Return early to avoid failing assertion

src/librustc_lint/types.rs

@@ -73,7 +73,9 @@ fn lint_overflowing_range_endpoint<'a, 'tcx>(
     // We only want to handle exclusive (`..`) ranges,
     // which are represented as `ExprKind::Struct`.
     if let ExprKind::Struct(_, eps, _) = &parent_expr.node {
-        debug_assert_eq!(eps.len(), 2);
+        if eps.len() != 2 {
+            return false;
+        }
         // We can suggest using an inclusive range
         // (`..=`) instead only if it is the `end` that is
         // overflowing and only by 1.

src/test/ui/issues/issue-63364.rs

@@ -0,0 +1,10 @@
+fn part(_: u16) -> u32 {
+    1
+}
+
+fn main() {
+    for n in 100_000.. {
+    //~^ ERROR: literal out of range for `u16`
+        let _ = part(n);
+    }
+}

src/test/ui/issues/issue-63364.stderr

@@ -0,0 +1,10 @@
+error: literal out of range for `u16`
+  --> $DIR/issue-63364.rs:6:14
+   |
+LL |     for n in 100_000.. {
+   |              ^^^^^^^
+   |
+   = note: `#[deny(overflowing_literals)]` on by default
+
+error: aborting due to previous error
+