma => {
+ let sugg: String = std::iter::repeat([existing_name.as_str(), ", "])
+ .take(lt.count)
+ .flatten()
+ .collect();
+ (lt.span.shrink_to_hi(), sugg)
+ }
+ MissingLifetimeKind::Brackets => {
+ let sugg: String = std::iter::once("<")
+ .chain(
+ std::iter::repeat(existing_name.as_str()).take(lt.count).intersperse(", "),
+ )
+ .chain([">"])
+ .collect();
+ (lt.span.shrink_to_hi(), sugg)
+ }
+ };
+ for &lt in &lifetime_refs {
+ spans_suggs.push(build_sugg(lt));
+ }
+ debug!(?spans_suggs);
+ match in_scope_lifetimes.len() {
+ 0 => {
+ if let Some((param_lifetimes, _)) = function_param_lifetimes {
+ for lt in param_lifetimes {
+ spans_suggs.push(build_sugg(lt))
+ }
+ }
+ self.suggest_introducing_lifetime(
+ err,
+ None,
+ |err, higher_ranked, span, message, intro_sugg| {
+ err.multipart_suggestion_verbose(
+ message,
+ std::iter::once((span, intro_sugg))
+ .chain(spans_suggs.clone())
+ .collect(),
+ Applicability::MaybeIncorrect,
+ );
+ higher_ranked
+ },
+ );
+ }
+ 1 => {
+ err.multipart_suggestion_verbose(
+ &format!("consider using the `{}` lifetime", existing_name),
+ spans_suggs,
+ Applicability::MaybeIncorrect,
+ );
+
+ // Record as using the suggested resolution.
+ let (_, (_, res)) = in_scope_lifetimes[0];
+ for &lt in &lifetime_refs {
+ self.r.lifetimes_res_map.insert(lt.id, res);
+ }
+ }
+ _ => {
+ let lifetime_spans: Vec<_> =
+ in_scope_lifetimes.iter().map(|(ident, _)| ident.span).collect();
+ err.span_note(lifetime_spans, "these named lifetimes are available to use");
+
+ if spans_suggs.len() > 0 {
+ // This happens when we have `Foo<T>` where we point at the space before `T`,
+ // but this can be confusing so we give a suggestion with placeholders.
+ err.multipart_suggestion_verbose(
+ "consider using one of the available lifetimes here",
+ spans_suggs,
+ Applicability::HasPlaceholders,
+ );
+ }
+ }
+ }
+ }
+}
+
+/// Report lifetime/lifetime shadowing as an error.
+pub fn signal_lifetime_shadowing(sess: &Session, orig: Ident, shadower: Ident) {
+ let mut err = struct_span_err!(
+ sess,
+ shadower.span,
+ E0496,
+ "lifetime name `{}` shadows a lifetime name that is already in scope",
+ orig.name,
+ );
+ err.span_label(orig.span, "first declared here");
+ err.span_label(shadower.span, format!("lifetime `{}` already in scope", orig.name));
+ err.emit();
+}
+
+/// Shadowing involving a label is only a warning for historical reasons.
+//FIXME: make this a proper lint.
+pub fn signal_label_shadowing(sess: &Session, orig: Span, shadower: Ident) {
+ let name = shadower.name;
+ let shadower = shadower.span;
+ let mut err = sess.struct_span_warn(
+ shadower,
+ &format!("label name `{}` shadows a label name that is already in scope", name),
+ );
+ err.span_label(orig, "first declared here");
+ err.span_label(shadower, format!("label `{}` already in scope", name));
+ err.emit();
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-11 18:02:29 +0000