| // Copyright 2014 The Rust Project Developers. See the COPYRIGHT |
| // file at the top-level directory of this distribution and at |
| // http://rust-lang.org/COPYRIGHT. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| //! Give useful errors and suggestions to users when an item can't be |
| //! found or is otherwise invalid. |
| |
| use check::FnCtxt; |
| use rustc::hir::map as hir_map; |
| use rustc_data_structures::sync::Lrc; |
| use rustc::ty::{self, Ty, TyCtxt, ToPolyTraitRef, ToPredicate, TypeFoldable}; |
| use hir::def::Def; |
| use hir::def_id::{CRATE_DEF_INDEX, DefId}; |
| use middle::lang_items::FnOnceTraitLangItem; |
| use namespace::Namespace; |
| use rustc::traits::Obligation; |
| use util::nodemap::FxHashSet; |
| |
| use syntax::ast; |
| use syntax::util::lev_distance::find_best_match_for_name; |
| use errors::DiagnosticBuilder; |
| use syntax_pos::{Span, FileName}; |
| |
| |
| use rustc::hir::def_id::LOCAL_CRATE; |
| use rustc::hir; |
| use rustc::hir::print; |
| use rustc::infer::type_variable::TypeVariableOrigin; |
| use rustc::ty::TyAdt; |
| |
| use std::cmp::Ordering; |
| |
| use super::{MethodError, NoMatchData, CandidateSource}; |
| use super::probe::Mode; |
| |
| impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> { |
| fn is_fn_ty(&self, ty: &Ty<'tcx>, span: Span) -> bool { |
| let tcx = self.tcx; |
| match ty.sty { |
| // Not all of these (e.g. unsafe fns) implement FnOnce |
| // so we look for these beforehand |
| ty::TyClosure(..) | |
| ty::TyFnDef(..) | |
| ty::TyFnPtr(_) => true, |
| // If it's not a simple function, look for things which implement FnOnce |
| _ => { |
| let fn_once = match tcx.lang_items().require(FnOnceTraitLangItem) { |
| Ok(fn_once) => fn_once, |
| Err(..) => return false, |
| }; |
| |
| self.autoderef(span, ty).any(|(ty, _)| { |
| self.probe(|_| { |
| let fn_once_substs = tcx.mk_substs_trait(ty, &[ |
| self.next_ty_var(TypeVariableOrigin::MiscVariable(span)).into() |
| ]); |
| let trait_ref = ty::TraitRef::new(fn_once, fn_once_substs); |
| let poly_trait_ref = trait_ref.to_poly_trait_ref(); |
| let obligation = |
| Obligation::misc(span, |
| self.body_id, |
| self.param_env, |
| poly_trait_ref.to_predicate()); |
| self.predicate_may_hold(&obligation) |
| }) |
| }) |
| } |
| } |
| } |
| |
| pub fn report_method_error(&self, |
| span: Span, |
| rcvr_ty: Ty<'tcx>, |
| item_name: ast::Ident, |
| rcvr_expr: Option<&hir::Expr>, |
| error: MethodError<'tcx>, |
| args: Option<&'gcx [hir::Expr]>) { |
| // avoid suggestions when we don't know what's going on. |
| if rcvr_ty.references_error() { |
| return; |
| } |
| |
| let report_candidates = |err: &mut DiagnosticBuilder, mut sources: Vec<CandidateSource>| { |
| |
| sources.sort(); |
| sources.dedup(); |
| // Dynamic limit to avoid hiding just one candidate, which is silly. |
| let limit = if sources.len() == 5 { 5 } else { 4 }; |
| |
| for (idx, source) in sources.iter().take(limit).enumerate() { |
| match *source { |
| CandidateSource::ImplSource(impl_did) => { |
| // Provide the best span we can. Use the item, if local to crate, else |
| // the impl, if local to crate (item may be defaulted), else nothing. |
| let item = self.associated_item(impl_did, item_name, Namespace::Value) |
| .or_else(|| { |
| self.associated_item( |
| self.tcx.impl_trait_ref(impl_did).unwrap().def_id, |
| item_name, |
| Namespace::Value, |
| ) |
| }).unwrap(); |
| let note_span = self.tcx.hir.span_if_local(item.def_id).or_else(|| { |
| self.tcx.hir.span_if_local(impl_did) |
| }); |
| |
| let impl_ty = self.impl_self_ty(span, impl_did).ty; |
