@files = { local(@ARGV, $/) = @filenames; <> }; # missing 'do'

##</code><code>##

    @files = do { local(@ARGV, $/) = @filenames; <> };

##</code><code>##

    @foo{ @foo } = 0 .. @foo; # off-by-one error

##</code><code>##

    @foo{ @foo } = 0 .. $#foo;