private static Expression /*!*/ ConvertResult(Expression /*!*/ expression, Type /*!*/ resultType)
{
if (resultType.IsGenericType() && resultType.GetGenericTypeDefinition() == typeof(Union <,>))
{
var args = resultType.GetGenericArguments();
var ctor = resultType.GetConstructor(args);
if (args[0].IsAssignableFrom(expression.Type))
{
return(Ast.New(ctor, expression, AstUtils.Default(args[1])));
}
else
{
Debug.Assert(args[1].IsAssignableFrom(expression.Type));
return(Ast.New(ctor, AstUtils.Default(args[0]), expression));
}
}
else
{
return(AstUtils.Convert(expression, resultType));
}
}