Replace v->var->lb with simple_meet

and remove the unneeded Null check.

Co-Authored-By: Jameson Nash <[email protected]>

src/subtype.c

@@ -3248,20 +3248,14 @@ static int merge_env(jl_stenv_t *e, jl_value_t **root, jl_savedenv_t *se, int co
     }
     int n = 0;
     jl_varbinding_t *v = e->vars;
-    jl_value_t *ub = NULL, *vub = NULL;
-    JL_GC_PUSH2(&ub, &vub);
     while (v != NULL) {
-        jl_value_t *lb = jl_svecref(*root, n);
-        if (v->lb != lb)
-            jl_svecset(*root, n, lb ? v->var->lb : v->lb);
-        ub = jl_svecref(*root, n+1);
-        vub = v->ub;
-        if (vub != ub)
-            jl_svecset(*root, n+1, ub ? simple_join(ub, vub) : vub);
+        // update the low bound
+        jl_svecset(*root, n, simple_meet(jl_svecref(*root, n), v->lb));
+        // update the up bound
+        jl_svecset(*root, n+1, simple_join(jl_svecref(*root, n+1), v->ub));
         n = n + 3;
         v = v->prev;
     }
-    JL_GC_POP();
     return count + 1;
 }