normalize more Tuple{Vararg{T,N}} to Tuple{T,...}

c.f. "Instantiate Tuple{Vararg{Int,3}} as Tuple{Int,Int,Int}"

Author: vtjnash

src/jltypes.c

@@ -2057,6 +2057,18 @@ static jl_value_t *inst_datatype(jl_datatype_t *dt, jl_svec_t *p, jl_value_t **i
     if (stack_lkup)
         return stack_lkup;
 
+    if (istuple && ntp == 1 && jl_is_vararg_type(iparams[0])) {
+        // normalize Tuple{Vararg{Int,3}} to Tuple{Int,Int,Int}
+        jl_datatype_t *va = (jl_datatype_t*)iparams[0];
+        if (jl_is_long(jl_tparam1(va))) {
+            ssize_t nt = jl_unbox_long(jl_tparam1(va));
+            if (nt < 0)
+                jl_errorf("apply_type: Vararg length N is negative: %zd", nt);
+            if (jl_is_leaf_type(jl_tparam0(va)))
+                return jl_tupletype_fill(nt, jl_tparam0(va));
+        }
+    }
+
     // always use original type constructor
     if (!istuple) {
         if (jl_is_vararg_type((jl_value_t*)dt) && ntp == 2) {
@@ -2164,15 +2176,6 @@ static void check_tuple_parameter(jl_value_t *pi, size_t i, size_t np)
 
 static jl_tupletype_t *jl_apply_tuple_type_v_(jl_value_t **p, size_t np, jl_svec_t *params)
 {
-    if (np == 1 && jl_is_vararg_type(p[0])) {
-        jl_datatype_t *va = (jl_datatype_t*)p[0];
-        if (jl_is_long(jl_tparam1(va))) {
-            ssize_t nt = jl_unbox_long(jl_tparam1(va));
-            if (nt < 0)
-                jl_errorf("size or dimension is negative: %zd", nt);
-            return (jl_tupletype_t*)jl_tupletype_fill(nt, jl_tparam0(va));
-        }
-    }
     int isabstract = 0, cacheable = 1;
     for(size_t i=0; i < np; i++) {
         jl_value_t *pi = p[i];