private bool HasImplicitReferenceTypeParameterConversion(
TypeParameterType pSource, CType pDest)
{
Debug.Assert(pSource != null);
Debug.Assert(pDest != null);
if (!pSource.IsRefType())
{
// Not a reference conversion.
return(false);
}
// The following implicit conversions exist for a given type parameter T:
//
// * From T to its effective base class C.
AggregateType pEBC = pSource.GetEffectiveBaseClass();
if (pDest == pEBC)
{
return(true);
}
// * From T to any base class of C.
if (IsBaseClass(pEBC, pDest))
{
return(true);
}
// * From T to any interface implemented by C.
if (IsBaseInterface(pEBC, pDest))
{
return(true);
}
// * From T to any interface type I in T's effective interface set, and
// from T to any base interface of I.
TypeArray pInterfaces = pSource.GetInterfaceBounds();
for (int i = 0; i < pInterfaces.Size; ++i)
{
if (pInterfaces.Item(i) == pDest)
{
return(true);
}
}
// * From T to a type parameter U, provided T depends on U.
if (pDest.IsTypeParameterType() && pSource.DependsOn(pDest.AsTypeParameterType()))
{
return(true);
}
return(false);
}
private bool HasImplicitTypeParameterBaseConversion(
TypeParameterType pSource, CType pDest)
{
Debug.Assert(pSource != null);
Debug.Assert(pDest != null);
if (HasImplicitReferenceTypeParameterConversion(pSource, pDest))
{
return(true);
}
if (HasImplicitBoxingTypeParameterConversion(pSource, pDest))
{
return(true);
}
return(pDest is TypeParameterType typeParamDest && pSource.DependsOn(typeParamDest));
}
private bool HasImplicitTypeParameterBaseConversion(
TypeParameterType pSource, CType pDest)
{
Debug.Assert(pSource != null);
Debug.Assert(pDest != null);
if (HasImplicitReferenceTypeParameterConversion(pSource, pDest))
{
return true;
}
if (HasImplicitBoxingTypeParameterConversion(pSource, pDest))
{
return true;
}
if (pDest.IsTypeParameterType() && pSource.DependsOn(pDest.AsTypeParameterType()))
{
return true;
}
return false;
}
private bool HasImplicitReferenceTypeParameterConversion(
TypeParameterType pSource, CType pDest)
{
Debug.Assert(pSource != null);
Debug.Assert(pDest != null);
if (!pSource.IsRefType())
{
// Not a reference conversion.
return false;
}
// The following implicit conversions exist for a given type parameter T:
//
// * From T to its effective base class C.
AggregateType pEBC = pSource.GetEffectiveBaseClass();
if (pDest == pEBC)
{
return true;
}
// * From T to any base class of C.
if (IsBaseClass(pEBC, pDest))
{
return true;
}
// * From T to any interface implemented by C.
if (IsBaseInterface(pEBC, pDest))
{
return true;
}
// * From T to any interface type I in T's effective interface set, and
// from T to any base interface of I.
TypeArray pInterfaces = pSource.GetInterfaceBounds();
for (int i = 0; i < pInterfaces.Size; ++i)
{
if (pInterfaces.Item(i) == pDest)
{
return true;
}
}
// * From T to a type parameter U, provided T depends on U.
if (pDest.IsTypeParameterType() && pSource.DependsOn(pDest.AsTypeParameterType()))
{
return true;
}
return false;
}