| |
| let insertion = match self.tcx.impl_trait_ref(impl_did) { |
| None => String::new(), |
| Some(trait_ref) => { |
| format!(" of the trait `{}`", |
| self.tcx.item_path_str(trait_ref.def_id)) |
| } |
| }; |
| |
| let note_str = if sources.len() > 1 { |
| format!("candidate #{} is defined in an impl{} for the type `{}`", |
| idx + 1, |
| insertion, |
| impl_ty) |
| } else { |
| format!("the candidate is defined in an impl{} for the type `{}`", |
| insertion, |
| impl_ty) |
| }; |
| if let Some(note_span) = note_span { |
| // We have a span pointing to the method. Show note with snippet. |
| err.span_note(self.tcx.sess.source_map().def_span(note_span), |
| ¬e_str); |
| } else { |
| err.note(¬e_str); |
| } |
| } |
| CandidateSource::TraitSource(trait_did) => { |
| let item = self |
| .associated_item(trait_did, item_name, Namespace::Value) |
| .unwrap(); |
| let item_span = self.tcx.sess.source_map() |
| .def_span(self.tcx.def_span(item.def_id)); |
| if sources.len() > 1 { |
| span_note!(err, |
| item_span, |
| "candidate #{} is defined in the trait `{}`", |
| idx + 1, |
| self.tcx.item_path_str(trait_did)); |
| } else { |
| span_note!(err, |
| item_span, |
| "the candidate is defined in the trait `{}`", |
| self.tcx.item_path_str(trait_did)); |
| } |
| err.help(&format!("to disambiguate the method call, write `{}::{}({}{})` \ |
| instead", |
| self.tcx.item_path_str(trait_did), |
| item_name, |
| if rcvr_ty.is_region_ptr() && args.is_some() { |
| if rcvr_ty.is_mutable_pointer() { |
| "&mut " |
| } else { |
| "&" |
| } |
| } else { |
| "" |
| }, |
| args.map(|arg| arg.iter() |
| .map(|arg| print::to_string(print::NO_ANN, |
| |s| s.print_expr(arg))) |
| .collect::<Vec<_>>() |
| .join(", ")).unwrap_or("...".to_owned()))); |
| } |
| } |
| } |
| if sources.len() > limit { |
| err.note(&format!("and {} others", sources.len() - limit)); |
| } |
| }; |
| |
| match error { |
| MethodError::NoMatch(NoMatchData { |
| static_candidates: static_sources, |
| unsatisfied_predicates, |
| out_of_scope_traits, |
| lev_candidate, |
| mode, |
| }) => { |
| let tcx = self.tcx; |
| |
| let actual = self.resolve_type_vars_if_possible(&rcvr_ty); |
| let ty_string = self.ty_to_string(actual); |
| let is_method = mode == Mode::MethodCall; |
| let mut suggestion = None; |
| let item_kind = if is_method { |
| "method" |
| } else if actual.is_enum() { |
| if let TyAdt(ref adt_def, _) = actual.sty { |
| let names = adt_def.variants.iter().map(|s| &s.name); |
| suggestion = find_best_match_for_name(names, |
| &item_name.as_str(), |
| None); |
| } |
| "variant" |
| } else { |
| match (item_name.as_str().chars().next(), actual.is_fresh_ty()) { |
| (Some(name), false) if name.is_lowercase() => { |
| "function or associated item" |
| } |
| (Some(_), false) => "associated item", |
| (Some(_), true) | (None, false) => { |
| "variant or associated item" |
| } |
| (None, true) => "variant", |
| } |
| }; |
| let mut err = if !actual.references_error() { |
| // Suggest clamping down the type if the method that is being attempted to |
| // be used exists at all, and the type is an ambiuous numeric type |
| // ({integer}/{float}). |
| let mut candidates = all_traits(self.tcx) |
| .into_iter() |
| .filter(|info| { |
| self.associated_item(info.def_id, item_name, Namespace::Value).is_some() |
| }); |
| if let (true, false, Some(expr), Some(_)) = (actual.is_numeric(), |
| actual.has_concrete_skeleton(), |
| rcvr_expr, |
| candidates.next()) { |
| let mut err = struct_span_err!( |
| tcx.sess, |
| span, |
| E0689, |
