Only remove one reference in implicit_clone

Author: Jarcho

clippy_lints/src/methods/implicit_clone.rs

@@ -4,7 +4,7 @@ use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir as hir;
 use rustc_lint::LateContext;
-use rustc_middle::ty::TyS;
+use rustc_middle::ty::{self, TyS};
 use rustc_span::{sym, Span};
 
 use super::IMPLICIT_CLONE;
@@ -14,7 +14,12 @@ pub fn check(cx: &LateContext<'_>, method_name: &str, expr: &hir::Expr<'_>, recv
         if let Some(method_def_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id);
         if is_clone_like(cx, method_name, method_def_id);
         let return_type = cx.typeck_results().expr_ty(expr);
-        let input_type = cx.typeck_results().expr_ty(recv).peel_refs();
+        let input_type = cx.typeck_results().expr_ty(recv);
+        // Remove only a single reference. `(&&T)::clone()` returns `&T`
+        let input_type = match input_type.kind() {
+            ty::Ref(_, ty, _) => ty,
+            _ => input_type,
+        };
         if let Some(ty_name) = input_type.ty_adt_def().map(|adt_def| cx.tcx.item_name(adt_def.did));
         if TyS::same_type(return_type, input_type);
         then {

tests/ui/implicit_clone.rs

@@ -105,4 +105,10 @@ fn main() {
     let os_str = OsStr::new("foo");
     let _ = os_str.to_owned();
     let _ = os_str.to_os_string();
+
+    // issue #8227
+    let pathbuf_ref = &pathbuf;
+    let pathbuf_ref = &pathbuf_ref;
+    let _ = pathbuf_ref.to_owned();
+    let _ = pathbuf_ref.to_path_buf();
 }