| // Copyright 2016 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. |
| |
| // Validate AST before lowering it to HIR |
| // |
| // This pass is supposed to catch things that fit into AST data structures, |
| // but not permitted by the language. It runs after expansion when AST is frozen, |
| // so it can check for erroneous constructions produced by syntax extensions. |
| // This pass is supposed to perform only simple checks not requiring name resolution |
| // or type checking or some other kind of complex analysis. |
| |
| use rustc::lint; |
| use rustc::session::Session; |
| use syntax::ast::*; |
| use syntax::attr; |
| use syntax::codemap::Spanned; |
| use syntax::parse::token; |
| use syntax::symbol::keywords; |
| use syntax::visit::{self, Visitor}; |
| use syntax_pos::Span; |
| use errors; |
| |
| struct AstValidator<'a> { |
| session: &'a Session, |
| } |
| |
| impl<'a> AstValidator<'a> { |
| fn err_handler(&self) -> &errors::Handler { |
| &self.session.parse_sess.span_diagnostic |
| } |
| |
| fn check_label(&self, label: Ident, span: Span, id: NodeId) { |
| if label.name == keywords::StaticLifetime.name() { |
| self.err_handler().span_err(span, &format!("invalid label name `{}`", label.name)); |
| } |
| if label.name == "'_" { |
| self.session.add_lint(lint::builtin::LIFETIME_UNDERSCORE, |
| id, |
| span, |
| format!("invalid label name `{}`", label.name)); |
| } |
| } |
| |
| fn invalid_visibility(&self, vis: &Visibility, span: Span, note: Option<&str>) { |
| if vis != &Visibility::Inherited { |
| let mut err = struct_span_err!(self.session, |
| span, |
| E0449, |
| "unnecessary visibility qualifier"); |
| if vis == &Visibility::Public { |
| err.span_label(span, &format!("`pub` not needed here")); |
| } |
| if let Some(note) = note { |
| err.note(note); |
| } |
| err.emit(); |
| } |
| } |
| |
| fn check_decl_no_pat<ReportFn: Fn(Span, bool)>(&self, decl: &FnDecl, report_err: ReportFn) { |
| for arg in &decl.inputs { |
| match arg.pat.node { |
| PatKind::Ident(BindingMode::ByValue(Mutability::Immutable), _, None) | |
| PatKind::Wild => {} |
| PatKind::Ident(..) => report_err(arg.pat.span, true), |
| _ => report_err(arg.pat.span, false), |
| } |
| } |
| } |
| |
| fn check_trait_fn_not_const(&self, constness: Spanned<Constness>) { |
| match constness.node { |
| Constness::Const => { |
| struct_span_err!(self.session, constness.span, E0379, |
| "trait fns cannot be declared const") |
| .span_label(constness.span, &format!("trait fns cannot be const")) |
| .emit(); |
| } |
| _ => {} |
| } |
| } |
| |
| fn no_questions_in_bounds(&self, bounds: &TyParamBounds, where_: &str, is_trait: bool) { |
| for bound in bounds { |
| if let TraitTyParamBound(ref poly, TraitBoundModifier::Maybe) = *bound { |
| let mut err = self.err_handler().struct_span_err(poly.span, |
| &format!("`?Trait` is not permitted in {}", where_)); |
| if is_trait { |
| err.note(&format!("traits are `?{}` by default", poly.trait_ref.path)); |
| } |
| err.emit(); |
| } |
| } |
| } |
| } |
| |
| impl<'a> Visitor<'a> for AstValidator<'a> { |
| fn visit_lifetime(&mut self, lt: &'a Lifetime) { |
| if lt.name == "'_" { |
| self.session.add_lint(lint::builtin::LIFETIME_UNDERSCORE, |
| lt.id, |
| lt.span, |
| format!("invalid lifetime name `{}`", lt.name)); |
