Why does this work
  my %hash = map { $_ => "stuff_$_" } qw(asdf qwert zxcv);

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But this 
  my %hash = map { "stuff_$_" => $_ } qw(asdf qwert zxcv);

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results in a syntax error (syntax error ... near "} qw(asdf qwert zxcv)")

The only difference is the order of the values in the BLOCK.

perl 5.8.5
FOLLOW UP:
Since I don't particularly like any of the solutions to this problem that have been proposed (although most do work) I decided to follow the advice of a co-worker
Back in my day we used 'foreach' and we liked it!

It would seem to me that the more common case would be using map to generate key-values pairs for each iteration instead of an anonymous hash for each. So why not make the later have to use something extra... for instance: 
   my %hash = map { {"stuff_$_" => $_} } qw(asdf qwert zxcv);

[download]
would easily tell the parser it's an anon-hash. So anything with a '{' is a block until otherwise told it is not.

In reply to order in map by mpeters

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