From 988b813649c147383bcce125c9afbb0adc681110 Mon Sep 17 00:00:00 2001
From: Jason Newcomb <jsnewcomb@pm.me>
Date: Sat, 2 Jul 2022 15:32:29 -0400
Subject: [PATCH] Use correct substitutions when checking if `needless_borrow`
can apply to a method receiver
---
clippy_lints/src/dereference.rs | 11 ++++++++---
tests/ui/needless_borrow.fixed | 12 ++++++++++++
tests/ui/needless_borrow.rs | 12 ++++++++++++
3 files changed, 32 insertions(+), 3 deletions(-)
diff --git a/clippy_lints/src/dereference.rs b/clippy_lints/src/dereference.rs
index 59dcc1ebf19..d6bd43a7494 100644
--- a/clippy_lints/src/dereference.rs
+++ b/clippy_lints/src/dereference.rs
@@ -756,9 +756,14 @@ fn walk_parents<'tcx>(cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) -> (Position, &
} else if let Some(trait_id) = cx.tcx.trait_of_item(id)
&& let arg_ty = cx.tcx.erase_regions(cx.typeck_results().expr_ty_adjusted(e))
&& let ty::Ref(_, sub_ty, _) = *arg_ty.kind()
- && let subs = cx.typeck_results().node_substs_opt(child_id).unwrap_or_else(
- || cx.tcx.mk_substs([].iter())
- ) && let impl_ty = if cx.tcx.fn_sig(id).skip_binder().inputs()[0].is_ref() {
+ && let subs = match cx
+ .typeck_results()
+ .node_substs_opt(parent.hir_id)
+ .and_then(|subs| subs.get(1..))
+ {
+ Some(subs) => cx.tcx.mk_substs(subs.iter().copied()),
+ None => cx.tcx.mk_substs([].iter()),
+ } && let impl_ty = if cx.tcx.fn_sig(id).skip_binder().inputs()[0].is_ref() {
// Trait methods taking `&self`
sub_ty
} else {
diff --git a/tests/ui/needless_borrow.fixed b/tests/ui/needless_borrow.fixed
index cb005122436..09afe2ddbbf 100644
--- a/tests/ui/needless_borrow.fixed
+++ b/tests/ui/needless_borrow.fixed
@@ -115,6 +115,18 @@ fn main() {
fn foo_ref(&self) {}
}
(&&()).foo_ref(); // Don't lint. `&()` will call `<() as FooRef>::foo_ref`
+
+ struct S;
+ impl From<S> for u32 {
+ fn from(s: S) -> Self {
+ (&s).into()
+ }
+ }
+ impl From<&S> for u32 {
+ fn from(s: &S) -> Self {
+ 0
+ }
+ }
}
#[allow(clippy::needless_borrowed_reference)]
diff --git a/tests/ui/needless_borrow.rs b/tests/ui/needless_borrow.rs
index d636a401003..3ae4722a1f8 100644
--- a/tests/ui/needless_borrow.rs
+++ b/tests/ui/needless_borrow.rs
@@ -115,6 +115,18 @@ fn main() {
fn foo_ref(&self) {}
}
(&&()).foo_ref(); // Don't lint. `&()` will call `<() as FooRef>::foo_ref`
+
+ struct S;
+ impl From<S> for u32 {
+ fn from(s: S) -> Self {
+ (&s).into()
+ }
+ }
+ impl From<&S> for u32 {
+ fn from(s: &S) -> Self {
+ 0
+ }
+ }
}
#[allow(clippy::needless_borrowed_reference)]