From f4fb7c54a806be54b3d0be7d39c83893d1594361 Mon Sep 17 00:00:00 2001
From: Keno Fischer <keno@juliacomputing.com>
Date: Tue, 21 Feb 2023 02:25:35 +0000
Subject: [PATCH] Make opaque closure constructor more robust

By type checking the nargs argument rather than just assuming. It's
easy for people to end up with the wrong integer type here.
---
 src/method.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/method.c b/src/method.c
index b1f4051e28a82..69390c7841a14 100644
--- a/src/method.c
+++ b/src/method.c
@@ -99,14 +99,16 @@ static jl_value_t *resolve_globals(jl_value_t *expr, jl_module_t *module, jl_sve
                     jl_error("opaque_closure_method: invalid syntax");
                 }
                 jl_value_t *name = jl_exprarg(e, 0);
-                jl_value_t *nargs = jl_exprarg(e, 1);
+                jl_value_t *oc_nargs = jl_exprarg(e, 1);
                 int isva = jl_exprarg(e, 2) == jl_true;
                 jl_value_t *functionloc = jl_exprarg(e, 3);
                 jl_value_t *ci = jl_exprarg(e, 4);
                 if (!jl_is_code_info(ci)) {
                     jl_error("opaque_closure_method: lambda should be a CodeInfo");
+                } else if (!jl_is_long(oc_nargs)) {
+                    jl_type_error("opaque_closure_method", (jl_value_t*)jl_long_type, oc_nargs);
                 }
-                jl_method_t *m = jl_make_opaque_closure_method(module, name, jl_unbox_long(nargs), functionloc, (jl_code_info_t*)ci, isva);
+                jl_method_t *m = jl_make_opaque_closure_method(module, name, jl_unbox_long(oc_nargs), functionloc, (jl_code_info_t*)ci, isva);
                 return (jl_value_t*)m;
             }
             if (e->head == jl_cfunction_sym) {