| } |
| |
| visit::walk_lifetime(self, lt) |
| } |
| |
| fn visit_expr(&mut self, expr: &'a Expr) { |
| match expr.node { |
| ExprKind::While(.., Some(ident)) | |
| ExprKind::Loop(_, Some(ident)) | |
| ExprKind::WhileLet(.., Some(ident)) | |
| ExprKind::ForLoop(.., Some(ident)) | |
| ExprKind::Break(Some(ident), _) | |
| ExprKind::Continue(Some(ident)) => { |
| self.check_label(ident.node, ident.span, expr.id); |
| } |
| _ => {} |
| } |
| |
| visit::walk_expr(self, expr) |
| } |
| |
| fn visit_ty(&mut self, ty: &'a Ty) { |
| match ty.node { |
| TyKind::BareFn(ref bfty) => { |
| self.check_decl_no_pat(&bfty.decl, |span, _| { |
| let mut err = struct_span_err!(self.session, |
| span, |
| E0561, |
| "patterns aren't allowed in function pointer \ |
| types"); |
| err.span_note(span, |
| "this is a recent error, see issue #35203 for more details"); |
| err.emit(); |
| }); |
| } |
| TyKind::TraitObject(ref bounds) => { |
| let mut any_lifetime_bounds = false; |
| for bound in bounds { |
| if let RegionTyParamBound(ref lifetime) = *bound { |
| if any_lifetime_bounds { |
| span_err!(self.session, lifetime.span, E0226, |
| "only a single explicit lifetime bound is permitted"); |
| break; |
| } |
| any_lifetime_bounds = true; |
| } |
| } |
| self.no_questions_in_bounds(bounds, "trait object types", false); |
| } |
| TyKind::ImplTrait(ref bounds) => { |
| if !bounds.iter() |
| .any(|b| if let TraitTyParamBound(..) = *b { true } else { false }) { |
| self.err_handler().span_err(ty.span, "at least one trait must be specified"); |
| } |
| } |
| _ => {} |
| } |
| |
| visit::walk_ty(self, ty) |
| } |
| |
| fn visit_path(&mut self, path: &'a Path, id: NodeId) { |
| if path.segments.len() >= 2 && path.is_global() { |
| let ident = path.segments[1].identifier; |
| if token::Ident(ident).is_path_segment_keyword() { |
| self.session.add_lint(lint::builtin::SUPER_OR_SELF_IN_GLOBAL_PATH, |
| id, |
| path.span, |
| format!("global paths cannot start with `{}`", ident)); |
| } |
| } |
| |
| visit::walk_path(self, path) |
| } |
| |
| fn visit_item(&mut self, item: &'a Item) { |
| match item.node { |
| ItemKind::Use(ref view_path) => { |
| let path = view_path.node.path(); |
| if path.segments.iter().any(|segment| segment.parameters.is_some()) { |
| self.err_handler() |
| .span_err(path.span, "type or lifetime parameters in import path"); |
| } |
| } |
| ItemKind::Impl(.., Some(..), _, ref impl_items) => { |
| self.invalid_visibility(&item.vis, item.span, None); |
| for impl_item in impl_items { |
| self.invalid_visibility(&impl_item.vis, impl_item.span, None); |
| if let ImplItemKind::Method(ref sig, _) = impl_item.node { |
| self.check_trait_fn_not_const(sig.constness); |
| } |
| } |
| } |
| ItemKind::Impl(.., None, _, _) => { |
| self.invalid_visibility(&item.vis, |
| item.span, |
| Some("place qualifiers on individual impl items instead")); |
| } |
| ItemKind::DefaultImpl(..) => { |
| self.invalid_visibility(&item.vis, item.span, None); |
| } |
| ItemKind::ForeignMod(..) => { |
| self.invalid_visibility(&item.vis, |
| item.span, |
| Some("place qualifiers on individual foreign items \ |
| instead")); |
| } |
| ItemKind::Enum(ref def, _) => { |
| for variant in &def.variants { |
| for field in variant.node.data.fields() { |
