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| 1 | +// Copyright 2016 The Rust Project Developers. See the COPYRIGHT |
| 2 | +// file at the top-level directory of this distribution and at |
| 3 | +// http://rust-lang.org/COPYRIGHT. |
| 4 | +// |
| 5 | +// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| 6 | +// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| 7 | +// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| 8 | +// option. This file may not be copied, modified, or distributed |
| 9 | +// except according to those terms. |
| 10 | + |
| 11 | +// Validate AST before lowering it to HIR |
| 12 | +// |
| 13 | +// This pass is supposed to catch things that fit into AST data structures, |
| 14 | +// but not permitted by the language. It runs after expansion when AST is frozen, |
| 15 | +// so it can check for erroneous constructions produced by syntax extensions. |
| 16 | +// This pass is supposed to perform only simple checks not requiring name resolution |
| 17 | +// or type checking or some other kind of complex analysis. |
| 18 | + |
| 19 | +use rustc::lint; |
| 20 | +use rustc::session::Session; |
| 21 | +use syntax::ast::*; |
| 22 | +use syntax::codemap::Span; |
| 23 | +use syntax::errors; |
| 24 | +use syntax::parse::token::{self, keywords}; |
| 25 | +use syntax::visit::{self, Visitor}; |
| 26 | + |
| 27 | +struct AstValidator<'a> { |
| 28 | + session: &'a Session, |
| 29 | +} |
| 30 | + |
| 31 | +impl<'a> AstValidator<'a> { |
| 32 | + fn err_handler(&self) -> &errors::Handler { |
| 33 | + &self.session.parse_sess.span_diagnostic |
| 34 | + } |
| 35 | + |
| 36 | + fn check_label(&self, label: Ident, span: Span, id: NodeId) { |
| 37 | + if label.name == keywords::StaticLifetime.name() { |
| 38 | + self.err_handler().span_err(span, &format!("invalid label name `{}`", label.name)); |
| 39 | + } |
| 40 | + if label.name.as_str() == "'_" { |
| 41 | + self.session.add_lint( |
| 42 | + lint::builtin::LIFETIME_UNDERSCORE, id, span, |
| 43 | + format!("invalid label name `{}`", label.name) |
| 44 | + ); |
| 45 | + } |
| 46 | + } |
| 47 | + |
| 48 | + fn invalid_visibility(&self, vis: &Visibility, span: Span, note: Option<&str>) { |
| 49 | + if vis != &Visibility::Inherited { |
| 50 | + let mut err = struct_span_err!(self.session, span, E0449, |
| 51 | + "unnecessary visibility qualifier"); |
| 52 | + if let Some(note) = note { |
| 53 | + err.span_note(span, note); |
| 54 | + } |
| 55 | + err.emit(); |
| 56 | + } |
| 57 | + } |
| 58 | +} |
| 59 | + |
| 60 | +impl<'a, 'v> Visitor<'v> for AstValidator<'a> { |
| 61 | + fn visit_lifetime(&mut self, lt: &Lifetime) { |
| 62 | + if lt.name.as_str() == "'_" { |
| 63 | + self.session.add_lint( |
| 64 | + lint::builtin::LIFETIME_UNDERSCORE, lt.id, lt.span, |
| 65 | + format!("invalid lifetime name `{}`", lt.name) |
| 66 | + ); |
| 67 | + } |
| 68 | + |
| 69 | + visit::walk_lifetime(self, lt) |
| 70 | + } |
| 71 | + |
| 72 | + fn visit_expr(&mut self, expr: &Expr) { |
| 73 | + match expr.node { |
| 74 | + ExprKind::While(_, _, Some(ident)) | ExprKind::Loop(_, Some(ident)) | |
| 75 | + ExprKind::WhileLet(_, _, _, Some(ident)) | ExprKind::ForLoop(_, _, _, Some(ident)) | |
| 76 | + ExprKind::Break(Some(ident)) | ExprKind::Again(Some(ident)) => { |
| 77 | + self.check_label(ident.node, ident.span, expr.id); |
| 78 | + } |
| 79 | + _ => {} |
| 80 | + } |
| 81 | + |
| 82 | + visit::walk_expr(self, expr) |
