Fix span of error in Parse for Index
diff --git a/src/expr.rs b/src/expr.rs
index 59e1edf..44b95cb 100644
--- a/src/expr.rs
+++ b/src/expr.rs
@@ -2771,7 +2771,7 @@
                     span: lit.span(),
                 })
             } else {
-                Err(input.error("expected unsuffixed integer"))
+                Err(Error::new(lit.span(), "expected unsuffixed integer"))
             }
         }
     }