uplift clippy::clone_double_ref as suspicious_double_ref_op

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -40,7 +40,6 @@ use regex::Regex;
 use tempfile::Builder as TempFileBuilder;
 
 use itertools::Itertools;
-use std::borrow::Borrow;
 use std::cell::OnceCell;
 use std::collections::BTreeSet;
 use std::ffi::OsString;
@@ -573,17 +572,17 @@ fn link_dwarf_object<'a>(
 
     impl<Relocations> ThorinSession<Relocations> {
         fn alloc_mmap(&self, data: Mmap) -> &Mmap {
-            (*self.arena_mmap.alloc(data)).borrow()
+            &*self.arena_mmap.alloc(data)
         }
     }
 
     impl<Relocations> thorin::Session<Relocations> for ThorinSession<Relocations> {
         fn alloc_data(&self, data: Vec<u8>) -> &[u8] {
-            (*self.arena_data.alloc(data)).borrow()
+            &*self.arena_data.alloc(data)
         }
 
         fn alloc_relocation(&self, data: Relocations) -> &Relocations {
-            (*self.arena_relocations.alloc(data)).borrow()
+            &*self.arena_relocations.alloc(data)
         }
 
         fn read_input(&self, path: &Path) -> std::io::Result<&[u8]> {

compiler/rustc_lint/messages.ftl

@@ -50,6 +50,9 @@ lint_deprecated_lint_name =
 lint_renamed_or_removed_lint = {$msg}
     .suggestion = use the new name
 
+lint_suspicious_double_ref_op =
+    using `.{$call}()` on a double reference, which returns `{$ty}` instead of {$op} the inner type
+
 lint_unknown_lint =
     unknown lint: `{$name}`
     .suggestion = did you mean

compiler/rustc_lint/src/lints.rs

@@ -1150,6 +1150,14 @@ pub struct NoopMethodCallDiag<'a> {
     pub label: Span,
 }
 
+#[derive(LintDiagnostic)]
+#[diag(lint_suspicious_double_ref_op)]
+pub struct SuspiciousDoubleRefDiag<'a> {
+    pub call: Symbol,
+    pub ty: Ty<'a>,
+    pub op: &'static str,
+}
+
 // pass_by_value.rs
 #[derive(LintDiagnostic)]
 #[diag(lint_pass_by_value)]

compiler/rustc_lint/src/noop_method_call.rs

@@ -1,10 +1,11 @@
 use crate::context::LintContext;
-use crate::lints::NoopMethodCallDiag;
+use crate::lints::{NoopMethodCallDiag, SuspiciousDoubleRefDiag};
 use crate::LateContext;
 use crate::LateLintPass;
 use rustc_hir::def::DefKind;
 use rustc_hir::{Expr, ExprKind};
 use rustc_middle::ty;
+use rustc_middle::ty::adjustment::Adjust;
 use rustc_span::symbol::sym;
 
 declare_lint! {
@@ -35,14 +36,44 @@ declare_lint! {
     "detects the use of well-known noop methods"
 }
 
-declare_lint_pass!(NoopMethodCall => [NOOP_METHOD_CALL]);
+declare_lint! {
+    /// The `suspicious_double_ref_op` lint checks for usage of `.clone()`/`.borrow()`/`.deref()`
+    /// on an `&&T` when `T: !Deref/Borrow/Clone`, which means the call will return the inner `&T`,
+    /// instead of performing the operation on the underlying `T` and can be confusing.
+    ///
+    /// ### Example
+    ///
+    /// ```rust
+    /// # #![allow(unused)]
+    /// struct Foo;
+    /// let foo = &&Foo;
+    /// let clone: &Foo = foo.clone();
+    /// ```
+    ///
+    /// {{produces}}
+    ///
+    /// ### Explanation
+    ///
+    /// Since `Foo` doesn't implement `Clone`, running `.clone()` only dereferences the double
+    /// reference, instead of cloning the inner type which should be what was intended.
+    pub SUSPICIOUS_DOUBLE_REF_OP,
+    Warn,
+    "suspicious call of trait method on `&&T`"
+}
+
+declare_lint_pass!(NoopMethodCall => [NOOP_METHOD_CALL, SUSPICIOUS_DOUBLE_REF_OP]);
 
