public static bool CheckConstraints(this MethodDesc method, InstantiationContext context = null)
{
if (!method.OwningType.CheckConstraints(context))
{
return(false);
}
// Non-generic methods always pass constraints check
if (!method.HasInstantiation)
{
return(true);
}
var paramContext = new InstantiationContext(method.OwningType.Instantiation, method.Instantiation);
MethodDesc uninstantiatedMethod = method.GetMethodDefinition();
for (int i = 0; i < uninstantiatedMethod.Instantiation.Length; i++)
{
if (!VerifyGenericParamConstraint(paramContext, (GenericParameterDesc)uninstantiatedMethod.Instantiation[i], context, method.Instantiation[i]))
{
return(false);
}
}
return(true);
}
private static void GetInstantiatedConstraintsRecursive(InstantiationContext typeContext, TypeDesc type, ref ArrayBuilder <TypeDesc> instantiatedConstraints)
{
if (!type.IsGenericParameter || typeContext == null)
{
return;
}
GenericParameterDesc genericParam = (GenericParameterDesc)type;
foreach (var constraint in genericParam.TypeConstraints)
{
var instantiatedType = constraint.InstantiateSignature(typeContext.TypeInstantiation, typeContext.MethodInstantiation);
if (instantiatedType.IsGenericParameter)
{
// Make sure it is save to call this method recursively
if (!instantiatedConstraints.Contains(instantiatedType))
{
instantiatedConstraints.Add(instantiatedType);
// Constraints of this constraint apply to 'genericParam' too
GetInstantiatedConstraintsRecursive(typeContext, instantiatedType, ref instantiatedConstraints);
}
}
else
{
instantiatedConstraints.Add(instantiatedType);
}
}
}
private static bool VerifyGenericParamConstraint(InstantiationContext genericParamContext, GenericParameterDesc genericParam,
InstantiationContext instantiationParamContext, TypeDesc instantiationParam)
{
GenericConstraints constraints = genericParam.Constraints;
// Check class constraint
if ((constraints & GenericConstraints.ReferenceTypeConstraint) != 0)
{
if (!instantiationParam.IsGCPointer &&
!CheckGenericSpecialConstraint(instantiationParam, GenericConstraints.ReferenceTypeConstraint))
{
return(false);
}
}
// Check default constructor constraint
if ((constraints & GenericConstraints.DefaultConstructorConstraint) != 0)
{
if (!instantiationParam.HasExplicitOrImplicitDefaultConstructor() &&
!CheckGenericSpecialConstraint(instantiationParam, GenericConstraints.DefaultConstructorConstraint))
{
return(false);
}
}
// Check struct constraint
if ((constraints & GenericConstraints.NotNullableValueTypeConstraint) != 0)
{
if ((!instantiationParam.IsValueType || instantiationParam.IsNullable) &&
!CheckGenericSpecialConstraint(instantiationParam, GenericConstraints.NotNullableValueTypeConstraint))
{
return(false);
}
}
var instantiatedConstraints = new ArrayBuilder <TypeDesc>();
GetInstantiatedConstraintsRecursive(instantiationParamContext, instantiationParam, ref instantiatedConstraints);
foreach (var constraintType in genericParam.TypeConstraints)
{
var instantiatedType = constraintType.InstantiateSignature(genericParamContext.TypeInstantiation, genericParamContext.MethodInstantiation);
if (CanCastConstraint(ref instantiatedConstraints, instantiatedType))
{
continue;
}
if (!instantiationParam.CanCastTo(instantiatedType))
{
return(false);
}
}
return(true);
}
public static bool CheckConstraints(this TypeDesc type, InstantiationContext context = null)
{
TypeDesc uninstantiatedType = type.GetTypeDefinition();
// Non-generic types always pass constraints check
if (uninstantiatedType == type)
{
return(true);
}
var paramContext = new InstantiationContext(type.Instantiation, default(Instantiation));
for (int i = 0; i < uninstantiatedType.Instantiation.Length; i++)
{
if (!VerifyGenericParamConstraint(paramContext, (GenericParameterDesc)uninstantiatedType.Instantiation[i], context, type.Instantiation[i]))
{
return(false);
}
}
return(true);
}
