id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
8564	Variable hiding errors within nested let blocks in Phoenix	miremare@…	Thomas Heller	"I encounter errors when using nested let blocks in Phoenix whenever an ""inner"" local variable hides an ""outer"" local variable. The ""Visibility"" example from the documentation at http://www.boost.org/doc/libs/1_53_0/libs/phoenix/doc/html/phoenix/modules/scope/let.html also fails. Here is that ""Visibility"" example as a standalone module which fails:

{{{
#include <iostream>
#include <boost/phoenix.hpp>

namespace phoenix = boost::phoenix;
using namespace phoenix::local_names;

int main(int argc, char *argv[])
{
  phoenix::let(_x = 1, _y = "", World"")
  [
    phoenix::let(_x = ""Hello"") // hides the outer _x
    [
      std::cout << _x << _y // prints ""Hello, World""
    ]
  ]();

  return 0;
}
}}}

The errors I receive from GCC 4.7.2, GCC 4.8 snapshot, and Clang 3.2, with any of Boost 1.49, 1.53, or trunk, begin as follows:
  GCC:   ""error: function returning an array""

  Clang: ""error: function cannot return array type 'result_type' (aka 'char [6]')""

Another failing example provided in Eric Niebler's Stack Overflow answer [http://stackoverflow.com/questions/16408770/variable-hiding-within-nested-let-blocks-in-boost-phoenix here] is:

{{{
int y = 0;
int x = (phoenix::let(_a = 1, _b = 2)[phoenix::let(_b = 3)[ _a ]])(y);
}}}

...which contrasts with the following example; which does compile: 

{{{
int y = 0;
int x = (phoenix::let(_a = 1, _b = 2)[phoenix::let(_b = _1)[ _a ]])(y);
}}}
"	Bugs	new	To Be Determined	phoenix	Boost 1.53.0	Problem