Fix `clippy::question_mark` on let-else with cfg (#15082)

Fixes rust-lang/rust-clippy#13642

changelog: Fix false positive in [`question_mark`] when else branch of
let-else contains `#[cfg]`

3 files changed, 25 insertions, 0 deletions

diff --git a/clippy_lints/src/question_mark.rs b/clippy_lints/src/question_mark.rs
index c02e5e0621c..de12a25b03d 100644
--- a/clippy_lints/src/question_mark.rs
+++ b/clippy_lints/src/question_mark.rs
@@ -142,6 +142,7 @@ fn check_let_some_else_return_none(cx: &LateContext<'_>, stmt: &Stmt<'_>) {
         && let Some(ret) = find_let_else_ret_expression(els)
         && let Some(inner_pat) = pat_and_expr_can_be_question_mark(cx, pat, ret)
         && !span_contains_comment(cx.tcx.sess.source_map(), els.span)
+        && !span_contains_cfg(cx, els.span)
     {
         let mut applicability = Applicability::MaybeIncorrect;
         let init_expr_str = Sugg::hir_with_applicability(cx, init_expr, "..", &mut applicability).maybe_paren();
diff --git a/tests/ui/question_mark.fixed b/tests/ui/question_mark.fixed
index 60dc1c101b6..8d6f5fbadca 100644
--- a/tests/ui/question_mark.fixed
+++ b/tests/ui/question_mark.fixed
@@ -453,3 +453,15 @@ fn const_in_pattern(x: Option<(i32, i32)>) -> Option<()> {
 
     None
 }
+
+fn issue_13642(x: Option<i32>) -> Option<()> {
+    let Some(x) = x else {
+        #[cfg(false)]
+        panic!();
+
+        #[cfg(true)]
+        return None;
+    };
+
+    None
+}
diff --git a/tests/ui/question_mark.rs b/tests/ui/question_mark.rs
index 99d0122a98f..f13eee29c11 100644
--- a/tests/ui/question_mark.rs
+++ b/tests/ui/question_mark.rs
@@ -549,3 +549,15 @@ fn const_in_pattern(x: Option<(i32, i32)>) -> Option<()> {
 
     None
 }
+
+fn issue_13642(x: Option<i32>) -> Option<()> {
+    let Some(x) = x else {
+        #[cfg(false)]
+        panic!();
+
+        #[cfg(true)]
+        return None;
+    };
+
+    None
+}