Script with a Source Generator doesn't compile

[mdonatas]

A script with a Source Generator fails to compile when run although intelli-sense shows that a Source Generator has run (at least during edit time) as correct xml-doc was made for the partial method.

Ext.AbcOrDefGeneratedRegex().IsMatch("abc").Dump();

public static partial class Ext
{
    [GeneratedRegex("abc|def", RegexOptions.IgnoreCase, "en-US")]
    public static partial Regex AbcOrDefGeneratedRegex();
}