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use rustc::lint::*;
use rustc::hir::*;
use utils::{is_automatically_derived, span_lint};
declare_lint! {
pub PARTIALEQ_NE_IMPL,
Warn,
"re-implementing `PartialEq::ne`"
}
#[derive(Clone, Copy)]
pub struct Pass;
impl LintPass for Pass {
fn get_lints(&self) -> LintArray {
lint_array!(PARTIALEQ_NE_IMPL)
}
}
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
fn check_item(&mut self, cx: &LateContext<'a, 'tcx>, item: &'tcx Item) {
if_let_chain! {[
let ItemImpl(_, _, _, Some(ref trait_ref), _, ref impl_items) = item.node,
!is_automatically_derived(&*item.attrs),
trait_ref.path.def.def_id() == cx.tcx.lang_items.eq_trait().unwrap(),
], {
for impl_item in impl_items {
if &*impl_item.name.as_str() == "ne" {
span_lint(cx,
PARTIALEQ_NE_IMPL,
impl_item.span,
"re-implementing `PartialEq::ne` is unnecessary")
}
}
}};
}
}