let statements fail to compile for void return types

[edaskel@…]

A let expression whose result is void will fail to compile, starting in 1.58. It appears to be related to commit b959ed0c33ef28ec978689a8b1235661fcde93fe and specifically the change from code of the form

return result-expression;

to

result_type r = result-expression; return r;

which will fail for result_type void, as assignments are not permitted.

A small test case that compiles in 1.57 but fails in 1.58 (gcc 4.8.2) is attached.

[edaskel@…]

Test case illustrating compile failure for void result type

[edaskel@…]

commit f63e401ea5cac691dcb91a6edaf8f92dbcaa91bc has been merged to fix this issue

[bugs@…]

I think this might be related to other compilation issues that exist for some time when targetting Phoenix V3:

• ​http://stackoverflow.com/a/19631830/85371 (phoenix::try_) or
• ​http://stackoverflow.com/a/29452921/85371 (phoenix::if_)

[edaskel@…]

This bug was fixed and can be closed.

[Kohei Takahashi]

Yes, it should be fixed in 1.59. ​https://github.com/boostorg/phoenix/commit/1a5348e5e46b348a816d30df30a724375c5a527e