diff --git a/clippy_lints/src/declared_lints.rs b/clippy_lints/src/declared_lints.rs
index 9c1e1f6702d..0eec18a91bc 100644
--- a/clippy_lints/src/declared_lints.rs
+++ b/clippy_lints/src/declared_lints.rs
@@ -140,6 +140,7 @@ pub(crate) static LINTS: &[&crate::LintInfo] = &[
crate::double_parens::DOUBLE_PARENS_INFO,
crate::drop_forget_ref::DROP_NON_DROP_INFO,
crate::drop_forget_ref::FORGET_NON_DROP_INFO,
+ crate::drop_forget_ref::MEM_FORGET_INFO,
crate::drop_forget_ref::UNDROPPED_MANUALLY_DROPS_INFO,
crate::duplicate_mod::DUPLICATE_MOD_INFO,
crate::else_if_without_else::ELSE_IF_WITHOUT_ELSE_INFO,
@@ -310,7 +311,6 @@ pub(crate) static LINTS: &[&crate::LintInfo] = &[
crate::matches::TRY_ERR_INFO,
crate::matches::WILDCARD_ENUM_MATCH_ARM_INFO,
crate::matches::WILDCARD_IN_OR_PATTERNS_INFO,
- crate::mem_forget::MEM_FORGET_INFO,
crate::mem_replace::MEM_REPLACE_OPTION_WITH_NONE_INFO,
crate::mem_replace::MEM_REPLACE_WITH_DEFAULT_INFO,
crate::mem_replace::MEM_REPLACE_WITH_UNINIT_INFO,
diff --git a/clippy_lints/src/drop_forget_ref.rs b/clippy_lints/src/drop_forget_ref.rs
index 9c60edb1794..36b231023a7 100644
--- a/clippy_lints/src/drop_forget_ref.rs
+++ b/clippy_lints/src/drop_forget_ref.rs
@@ -6,6 +6,7 @@ use rustc_hir::{Arm, Expr, ExprKind, LangItem, Node};
use rustc_lint::{LateContext, LateLintPass};
use rustc_session::{declare_lint_pass, declare_tool_lint};
use rustc_span::sym;
+use std::borrow::Cow;
declare_clippy_lint! {
/// ### What it does
@@ -76,6 +77,27 @@ declare_clippy_lint! {
"use of safe `std::mem::drop` function to drop a std::mem::ManuallyDrop, which will not drop the inner value"
}
+declare_clippy_lint! {
+ /// ### What it does
+ /// Checks for usage of `std::mem::forget(t)` where `t` is
+ /// `Drop` or has a field that implements `Drop`.
+ ///
+ /// ### Why is this bad?
+ /// `std::mem::forget(t)` prevents `t` from running its
+ /// destructor, possibly causing leaks.
+ ///
+ /// ### Example
+ /// ```rust
+ /// # use std::mem;
+ /// # use std::rc::Rc;
+ /// mem::forget(Rc::new(55))
+ /// ```
+ #[clippy::version = "pre 1.29.0"]
+ pub MEM_FORGET,
+ restriction,
+ "`mem::forget` usage on `Drop` types, likely to cause memory leaks"
+}
+
const DROP_NON_DROP_SUMMARY: &str = "call to `std::mem::drop` with a value that does not implement `Drop`. \
Dropping such a type only extends its contained lifetimes";
const FORGET_NON_DROP_SUMMARY: &str = "call to `std::mem::forget` with a value that does not implement `Drop`. \
@@ -84,7 +106,8 @@ const FORGET_NON_DROP_SUMMARY: &str = "call to `std::mem::forget` with a value t
declare_lint_pass!(DropForgetRef => [
DROP_NON_DROP,
FORGET_NON_DROP,
- UNDROPPED_MANUALLY_DROPS
+ UNDROPPED_MANUALLY_DROPS,
+ MEM_FORGET,
]);
impl<'tcx> LateLintPass<'tcx> for DropForgetRef {
@@ -121,18 +144,29 @@ impl<'tcx> LateLintPass<'tcx> for DropForgetRef {
|| drop_is_single_call_in_arm
) =>
{
- (DROP_NON_DROP, DROP_NON_DROP_SUMMARY)
- },
- sym::mem_forget if !arg_ty.needs_drop(cx.tcx, cx.param_env) => {
- (FORGET_NON_DROP, FORGET_NON_DROP_SUMMARY)
+ (DROP_NON_DROP, DROP_NON_DROP_SUMMARY.into())
},
+ sym::mem_forget => {
+ if arg_ty.needs_drop(cx.tcx, cx.param_env) {
+ (MEM_FORGET, Cow::Owned(format!(
+ "usage of `mem::forget` on {}",
+ if arg_ty.ty_adt_def().map_or(false, |def| def.has_dtor(cx.tcx)) {
+ "`Drop` type"
+ } else {
+ "type with `Drop` fields"
+ }
+ )))
+ } else {
+ (FORGET_NON_DROP, FORGET_NON_DROP_SUMMARY.into())
+ }
+ }
_ => return,
};
span_lint_and_note(
cx,
lint,
expr.span,
- msg,
+ &msg,
Some(arg.span),
&format!("argument has type `{arg_ty}`"),
);
diff --git a/clippy_lints/src/lib.rs b/clippy_lints/src/lib.rs
index 3fb4e6c8fa5..71b8af7a821 100644
--- a/clippy_lints/src/lib.rs
+++ b/clippy_lints/src/lib.rs
@@ -196,7 +196,6 @@ mod manual_strip;
mod map_unit_fn;
