swift234

Treat '|' as a delimiter while parsing the signature of a closure.

'|' is part of the character set for operators, but within the
signature of a closure we need to treat the first non-nested '|' as
the closing delimiter for the closure parameter list. For example,

  { |x = 1| 2 + x}

parses with the default value of '1' for x, with the body 2 + x. If
the '|' operator is needed in the default value, it can be wrapped in
parentheses:

  { |x = (1|2)| x }

Note that we have problems with both name binding and type checking
for default values in closures (<rdar://problem/13372694>), so they
aren't actually enabled. However, this allows us to parse them and
recover better in their presence.



Swift SVN r5202