Only one of these can work:

print $handles{foo};
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print $strings{foo};
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The latter was picked to work. As such,

print $x{y} "Wow!\n";
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is as much an error as

$s = $x{y} "Wow!\n";
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If the file handle expression is non-trivial, you can't omit the curlies around the expression.

print $fh "...";
print { $fh } "...";
print { $handles{foo} } "...";

print( $fh "..." );
print( { $fh } "..." );
print( { $handles{foo} } "..." );
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print