diff --git a/clippy_lints/src/large_stack_arrays.rs b/clippy_lints/src/large_stack_arrays.rs
index 620e27fa67c6..7bb7bc91f0c9 100644
--- a/clippy_lints/src/large_stack_arrays.rs
+++ b/clippy_lints/src/large_stack_arrays.rs
@@ -94,6 +94,15 @@ impl<'tcx> LateLintPass<'tcx> for LargeStackArrays {
             })
             && u128::from(self.maximum_allowed_size) < u128::from(element_count) * u128::from(element_size)
         {
+            // libtest might generate a large array containing the test cases, and no span will be associated
+            // to it. In this case it is better not to complain.
+            //
+            // Note that this condition is not checked explicitly by a unit test. Do not remove it without
+            // ensuring that <https://github.com/rust-lang/rust-clippy/issues/13774> stays fixed.
+            if expr.span.is_dummy() {
+                return;
+            }
+
             span_lint_and_then(
                 cx,
                 LARGE_STACK_ARRAYS,