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use clippy_utils::diagnostics::span_lint_and_then;
use clippy_utils::{fn_def_id, get_parent_expr, path_def_id};
use rustc_hir::{def::Res, def_id::DefIdMap, Expr, ExprKind};
use rustc_lint::{LateContext, LateLintPass};
use rustc_session::{declare_tool_lint, impl_lint_pass};
use crate::utils::conf;
declare_clippy_lint! {
/// ### What it does
/// Denies the configured methods and functions in clippy.toml
///
/// Note: Even though this lint is warn-by-default, it will only trigger if
/// methods are defined in the clippy.toml file.
///
/// ### Why is this bad?
/// Some methods are undesirable in certain contexts, and it's beneficial to
/// lint for them as needed.
///
/// ### Example
/// An example clippy.toml configuration:
/// ```toml
/// # clippy.toml
/// disallowed-methods = [
/// # Can use a string as the path of the disallowed method.
/// "std::boxed::Box::new",
/// # Can also use an inline table with a `path` key.
/// { path = "std::time::Instant::now" },
/// # When using an inline table, can add a `reason` for why the method
/// # is disallowed.
/// { path = "std::vec::Vec::leak", reason = "no leaking memory" },
/// ]
/// ```
///
/// ```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.
/// // The diagnostic contains the message "no leaking memory".
///
/// let _now = Instant::now(); // Instant::now is disallowed in the config.
///
/// let _box = Box::new(3); // Box::new 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.
/// ```
#[clippy::version = "1.49.0"]
pub DISALLOWED_METHODS,
style,
"use of a disallowed method call"
}
#[derive(Clone, Debug)]
pub struct DisallowedMethods {
conf_disallowed: Vec<conf::DisallowedMethod>,
disallowed: DefIdMap<usize>,
}
impl DisallowedMethods {
pub fn new(conf_disallowed: Vec<conf::DisallowedMethod>) -> Self {
Self {
conf_disallowed,
disallowed: DefIdMap::default(),
}
}
}
impl_lint_pass!(DisallowedMethods => [DISALLOWED_METHODS]);
impl<'tcx> LateLintPass<'tcx> for DisallowedMethods {
fn check_crate(&mut self, cx: &LateContext<'_>) {
for (index, conf) in self.conf_disallowed.iter().enumerate() {
let segs: Vec<_> = conf.path().split("::").collect();
if let Res::Def(_, id) = clippy_utils::def_path_res(cx, &segs) {
self.disallowed.insert(id, index);
}
}
}
fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
let uncalled_path = if let Some(parent) = get_parent_expr(cx, expr)
&& let ExprKind::Call(receiver, _) = parent.kind
&& receiver.hir_id == expr.hir_id
{
None
} else {
path_def_id(cx, expr)
};
let def_id = match uncalled_path.or_else(|| fn_def_id(cx, expr)) {
Some(def_id) => def_id,
None => return,
};
let conf = match self.disallowed.get(&def_id) {
Some(&index) => &self.conf_disallowed[index],
None => return,
};
let msg = format!("use of a disallowed method `{}`", conf.path());
span_lint_and_then(cx, DISALLOWED_METHODS, expr.span, &msg, |diag| {
if let conf::DisallowedMethod::WithReason {
reason: Some(reason), ..
} = conf
{
diag.note(&format!("{} (from clippy.toml)", reason));
}
});
}
}
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