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Compiler Error C2991

Error Message

redefinition of type parameter 'parameter'

There was a type conflict between two generic or template definitions of parameter. When defining multiple generic or template parameters, you must use equivalent types.

The following sample generates C2991:

// C2991.cpp
// compile with: /c
template<class T, class T> struct TC {};   // C2991
// try the following line instead
// template<class T, class T2> struct TC {};

C2991 can also occur when using generics:

// C2991b.cpp
// compile with: /clr /c
generic<class T,class T> ref struct GC {};   // C2991
// try the following line instead
// generic<class T,class T2> ref struct GC {};