move_ref_pattern: don't ICE on unreachable 2xby-move conflicts

Author: Centril

src/librustc_mir_build/hair/pattern/check_match.rs

@@ -648,9 +648,6 @@ fn check_borrow_conflicts_in_at_patterns(cx: &MatchVisitor<'_, '_>, pat: &Pat<'_
             let mut conflicts_ref = Vec::new();
             sub.each_binding(|_, hir_id, span, _| {
                 match tables.extract_binding_mode(sess, hir_id, span) {
-                    Some(ty::BindByValue(_)) if is_binding_by_move(cx, hir_id, span) => {
-                        sess.delay_span_bug(span, "by-move in subpat unchecked by borrowck");
-                    }
                     Some(ty::BindByValue(_)) | None => {}
                     Some(ty::BindByReference(_)) => conflicts_ref.push(span),
                 }

src/test/ui/pattern/move-ref-patterns/by-move-sub-pat-unreachable.rs

@@ -0,0 +1,15 @@
+// When conflicts between by-move bindings in `by_move_1 @ has_by_move` patterns
+// happen and that code is unreachable according to borrowck, we accept this code.
+// In particular, we want to ensure here that an ICE does not happen, which it did originally.
+
+// check-pass
+
+#![feature(move_ref_pattern)]
+#![feature(bindings_after_at)]
+
+fn main() {
+    return;
+
+    struct S;
+    let a @ (b, c) = (S, S);
+}