Re: [patch] Support noexcept-specifications for transaction statements and expressions.

[Jason Merrill]

At this point I think it'd be simpler to handle noexcept in a 
transaction-expression directly in cp_parser_transaction_expression.

Since TRANSACTION_EXPR_NOEX is only for the template representation, I'd 
rather not add it to the language-independent tree code.  Maybe 
introduce a C++ template-specific NOEXCEPT_REGION tree code?

Jason