From ae1d71bc3f8faa53b37fdce51301477bbd4d6a1b Mon Sep 17 00:00:00 2001
From: Jameson Nash <vtjnash@gmail.com>
Date: Thu, 7 Sep 2023 16:08:55 +0000
Subject: [PATCH] implement validation of Vararg type parameter on construction

It does not seem necessary to allow this, though it does lead to this
printing issue to disallow it:

    julia> Tuple{1, 1, 1, 1}
    NTuple{4, 1}

Fix #51228
---
 src/builtins.c       | 2 +-
 src/jltypes.c        | 2 +-
 src/julia_internal.h | 2 --
 3 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/src/builtins.c b/src/builtins.c
index d0d4b3bf1dbefa..7dd75062e7d22d 100644
--- a/src/builtins.c
+++ b/src/builtins.c
@@ -1324,7 +1324,7 @@ static int is_nestable_type_param(jl_value_t *t)
     return 0;
 }
 
-int jl_valid_type_param(jl_value_t *v)
+static int jl_valid_type_param(jl_value_t *v)
 {
     if (jl_is_tuple(v) || jl_is_namedtuple(v))
         return is_nestable_type_param(jl_typeof(v));
diff --git a/src/jltypes.c b/src/jltypes.c
index 4e566339e30149..7985174cf90c46 100644
--- a/src/jltypes.c
+++ b/src/jltypes.c
@@ -2428,7 +2428,7 @@ jl_vararg_t *jl_wrap_vararg(jl_value_t *t, jl_value_t *n, int check)
             }
         }
         if (t) {
-            if (!jl_valid_type_param(t)) {
+            if (!jl_is_type(t) && !jl_is_typevar(t)) {
                 jl_type_error_rt("Vararg", "type", (jl_value_t*)jl_type_type, t);
             }
             t = normalize_unionalls(t);
diff --git a/src/julia_internal.h b/src/julia_internal.h
index b2ba10d7bd084a..37eb00db5a1d9a 100644
--- a/src/julia_internal.h
+++ b/src/julia_internal.h
@@ -655,8 +655,6 @@ int get_root_reference(rle_reference *rr, jl_method_t *m, size_t i) JL_NOTSAFEPO
 jl_value_t *lookup_root(jl_method_t *m, uint64_t key, int index) JL_NOTSAFEPOINT;
 int nroots_with_key(jl_method_t *m, uint64_t key) JL_NOTSAFEPOINT;
 
-int jl_valid_type_param(jl_value_t *v);
-
 JL_DLLEXPORT jl_value_t *jl_apply_2va(jl_value_t *f, jl_value_t **args, uint32_t nargs);
 
 void JL_NORETURN jl_method_error(jl_function_t *f, jl_value_t **args, size_t na, size_t world);