From e71ac41d44fd2fdffcb94f6000ad2cffad5c61cd Mon Sep 17 00:00:00 2001
From: Jason Newcomb <jsnewcomb@pm.me>
Date: Tue, 15 Mar 2022 21:51:07 -0400
Subject: Fix `transmute_undefined_repr` for single element tuples

---
 clippy_lints/src/transmute/transmute_undefined_repr.rs | 5 +++--
 tests/ui/transmute_undefined_repr.rs                   | 9 +++++++++
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/clippy_lints/src/transmute/transmute_undefined_repr.rs b/clippy_lints/src/transmute/transmute_undefined_repr.rs
index 6edff224092..3cd9d208943 100644
--- a/clippy_lints/src/transmute/transmute_undefined_repr.rs
+++ b/clippy_lints/src/transmute/transmute_undefined_repr.rs
@@ -282,10 +282,11 @@ fn reduce_ty<'tcx>(cx: &LateContext<'tcx>, mut ty: Ty<'tcx>) -> ReducedTy<'tcx>
             },
             ty::Tuple(args) if args.is_empty() => ReducedTy::TypeErasure,
             ty::Tuple(args) => {
-                let Some(sized_ty) = args.iter().find(|&ty| !is_zero_sized_ty(cx, ty)) else {
+                let mut iter = args.iter();
+                let Some(sized_ty) = iter.find(|&ty| !is_zero_sized_ty(cx, ty)) else {
                     return ReducedTy::OrderedFields(ty);
                 };
-                if args.iter().all(|ty| is_zero_sized_ty(cx, ty)) {
+                if iter.all(|ty| is_zero_sized_ty(cx, ty)) {
                     ty = sized_ty;
                     continue;
                 }
diff --git a/tests/ui/transmute_undefined_repr.rs b/tests/ui/transmute_undefined_repr.rs
index b163d605634..e7a59dbed95 100644
--- a/tests/ui/transmute_undefined_repr.rs
+++ b/tests/ui/transmute_undefined_repr.rs
@@ -87,5 +87,14 @@ fn main() {
 
         let _: *const [u8] = transmute(value::<Box<[u8]>>()); // Ok
         let _: Box<[u8]> = transmute(value::<*mut [u8]>()); // Ok
+
+        let _: Ty2<u32, u32> = transmute(value::<(Ty2<u32, u32>,)>()); // Ok
+        let _: (Ty2<u32, u32>,) = transmute(value::<Ty2<u32, u32>>()); // Ok
+
+        let _: Ty2<u32, u32> = transmute(value::<(Ty2<u32, u32>, ())>()); // Ok
+        let _: (Ty2<u32, u32>, ()) = transmute(value::<Ty2<u32, u32>>()); // Ok
+
+        let _: Ty2<u32, u32> = transmute(value::<((), Ty2<u32, u32>)>()); // Ok
+        let _: ((), Ty2<u32, u32>) = transmute(value::<Ty2<u32, u32>>()); // Ok
     }
 }
-- 
cgit 1.4.1-3-g733a5