 impl<'tcx> LateLintPass<'tcx> for NoopMethodCall {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
         // We only care about method calls.
-        let ExprKind::MethodCall(call, receiver, ..) = &expr.kind else {
+        let ExprKind::MethodCall(call, receiver, _, call_span) = &expr.kind else {
-            return
+            return;
         };
+
+        if call_span.from_expansion() {
+            return;
+        }
+
         // We only care about method calls corresponding to the `Clone`, `Deref` and `Borrow`
         // traits and ignore any other method call.
         let did = match cx.typeck_results().type_dependent_def(expr.hir_id) {
@@ -70,25 +101,39 @@ impl<'tcx> LateLintPass<'tcx> for NoopMethodCall {
         };
         // (Re)check that it implements the noop diagnostic.
         let Some(name) = cx.tcx.get_diagnostic_name(i.def_id()) else { return };
-        if !matches!(
+
-            name,
+        let op = match name {
-            sym::noop_method_borrow | sym::noop_method_clone | sym::noop_method_deref
+            sym::noop_method_borrow => "borrowing",
-        ) {
+            sym::noop_method_clone => "cloning",
-            return;
+            sym::noop_method_deref => "dereferencing",
-        }
+            _ => return,
+        };
+
         let receiver_ty = cx.typeck_results().expr_ty(receiver);
         let expr_ty = cx.typeck_results().expr_ty_adjusted(expr);
-        if receiver_ty != expr_ty {
+        let arg_adjustments = cx.typeck_results().expr_adjustments(receiver);
-            // This lint will only trigger if the receiver type and resulting expression \
+
-            // type are the same, implying that the method call is unnecessary.
+        // If there is any user defined auto-deref step, then we don't want to warn.
+        // https://github.com/rust-lang/rust-clippy/issues/9272
+        if arg_adjustments.iter().any(|adj| matches!(adj.kind, Adjust::Deref(Some(_)))) {
             return;
         }
+
         let expr_span = expr.span;
         let span = expr_span.with_lo(receiver.span.hi());
+
+        if receiver_ty == expr_ty {
             cx.emit_spanned_lint(
                 NOOP_METHOD_CALL,
                 span,
                 NoopMethodCallDiag { method: call.ident.name, receiver_ty, label: span },
             );
+        } else {
+            cx.emit_spanned_lint(
+                SUSPICIOUS_DOUBLE_REF_OP,
+                span,
+                SuspiciousDoubleRefDiag { call: call.ident.name, ty: expr_ty, op },
+            )
+        }
     }
 }

src/tools/clippy/clippy_lints/src/declared_lints.rs

@@ -313,7 +313,6 @@ pub(crate) static LINTS: &[&crate::LintInfo] = &[
     crate::methods::CHARS_NEXT_CMP_INFO,
     crate::methods::CLEAR_WITH_DRAIN_INFO,
     crate::methods::CLONED_INSTEAD_OF_COPIED_INFO,
-    crate::methods::CLONE_DOUBLE_REF_INFO,
     crate::methods::CLONE_ON_COPY_INFO,
     crate::methods::CLONE_ON_REF_PTR_INFO,
     crate::methods::COLLAPSIBLE_STR_REPLACE_INFO,

src/tools/clippy/clippy_lints/src/methods/clone_on_copy.rs

@@ -1,7 +1,6 @@
-use clippy_utils::diagnostics::{span_lint_and_sugg, span_lint_and_then};
+use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::get_parent_node;
 use clippy_utils::source::snippet_with_context;
-use clippy_utils::sugg;
 use clippy_utils::ty::is_copy;
 use rustc_errors::Applicability;
 use rustc_hir::{BindingAnnotation, ByRef, Expr, ExprKind, MatchSource, Node, PatKind, QPath};
@@ -9,7 +8,6 @@ use rustc_lint::LateContext;
 use rustc_middle::ty::{self, adjustment::Adjust, print::with_forced_trimmed_paths};
 use rustc_span::symbol::{sym, Symbol};
 
-use super::CLONE_DOUBLE_REF;
 use super::CLONE_ON_COPY;
 
 /// Checks for the `CLONE_ON_COPY` lint.
@@ -42,41 +40,7 @@ pub(super) fn check(
 
     let ty = cx.typeck_results().expr_ty(expr);
     if let ty::Ref(_, inner, _) = arg_ty.kind() {
-        if let ty::Ref(_, innermost, _) = inner.kind() {
+        if let ty::Ref(..) = inner.kind() {
-            span_lint_and_then(
-                cx,
-                CLONE_DOUBLE_REF,
-                expr.span,
-                &with_forced_trimmed_paths!(format!(
-                    "using `clone` on a double-reference; \
-                    this will copy the reference of type `{ty}` instead of cloning the inner type"
-                )),
-                |diag| {
-                    if let Some(snip) = sugg::Sugg::hir_opt(cx, arg) {
-                        let mut ty = innermost;
-                        let mut n = 0;
-                        while let ty::Ref(_, inner, _) = ty.kind() {
-                            ty = inner;
-                            n += 1;
-                        }
-                        let refs = "&".repeat(n + 1);
-                        let derefs = "*".repeat(n);
-                        let explicit = with_forced_trimmed_paths!(format!("<{refs}{ty}>::clone({snip})"));
-                        diag.span_suggestion(
-                            expr.span,
-                            "try dereferencing it",
-                            with_forced_trimmed_paths!(format!("{refs}({derefs}{}).clone()", snip.deref())),
-                            Applicability::MaybeIncorrect,
-                        );
-                        diag.span_suggestion(
-                            expr.span,
-                            "or try being explicit if you are sure, that you want to clone a reference",
-                            explicit,
-                            Applicability::MaybeIncorrect,
-                        );
-                    }
-                },
-            );
             return; // don't report clone_on_copy
         }
     }

src/tools/clippy/clippy_lints/src/methods/mod.rs

@@ -984,29 +984,6 @@ declare_clippy_lint! {
     "using 'clone' on a ref-counted pointer"
 }
 
