c++ - Reference initialization in C++11 default constructor - 


struct x {};  struct y {      y() = default;     x& x; };

works fine in c++11. wish know how y::x initialized behind scenes?

it doesn't compile in major compiler. compile, until of creation of object of type y.

if create object of type y, output of clang be

error: call implicitly-deleted default constructor of 'y' note: explicitly defaulted function implicitly deleted here     y() = default; note: default constructor of 'y' implicitly deleted because field 'x' of reference type 'x &' not initialized     x& x;

when declare user-defined constructor, empty function, there error, without creation of object.

michael burr right. implicitly-defaulted constructor works fine. there no problems diagnostic here, can see.


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