rust/src/needless_features.rs
2015-12-14 22:16:56 +01:00

68 lines
2.2 KiB
Rust

//! Checks for usage of nightly features that have simple stable equivalents
//!
//! This lint is **warn** by default
use rustc::lint::*;
use rustc_front::hir::*;
use utils::span_lint;
use utils;
/// **What it does:** This lint `Warn`s on use of the `as_slice(..)` function, which is unstable.
///
/// **Why is this bad?** Using this function doesn't make your code better, but it will preclude it from building with stable Rust.
///
/// **Known problems:** None.
///
/// **Example:** `x.as_slice(..)`
declare_lint! {
pub UNSTABLE_AS_SLICE,
Warn,
"as_slice is not stable and can be replaced by & v[..]\
see https://github.com/rust-lang/rust/issues/27729"
}
/// **What it does:** This lint `Warn`s on use of the `as_mut_slice(..)` function, which is unstable.
///
/// **Why is this bad?** Using this function doesn't make your code better, but it will preclude it from building with stable Rust.
///
/// **Known problems:** None.
///
/// **Example:** `x.as_mut_slice(..)`
declare_lint! {
pub UNSTABLE_AS_MUT_SLICE,
Warn,
"as_mut_slice is not stable and can be replaced by &mut v[..]\
see https://github.com/rust-lang/rust/issues/27729"
}
#[derive(Copy,Clone)]
pub struct NeedlessFeaturesPass;
impl LintPass for NeedlessFeaturesPass {
fn get_lints(&self) -> LintArray {
lint_array!(UNSTABLE_AS_SLICE, UNSTABLE_AS_MUT_SLICE)
}
}
impl LateLintPass for NeedlessFeaturesPass {
fn check_expr(&mut self, cx: &LateContext, expr: &Expr) {
if let ExprMethodCall(ref name, _, _) = expr.node {
if name.node.as_str() == "as_slice" && check_paths(cx, expr) {
span_lint(cx, UNSTABLE_AS_SLICE, expr.span,
"used as_slice() from the 'convert' nightly feature. Use &[..] \
instead");
}
if name.node.as_str() == "as_mut_slice" && check_paths(cx, expr) {
span_lint(cx, UNSTABLE_AS_MUT_SLICE, expr.span,
"used as_mut_slice() from the 'convert' nightly feature. Use &mut [..] \
instead");
}
}
}
}
fn check_paths(cx: &LateContext, expr: &Expr) -> bool {
utils::match_impl_method(cx, expr, &["collections", "vec", "Vec<T>"])
}