| // 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::parse::token::{self, 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.as_str() == "'_" { |
| 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 let Some(note) = note { |
| err.span_note(span, 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), |
| } |
| } |
| } |
| } |
| |
| impl<'a> Visitor for AstValidator<'a> { |
| fn visit_lifetime(&mut self, lt: &Lifetime) { |
| if lt.name.as_str() == "'_" { |
| 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: &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: &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(); |
| }); |
| } |
| _ => {} |
| } |
| |
| visit::walk_ty(self, ty) |
| } |
| |
| fn visit_path(&mut self, path: &Path, id: NodeId) { |
| if path.global && path.segments.len() > 0 { |
| let ident = path.segments[0].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: &Item) { |
| match item.node { |
| ItemKind::Use(ref view_path) => { |
| let path = view_path.node.path(); |
| if !path.segments.iter().all(|segment| segment.parameters.is_empty()) { |
| 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); |
| } |
| } |
| 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); |
| } |
| } |
| } |
| _ => {} |
| } |
| |
| visit::walk_item(self, item) |
| } |
| |
| fn visit_foreign_item(&mut self, fi: &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"); |
| 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_variant_data(&mut self, vdata: &VariantData, _: Ident, |
| _: &Generics, _: NodeId, span: Span) { |
| if vdata.fields().is_empty() { |
| if vdata.is_tuple() { |
| self.err_handler().struct_span_err(span, "empty tuple structs and enum variants \ |
| are not allowed, use unit structs and \ |
| enum variants instead") |
| .span_help(span, "remove trailing `()` to make a unit \ |
| struct or unit enum variant") |
| .emit(); |
| } |
| } |
| |
| visit::walk_struct_def(self, vdata) |
| } |
| |
| fn visit_vis(&mut self, vis: &Visibility) { |
| match *vis { |
| Visibility::Restricted{ref path, ..} => { |
| if !path.segments.iter().all(|segment| segment.parameters.is_empty()) { |
| self.err_handler().span_err(path.span, "type or lifetime parameters \ |
| in visibility path"); |
| } |
| } |
| _ => {} |
| } |
| |
| visit::walk_vis(self, vis) |
| } |
| } |
| |
| pub fn check_crate(session: &Session, krate: &Crate) { |
| visit::walk_crate(&mut AstValidator { session: session }, krate) |
| } |