-declare_clippy_lint! {
-    /// ### What it does
-    /// Checks for usage of `.clone()` on an `&&T`.
-    ///
-    /// ### Why is this bad?
-    /// Cloning an `&&T` copies the inner `&T`, instead of
-    /// cloning the underlying `T`.
-    ///
-    /// ### Example
-    /// ```rust
-    /// fn main() {
-    ///     let x = vec![1];
-    ///     let y = &&x;
-    ///     let z = y.clone();
-    ///     println!("{:p} {:p}", *y, z); // prints out the same pointer
-    /// }
-    /// ```
-    #[clippy::version = "pre 1.29.0"]
-    pub CLONE_DOUBLE_REF,
-    correctness,
-    "using `clone` on `&&T`"
-}
-
 declare_clippy_lint! {
     /// ### What it does
     /// Checks for usage of `.to_string()` on an `&&T` where
@@ -3258,7 +3235,6 @@ impl_lint_pass!(Methods => [
     CHARS_LAST_CMP,
     CLONE_ON_COPY,
     CLONE_ON_REF_PTR,
-    CLONE_DOUBLE_REF,
     COLLAPSIBLE_STR_REPLACE,
     ITER_OVEREAGER_CLONED,
     CLONED_INSTEAD_OF_COPIED,

src/tools/clippy/clippy_lints/src/renamed_lints.rs

@@ -30,6 +30,7 @@ pub static RENAMED_LINTS: &[(&str, &str)] = &[
     ("clippy::stutter", "clippy::module_name_repetitions"),
     ("clippy::to_string_in_display", "clippy::recursive_format_impl"),
     ("clippy::zero_width_space", "clippy::invisible_characters"),
+    ("clippy::clone_double_ref", "suspicious_double_ref_op"),
     ("clippy::drop_bounds", "drop_bounds"),
     ("clippy::for_loop_over_option", "for_loops_over_fallibles"),
     ("clippy::for_loop_over_result", "for_loops_over_fallibles"),

src/tools/clippy/tests/ui/explicit_deref_methods.fixed

@@ -3,7 +3,7 @@
 #![allow(unused_variables)]
 #![allow(
     clippy::borrow_deref_ref,
-    clippy::clone_double_ref,
+    suspicious_double_ref_op,
     clippy::explicit_auto_deref,
     clippy::needless_borrow,
     clippy::uninlined_format_args

src/tools/clippy/tests/ui/explicit_deref_methods.rs

@@ -3,7 +3,7 @@
 #![allow(unused_variables)]
 #![allow(
     clippy::borrow_deref_ref,
-    clippy::clone_double_ref,
+    suspicious_double_ref_op,
     clippy::explicit_auto_deref,
     clippy::needless_borrow,
     clippy::uninlined_format_args

src/tools/clippy/tests/ui/rename.fixed

@@ -36,6 +36,7 @@
 #![allow(enum_intrinsics_non_enums)]
 #![allow(non_fmt_panics)]
 #![allow(named_arguments_used_positionally)]
+#![allow(suspicious_double_ref_op)]
 #![allow(temporary_cstring_as_ptr)]
 #![allow(unknown_lints)]
 #![allow(unused_labels)]
@@ -67,6 +68,7 @@
 #![warn(clippy::module_name_repetitions)]
 #![warn(clippy::recursive_format_impl)]
 #![warn(clippy::invisible_characters)]
+#![warn(suspicious_double_ref_op)]
 #![warn(drop_bounds)]
 #![warn(for_loops_over_fallibles)]
 #![warn(for_loops_over_fallibles)]

src/tools/clippy/tests/ui/rename.rs

@@ -36,6 +36,7 @@
 #![allow(enum_intrinsics_non_enums)]
 #![allow(non_fmt_panics)]
 #![allow(named_arguments_used_positionally)]
+#![allow(suspicious_double_ref_op)]
 #![allow(temporary_cstring_as_ptr)]
 #![allow(unknown_lints)]
 #![allow(unused_labels)]
@@ -67,6 +68,7 @@
 #![warn(clippy::stutter)]
 #![warn(clippy::to_string_in_display)]
 #![warn(clippy::zero_width_space)]
+#![warn(clippy::clone_double_ref)]
 #![warn(clippy::drop_bounds)]
 #![warn(clippy::for_loop_over_option)]
 #![warn(clippy::for_loop_over_result)]

