diff --git a/clippy_lints/src/methods/useless_asref.rs b/clippy_lints/src/methods/useless_asref.rs index 82313257e5c42..6d3da42775f47 100644 --- a/clippy_lints/src/methods/useless_asref.rs +++ b/clippy_lints/src/methods/useless_asref.rs @@ -55,12 +55,19 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, call_name: &str, let (base_res_ty, res_depth) = walk_ptrs_ty_depth(res_ty); let (base_rcv_ty, rcv_depth) = walk_ptrs_ty_depth(rcv_ty); if base_rcv_ty == base_res_ty && rcv_depth >= res_depth { - // allow the `as_ref` or `as_mut` if it is followed by another method call - if let Some(parent) = get_parent_expr(cx, expr) - && let hir::ExprKind::MethodCall(segment, ..) = parent.kind - && segment.ident.span != expr.span - { - return; + if let Some(parent) = get_parent_expr(cx, expr) { + // allow the `as_ref` or `as_mut` if it is followed by another method call + if let hir::ExprKind::MethodCall(segment, ..) = parent.kind + && segment.ident.span != expr.span + { + return; + } + + // allow the `as_ref` or `as_mut` if they belong to a closure that changes + // the number of references + if matches!(parent.kind, hir::ExprKind::Closure(..)) && rcv_depth != res_depth { + return; + } } let mut applicability = Applicability::MachineApplicable; diff --git a/tests/ui/useless_asref.fixed b/tests/ui/useless_asref.fixed index ddbb9255b4667..2f179200bb37a 100644 --- a/tests/ui/useless_asref.fixed +++ b/tests/ui/useless_asref.fixed @@ -198,6 +198,11 @@ fn issue_12528() { let _ = opt.as_ref().map(RcWeak::clone); } +fn issue_14088() { + let s = Some("foo"); + let _: Option<&str> = s.as_ref().map(|x| x.as_ref()); +} + fn main() { not_ok(); ok(); diff --git a/tests/ui/useless_asref.rs b/tests/ui/useless_asref.rs index b0405e930a259..9851a0caac4fd 100644 --- a/tests/ui/useless_asref.rs +++ b/tests/ui/useless_asref.rs @@ -198,6 +198,11 @@ fn issue_12528() { let _ = opt.as_ref().map(RcWeak::clone); } +fn issue_14088() { + let s = Some("foo"); + let _: Option<&str> = s.as_ref().map(|x| x.as_ref()); +} + fn main() { not_ok(); ok();