Compiler Error C3446

'class': a default member initializer is not allowed for a member of a value class

In Visual Studio 2015 and earlier, the compiler permitted (but ignored) a default member initializer for a member of a value class. Default initialization of a value class always zero-initializes the members; a default constructor is not permitted. In Visual Studio 2017, default member initializers raise a compiler error, as shown in this example:

Example

The following sample generates C3446 in Visual Studio 2017 and later:

// C3446.cpp
value struct V
{
       int i = 0; // error C3446: 'V::i': a default member initializer
                  // is not allowed for a member of a value class
       int j {0}; // C3446
};

To correct the error, remove the initializer:

// C3446b.cpp
value struct V
{
       int i;
       int j;
};