This follows on from Indirect Object Syntax but it is a different question so it gets its own place!

In doing some of the reading that came out from Indirect Object Syntax, especially this on SO from ikegami, I have noticed that often (but not always) hash keys are not quoted literals but barewords. Given the potential for confusion that has been shown from Indirect Object Syntax, it seems that this is another place where confusion could arise.

I have noticed this before but never really thought anything of it. 

my $value = $hash{ key };

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I never write it like that. I always quote it unless the key is non-constant. 
my $value = $hash{'key'};
my $value = $hash{ $key_value };
my $value = $hash{"st_$id"};

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Is there a difference between $hash{ key } and $hash{'key'}?

In reply to Quoting hash keys by Bod

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