This documentation is archived and is not being maintained.

Compiler Error C3868

'type': constraints on generic parameter 'parameter' differ from those on the declaration

Multiple declarations must have the same generic constraints. For more information, see Generics (Visual C++).

The following sample generates C3868.

// C3868.cpp
// compile with: /clr /c
interface struct I1;

generic <typename T> ref struct MyStruct;
generic <typename U> where U : I1 ref struct MyStruct;   // C3868

// OK
generic <typename T> ref struct MyStruct2;
generic <typename U> ref struct MyStruct2;

generic <typename T> where T : I1 ref struct MyStruct3;
generic <typename U> where U : I1 ref struct MyStruct3;