rust/clippy_lints/src/disallowed_names.rs

78 lines
2.2 KiB
Rust

use clippy_utils::{diagnostics::span_lint, is_test_module_or_function};
use rustc_data_structures::fx::FxHashSet;
use rustc_hir::{Item, Pat, PatKind};
use rustc_lint::{LateContext, LateLintPass};
use rustc_session::{declare_tool_lint, impl_lint_pass};
declare_clippy_lint! {
/// ### What it does
/// Checks for usage of disallowed names for variables, such
/// as `foo`.
///
/// ### Why is this bad?
/// These names are usually placeholder names and should be
/// avoided.
///
/// ### Example
/// ```rust
/// let foo = 3.14;
/// ```
#[clippy::version = "pre 1.29.0"]
pub DISALLOWED_NAMES,
style,
"usage of a disallowed/placeholder name"
}
#[derive(Clone, Debug)]
pub struct DisallowedNames {
disallow: FxHashSet<String>,
test_modules_deep: u32,
}
impl DisallowedNames {
pub fn new(disallow: FxHashSet<String>) -> Self {
Self {
disallow,
test_modules_deep: 0,
}
}
fn in_test_module(&self) -> bool {
self.test_modules_deep != 0
}
}
impl_lint_pass!(DisallowedNames => [DISALLOWED_NAMES]);
impl<'tcx> LateLintPass<'tcx> for DisallowedNames {
fn check_item(&mut self, cx: &LateContext<'_>, item: &Item<'_>) {
if is_test_module_or_function(cx.tcx, item) {
self.test_modules_deep = self.test_modules_deep.saturating_add(1);
}
}
fn check_pat(&mut self, cx: &LateContext<'tcx>, pat: &'tcx Pat<'_>) {
// Check whether we are under the `test` attribute.
if self.in_test_module() {
return;
}
if let PatKind::Binding(.., ident, _) = pat.kind {
if self.disallow.contains(&ident.name.to_string()) {
span_lint(
cx,
DISALLOWED_NAMES,
ident.span,
&format!("use of a disallowed/placeholder name `{}`", ident.name),
);
}
}
}
fn check_item_post(&mut self, cx: &LateContext<'_>, item: &Item<'_>) {
if is_test_module_or_function(cx.tcx, item) {
self.test_modules_deep = self.test_modules_deep.saturating_sub(1);
}
}
}