src/tools/clippy/tests/ui/rename.stderr

@@ -1,5 +1,5 @@
 error: lint `clippy::almost_complete_letter_range` has been renamed to `clippy::almost_complete_range`
-  --> $DIR/rename.rs:42:9
+  --> $DIR/rename.rs:43:9
    |
 LL | #![warn(clippy::almost_complete_letter_range)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::almost_complete_range`
@@ -7,250 +7,256 @@ LL | #![warn(clippy::almost_complete_letter_range)]
    = note: `-D renamed-and-removed-lints` implied by `-D warnings`
 
 error: lint `clippy::blacklisted_name` has been renamed to `clippy::disallowed_names`
-  --> $DIR/rename.rs:43:9
+  --> $DIR/rename.rs:44:9
    |
 LL | #![warn(clippy::blacklisted_name)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::disallowed_names`
 
 error: lint `clippy::block_in_if_condition_expr` has been renamed to `clippy::blocks_in_if_conditions`
-  --> $DIR/rename.rs:44:9
+  --> $DIR/rename.rs:45:9
    |
 LL | #![warn(clippy::block_in_if_condition_expr)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::blocks_in_if_conditions`
 
 error: lint `clippy::block_in_if_condition_stmt` has been renamed to `clippy::blocks_in_if_conditions`
-  --> $DIR/rename.rs:45:9
+  --> $DIR/rename.rs:46:9
    |
 LL | #![warn(clippy::block_in_if_condition_stmt)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::blocks_in_if_conditions`
 
 error: lint `clippy::box_vec` has been renamed to `clippy::box_collection`
-  --> $DIR/rename.rs:46:9
+  --> $DIR/rename.rs:47:9
    |
 LL | #![warn(clippy::box_vec)]
    |         ^^^^^^^^^^^^^^^ help: use the new name: `clippy::box_collection`
 
 error: lint `clippy::const_static_lifetime` has been renamed to `clippy::redundant_static_lifetimes`
-  --> $DIR/rename.rs:47:9
+  --> $DIR/rename.rs:48:9
    |
 LL | #![warn(clippy::const_static_lifetime)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::redundant_static_lifetimes`
 
 error: lint `clippy::cyclomatic_complexity` has been renamed to `clippy::cognitive_complexity`
-  --> $DIR/rename.rs:48:9
+  --> $DIR/rename.rs:49:9
    |
 LL | #![warn(clippy::cyclomatic_complexity)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::cognitive_complexity`
 
 error: lint `clippy::derive_hash_xor_eq` has been renamed to `clippy::derived_hash_with_manual_eq`
-  --> $DIR/rename.rs:49:9
+  --> $DIR/rename.rs:50:9
    |
 LL | #![warn(clippy::derive_hash_xor_eq)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::derived_hash_with_manual_eq`
 
 error: lint `clippy::disallowed_method` has been renamed to `clippy::disallowed_methods`
-  --> $DIR/rename.rs:50:9
+  --> $DIR/rename.rs:51:9
    |
 LL | #![warn(clippy::disallowed_method)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::disallowed_methods`
 
 error: lint `clippy::disallowed_type` has been renamed to `clippy::disallowed_types`
-  --> $DIR/rename.rs:51:9
+  --> $DIR/rename.rs:52:9
    |
 LL | #![warn(clippy::disallowed_type)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::disallowed_types`
 
 error: lint `clippy::eval_order_dependence` has been renamed to `clippy::mixed_read_write_in_expression`
-  --> $DIR/rename.rs:52:9
+  --> $DIR/rename.rs:53:9
    |
 LL | #![warn(clippy::eval_order_dependence)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::mixed_read_write_in_expression`
 
 error: lint `clippy::identity_conversion` has been renamed to `clippy::useless_conversion`
-  --> $DIR/rename.rs:53:9
+  --> $DIR/rename.rs:54:9
    |
 LL | #![warn(clippy::identity_conversion)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::useless_conversion`
 
 error: lint `clippy::if_let_some_result` has been renamed to `clippy::match_result_ok`
-  --> $DIR/rename.rs:54:9
+  --> $DIR/rename.rs:55:9
    |
 LL | #![warn(clippy::if_let_some_result)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::match_result_ok`
 
 error: lint `clippy::logic_bug` has been renamed to `clippy::overly_complex_bool_expr`
-  --> $DIR/rename.rs:55:9
+  --> $DIR/rename.rs:56:9
    |
 LL | #![warn(clippy::logic_bug)]
    |         ^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::overly_complex_bool_expr`
 
 error: lint `clippy::new_without_default_derive` has been renamed to `clippy::new_without_default`
-  --> $DIR/rename.rs:56:9
+  --> $DIR/rename.rs:57:9
    |
 LL | #![warn(clippy::new_without_default_derive)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::new_without_default`
 
 error: lint `clippy::option_and_then_some` has been renamed to `clippy::bind_instead_of_map`
-  --> $DIR/rename.rs:57:9
+  --> $DIR/rename.rs:58:9
    |
 LL | #![warn(clippy::option_and_then_some)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::bind_instead_of_map`
 
