Compiler Error C3218
Visual Studio 2015
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The latest version of this topic can be found at Compiler Error C3218.
type' : type not allowed as a constraint
For a type to be a constraint, it must be either a value type or reference to a managed class or interface.
The following sample generates C3218.
// C3218.cpp
// compile with: /clr /c
class A {};
ref class B {};
// Delete the following 3 lines to resolve.
generic <class T>
where T : A // C3218
ref class C {};
// OK
generic <class T>
where T : B
ref class D {};
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