| self.invalid_visibility(&field.vis, field.span, None); |
| } |
| } |
| } |
| ItemKind::Trait(.., ref bounds, ref trait_items) => { |
| self.no_questions_in_bounds(bounds, "supertraits", true); |
| for trait_item in trait_items { |
| if let TraitItemKind::Method(ref sig, ref block) = trait_item.node { |
| self.check_trait_fn_not_const(sig.constness); |
| if block.is_none() { |
| self.check_decl_no_pat(&sig.decl, |span, _| { |
| self.session.add_lint(lint::builtin::PATTERNS_IN_FNS_WITHOUT_BODY, |
| trait_item.id, span, |
| "patterns aren't allowed in methods \ |
| without bodies".to_string()); |
| }); |
| } |
| } |
| } |
| } |
| ItemKind::Mod(_) => { |
| // Ensure that `path` attributes on modules are recorded as used (c.f. #35584). |
| attr::first_attr_value_str_by_name(&item.attrs, "path"); |
| if let Some(attr) = |
| item.attrs.iter().find(|attr| attr.name() == "warn_directory_ownership") { |
| let lint = lint::builtin::LEGACY_DIRECTORY_OWNERSHIP; |
| let msg = "cannot declare a new module at this location"; |
| self.session.add_lint(lint, item.id, item.span, msg.to_string()); |
| attr::mark_used(attr); |
| } |
| } |
| ItemKind::Union(ref vdata, _) => { |
| if !vdata.is_struct() { |
| self.err_handler().span_err(item.span, |
| "tuple and unit unions are not permitted"); |
| } |
| if vdata.fields().len() == 0 { |
| self.err_handler().span_err(item.span, |
| "unions cannot have zero fields"); |
| } |
| } |
| _ => {} |
| } |
| |
| visit::walk_item(self, item) |
| } |
| |
| fn visit_foreign_item(&mut self, fi: &'a ForeignItem) { |
| match fi.node { |
| ForeignItemKind::Fn(ref decl, _) => { |
| self.check_decl_no_pat(decl, |span, is_recent| { |
| let mut err = struct_span_err!(self.session, |
| span, |
| E0130, |
| "patterns aren't allowed in foreign function \ |
| declarations"); |
| err.span_label(span, &format!("pattern not allowed in foreign function")); |
| if is_recent { |
| err.span_note(span, |
| "this is a recent error, see issue #35203 for more details"); |
| } |
| err.emit(); |
| }); |
| } |
| ForeignItemKind::Static(..) => {} |
| } |
| |
| visit::walk_foreign_item(self, fi) |
| } |
| |
| fn visit_vis(&mut self, vis: &'a Visibility) { |
| match *vis { |
| Visibility::Restricted { ref path, .. } => { |
| if !path.segments.iter().all(|segment| segment.parameters.is_none()) { |
| self.err_handler() |
| .span_err(path.span, "type or lifetime parameters in visibility path"); |
| } |
| } |
| _ => {} |
| } |
| |
| visit::walk_vis(self, vis) |
| } |
| |
| fn visit_generics(&mut self, g: &'a Generics) { |
| let mut seen_default = None; |
| for ty_param in &g.ty_params { |
| if ty_param.default.is_some() { |
| seen_default = Some(ty_param.span); |
| } else if let Some(span) = seen_default { |
| self.err_handler() |
| .span_err(span, "type parameters with a default must be trailing"); |
| break |
| } |
| } |
| for predicate in &g.where_clause.predicates { |
| if let WherePredicate::EqPredicate(ref predicate) = *predicate { |
| self.err_handler().span_err(predicate.span, "equality constraints are not yet \ |
| supported in where clauses (#20041)"); |
| } |
| } |
| visit::walk_generics(self, g) |
| } |
| } |
| |
| pub fn check_crate(session: &Session, krate: &Crate) { |
| visit::walk_crate(&mut AstValidator { session: session }, krate) |
| } |