| "can't call {} `{}` on ambiguous numeric type `{}`", |
| item_kind, |
| item_name, |
| ty_string |
| ); |
| let concrete_type = if actual.is_integral() { |
| "i32" |
| } else { |
| "f32" |
| }; |
| match expr.node { |
| hir::ExprKind::Lit(ref lit) => { // numeric literal |
| let snippet = tcx.sess.source_map().span_to_snippet(lit.span) |
| .unwrap_or("<numeric literal>".to_string()); |
| |
| err.span_suggestion(lit.span, |
| &format!("you must specify a concrete type for \ |
| this numeric value, like `{}`", |
| concrete_type), |
| format!("{}_{}", |
| snippet, |
| concrete_type)); |
| } |
| hir::ExprKind::Path(ref qpath) => { // local binding |
| if let &hir::QPath::Resolved(_, ref path) = &qpath { |
| if let hir::def::Def::Local(node_id) = path.def { |
| let span = tcx.hir.span(node_id); |
| let snippet = tcx.sess.source_map().span_to_snippet(span) |
| .unwrap(); |
| let filename = tcx.sess.source_map().span_to_filename(span); |
| |
| let parent_node = self.tcx.hir.get( |
| self.tcx.hir.get_parent_node(node_id), |
| ); |
| let msg = format!( |
| "you must specify a type for this binding, like `{}`", |
| concrete_type, |
| ); |
| |
| match (filename, parent_node) { |
| (FileName::Real(_), hir_map::NodeLocal(hir::Local { |
| source: hir::LocalSource::Normal, |
| ty, |
| .. |
| })) => { |
| err.span_suggestion( |
| // account for `let x: _ = 42;` |
| // ^^^^ |
| span.to(ty.as_ref().map(|ty| ty.span) |
| .unwrap_or(span)), |
| &msg, |
| format!("{}: {}", snippet, concrete_type), |
| ); |
| } |
| _ => { |
| err.span_label(span, msg); |
| } |
| } |
| } |
| } |
| } |
| _ => {} |
| } |
| err.emit(); |
| return; |
| } else { |
| let mut err = struct_span_err!( |
| tcx.sess, |
| span, |
| E0599, |
| "no {} named `{}` found for type `{}` in the current scope", |
| item_kind, |
| item_name, |
| ty_string |
| ); |
| if let Some(suggestion) = suggestion { |
| err.note(&format!("did you mean `{}::{}`?", ty_string, suggestion)); |
| } |
| err |
| } |
| } else { |
| tcx.sess.diagnostic().struct_dummy() |
| }; |
| |
| if let Some(def) = actual.ty_adt_def() { |
| if let Some(full_sp) = tcx.hir.span_if_local(def.did) { |
| let def_sp = tcx.sess.source_map().def_span(full_sp); |
| err.span_label(def_sp, format!("{} `{}` not found {}", |
| item_kind, |
| item_name, |
| if def.is_enum() && !is_method { |
| "here" |
| } else { |
| "for this" |
| })); |
| } |
| } |
| |
| // If the method name is the name of a field with a function or closure type, |
| // give a helping note that it has to be called as (x.f)(...). |
| if let Some(expr) = rcvr_expr { |
| for (ty, _) in self.autoderef(span, rcvr_ty) { |
| match ty.sty { |
| ty::TyAdt(def, substs) if !def.is_enum() => { |
| let variant = &def.non_enum_variant(); |
| if let Some(index) = self.tcx.find_field_index(item_name, variant) { |
| let field = &variant.fields[index]; |
| let snippet = tcx.sess.source_map().span_to_snippet(expr.span); |
| let expr_string = match snippet { |
| Ok(expr_string) => expr_string, |
| _ => "s".into(), // Default to a generic placeholder for the |
| // expression when we can't generate a |
| // string snippet |
| }; |
| |
| let field_ty = field.ty(tcx, substs); |
| let scope = self.tcx.hir.get_module_parent(self.body_id); |
| if field.vis.is_accessible_from(scope, self.tcx) { |
| if self.is_fn_ty(&field_ty, span) { |
| err.help(&format!("use `({0}.{1})(...)` if you \ |
| meant to call the function \ |
| stored in the `{1}` field", |
| expr_string, |
| item_name)); |
| } else { |
| err.help(&format!("did you mean to write `{0}.{1}` \ |