mod match_result_ok;
mod matches;
-mod mem_forget;
mod mem_replace;
mod methods;
mod min_ident_chars;
@@ -744,7 +743,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
let missing_docs_in_crate_items = conf.missing_docs_in_crate_items;
store.register_late_pass(move |_| Box::new(doc::DocMarkdown::new(doc_valid_idents.clone())));
store.register_late_pass(|_| Box::new(neg_multiply::NegMultiply));
- store.register_late_pass(|_| Box::new(mem_forget::MemForget));
store.register_late_pass(|_| Box::new(let_if_seq::LetIfSeq));
store.register_late_pass(|_| Box::new(mixed_read_write_in_expression::EvalOrderDependence));
store.register_late_pass(move |_| Box::new(missing_doc::MissingDoc::new(missing_docs_in_crate_items)));
diff --git a/clippy_lints/src/mem_forget.rs b/clippy_lints/src/mem_forget.rs
deleted file mode 100644
index fdd55260483..00000000000
--- a/clippy_lints/src/mem_forget.rs
+++ /dev/null
@@ -1,54 +0,0 @@
-use clippy_utils::diagnostics::span_lint;
-use rustc_hir::{Expr, ExprKind};
-use rustc_lint::{LateContext, LateLintPass};
-use rustc_session::{declare_lint_pass, declare_tool_lint};
-use rustc_span::sym;
-
-declare_clippy_lint! {
- /// ### What it does
- /// Checks for usage of `std::mem::forget(t)` where `t` is
- /// `Drop` or has a field that implements `Drop`.
- ///
- /// ### Why is this bad?
- /// `std::mem::forget(t)` prevents `t` from running its
- /// destructor, possibly causing leaks.
- ///
- /// ### Example
- /// ```rust
- /// # use std::mem;
- /// # use std::rc::Rc;
- /// mem::forget(Rc::new(55))
- /// ```
- #[clippy::version = "pre 1.29.0"]
- pub MEM_FORGET,
- restriction,
- "`mem::forget` usage on `Drop` types, likely to cause memory leaks"
-}
-
-declare_lint_pass!(MemForget => [MEM_FORGET]);
-
-impl<'tcx> LateLintPass<'tcx> for MemForget {
- fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) {
- if let ExprKind::Call(path_expr, [ref first_arg, ..]) = e.kind
- && let ExprKind::Path(ref qpath) = path_expr.kind
- && let Some(def_id) = cx.qpath_res(qpath, path_expr.hir_id).opt_def_id()
- && cx.tcx.is_diagnostic_item(sym::mem_forget, def_id)
- && let forgot_ty = cx.typeck_results().expr_ty(first_arg)
- && forgot_ty.needs_drop(cx.tcx, cx.param_env)
- {
- span_lint(
- cx,
- MEM_FORGET,
- e.span,
- &format!(
- "usage of `mem::forget` on {}",
- if forgot_ty.ty_adt_def().map_or(false, |def| def.has_dtor(cx.tcx)) {
- "`Drop` type"
- } else {
- "type with `Drop` fields"
- }
- ),
- );
- }
- }
-}
diff --git a/tests/ui/mem_forget.stderr b/tests/ui/mem_forget.stderr
index 50711120a15..6e3c31804d7 100644
--- a/tests/ui/mem_forget.stderr
+++ b/tests/ui/mem_forget.stderr
@@ -4,6 +4,11 @@ error: usage of `mem::forget` on `Drop` type
LL | memstuff::forget(six);
| ^^^^^^^^^^^^^^^^^^^^^
|
+note: argument has type `std::sync::Arc<i32>`
+ --> $DIR/mem_forget.rs:14:22
+ |
+LL | memstuff::forget(six);
+ | ^^^
= note: `-D clippy::mem-forget` implied by `-D warnings`
error: usage of `mem::forget` on `Drop` type
@@ -11,18 +16,36 @@ error: usage of `mem::forget` on `Drop` type
|
LL | std::mem::forget(seven);
| ^^^^^^^^^^^^^^^^^^^^^^^
+ |
+note: argument has type `std::rc::Rc<i32>`
+ --> $DIR/mem_forget.rs:17:22
+ |
+LL | std::mem::forget(seven);
+ | ^^^^^
error: usage of `mem::forget` on `Drop` type
--> $DIR/mem_forget.rs:20:5
|
LL | forgetSomething(eight);
| ^^^^^^^^^^^^^^^^^^^^^^
+ |
+note: argument has type `std::vec::Vec<i32>`
+ --> $DIR/mem_forget.rs:20:21
+ |
+LL | forgetSomething(eight);
+ | ^^^^^
error: usage of `mem::forget` on type with `Drop` fields
--> $DIR/mem_forget.rs:23:5
|
LL | std::mem::forget(string);
| ^^^^^^^^^^^^^^^^^^^^^^^^
+ |
+note: argument has type `std::string::String`
+ --> $DIR/mem_forget.rs:23:22
+ |
+LL | std::mem::forget(string);
+ | ^^^^^^
error: aborting due to 4 previous errors