Function freezeTypes

src/simplicity/typeInference.c:524–539

Create a type DAG that supports all the type annotations of the Simplicity expression, 'dag', * and the input and output types of whole expression. * * If the Simplicity DAG, 'dag', has a principal type (including constraints due to sharing of subexpressions), * and 'arrow[i]'s and 'source' and 'target' field's unification variables are bound to the principal source and target types * of sube

 *               unification_arrow arrow[len] is a graph of bindings that satisfies the typing constraints of imposed by 'dag'.
 */
static simplicity_err freezeTypes(type* type_dag, dag_node* dag, unification_arrow* arrow, const size_t len) {
  /* First entry of type_dag gets assigned to the ONE type. */
  type_dag[0] = (type){ .kind = ONE };
  size_t type_dag_used = 1;

  for (size_t i = 0; i < len; ++i) {
    if (!(freeze(&(dag[i].sourceType), type_dag, &type_dag_used, &(arrow[i].source)) &&
          freeze(&(dag[i].targetType), type_dag, &type_dag_used, &(arrow[i].target)))) {
      return SIMPLICITY_ERR_TYPE_INFERENCE_OCCURS_CHECK;
    }
  }

  simplicity_computeTypeAnalyses(type_dag, type_dag_used);

  return SIMPLICITY_NO_ERROR;
}

/* If the Simplicity DAG, 'dag', has a principal type (including constraints due to sharing of subexpressions),
 * then allocate a well-formed type DAG containing all the types needed for all the subexpressions of 'dag',