rust/clippy_lints/src/disallowed_method.rs

91 lines
3.0 KiB
Rust

use clippy_utils::diagnostics::span_lint;
use clippy_utils::fn_def_id;
use rustc_data_structures::fx::FxHashSet;
use rustc_hir::Expr;
use rustc_lint::{LateContext, LateLintPass};
use rustc_session::{declare_tool_lint, impl_lint_pass};
use rustc_span::Symbol;
declare_clippy_lint! {
/// **What it does:** Denies the configured methods and functions in clippy.toml
///
/// **Why is this bad?** Some methods are undesirable in certain contexts,
/// and it's beneficial to lint for them as needed.
///
/// **Known problems:** Currently, you must write each function as a
/// fully-qualified path. This lint doesn't support aliases or reexported
/// names; be aware that many types in `std` are actually reexports.
///
/// For example, if you want to disallow `Duration::as_secs`, your clippy.toml
/// configuration would look like
/// `disallowed-methods = ["core::time::Duration::as_secs"]` and not
/// `disallowed-methods = ["std::time::Duration::as_secs"]` as you might expect.
///
/// **Example:**
///
/// An example clippy.toml configuration:
/// ```toml
/// # clippy.toml
/// disallowed-methods = ["alloc::vec::Vec::leak", "std::time::Instant::now"]
/// ```
///
/// ```rust,ignore
/// // Example code where clippy issues a warning
/// let xs = vec![1, 2, 3, 4];
/// xs.leak(); // Vec::leak is disallowed in the config.
///
/// let _now = Instant::now(); // Instant::now is disallowed in the config.
/// ```
///
/// Use instead:
/// ```rust,ignore
/// // Example code which does not raise clippy warning
/// let mut xs = Vec::new(); // Vec::new is _not_ disallowed in the config.
/// xs.push(123); // Vec::push is _not_ disallowed in the config.
/// ```
pub DISALLOWED_METHOD,
nursery,
"use of a disallowed method call"
}
#[derive(Clone, Debug)]
pub struct DisallowedMethod {
disallowed: FxHashSet<Vec<Symbol>>,
}
impl DisallowedMethod {
pub fn new(disallowed: &FxHashSet<String>) -> Self {
Self {
disallowed: disallowed
.iter()
.map(|s| s.split("::").map(|seg| Symbol::intern(seg)).collect::<Vec<_>>())
.collect(),
}
}
}
impl_lint_pass!(DisallowedMethod => [DISALLOWED_METHOD]);
impl<'tcx> LateLintPass<'tcx> for DisallowedMethod {
fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
if let Some(def_id) = fn_def_id(cx, expr) {
let func_path = cx.get_def_path(def_id);
if self.disallowed.contains(&func_path) {
let func_path_string = func_path
.into_iter()
.map(Symbol::to_ident_string)
.collect::<Vec<_>>()
.join("::");
span_lint(
cx,
DISALLOWED_METHOD,
expr.span,
&format!("use of a disallowed method `{}`", func_path_string),
);
}
}
}
}