1 // Copyright 2012-2014 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.
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.
11 //! Lints, aka compiler warnings.
13 //! A 'lint' check is a kind of miscellaneous constraint that a user _might_
14 //! want to enforce, but might reasonably want to permit as well, on a
15 //! module-by-module basis. They contrast with static constraints enforced by
16 //! other phases of the compiler, which are generally required to hold in order
17 //! to compile the program at all.
19 //! Most lints can be written as `LintPass` instances. These run just before
20 //! translation to LLVM bytecode. The `LintPass`es built into rustc are defined
21 //! within `builtin.rs`, which has further comments on how to add such a lint.
23 //! Some of rustc's lints are defined elsewhere in the compiler and work by
24 //! calling `add_lint()` on the overall `Session` object. This works when
25 //! it happens before the main lint pass, which emits the lints stored by
26 //! `add_lint()`. To emit lints after the main lint pass (from trans, for
27 //! example) requires more effort. See `emit_lint` and `GatherNodeLevels`
32 use middle::privacy::ExportedItems;
34 use syntax::codemap::Span;
35 use syntax::visit::FnKind;
38 pub use lint::context::{Context, LintStore, raw_emit_lint, check_crate};
40 /// Specification of a single lint.
42 /// A string identifier for the lint.
44 /// Written with underscores, e.g. "unused_imports".
45 /// This identifies the lint in attributes and in
46 /// command-line arguments. On the command line,
47 /// underscores become dashes.
48 pub name: &'static str,
50 /// Default level for the lint.
51 pub default_level: Level,
53 /// Description of the lint or the issue it detects.
55 /// e.g. "imports that are never used"
56 pub desc: &'static str,
59 /// Build a `Lint` initializer.
61 macro_rules! lint_initializer (
62 ($name:ident, $level:ident, $desc:expr) => (
64 name: stringify!($name),
65 default_level: ::rustc::lint::$level,
71 /// Declare a static item of type `&'static Lint`.
73 macro_rules! declare_lint (
74 // FIXME(#14660): deduplicate
75 (pub $name:ident, $level:ident, $desc:expr) => (
76 pub static $name: &'static ::rustc::lint::Lint
77 = &lint_initializer!($name, $level, $desc);
79 ($name:ident, $level:ident, $desc:expr) => (
80 static $name: &'static ::rustc::lint::Lint
81 = &lint_initializer!($name, $level, $desc);
85 /// Declare a static `LintArray` and return it as an expression.
87 macro_rules! lint_array ( ($( $lint:expr ),*) => (
89 static array: LintArray = &[ $( $lint ),* ];
94 pub type LintArray = &'static [&'static Lint];
96 /// Trait for types providing lint checks.
98 /// Each `check` method checks a single syntax node, and should not
99 /// invoke methods recursively (unlike `Visitor`). By default they
102 // FIXME: eliminate the duplication with `Visitor`. But this also
103 // contains a few lint-specific methods with no equivalent in `Visitor`.
105 /// Get descriptions of the lints this `LintPass` object can emit.
107 /// NB: there is no enforcement that the object only emits lints it registered.
108 /// And some `rustc` internal `LintPass`es register lints to be emitted by other
109 /// parts of the compiler. If you want enforced access restrictions for your
110 /// `Lint`, make it a private `static` item in its own module.