 error: lint `clippy::option_expect_used` has been renamed to `clippy::expect_used`
-  --> $DIR/rename.rs:58:9
+  --> $DIR/rename.rs:59:9
    |
 LL | #![warn(clippy::option_expect_used)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::expect_used`
 
 error: lint `clippy::option_map_unwrap_or` has been renamed to `clippy::map_unwrap_or`
-  --> $DIR/rename.rs:59:9
+  --> $DIR/rename.rs:60:9
    |
 LL | #![warn(clippy::option_map_unwrap_or)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::map_unwrap_or`
 
 error: lint `clippy::option_map_unwrap_or_else` has been renamed to `clippy::map_unwrap_or`
-  --> $DIR/rename.rs:60:9
+  --> $DIR/rename.rs:61:9
    |
 LL | #![warn(clippy::option_map_unwrap_or_else)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::map_unwrap_or`
 
 error: lint `clippy::option_unwrap_used` has been renamed to `clippy::unwrap_used`
-  --> $DIR/rename.rs:61:9
+  --> $DIR/rename.rs:62:9
    |
 LL | #![warn(clippy::option_unwrap_used)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::unwrap_used`
 
 error: lint `clippy::ref_in_deref` has been renamed to `clippy::needless_borrow`
-  --> $DIR/rename.rs:62:9
+  --> $DIR/rename.rs:63:9
    |
 LL | #![warn(clippy::ref_in_deref)]
    |         ^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::needless_borrow`
 
 error: lint `clippy::result_expect_used` has been renamed to `clippy::expect_used`
-  --> $DIR/rename.rs:63:9
+  --> $DIR/rename.rs:64:9
    |
 LL | #![warn(clippy::result_expect_used)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::expect_used`
 
 error: lint `clippy::result_map_unwrap_or_else` has been renamed to `clippy::map_unwrap_or`
-  --> $DIR/rename.rs:64:9
+  --> $DIR/rename.rs:65:9
    |
 LL | #![warn(clippy::result_map_unwrap_or_else)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::map_unwrap_or`
 
 error: lint `clippy::result_unwrap_used` has been renamed to `clippy::unwrap_used`
-  --> $DIR/rename.rs:65:9
+  --> $DIR/rename.rs:66:9
    |
 LL | #![warn(clippy::result_unwrap_used)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::unwrap_used`
 
 error: lint `clippy::single_char_push_str` has been renamed to `clippy::single_char_add_str`
-  --> $DIR/rename.rs:66:9
+  --> $DIR/rename.rs:67:9
    |
 LL | #![warn(clippy::single_char_push_str)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::single_char_add_str`
 
 error: lint `clippy::stutter` has been renamed to `clippy::module_name_repetitions`
-  --> $DIR/rename.rs:67:9
+  --> $DIR/rename.rs:68:9
    |
 LL | #![warn(clippy::stutter)]
    |         ^^^^^^^^^^^^^^^ help: use the new name: `clippy::module_name_repetitions`
 
 error: lint `clippy::to_string_in_display` has been renamed to `clippy::recursive_format_impl`
-  --> $DIR/rename.rs:68:9
+  --> $DIR/rename.rs:69:9
    |
 LL | #![warn(clippy::to_string_in_display)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::recursive_format_impl`
 
 error: lint `clippy::zero_width_space` has been renamed to `clippy::invisible_characters`
-  --> $DIR/rename.rs:69:9
+  --> $DIR/rename.rs:70:9
    |
 LL | #![warn(clippy::zero_width_space)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::invisible_characters`
 
+error: lint `clippy::clone_double_ref` has been renamed to `suspicious_double_ref_op`
+  --> $DIR/rename.rs:71:9
+   |
+LL | #![warn(clippy::clone_double_ref)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `suspicious_double_ref_op`
+
 error: lint `clippy::drop_bounds` has been renamed to `drop_bounds`
-  --> $DIR/rename.rs:70:9
+  --> $DIR/rename.rs:72:9
    |
 LL | #![warn(clippy::drop_bounds)]
    |         ^^^^^^^^^^^^^^^^^^^ help: use the new name: `drop_bounds`
 
 error: lint `clippy::for_loop_over_option` has been renamed to `for_loops_over_fallibles`
-  --> $DIR/rename.rs:71:9
+  --> $DIR/rename.rs:73:9
    |
 LL | #![warn(clippy::for_loop_over_option)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `for_loops_over_fallibles`
 
 error: lint `clippy::for_loop_over_result` has been renamed to `for_loops_over_fallibles`
-  --> $DIR/rename.rs:72:9
+  --> $DIR/rename.rs:74:9
    |
 LL | #![warn(clippy::for_loop_over_result)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `for_loops_over_fallibles`
 
