A Closer Look

Where is Int defined?

• Moose::Util::TypeConstraints.
• Standard type constraints:

Any, Item, Bool, Undef, Defined, Value, Num, Int, Str, 
Ref, ScalarRef, ArrayRef, HashRef, CodeRef, RegexpRef, 
GlobRef, FileHandle, Object and Role

• Type constraints are subtype-able
• Unrecognized type constraints are assumed to be classes

 has 'date' => (isa => 'DateTime'); # DWIM