111 fn get_lints(&self) -> LintArray;
113 fn check_crate(&mut self, _: &Context, _: &ExportedItems, _: &ast::Crate) { }
114 fn check_ident(&mut self, _: &Context, _: Span, _: ast::Ident) { }
115 fn check_mod(&mut self, _: &Context, _: &ast::Mod, _: Span, _: ast::NodeId) { }
116 fn check_view_item(&mut self, _: &Context, _: &ast::ViewItem) { }
117 fn check_foreign_item(&mut self, _: &Context, _: &ast::ForeignItem) { }
118 fn check_item(&mut self, _: &Context, _: &ast::Item) { }
119 fn check_local(&mut self, _: &Context, _: &ast::Local) { }
120 fn check_block(&mut self, _: &Context, _: &ast::Block) { }
121 fn check_stmt(&mut self, _: &Context, _: &ast::Stmt) { }
122 fn check_arm(&mut self, _: &Context, _: &ast::Arm) { }
123 fn check_pat(&mut self, _: &Context, _: &ast::Pat) { }
124 fn check_decl(&mut self, _: &Context, _: &ast::Decl) { }
125 fn check_expr(&mut self, _: &Context, _: &ast::Expr) { }
126 fn check_expr_post(&mut self, _: &Context, _: &ast::Expr) { }
127 fn check_ty(&mut self, _: &Context, _: &ast::Ty) { }
128 fn check_generics(&mut self, _: &Context, _: &ast::Generics) { }
129 fn check_fn(&mut self, _: &Context,
130 _: &FnKind, _: &ast::FnDecl, _: &ast::Block, _: Span, _: ast::NodeId) { }
131 fn check_ty_method(&mut self, _: &Context, _: &ast::TypeMethod) { }
132 fn check_trait_method(&mut self, _: &Context, _: &ast::TraitMethod) { }
133 fn check_struct_def(&mut self, _: &Context,
134 _: &ast::StructDef, _: ast::Ident, _: &ast::Generics, _: ast::NodeId) { }
135 fn check_struct_def_post(&mut self, _: &Context,
136 _: &ast::StructDef, _: ast::Ident, _: &ast::Generics, _: ast::NodeId) { }
137 fn check_struct_field(&mut self, _: &Context, _: &ast::StructField) { }
138 fn check_variant(&mut self, _: &Context, _: &ast::Variant, _: &ast::Generics) { }
139 fn check_opt_lifetime_ref(&mut self, _: &Context, _: Span, _: &Option<ast::Lifetime>) { }
140 fn check_lifetime_ref(&mut self, _: &Context, _: &ast::Lifetime) { }
141 fn check_lifetime_decl(&mut self, _: &Context, _: &ast::Lifetime) { }
142 fn check_explicit_self(&mut self, _: &Context, _: &ast::ExplicitSelf) { }
143 fn check_mac(&mut self, _: &Context, _: &ast::Mac) { }
144 fn check_path(&mut self, _: &Context, _: &ast::Path, _: ast::NodeId) { }
145 fn check_attribute(&mut self, _: &Context, _: &ast::Attribute) { }
147 /// Called when entering a syntax node that can have lint attributes such
148 /// as `#[allow(...)]`. Called with *all* the attributes of that node.
149 fn enter_lint_attrs(&mut self, _: &Context, _: &[ast::Attribute]) { }
151 /// Counterpart to `enter_lint_attrs`.
152 fn exit_lint_attrs(&mut self, _: &Context, _: &[ast::Attribute]) { }
155 /// A lint pass boxed up as a trait object.
156 pub type LintPassObject = Box<LintPass + 'static>;
158 /// Identifies a lint known to the compiler.
161 // Identity is based on pointer equality of this field.
165 impl PartialEq for LintId {
166 fn eq(&self, other: &LintId) -> bool {
167 (self.lint as *Lint) == (other.lint as *Lint)
171 impl Eq for LintId { }
173 impl<S: hash::Writer> hash::Hash<S> for LintId {
174 fn hash(&self, state: &mut S) {
175 let ptr = self.lint as *Lint;
181 /// Get the `LintId` for a `Lint`.
182 pub fn of(lint: &'static Lint) -> LintId {
188 /// Get the name of the lint.
189 pub fn as_str(&self) -> &'static str {
194 /// Setting for how to handle a lint.
195 #[deriving(Clone, PartialEq, PartialOrd, Eq, Ord)]
197 Allow, Warn, Deny, Forbid
201 /// Convert a level to a lower-case string.
202 pub fn as_str(self) -> &'static str {
211 /// Convert a lower-case string to a level.
212 pub fn from_str(x: &str) -> Option<Level> {
214 "allow" => Some(Allow),
215 "warn" => Some(Warn),
216 "deny" => Some(Deny),
217 "forbid" => Some(Forbid),
223 /// How a lint level was set.
224 #[deriving(Clone, PartialEq, Eq)]
225 pub enum LintSource {
226 /// Lint is at the default level as declared
227 /// in rustc or a plugin.
230 /// Lint level was set by an attribute.
233 /// Lint level was set by a command-line flag.
237 pub type LevelSource = (Level, LintSource);