# in FooInterface.pm
package FooInterface;

use Class::Trait 'base';

our @REQUIRES = qw(foo bar baz);

##</code><code>##

package Foo;
    
use Class::Trait 'FooInterface';
    
sub foo {}
sub bar {}
# missing &baz

##</code><code>##

stevan% perl test.pl
Requirement (baz) for FooInterface not in Foo at test.pl line 0
INIT failed--call queue aborted.