https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63151
Bug ID: 63151 Summary: Accessibility error when brace-constructing base class with protected defaulted constructor and member variable Product: gcc Version: 4.9.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: lukeallardyce at gmail dot com struct Foo { protected: Foo() = default; int t; }; struct Bar : public Foo { Bar(): Foo{} { } }; g++ -std=c++1y -c test.cpp test.cpp: In constructor 'Bar::Bar()': test.cpp:4:3: error: 'Foo::Foo()' is protected Foo() = default; ^ test.cpp:12:14: error: within this context Bar(): Foo{} { } The problem seems to be an astral conjunction of the braces, the defaulted base class constructor, and the presence of a member variable in the base class. Removing any one of these gives no error: class Foo { protected: Foo() {} // Fine int t; }; class Foo { protected: Foo() = default; // Also fine }; class Bar : public Foo { Bar(): Foo() { } // Also fine }; Tested on: Linux (Arch): gcc version 4.9.1 (GCC) OSX: gcc version 4.9.1 (MacPorts gcc49 4.9.1_0) Windows: gcc version 4.9.0 (x86_64-win32-seh-rev2, Built by MinGW-W64 project)