 error: lint `clippy::for_loops_over_fallibles` has been renamed to `for_loops_over_fallibles`
-  --> $DIR/rename.rs:73:9
+  --> $DIR/rename.rs:75:9
    |
 LL | #![warn(clippy::for_loops_over_fallibles)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `for_loops_over_fallibles`
 
 error: lint `clippy::into_iter_on_array` has been renamed to `array_into_iter`
-  --> $DIR/rename.rs:74:9
+  --> $DIR/rename.rs:76:9
    |
 LL | #![warn(clippy::into_iter_on_array)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `array_into_iter`
 
 error: lint `clippy::invalid_atomic_ordering` has been renamed to `invalid_atomic_ordering`
-  --> $DIR/rename.rs:75:9
+  --> $DIR/rename.rs:77:9
    |
 LL | #![warn(clippy::invalid_atomic_ordering)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `invalid_atomic_ordering`
 
 error: lint `clippy::invalid_ref` has been renamed to `invalid_value`
-  --> $DIR/rename.rs:76:9
+  --> $DIR/rename.rs:78:9
    |
 LL | #![warn(clippy::invalid_ref)]
    |         ^^^^^^^^^^^^^^^^^^^ help: use the new name: `invalid_value`
 
 error: lint `clippy::let_underscore_drop` has been renamed to `let_underscore_drop`
-  --> $DIR/rename.rs:77:9
+  --> $DIR/rename.rs:79:9
    |
 LL | #![warn(clippy::let_underscore_drop)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `let_underscore_drop`
 
 error: lint `clippy::mem_discriminant_non_enum` has been renamed to `enum_intrinsics_non_enums`
-  --> $DIR/rename.rs:78:9
+  --> $DIR/rename.rs:80:9
    |
 LL | #![warn(clippy::mem_discriminant_non_enum)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `enum_intrinsics_non_enums`
 
 error: lint `clippy::panic_params` has been renamed to `non_fmt_panics`
-  --> $DIR/rename.rs:79:9
+  --> $DIR/rename.rs:81:9
    |
 LL | #![warn(clippy::panic_params)]
    |         ^^^^^^^^^^^^^^^^^^^^ help: use the new name: `non_fmt_panics`
 
 error: lint `clippy::positional_named_format_parameters` has been renamed to `named_arguments_used_positionally`
-  --> $DIR/rename.rs:80:9
+  --> $DIR/rename.rs:82:9
    |
 LL | #![warn(clippy::positional_named_format_parameters)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `named_arguments_used_positionally`
 
 error: lint `clippy::temporary_cstring_as_ptr` has been renamed to `temporary_cstring_as_ptr`
-  --> $DIR/rename.rs:81:9
+  --> $DIR/rename.rs:83:9
    |
 LL | #![warn(clippy::temporary_cstring_as_ptr)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `temporary_cstring_as_ptr`
 
 error: lint `clippy::unknown_clippy_lints` has been renamed to `unknown_lints`
-  --> $DIR/rename.rs:82:9
+  --> $DIR/rename.rs:84:9
    |
 LL | #![warn(clippy::unknown_clippy_lints)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `unknown_lints`
 
 error: lint `clippy::unused_label` has been renamed to `unused_labels`
-  --> $DIR/rename.rs:83:9
+  --> $DIR/rename.rs:85:9
    |
 LL | #![warn(clippy::unused_label)]
    |         ^^^^^^^^^^^^^^^^^^^^ help: use the new name: `unused_labels`
 
-error: aborting due to 42 previous errors
+error: aborting due to 43 previous errors
 

src/tools/clippy/tests/ui/unnecessary_clone.rs

@@ -42,14 +42,6 @@ fn clone_on_copy_generic<T: Copy>(t: T) {
     Some(t).clone();
 }
 
-fn clone_on_double_ref() {
-    let x = vec![1];
-    let y = &&x;
-    let z: &Vec<_> = y.clone();
-
-    println!("{:p} {:p}", *y, z);
-}
-
 mod many_derefs {
     struct A;
     struct B;
@@ -84,11 +76,6 @@ mod many_derefs {
         let _: E = a.clone();
         let _: E = *****a;
     }
-
-    fn check(mut encoded: &[u8]) {
-        let _ = &mut encoded.clone();
-        let _ = &encoded.clone();
-    }
 }
 
 mod issue2076 {

src/tools/clippy/tests/ui/unnecessary_clone.stderr

@@ -44,63 +44,17 @@ error: using `clone` on type `Option<T>` which implements the `Copy` trait
 LL |     Some(t).clone();
    |     ^^^^^^^^^^^^^^^ help: try removing the `clone` call: `Some(t)`
 
