Perl::Critic::Policy::BuiltinFunctions::ProhibitUniversalCan(3pm)

Perl::Critic::Policy::BuiltinFunctions::ProhibitUniversalCan3pm

Write "eval { $foo->can($name) }" instead of "universal::can($foo, $name)".

Affiliation

This Policy is part of the core Perl::Critic distribution.

Overview

    print UNIVERSAL::can($obj, 'Foo::Bar') ? 'yes' : 'no';  #not ok
    print eval { $obj->can('Foo::Bar') } ? 'yes' : 'no';    #ok

As of Perl 5.9.3, the use of UNIVERSAL::can as a function has been deprecated and the method form is preferred instead. Formerly, the functional form was recommended because it gave valid results even when the object was "undef" or an unblessed scalar. However, the functional form makes it impossible for packages to override can(), a technique which is crucial for implementing mock objects and some facades.

See UNIVERSAL::can for a more thorough discussion of this topic.

Configuration

This Policy is not configurable except for the standard options.

Releases

10 releases since Debian 5.0 (Lenny); the text changed 9 times.

  1. 5.0
  2. 6.0
  3. 7
  4. 8
  5. 9
  6. 10
  7. 11
  8. 12
  9. 13
  10. Arch

Author

Chris Dolan <[email protected]>

From perl-perl-critic 1.156-3 in Arch Linux 2026-11-01. Parsed by carta from the page's man source.