[Bug c++/85717] New: anonymous union in initializer list : do not handle the types correctly

["daffra.claudio at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85717

            Bug ID: 85717
           Summary: anonymous union in initializer list : do not handle
                    the types correctly
           Product: gcc
           Version: 5.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: daffra.claudio at gmail dot com
  Target Milestone: ---

Created attachment 44100
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=44100&action=edit
anonymous union in initializer list : do not handle the types correctly

anonymous union in initializer list : do not handle the types correctly

when i use initializer list in anonyumouse union, g++ gives this error code
more or less i expected;

        C:\prj\cd>g++ src\prova.cpp -o prova.exe -std=c++14
        src\prova.cpp: In function 'int main()':
        src\prova.cpp:31:5: error: narrowing conversion of
'3.3999999999999999e+0' from 'double' to 'uint64_t {aka long long unsigned
int}' inside { } [-Wnarrowing]
          t1 = { 1 ,"a",3.4 } ;
     ^

indeed in a normal way, code below all works o perfectly         

        t1.real = 6.6 ;
        std::cout << t1.real << "\n" ;

        t1.integer = 3 ;
        std::cout << t1.integer << "\n" ;

despite result change if i swith union member

                union {
                        uint64_t                integer ;       
                        double          real;
                } ;     

i put

                union {
                        double          real;                   
                        uint64_t                integer ;       
                } ;     

source code error  

        #include <iostream>
        #include <string>
        #include <stdio.h>
        #include <stdint.h>
        #include <assert.h>

        typedef struct  token_s
        {
                uint8_t                 sym ;   
                std::string     tok ;
                union {

                        double          real;
                                uint64_t                integer ;               
                } ;

        } token_t ;

        int main ( void )
        {
                assert ( sizeof(uint64_t)==sizeof(double) ) ;

                token_t t1 ;

                t1.real = 6.6 ;
                std::cout << t1.real << "\n" ;

                t1.integer = 3 ;
                std::cout << t1.integer << "\n" ;

                t1 = { 1 ,"a",3.4 } ;   
                std::cout << t1.real << "\n" ;

                t1 = { 1 ,"a",2 } ;
                std::cout << t1.integer << "\n" ;       

                return 0 ;
        }