presto-spi/src/main/java/io/prestosql/spi/type/CharType.java/CharType/CharType
class CharType:    private CharType(long length)
    {
        super(
                new TypeSignature(
                        StandardTypes.CHAR,
                        singletonList(TypeSignatureParameter.numericParameter(length))),
                Slice.class);

        if (length < 0 || length > MAX_LENGTH) {
            throw new PrestoException(INVALID_FUNCTION_ARGUMENT, format("CHAR length scale must be in range [0, %s]", MAX_LENGTH));
        }
        this.length = (int) length;
    }