I'm not sure if it's wanted behaviour, but it's quite confusing so I report it.

In config.xsd of psalm, errorLevel's default value is 1. However, when errorLevel is not present in psalm.xml, totallyTyped is ignored (it doesn't activate Mixed* if =true). When we manually add errorLevel=1, it now works.

It's quite confusing for existing Psalm.xml because it will disable Mixed* rules if config file is not changed while upgrading to 3.9