Method plus

src/main/java/org/codehaus/groovy/runtime/GStringImpl.java:90–94

(GString that)

    }

    @Override
    public GString plus(GString that) {
        GString thatFrozen = that instanceof GStringImpl ? ((GStringImpl) that).freeze() : that;
        return GStringUtil.plusImpl(super.getValues(), thatFrozen.getValues(), strings, thatFrozen.getStrings());
    }

    @Override
    public Writer writeTo(Writer out) throws IOException {