the bin/vala-0.54 shell script executes bin/valac-0.54 which executes bin/.valac-0.54-real. it should execute bin/.vala-0.54-real instead.
expected (was the case before guix's update): $ vala hello.vala Hello, World! $ ls hello.vala actual: $ vala hello.vala $ ls hello hello.vala $ ./hello Hello, World!