Fix #30807

Author: Keno

src/jltypes.c

@@ -1751,6 +1751,11 @@ jl_vararg_marker_t *jl_wrap_vararg(jl_value_t *t, jl_value_t *n)
             jl_errorf("Vararg length is negative: %zd", jl_unbox_long(n));
         }
     }
+    if (t) {
+        if (!jl_is_typevar(t) && !jl_is_type(t)) {
+            jl_type_error_rt("Vararg", "type", (jl_value_t*)jl_type_type, t);
+        }
+    }
     jl_ptls_t ptls = jl_get_ptls_states();
     jl_vararg_marker_t *vm = (jl_vararg_marker_t *)jl_gc_alloc(ptls, sizeof(jl_vararg_marker_t), jl_vararg_marker_type);
     vm->T = t;

test/core.jl

@@ -7507,3 +7507,6 @@ let array = Int[]
 end
 @test compare_union37557(Ref{Union{Int,Vector{Int}}}(1),
                          Ref{Union{Int,Vector{Int}}}(1))
+
+# Issue #30807
+@test_throws TypeError NTuple{<:Any, 3}