| instead of `{0}.{1}(...)`?", |
| expr_string, |
| item_name)); |
| } |
| err.span_label(span, "field, not a method"); |
| } else { |
| err.span_label(span, "private field, not a method"); |
| } |
| break; |
| } |
| } |
| _ => {} |
| } |
| } |
| } else { |
| err.span_label(span, format!("{} not found in `{}`", item_kind, ty_string)); |
| } |
| |
| if self.is_fn_ty(&rcvr_ty, span) { |
| macro_rules! report_function { |
| ($span:expr, $name:expr) => { |
| err.note(&format!("{} is a function, perhaps you wish to call it", |
| $name)); |
| } |
| } |
| |
| if let Some(expr) = rcvr_expr { |
| if let Ok(expr_string) = tcx.sess.source_map().span_to_snippet(expr.span) { |
| report_function!(expr.span, expr_string); |
| } else if let hir::ExprKind::Path(hir::QPath::Resolved(_, ref path)) = |
| expr.node |
| { |
| if let Some(segment) = path.segments.last() { |
| report_function!(expr.span, segment.ident); |
| } |
| } |
| } |
| } |
| |
| if !static_sources.is_empty() { |
| err.note("found the following associated functions; to be used as methods, \ |
| functions must have a `self` parameter"); |
| err.span_label(span, "this is an associated function, not a method"); |
| } |
| if static_sources.len() == 1 { |
| if let Some(expr) = rcvr_expr { |
| err.span_suggestion(expr.span.to(span), |
| "use associated function syntax instead", |
| format!("{}::{}", |
| self.ty_to_string(actual), |
| item_name)); |
| } else { |
| err.help(&format!("try with `{}::{}`", |
| self.ty_to_string(actual), item_name)); |
| } |
| |
| report_candidates(&mut err, static_sources); |
| } else if static_sources.len() > 1 { |
| |
| report_candidates(&mut err, static_sources); |
| } |
| |
| if !unsatisfied_predicates.is_empty() { |
| let bound_list = unsatisfied_predicates.iter() |
| .map(|p| format!("`{} : {}`", p.self_ty(), p)) |
| .collect::<Vec<_>>() |
| .join("\n"); |
| err.note(&format!("the method `{}` exists but the following trait bounds \ |
| were not satisfied:\n{}", |
| item_name, |
| bound_list)); |
| } |
| |
| if actual.is_numeric() && actual.is_fresh() { |
| |
| } else { |
| self.suggest_traits_to_import(&mut err, |
| span, |
| rcvr_ty, |
| item_name, |
| rcvr_expr, |
| out_of_scope_traits); |
| } |
| |
| if let Some(lev_candidate) = lev_candidate { |
| err.help(&format!("did you mean `{}`?", lev_candidate.ident)); |
| } |
| err.emit(); |
| } |
| |
| MethodError::Ambiguity(sources) => { |
| let mut err = struct_span_err!(self.sess(), |
| span, |
| E0034, |
| "multiple applicable items in scope"); |
| err.span_label(span, format!("multiple `{}` found", item_name)); |
| |
| report_candidates(&mut err, sources); |
| err.emit(); |
| } |
| |
| MethodError::PrivateMatch(def, out_of_scope_traits) => { |
| let mut err = struct_span_err!(self.tcx.sess, span, E0624, |
| "{} `{}` is private", def.kind_name(), item_name); |
| self.suggest_valid_traits(&mut err, out_of_scope_traits); |
| err.emit(); |
| } |
| |
| MethodError::IllegalSizedBound(candidates) => { |
| let msg = format!("the `{}` method cannot be invoked on a trait object", item_name); |
| let mut err = self.sess().struct_span_err(span, &msg); |
| if !candidates.is_empty() { |
| let help = format!("{an}other candidate{s} {were} found in the following \ |
| trait{s}, perhaps add a `use` for {one_of_them}:", |
| an = if candidates.len() == 1 {"an" } else { "" }, |
| s = if candidates.len() == 1 { "" } else { "s" }, |
| were = if candidates.len() == 1 { "was" } else { "were" }, |
| one_of_them = if candidates.len() == 1 { |
| "it" |
| } else { |
| "one_of_them" |
| }); |
