https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77563
Jonathan Wakely <redi at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Keywords| |accepts-invalid Status|UNCONFIRMED |NEW Last reconfirmed| |2016-09-13 Known to work| |4.5.4 Summary|explicit constructor breaks |[5/6/7 Regression] explicit |narrowing conversion |constructor breaks |overload resolution |narrowing conversion | |overload resolution Ever confirmed|0 |1 Known to fail| |5.4.0, 6.2.0, 7.0 --- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> --- 4.5.4 got this right: ex.cc: In function ‘int main()’: ex.cc:15:7: error: conversion from ‘long int’ to ‘A’ is ambiguous ex.cc:6:3: note: candidates are: A::A(uint32_t) ex.cc:5:3: note: A::A(int32_t) Since GCC 4.6 the error has been misleading, and since GCC 6 it's accepts-invalid.