13:08 >perl -MData::Dump -wE "@a = @a || (1 .. 3); dd \@a;"
[1, 2, 3]

13:08 >perl -MData::Dump -wE "@a ||= (1 .. 3); dd \@a;"
Can't modify array dereference in logical or assignment (||=) at -e line 1, near ");"
Execution of -e aborted due to compilation errors.

13:09 >perl -v

This is perl 5, version 18, subversion 0 (v5.18.0) built for MSWin32-x86-multi-thread-64int