[Pkg-vala-maintainers] Bug#838829: valac: Feature Regression in vala 0.34

[Sebastian Reichel]

Package: valac
Version: 0.34.0-1
Severity: serious
Tags: upstream
Justification: upstream regression causes FTBFS in other package(s)

Hi,

valac no longer supports abstract functions with generics. This
construct is used by the freesmartphone.org stack, which is
packaged for Debian and FTBFS with valac > 0.34.0-1. This has
been reported in Debian Bug #838705.

The below standalone testcase, which compiles warning free
in vala 0.32, no longer works in vala 0.34 and demonstrates the
problem.

As far as I can see the regression has been introduced by the
following change:
https://mail.gnome.org/archives/commits-list/2016-July/msg02876.html

---------------------------------------------------------
public abstract class basecl : Object {
	public abstract void test<T>(T parameter);
}

public class inheritcl : basecl {
	public override void test<T>(T parameter) {
		stdout.printf("Just a test!\n");
	}
}

int main(string[] args) {
	var obj = new inheritcl();
	obj.test<string>("test");
	return 0;
}
---------------------------------------------------------

-- Sebastian