compiler-warning-level-1-c4688.md

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Learn more about: Compiler Warning (level 1) C4688	Compiler Warning (level 1) C4688	11/04/2016	C4688	C4688	a027df3c-b2b8-4c49-8539-c2bc42db74e8

Compiler Warning (level 1) C4688

'constraint': constraint list contains assembly private type 'type'

A constraint list has an assembly private type, meaning it will not be available when the type is accessed from outside the assembly. For more information, see Generics.

Example

The following sample generates C4688.

// C4688.cpp
// compile with: /clr /c /W1
ref struct A {};   // private type
public ref struct B {};

// Delete the following 3 lines to resolve.
generic <class T>
where T : A   // C4688
public ref struct M {};

generic <class T>
where T : B
public ref struct N {};