| self.suggest_use_candidates(&mut err, help, candidates); |
| } |
| err.emit(); |
| } |
| |
| MethodError::BadReturnType => { |
| bug!("no return type expectations but got BadReturnType") |
| } |
| } |
| } |
| |
| fn suggest_use_candidates(&self, |
| err: &mut DiagnosticBuilder, |
| mut msg: String, |
| candidates: Vec<DefId>) { |
| let module_did = self.tcx.hir.get_module_parent(self.body_id); |
| let module_id = self.tcx.hir.as_local_node_id(module_did).unwrap(); |
| let krate = self.tcx.hir.krate(); |
| let (span, found_use) = UsePlacementFinder::check(self.tcx, krate, module_id); |
| if let Some(span) = span { |
| let path_strings = candidates.iter().map(|did| { |
| // produce an additional newline to separate the new use statement |
| // from the directly following item. |
| let additional_newline = if found_use { |
| "" |
| } else { |
| "\n" |
| }; |
| format!("use {};\n{}", self.tcx.item_path_str(*did), additional_newline) |
| }).collect(); |
| |
| err.span_suggestions(span, &msg, path_strings); |
| } else { |
| let limit = if candidates.len() == 5 { 5 } else { 4 }; |
| for (i, trait_did) in candidates.iter().take(limit).enumerate() { |
| if candidates.len() > 1 { |
| msg.push_str(&format!("\ncandidate #{}: `use {};`", |
| i + 1, |
| self.tcx.item_path_str(*trait_did))); |
| } else { |
| msg.push_str(&format!("\n`use {};`", |
| self.tcx.item_path_str(*trait_did))); |
| } |
| } |
| if candidates.len() > limit { |
| msg.push_str(&format!("\nand {} others", candidates.len() - limit)); |
| } |
| err.note(&msg[..]); |
| } |
| } |
| |
| fn suggest_valid_traits(&self, |
| err: &mut DiagnosticBuilder, |
| valid_out_of_scope_traits: Vec<DefId>) -> bool { |
| if !valid_out_of_scope_traits.is_empty() { |
| let mut candidates = valid_out_of_scope_traits; |
| candidates.sort(); |
| candidates.dedup(); |
| err.help("items from traits can only be used if the trait is in scope"); |
| let msg = format!("the following {traits_are} implemented but not in scope, \ |
| perhaps add a `use` for {one_of_them}:", |
| traits_are = if candidates.len() == 1 { |
| "trait is" |
| } else { |
| "traits are" |
| }, |
| one_of_them = if candidates.len() == 1 { |
| "it" |
| } else { |
| "one of them" |
| }); |
| |
| self.suggest_use_candidates(err, msg, candidates); |
| true |
| } else { |
| false |
| } |
| } |
| |
| fn suggest_traits_to_import(&self, |
| err: &mut DiagnosticBuilder, |
| span: Span, |
| rcvr_ty: Ty<'tcx>, |
| item_name: ast::Ident, |
| rcvr_expr: Option<&hir::Expr>, |
| valid_out_of_scope_traits: Vec<DefId>) { |
| if self.suggest_valid_traits(err, valid_out_of_scope_traits) { |
| return; |
| } |
| |
| let type_is_local = self.type_derefs_to_local(span, rcvr_ty, rcvr_expr); |
| |
| // there's no implemented traits, so lets suggest some traits to |
| // implement, by finding ones that have the item name, and are |
| // legal to implement. |
| let mut candidates = all_traits(self.tcx) |
| .into_iter() |
| .filter(|info| { |
| // we approximate the coherence rules to only suggest |
| // traits that are legal to implement by requiring that |
| // either the type or trait is local. Multidispatch means |
| // this isn't perfect (that is, there are cases when |
| // implementing a trait would be legal but is rejected |
| // here). |
| (type_is_local || info.def_id.is_local()) && |
| self.associated_item(info.def_id, item_name, Namespace::Value) |
| .filter(|item| { |
| // We only want to suggest public or local traits (#45781). |
| item.vis == ty::Visibility::Public || info.def_id.is_local() |
| }) |
| .is_some() |
| }) |
| .collect::<Vec<_>>(); |