-error: using `clone` on a double-reference; this will copy the reference of type `&Vec<i32>` instead of cloning the inner type
-  --> $DIR/unnecessary_clone.rs:48:22
-   |
-LL |     let z: &Vec<_> = y.clone();
-   |                      ^^^^^^^^^
-   |
-   = note: `#[deny(clippy::clone_double_ref)]` on by default
-help: try dereferencing it
-   |
-LL |     let z: &Vec<_> = &(*y).clone();
-   |                      ~~~~~~~~~~~~~
-help: or try being explicit if you are sure, that you want to clone a reference
-   |
-LL |     let z: &Vec<_> = <&Vec<i32>>::clone(y);
-   |                      ~~~~~~~~~~~~~~~~~~~~~
-
 error: using `clone` on type `E` which implements the `Copy` trait
-  --> $DIR/unnecessary_clone.rs:84:20
+  --> $DIR/unnecessary_clone.rs:76:20
    |
 LL |         let _: E = a.clone();
    |                    ^^^^^^^^^ help: try dereferencing it: `*****a`
 
-error: using `clone` on a double-reference; this will copy the reference of type `&[u8]` instead of cloning the inner type
-  --> $DIR/unnecessary_clone.rs:89:22
-   |
-LL |         let _ = &mut encoded.clone();
-   |                      ^^^^^^^^^^^^^^^
-   |
-help: try dereferencing it
-   |
-LL |         let _ = &mut &(*encoded).clone();
-   |                      ~~~~~~~~~~~~~~~~~~~
-help: or try being explicit if you are sure, that you want to clone a reference
-   |
-LL |         let _ = &mut <&[u8]>::clone(encoded);
-   |                      ~~~~~~~~~~~~~~~~~~~~~~~
-
-error: using `clone` on a double-reference; this will copy the reference of type `&[u8]` instead of cloning the inner type
-  --> $DIR/unnecessary_clone.rs:90:18
-   |
-LL |         let _ = &encoded.clone();
-   |                  ^^^^^^^^^^^^^^^
-   |
-help: try dereferencing it
-   |
-LL |         let _ = &&(*encoded).clone();
-   |                  ~~~~~~~~~~~~~~~~~~~
-help: or try being explicit if you are sure, that you want to clone a reference
-   |
-LL |         let _ = &<&[u8]>::clone(encoded);
-   |                  ~~~~~~~~~~~~~~~~~~~~~~~
-
 error: using `.clone()` on a ref-counted pointer
-  --> $DIR/unnecessary_clone.rs:108:14
+  --> $DIR/unnecessary_clone.rs:95:14
    |
 LL |         Some(try_opt!(Some(rc)).clone())
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `Rc::<u8>::clone(&try_opt!(Some(rc)))`
 
-error: aborting due to 12 previous errors
+error: aborting due to 9 previous errors
 

tests/ui/lint/noop-method-call.rs

@@ -19,18 +19,17 @@ fn main() {
     let clone_type_ref = &CloneType(1u32);
     let clone_type_ref_clone: CloneType<u32> = clone_type_ref.clone();
 
-    // Calling clone on a double reference doesn't warn since the method call itself
-    // peels the outer reference off
     let clone_type_ref = &&CloneType(1u32);
     let clone_type_ref_clone: &CloneType<u32> = clone_type_ref.clone();
+    //~^ WARNING using `.clone()` on a double reference, which returns `&CloneType<u32>`
 
     let non_deref_type = &PlainType(1u32);
     let non_deref_type_deref: &PlainType<u32> = non_deref_type.deref();
     //~^ WARNING call to `.deref()` on a reference in this situation does nothing
 
-    // Dereferencing a &&T does not warn since it has collapsed the double reference
     let non_deref_type = &&PlainType(1u32);
     let non_deref_type_deref: &PlainType<u32> = non_deref_type.deref();
+    //~^ WARNING using `.deref()` on a double reference, which returns `&PlainType<u32>`
 
     let non_borrow_type = &PlainType(1u32);
     let non_borrow_type_borrow: &PlainType<u32> = non_borrow_type.borrow();
@@ -41,7 +40,8 @@ fn main() {
     let non_borrow_type_borrow: &PlainType<u32> = non_borrow_type.borrow();
 
     let xs = ["a", "b", "c"];
-    let _v: Vec<&str> = xs.iter().map(|x| x.clone()).collect(); // ok, but could use `*x` instead
+    let _v: Vec<&str> = xs.iter().map(|x| x.clone()).collect(); // could use `*x` instead
+    //~^ WARNING using `.clone()` on a double reference, which returns `&str`
 }
 
 fn generic<T>(non_clone_type: &PlainType<T>) {

tests/ui/lint/noop-method-call.stderr

@@ -11,22 +11,42 @@ note: the lint level is defined here
 LL | #![warn(noop_method_call)]
    |         ^^^^^^^^^^^^^^^^
 
