That's because first code generation is run during Test.String compilation, which does not have Test method.

Add something like this at the beginning:

#; don't generate any code if it not for a property
quit:%mode="method" $$$OK

Thank you!

NoContext helped. What does it mean?

This works too btw:

d %code.WriteLine("  q ..Test()")

Can you share the code please?

Changed .. to z and compilation fails for me.

Okay, how do I make this work with methods?

On property get/set I need to call instance method.

I've tried this:

Class Test.String Extends %String
{

Method Get() As %String [ CodeMode = objectgenerator ]
{
    do %code.WriteLine($c(9) _ "Quit ..Test()")
    quit $$$OK
}

}

And class:

/// set obj = ##class(Test.Obj).%New()
/// w obj.prop
Class Test.Obj Extends %RegisteredObject
{

Property prop As Test.String;

Method Test()
{
    quit $random(100)
}

}

But it fails to compile.

Turns out it's much easier than I thought:

Class Test.String Extends %String
{

ClassMethod Get() As %String [ CodeMode = objectgenerator ]
{
    do %code.WriteLine($c(9) _ "Quit $g(^Test.String, 0)")
    quit $$$OK
}

ClassMethod Set(%val As %String) As %String [ CodeMode = objectgenerator ]
{
    do %code.WriteLine($c(9) _ "Set ^Test.String = %val")
    quit $$$OK
}

}

Example:

set obj = ##class(Test.Obj).%New()
write obj.prop
>0
set obj.prop=1
write obj.prop
>1

Can you please provide an example?

I'm aware only of %XML.PropertyParameters but there's nothing but parameters.

Here's what I've coded.

Property:

Class Test.String Extends %String
{

ClassMethod StorageToLogical(%val As %String) As %String [ CodeMode = objectgenerator ]
{
	set property = $g(%member)
	do %code.WriteLine($c(9) _ "Quit """ _ property _ """")
	quit $$$OK
}

ClassMethod LogicalToStorage(%val As %String) As %String [ CodeMode = objectgenerator ]
{
	set property = $g(%member)
	do %code.WriteLine($c(9) _ "Quit """ _ property _ """")
	quit $$$OK
}

}

Class:

Class Test.Obj Extends %RegisteredObject
{

Property prop As Test.String;

}

However reference to property does not return anything (expected to return property name):

w obj.prop
zw obj.prop
>""

Any ideas?