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.
22 //! rustc can also load user-defined lint plugins via the plugin mechanism.
24 //! Some of rustc's lints are defined elsewhere in the compiler and work by
25 //! calling `add_lint()` on the overall `Session` object. This works when
26 //! it happens before the main lint pass, which emits the lints stored by
27 //! `add_lint()`. To emit lints after the main lint pass (from trans, for
28 //! example) requires more effort. See `emit_lint` and `GatherNodeLevels`
31 pub use self::Level
::*;
32 pub use self::LintSource
::*;
35 use std
::ascii
::AsciiExt
;
36 use syntax
::codemap
::Span
;
37 use syntax
::visit
::FnKind
;
40 pub use lint
::context
::{Context, LintStore, raw_emit_lint, check_crate, gather_attrs}
;
42 /// Specification of a single lint.
45 /// A string identifier for the lint.
47 /// This identifies the lint in attributes and in command-line arguments.
48 /// In those contexts it is always lowercase, but this field is compared
49 /// in a way which is case-insensitive for ASCII characters. This allows
50 /// `declare_lint!()` invocations to follow the convention of upper-case
51 /// statics without repeating the name.
53 /// The name is written with underscores, e.g. "unused_imports".
54 /// On the command line, underscores become dashes.
55 pub name
: &'
static str,
57 /// Default level for the lint.
58 pub default_level
: Level
,
60 /// Description of the lint or the issue it detects.
62 /// e.g. "imports that are never used"
63 pub desc
: &'
static str,
67 /// Get the lint's name, with ASCII letters converted to lowercase.
68 pub fn name_lower(&self) -> String
{
69 self.name
.to_ascii_lowercase()
73 /// Build a `Lint` initializer.
75 macro_rules
! lint_initializer
{
76 ($name
:ident
, $level
:ident
, $desc
:expr
) => (
78 name
: stringify
!($name
),
79 default_level
: ::rustc
::lint
::$level
,
85 /// Declare a static item of type `&'static Lint`.
87 macro_rules
! declare_lint
{
88 // FIXME(#14660): deduplicate
89 (pub $name
:ident
, $level
:ident
, $desc
:expr
) => (
90 pub static $name
: &'
static ::rustc
::lint
::Lint
91 = &lint_initializer
!($name
, $level
, $desc
);
93 ($name
:ident
, $level
:ident
, $desc
:expr
) => (
94 static $name
: &'
static ::rustc
::lint
::Lint
95 = &lint_initializer
!($name
, $level
, $desc
);
99 /// Declare a static `LintArray` and return it as an expression.
101 macro_rules
! lint_array
{ ($
( $lint
:expr
),*) => (
103 #[allow(non_upper_case_globals)]
104 static array
: LintArray
= &[ $
( &$lint
),* ];
109 pub type LintArray
= &'
static [&'
static &'
static Lint
];
111 /// Trait for types providing lint checks.
113 /// Each `check` method checks a single syntax node, and should not
114 /// invoke methods recursively (unlike `Visitor`). By default they
117 // FIXME: eliminate the duplication with `Visitor`. But this also
118 // contains a few lint-specific methods with no equivalent in `Visitor`.
120 /// Get descriptions of the lints this `LintPass` object can emit.
122 /// NB: there is no enforcement that the object only emits lints it registered.
123 /// And some `rustc` internal `LintPass`es register lints to be emitted by other
124 /// parts of the compiler. If you want enforced access restrictions for your
125 /// `Lint`, make it a private `static` item in its own module.