| |
| if !candidates.is_empty() { |
| // sort from most relevant to least relevant |
| candidates.sort_by(|a, b| a.cmp(b).reverse()); |
| candidates.dedup(); |
| |
| // FIXME #21673 this help message could be tuned to the case |
| // of a type parameter: suggest adding a trait bound rather |
| // than implementing. |
| err.help("items from traits can only be used if the trait is implemented and in scope"); |
| let mut msg = format!("the following {traits_define} an item `{name}`, \ |
| perhaps you need to implement {one_of_them}:", |
| traits_define = if candidates.len() == 1 { |
| "trait defines" |
| } else { |
| "traits define" |
| }, |
| one_of_them = if candidates.len() == 1 { |
| "it" |
| } else { |
| "one of them" |
| }, |
| name = item_name); |
| |
| for (i, trait_info) in candidates.iter().enumerate() { |
| msg.push_str(&format!("\ncandidate #{}: `{}`", |
| i + 1, |
| self.tcx.item_path_str(trait_info.def_id))); |
| } |
| err.note(&msg[..]); |
| } |
| } |
| |
| /// Checks whether there is a local type somewhere in the chain of |
| /// autoderefs of `rcvr_ty`. |
| fn type_derefs_to_local(&self, |
| span: Span, |
| rcvr_ty: Ty<'tcx>, |
| rcvr_expr: Option<&hir::Expr>) |
| -> bool { |
| fn is_local(ty: Ty) -> bool { |
| match ty.sty { |
| ty::TyAdt(def, _) => def.did.is_local(), |
| ty::TyForeign(did) => did.is_local(), |
| |
| ty::TyDynamic(ref tr, ..) => tr.principal() |
| .map_or(false, |p| p.def_id().is_local()), |
| |
| ty::TyParam(_) => true, |
| |
| // everything else (primitive types etc.) is effectively |
| // non-local (there are "edge" cases, e.g. (LocalType,), but |
| // the noise from these sort of types is usually just really |
| // annoying, rather than any sort of help). |
| _ => false, |
| } |
| } |
| |
| // This occurs for UFCS desugaring of `T::method`, where there is no |
| // receiver expression for the method call, and thus no autoderef. |
| if rcvr_expr.is_none() { |
| return is_local(self.resolve_type_vars_with_obligations(rcvr_ty)); |
| } |
| |
| self.autoderef(span, rcvr_ty).any(|(ty, _)| is_local(ty)) |
| } |
| } |
| |
| #[derive(Copy, Clone)] |
| pub struct TraitInfo { |
| pub def_id: DefId, |
| } |
| |
| impl PartialEq for TraitInfo { |
| fn eq(&self, other: &TraitInfo) -> bool { |
| self.cmp(other) == Ordering::Equal |
| } |
| } |
| impl Eq for TraitInfo {} |
| impl PartialOrd for TraitInfo { |
| fn partial_cmp(&self, other: &TraitInfo) -> Option<Ordering> { |
| Some(self.cmp(other)) |
| } |
| } |
| impl Ord for TraitInfo { |
| fn cmp(&self, other: &TraitInfo) -> Ordering { |
| // local crates are more important than remote ones (local: |
| // cnum == 0), and otherwise we throw in the defid for totality |
| |
| let lhs = (other.def_id.krate, other.def_id); |
| let rhs = (self.def_id.krate, self.def_id); |
| lhs.cmp(&rhs) |
| } |
| } |
| |
| /// Retrieve all traits in this crate and any dependent crates. |
| pub fn all_traits<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Vec<TraitInfo> { |
| tcx.all_traits(LOCAL_CRATE).iter().map(|&def_id| TraitInfo { def_id }).collect() |
| } |
| |
| /// Compute all traits in this crate and any dependent crates. |
| fn compute_all_traits<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Vec<DefId> { |
| use rustc::hir::itemlikevisit; |
| |
| let mut traits = vec![]; |
| |
| // Crate-local: |
| // |
| // meh. |
| struct Visitor<'a, 'tcx: 'a> { |
| map: &'a hir_map::Map<'tcx>, |
| traits: &'a mut Vec<DefId>, |
| } |
| impl<'v, 'a, 'tcx> itemlikevisit::ItemLikeVisitor<'v> for Visitor<'a, 'tcx> { |