| 83 | + } |
| 84 | + |
| 85 | + fn visit_path(&mut self, path: &Path, id: NodeId) { |
| 86 | + if path.global && path.segments.len() > 0 { |
| 87 | + let ident = path.segments[0].identifier; |
| 88 | + if token::Ident(ident).is_path_segment_keyword() { |
| 89 | + self.session.add_lint( |
| 90 | + lint::builtin::SUPER_OR_SELF_IN_GLOBAL_PATH, id, path.span, |
| 91 | + format!("global paths cannot start with `{}`", ident) |
| 92 | + ); |
| 93 | + } |
| 94 | + } |
| 95 | + |
| 96 | + visit::walk_path(self, path) |
| 97 | + } |
| 98 | + |
| 99 | + fn visit_item(&mut self, item: &Item) { |
| 100 | + match item.node { |
| 101 | + ItemKind::Use(ref view_path) => { |
| 102 | + let path = view_path.node.path(); |
| 103 | + if !path.segments.iter().all(|segment| segment.parameters.is_empty()) { |
| 104 | + self.err_handler().span_err(path.span, "type or lifetime parameters \ |
| 105 | + in import path"); |
| 106 | + } |
| 107 | + } |
| 108 | + ItemKind::Impl(_, _, _, Some(..), _, ref impl_items) => { |
| 109 | + self.invalid_visibility(&item.vis, item.span, None); |
| 110 | + for impl_item in impl_items { |
| 111 | + self.invalid_visibility(&impl_item.vis, impl_item.span, None); |
| 112 | + } |
| 113 | + } |
| 114 | + ItemKind::Impl(_, _, _, None, _, _) => { |
| 115 | + self.invalid_visibility(&item.vis, item.span, Some("place qualifiers on individual \ |
| 116 | + impl items instead")); |
| 117 | + } |
| 118 | + ItemKind::DefaultImpl(..) => { |
| 119 | + self.invalid_visibility(&item.vis, item.span, None); |
| 120 | + } |
| 121 | + ItemKind::ForeignMod(..) => { |
| 122 | + self.invalid_visibility(&item.vis, item.span, Some("place qualifiers on individual \ |
| 123 | + foreign items instead")); |
| 124 | + } |
| 125 | + ItemKind::Enum(ref def, _) => { |
| 126 | + for variant in &def.variants { |
| 127 | + for field in variant.node.data.fields() { |
| 128 | + self.invalid_visibility(&field.vis, field.span, None); |
| 129 | + } |
| 130 | + } |
| 131 | + } |
| 132 | + _ => {} |
| 133 | + } |
| 134 | + |
| 135 | + visit::walk_item(self, item) |
| 136 | + } |
| 137 | + |
| 138 | + fn visit_variant_data(&mut self, vdata: &VariantData, _: Ident, |
| 139 | + _: &Generics, _: NodeId, span: Span) { |
| 140 | + if vdata.fields().is_empty() { |
| 141 | + if vdata.is_tuple() { |
| 142 | + self.err_handler().struct_span_err(span, "empty tuple structs and enum variants \ |
| 143 | + are not allowed, use unit structs and \ |
| 144 | + enum variants instead") |
| 145 | + .span_help(span, "remove trailing `()` to make a unit \ |
| 146 | + struct or unit enum variant") |
| 147 | + .emit(); |
| 148 | + } |
| 149 | + } |
| 150 | + |
| 151 | + visit::walk_struct_def(self, vdata) |
| 152 | + } |
| 153 | + |
| 154 | + fn visit_vis(&mut self, vis: &Visibility) { |
| 155 | + match *vis { |
| 156 | + Visibility::Restricted{ref path, ..} => { |
| 157 | + if !path.segments.iter().all(|segment| segment.parameters.is_empty()) { |
| 158 | + self.err_handler().span_err(path.span, "type or lifetime parameters \ |
| 159 | + in visibility path"); |
| 160 | + } |
| 161 | + } |
| 162 | + _ => {} |
| 163 | + } |
| 164 | + |
| 165 | + visit::walk_vis(self, vis) |
| 166 | + } |
| 167 | +} |
| 168 | + |
| 169 | +pub fn check_crate(session: &Session, krate: &Crate) { |
| 170 | + visit::walk_crate(&mut AstValidator { session: session }, krate) |
| 171 | +} |
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