126 fn get_lints(&self) -> LintArray
;
128 fn check_crate(&mut self, _
: &Context
, _
: &ast
::Crate
) { }
129 fn check_ident(&mut self, _
: &Context
, _
: Span
, _
: ast
::Ident
) { }
130 fn check_mod(&mut self, _
: &Context
, _
: &ast
::Mod
, _
: Span
, _
: ast
::NodeId
) { }
131 fn check_view_item(&mut self, _
: &Context
, _
: &ast
::ViewItem
) { }
132 fn check_foreign_item(&mut self, _
: &Context
, _
: &ast
::ForeignItem
) { }
133 fn check_item(&mut self, _
: &Context
, _
: &ast
::Item
) { }
134 fn check_local(&mut self, _
: &Context
, _
: &ast
::Local
) { }
135 fn check_block(&mut self, _
: &Context
, _
: &ast
::Block
) { }
136 fn check_stmt(&mut self, _
: &Context
, _
: &ast
::Stmt
) { }
137 fn check_arm(&mut self, _
: &Context
, _
: &ast
::Arm
) { }
138 fn check_pat(&mut self, _
: &Context
, _
: &ast
::Pat
) { }
139 fn check_decl(&mut self, _
: &Context
, _
: &ast
::Decl
) { }
140 fn check_expr(&mut self, _
: &Context
, _
: &ast
::Expr
) { }
141 fn check_expr_post(&mut self, _
: &Context
, _
: &ast
::Expr
) { }
142 fn check_ty(&mut self, _
: &Context
, _
: &ast
::Ty
) { }
143 fn check_generics(&mut self, _
: &Context
, _
: &ast
::Generics
) { }
144 fn check_fn(&mut self, _
: &Context
,
145 _
: FnKind
, _
: &ast
::FnDecl
, _
: &ast
::Block
, _
: Span
, _
: ast
::NodeId
) { }
146 fn check_ty_method(&mut self, _
: &Context
, _
: &ast
::TypeMethod
) { }
147 fn check_trait_method(&mut self, _
: &Context
, _
: &ast
::TraitItem
) { }
148 fn check_struct_def(&mut self, _
: &Context
,
149 _
: &ast
::StructDef
, _
: ast
::Ident
, _
: &ast
::Generics
, _
: ast
::NodeId
) { }
150 fn check_struct_def_post(&mut self, _
: &Context
,
151 _
: &ast
::StructDef
, _
: ast
::Ident
, _
: &ast
::Generics
, _
: ast
::NodeId
) { }
152 fn check_struct_field(&mut self, _
: &Context
, _
: &ast
::StructField
) { }
153 fn check_variant(&mut self, _
: &Context
, _
: &ast
::Variant
, _
: &ast
::Generics
) { }
154 fn check_variant_post(&mut self, _
: &Context
, _
: &ast
::Variant
, _
: &ast
::Generics
) { }
155 fn check_opt_lifetime_ref(&mut self, _
: &Context
, _
: Span
, _
: &Option
<ast
::Lifetime
>) { }
156 fn check_lifetime_ref(&mut self, _
: &Context
, _
: &ast
::Lifetime
) { }
157 fn check_lifetime_def(&mut self, _
: &Context
, _
: &ast
::LifetimeDef
) { }
158 fn check_explicit_self(&mut self, _
: &Context
, _
: &ast
::ExplicitSelf
) { }
159 fn check_mac(&mut self, _
: &Context
, _
: &ast
::Mac
) { }
160 fn check_path(&mut self, _
: &Context
, _
: &ast
::Path
, _
: ast
::NodeId
) { }
161 fn check_attribute(&mut self, _
: &Context
, _
: &ast
::Attribute
) { }
163 /// Called when entering a syntax node that can have lint attributes such
164 /// as `#[allow(...)]`. Called with *all* the attributes of that node.
165 fn enter_lint_attrs(&mut self, _
: &Context
, _
: &[ast
::Attribute
]) { }
167 /// Counterpart to `enter_lint_attrs`.
168 fn exit_lint_attrs(&mut self, _
: &Context
, _
: &[ast
::Attribute
]) { }
171 /// A lint pass boxed up as a trait object.
172 pub type LintPassObject
= Box
<LintPass
+ '
static>;
174 /// Identifies a lint known to the compiler.
175 #[derive(Clone, Copy)]
177 // Identity is based on pointer equality of this field.
181 impl PartialEq
for LintId
{
182 fn eq(&self, other
: &LintId
) -> bool
{
183 (self.lint
as *const Lint
) == (other
.lint
as *const Lint
)
187 impl Eq
for LintId { }
189 impl<S
: hash
::Writer
+ hash
::Hasher
> hash
::Hash
<S
> for LintId
{
190 fn hash(&self, state
: &mut S
) {
191 let ptr
= self.lint
as *const Lint
;
197 /// Get the `LintId` for a `Lint`.
198 pub fn of(lint
: &'
static Lint
) -> LintId
{
204 /// Get the name of the lint.
205 pub fn as_str(&self) -> String
{
206 self.lint
.name_lower()
210 /// Setting for how to handle a lint.
211 #[derive(Clone, Copy, PartialEq, PartialOrd, Eq, Ord, Show)]
213 Allow
, Warn
, Deny
, Forbid
217 /// Convert a level to a lower-case string.
218 pub fn as_str(self) -> &'
static str {
227 /// Convert a lower-case string to a level.
228 pub fn from_str(x
: &str) -> Option
<Level
> {
230 "allow" => Some(Allow
),
231 "warn" => Some(Warn
),
232 "deny" => Some(Deny
),
233 "forbid" => Some(Forbid
),
239 /// How a lint level was set.
240 #[derive(Clone, Copy, PartialEq, Eq)]
241 pub enum LintSource
{
242 /// Lint is at the default level as declared
243 /// in rustc or a plugin.
246 /// Lint level was set by an attribute.
249 /// Lint level was set by a command-line flag.
252 /// Lint level was set by the release channel.
256 pub type LevelSource
= (Level
, LintSource
);