| fn visit_item(&mut self, i: &'v hir::Item) { |
| match i.node { |
| hir::ItemKind::Trait(..) => { |
| let def_id = self.map.local_def_id(i.id); |
| self.traits.push(def_id); |
| } |
| _ => {} |
| } |
| } |
| |
| fn visit_trait_item(&mut self, _trait_item: &hir::TraitItem) { |
| } |
| |
| fn visit_impl_item(&mut self, _impl_item: &hir::ImplItem) { |
| } |
| } |
| tcx.hir.krate().visit_all_item_likes(&mut Visitor { |
| map: &tcx.hir, |
| traits: &mut traits, |
| }); |
| |
| // Cross-crate: |
| let mut external_mods = FxHashSet(); |
| fn handle_external_def(tcx: TyCtxt, |
| traits: &mut Vec<DefId>, |
| external_mods: &mut FxHashSet<DefId>, |
| def: Def) { |
| let def_id = def.def_id(); |
| match def { |
| Def::Trait(..) => { |
| traits.push(def_id); |
| } |
| Def::Mod(..) => { |
| if !external_mods.insert(def_id) { |
| return; |
| } |
| for child in tcx.item_children(def_id).iter() { |
| handle_external_def(tcx, traits, external_mods, child.def) |
| } |
| } |
| _ => {} |
| } |
| } |
| for &cnum in tcx.crates().iter() { |
| let def_id = DefId { |
| krate: cnum, |
| index: CRATE_DEF_INDEX, |
| }; |
| handle_external_def(tcx, &mut traits, &mut external_mods, Def::Mod(def_id)); |
| } |
| |
| traits |
| } |
| |
| pub fn provide(providers: &mut ty::query::Providers) { |
| providers.all_traits = |tcx, cnum| { |
| assert_eq!(cnum, LOCAL_CRATE); |
| Lrc::new(compute_all_traits(tcx)) |
| } |
| } |
| |
| struct UsePlacementFinder<'a, 'tcx: 'a, 'gcx: 'tcx> { |
| target_module: ast::NodeId, |
| span: Option<Span>, |
| found_use: bool, |
| tcx: TyCtxt<'a, 'gcx, 'tcx> |
| } |
| |
| impl<'a, 'tcx, 'gcx> UsePlacementFinder<'a, 'tcx, 'gcx> { |
| fn check( |
| tcx: TyCtxt<'a, 'gcx, 'tcx>, |
| krate: &'tcx hir::Crate, |
| target_module: ast::NodeId, |
| ) -> (Option<Span>, bool) { |
| let mut finder = UsePlacementFinder { |
| target_module, |
| span: None, |
| found_use: false, |
| tcx, |
| }; |
| hir::intravisit::walk_crate(&mut finder, krate); |
| (finder.span, finder.found_use) |
| } |
| } |
| |
| impl<'a, 'tcx, 'gcx> hir::intravisit::Visitor<'tcx> for UsePlacementFinder<'a, 'tcx, 'gcx> { |
| fn visit_mod( |
| &mut self, |
| module: &'tcx hir::Mod, |
| _: Span, |
| node_id: ast::NodeId, |
| ) { |
| if self.span.is_some() { |
| return; |
| } |
| if node_id != self.target_module { |
| hir::intravisit::walk_mod(self, module, node_id); |
| return; |
| } |
| // find a use statement |
| for item_id in &module.item_ids { |
| let item = self.tcx.hir.expect_item(item_id.id); |
| match item.node { |
| hir::ItemKind::Use(..) => { |
| // don't suggest placing a use before the prelude |
| // import or other generated ones |
| if item.span.ctxt().outer().expn_info().is_none() { |
| self.span = Some(item.span.shrink_to_lo()); |
| self.found_use = true; |
| return; |
| } |
| }, |
| // don't place use before extern crate |
| hir::ItemKind::ExternCrate(_) => {} |
| // but place them before the first other item |
| _ => if self.span.map_or(true, |span| item.span < span ) { |
| if item.span.ctxt().outer().expn_info().is_none() { |
| // don't insert between attributes and an item |
| if item.attrs.is_empty() { |
| self.span = Some(item.span.shrink_to_lo()); |
| } else { |
| // find the first attribute on the item |
| for attr in &item.attrs { |
| if self.span.map_or(true, |span| attr.span < span) { |
| self.span = Some(attr.span.shrink_to_lo()); |
| } |
| } |
| } |
| } |
| }, |
| } |
| } |
| } |
| fn nested_visit_map<'this>( |
| &'this mut self |
| ) -> hir::intravisit::NestedVisitorMap<'this, 'tcx> { |
| hir::intravisit::NestedVisitorMap::None |
| } |
| } |
