This 
perl -we 'my %h; my @x = ( @{$h{a}} )'

[download]
gives 'Use of uninitialized value $h{"a"} in array dereference at -e line 1.'

which seems desirable, but 

perl -wE 'my %h; foreach $x ( @{$h{a}} ) { say $x }; exists $h{a} and 
+print "true\n"'

[download]
creates the $h{a} key which seems kinda bad. Why is the foreach context treating ( @{$h{a}} ) differently?

In reply to autovivified hash key with foreach $x ( @{$h{a}} ) {} by Danny

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