Incorrect error column in PHP 8.6 JSON parser

[TimWolla]

Description

The following code:

<?php

var_dump(json_decode('
{"\u00FF"_'));/*
1234567890 */
var_dump(json_last_error_msg());

Resulted in this output:

NULL
string(30) "Syntax error near location 2:5"

But I expected this output instead:

NULL
string(30) "Syntax error near location 2:10"

see #22487 (comment)

PHP Version

PHP 8.6.0-dev (cli) (built: Jun 29 2026 19:08:37) (NTS DEBUG)
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Operating System

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