//!
//! This lint is **warn** by default
-use crate::utils::{snippet_opt, span_lint_and_then};
+use clippy_utils::diagnostics::span_lint_and_then;
+use clippy_utils::source::snippet_opt;
use if_chain::if_chain;
use rustc_errors::Applicability;
-use rustc_hir::{BindingAnnotation, BorrowKind, Expr, ExprKind, HirId, Item, Mutability, Pat, PatKind};
+use rustc_hir::{BindingAnnotation, BorrowKind, Expr, ExprKind, Mutability, Pat, PatKind};
use rustc_lint::{LateContext, LateLintPass};
use rustc_middle::ty;
use rustc_middle::ty::adjustment::{Adjust, Adjustment};
}
#[derive(Default)]
-pub struct NeedlessBorrow {
- derived_item: Option<HirId>,
-}
+pub struct NeedlessBorrow;
impl_lint_pass!(NeedlessBorrow => [NEEDLESS_BORROW]);
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NeedlessBorrow {
- fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr<'_>) {
- if e.span.from_expansion() || self.derived_item.is_some() {
+impl<'tcx> LateLintPass<'tcx> for NeedlessBorrow {
+ fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) {
+ if e.span.from_expansion() {
return;
}
- if let ExprKind::AddrOf(BorrowKind::Ref, Mutability::Not, ref inner) = e.kind {
- if let ty::Ref(..) = cx.tables().expr_ty(inner).kind {
- for adj3 in cx.tables().expr_adjustments(e).windows(3) {
+ if let ExprKind::AddrOf(BorrowKind::Ref, Mutability::Not, inner) = e.kind {
+ if let ty::Ref(_, ty, _) = cx.typeck_results().expr_ty(inner).kind() {
+ for adj3 in cx.typeck_results().expr_adjustments(e).windows(3) {
if let [Adjustment {
kind: Adjust::Deref(_), ..
}, Adjustment {
cx,
NEEDLESS_BORROW,
e.span,
- "this expression borrows a reference that is immediately dereferenced \
+ &format!(
+ "this expression borrows a reference (`&{}`) that is immediately dereferenced \
by the compiler",
+ ty
+ ),
|diag| {
if let Some(snippet) = snippet_opt(cx, inner.span) {
diag.span_suggestion(
}
}
}
- fn check_pat(&mut self, cx: &LateContext<'a, 'tcx>, pat: &'tcx Pat<'_>) {
- if pat.span.from_expansion() || self.derived_item.is_some() {
+ fn check_pat(&mut self, cx: &LateContext<'tcx>, pat: &'tcx Pat<'_>) {
+ if pat.span.from_expansion() {
return;
}
if_chain! {
if let PatKind::Binding(BindingAnnotation::Ref, .., name, _) = pat.kind;
- if let ty::Ref(_, tam, mutbl) = cx.tables().pat_ty(pat).kind;
+ if let ty::Ref(_, tam, mutbl) = *cx.typeck_results().pat_ty(pat).kind();
if mutbl == Mutability::Not;
- if let ty::Ref(_, _, mutbl) = tam.kind;
+ if let ty::Ref(_, _, mutbl) = *tam.kind();
// only lint immutable refs, because borrowed `&mut T` cannot be moved out
if mutbl == Mutability::Not;
then {
}
}
}
-
- fn check_item(&mut self, _: &LateContext<'a, 'tcx>, item: &'tcx Item<'_>) {
- if item.attrs.iter().any(|a| a.check_name(sym!(automatically_derived))) {
- debug_assert!(self.derived_item.is_none());
- self.derived_item = Some(item.hir_id);
- }
- }
-
- fn check_item_post(&mut self, _: &LateContext<'a, 'tcx>, item: &'tcx Item<'_>) {
- if let Some(id) = self.derived_item {
- if item.hir_id == id {
- self.derived_item = None;
- }
- }
- }
}