1 files changed, 65 insertions, 0 deletions
diff --git a/src/tools/clippy/clippy_lints/src/empty_drop.rs b/src/tools/clippy/clippy_lints/src/empty_drop.rs
new file mode 100644
index 000000000..ec063c0f7
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/empty_drop.rs
@@ -0,0 +1,65 @@
+use clippy_utils::{diagnostics::span_lint_and_sugg, peel_blocks};
+use if_chain::if_chain;
+use rustc_errors::Applicability;
+use rustc_hir::{Body, ExprKind, Impl, ImplItemKind, Item, ItemKind, Node};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for empty `Drop` implementations.
+    ///
+    /// ### Why is this bad?
+    /// Empty `Drop` implementations have no effect when dropping an instance of the type. They are
+    /// most likely useless. However, an empty `Drop` implementation prevents a type from being
+    /// destructured, which might be the intention behind adding the implementation as a marker.
+    ///
+    /// ### Example
+    /// ```rust
+    /// struct S;
+    ///
+    /// impl Drop for S {
+    ///     fn drop(&mut self) {}
+    /// }
+    /// ```
+    /// Use instead:
+    /// ```rust
+    /// struct S;
+    /// ```
+    #[clippy::version = "1.62.0"]
+    pub EMPTY_DROP,
+    restriction,
+    "empty `Drop` implementations"
+}
+declare_lint_pass!(EmptyDrop => [EMPTY_DROP]);
+
+impl LateLintPass<'_> for EmptyDrop {
+    fn check_item(&mut self, cx: &LateContext<'_>, item: &Item<'_>) {
+        if_chain! {
+            if let ItemKind::Impl(Impl {
+                of_trait: Some(ref trait_ref),
+                items: [child],
+                ..
+            }) = item.kind;
+            if trait_ref.trait_def_id() == cx.tcx.lang_items().drop_trait();
+            if let impl_item_hir = child.id.hir_id();
+            if let Some(Node::ImplItem(impl_item)) = cx.tcx.hir().find(impl_item_hir);
+            if let ImplItemKind::Fn(_, b) = &impl_item.kind;
+            if let Body { value: func_expr, .. } = cx.tcx.hir().body(*b);
+            let func_expr = peel_blocks(func_expr);
+            if let ExprKind::Block(block, _) = func_expr.kind;
+            if block.stmts.is_empty() && block.expr.is_none();
+            then {
+                span_lint_and_sugg(
+                    cx,
+                    EMPTY_DROP,
+                    item.span,
+                    "empty drop implementation",
+                    "try removing this impl",
+                    String::new(),
+                    Applicability::MaybeIncorrect
+                );
+            }
+        }
+    }
+}