+warning: using `.clone()` on a double reference, which returns `&CloneType<u32>` instead of cloning the inner type
+  --> $DIR/noop-method-call.rs:23:63
+   |
+LL |     let clone_type_ref_clone: &CloneType<u32> = clone_type_ref.clone();
+   |                                                               ^^^^^^^^
+   |
+   = note: `#[warn(suspicious_double_ref_op)]` on by default
+
 warning: call to `.deref()` on a reference in this situation does nothing
-  --> $DIR/noop-method-call.rs:28:63
+  --> $DIR/noop-method-call.rs:27:63
    |
 LL |     let non_deref_type_deref: &PlainType<u32> = non_deref_type.deref();
    |                                                               ^^^^^^^^ unnecessary method call
    |
    = note: the type `&PlainType<u32>` which `deref` is being called on is the same as the type returned from `deref`, so the method call does not do anything and can be removed
 
+warning: using `.deref()` on a double reference, which returns `&PlainType<u32>` instead of dereferencing the inner type
+  --> $DIR/noop-method-call.rs:31:63
+   |
+LL |     let non_deref_type_deref: &PlainType<u32> = non_deref_type.deref();
+   |                                                               ^^^^^^^^
+
 warning: call to `.borrow()` on a reference in this situation does nothing
-  --> $DIR/noop-method-call.rs:36:66
+  --> $DIR/noop-method-call.rs:35:66
    |
 LL |     let non_borrow_type_borrow: &PlainType<u32> = non_borrow_type.borrow();
    |                                                                  ^^^^^^^^^ unnecessary method call
    |
    = note: the type `&PlainType<u32>` which `borrow` is being called on is the same as the type returned from `borrow`, so the method call does not do anything and can be removed
 
+warning: using `.clone()` on a double reference, which returns `&str` instead of cloning the inner type
+  --> $DIR/noop-method-call.rs:43:44
+   |
+LL |     let _v: Vec<&str> = xs.iter().map(|x| x.clone()).collect(); // could use `*x` instead
+   |                                            ^^^^^^^^
+
 warning: call to `.clone()` on a reference in this situation does nothing
   --> $DIR/noop-method-call.rs:48:19
    |
@@ -43,5 +63,5 @@ LL |     non_clone_type.clone();
    |
    = note: the type `&PlainType<u32>` which `clone` is being called on is the same as the type returned from `clone`, so the method call does not do anything and can be removed
 
-warning: 5 warnings emitted
+warning: 8 warnings emitted
 

tests/ui/lint/suspicious-double-ref-op.rs

@@ -0,0 +1,30 @@
+#![feature(lazy_cell)]
+#![deny(suspicious_double_ref_op, noop_method_call)]
+
+pub fn clone_on_double_ref() {
+    let x = vec![1];
+    let y = &&x;
+    let z: &Vec<_> = y.clone();
+    //~^ ERROR using `.clone()` on a double reference, which returns `&Vec<i32>`
+
+    println!("{:p} {:p}", *y, z);
+}
+
+use std::sync::LazyLock;
+
+pub static STRS: LazyLock<&str> = LazyLock::new(|| "First");
+
+// https://github.com/rust-lang/rust-clippy/issues/9272
+fn rust_clippy_issue_9272() {
+    let str = STRS.clone();
+    println!("{str}")
+}
+
+fn check(mut encoded: &[u8]) {
+    let _ = &mut encoded.clone();
+    //~^ ERROR call to `.clone()` on a reference in this situation does nothing
+    let _ = &encoded.clone();
+    //~^ ERROR call to `.clone()` on a reference in this situation does nothing
+}
+
+fn main() {}

tests/ui/lint/suspicious-double-ref-op.stderr

@@ -0,0 +1,35 @@
+error: using `.clone()` on a double reference, which returns `&Vec<i32>` instead of cloning the inner type
+  --> $DIR/suspicious-double-ref-op.rs:7:23
+   |
+LL |     let z: &Vec<_> = y.clone();
+   |                       ^^^^^^^^
+   |
+note: the lint level is defined here
+  --> $DIR/suspicious-double-ref-op.rs:2:9
+   |
+LL | #![deny(suspicious_double_ref_op, noop_method_call)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: call to `.clone()` on a reference in this situation does nothing
+  --> $DIR/suspicious-double-ref-op.rs:24:25
+   |
+LL |     let _ = &mut encoded.clone();
+   |                         ^^^^^^^^ unnecessary method call
+   |
+   = note: the type `&[u8]` which `clone` is being called on is the same as the type returned from `clone`, so the method call does not do anything and can be removed
+note: the lint level is defined here
+  --> $DIR/suspicious-double-ref-op.rs:2:35
+   |
+LL | #![deny(suspicious_double_ref_op, noop_method_call)]
+   |                                   ^^^^^^^^^^^^^^^^
+
+error: call to `.clone()` on a reference in this situation does nothing
+  --> $DIR/suspicious-double-ref-op.rs:26:21
+   |
+LL |     let _ = &encoded.clone();
+   |                     ^^^^^^^^ unnecessary method call
+   |
+   = note: the type `&[u8]` which `clone` is being called on is the same as the type returned from `clone`, so the method call does not do anything and can be removed
+
+error: aborting due to 3 previous errors
+