rust/src/librustc/lint/builtin.rs

// Copyright 2012-2015 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.

//! Lints built in to rustc.
//!
//! This is a sibling of `lint::context` in order to ensure that
//! lints implemented here use the same public API as lint plugins.
//!
//! To add a new lint to rustc, declare it here using `declare_lint!()`.
//! Then add code to emit the new lint in the appropriate circumstances.
//! You can do that in an existing `LintPass` if it makes sense, or in
//! a new `LintPass`, or using `Session::add_lint` elsewhere in the
//! compiler. Only do the latter if the check can't be written cleanly
//! as a `LintPass`.
//!
//! If you define a new `LintPass`, you will also need to add it to the
//! `add_builtin!` or `add_builtin_with_new!` invocation in `context.rs`.
//! Use the former for unit-like structs and the latter for structs with
//! a `pub fn new()`.

use lint::{LintPass, LintArray};

declare_lint! {
    pub UNUSED_IMPORTS,
    Warn,
    "imports that are never used"
}

declare_lint! {
    pub UNUSED_EXTERN_CRATES,
    Allow,
    "extern crates that are never used"
}

declare_lint! {
    pub UNUSED_QUALIFICATIONS,
    Allow,
    "detects unnecessarily qualified names"
}

declare_lint! {
    pub UNKNOWN_LINTS,
    Warn,
    "unrecognized lint attribute"
}

declare_lint! {
    pub UNUSED_VARIABLES,
    Warn,
    "detect variables which are not used in any way"
}

declare_lint! {
    pub UNUSED_ASSIGNMENTS,
    Warn,
    "detect assignments that will never be read"
}

declare_lint! {
    pub DEAD_CODE,
    Warn,
    "detect unused, unexported items"
}

declare_lint! {
    pub UNREACHABLE_CODE,
    Warn,
    "detects unreachable code paths"
}

declare_lint! {
    pub WARNINGS,
    Warn,
    "mass-change the level for lints which produce warnings"
}

declare_lint! {
    pub UNUSED_FEATURES,
    Warn,
    "unused or unknown features found in crate-level #[feature] directives"
}

declare_lint! {
    pub STABLE_FEATURES,
    Warn,
    "stable features found in #[feature] directive"
}

declare_lint! {
    pub UNKNOWN_CRATE_TYPES,
    Deny,
    "unknown crate type found in #[crate_type] directive"
}

declare_lint! {
    pub VARIANT_SIZE_DIFFERENCES,
    Allow,
    "detects enums with widely varying variant sizes"
}

declare_lint! {
    pub FAT_PTR_TRANSMUTES,
    Allow,
    "detects transmutes of fat pointers"
}

/// Does nothing as a lint pass, but registers some `Lint`s
/// which are used by other parts of the compiler.
#[derive(Copy)]
pub struct HardwiredLints;

impl LintPass for HardwiredLints {
    fn get_lints(&self) -> LintArray {
        lint_array!(
            UNUSED_IMPORTS,
            UNUSED_EXTERN_CRATES,
            UNUSED_QUALIFICATIONS,
            UNKNOWN_LINTS,
            UNUSED_VARIABLES,
            UNUSED_ASSIGNMENTS,
            DEAD_CODE,
            UNREACHABLE_CODE,
            WARNINGS,
            UNUSED_FEATURES,
            STABLE_FEATURES,
            UNKNOWN_CRATE_TYPES,
            VARIANT_SIZE_DIFFERENCES,
            FAT_PTR_TRANSMUTES
        )
    }
}