presto-main/src/main/java/io/prestosql/sql/planner/TranslationMap.java/TranslationMap/putExpressionMappingsFrom
class TranslationMap:    public void putExpressionMappingsFrom(TranslationMap other)
    {
        expressionToSymbols.putAll(other.expressionToSymbols);
        expressionToExpressions.putAll(other.expressionToExpressions);
    }