/// <summary>
/// Gets which function member is better. (§ 14.4.2.2)
/// </summary>
/// <returns>0 if neither method is better. 1 if c1 is better. 2 if c2 is better.</returns>
int GetBetterFunctionMember(Candidate c1, Candidate c2)
{
int length = Math.Min(Math.Min(c1.Parameters.Count, c2.Parameters.Count), arguments.Count);
bool foundBetterParamIn1 = false;
bool foundBetterParamIn2 = false;
for (int i = 0; i < length; i++)
{
if (arguments[i] == null)
{
continue;
}
int res = MemberLookupHelper.GetBetterConversion(arguments[i], c1.Parameters[i].ReturnType, c2.Parameters[i].ReturnType);
if (res == 1)
{
foundBetterParamIn1 = true;
}
if (res == 2)
{
foundBetterParamIn2 = true;
}
}
if (foundBetterParamIn1 && !foundBetterParamIn2)
{
return(1);
}
if (foundBetterParamIn2 && !foundBetterParamIn1)
{
return(2);
}
if (foundBetterParamIn1 && foundBetterParamIn2)
{
return(0); // ambigous
}
// If none conversion is better than any other, it is possible that the
// expanded parameter lists are the same:
for (int i = 0; i < length; i++)
{
if (!object.Equals(c1.Parameters[i].ReturnType, c2.Parameters[i].ReturnType))
{
// if expanded parameters are not the same, neither function member is better
return(0);
}
}
// the expanded parameters are the same, apply the tie-breaking rules from the spec:
// if one method is generic and the other non-generic, the non-generic is better
bool m1IsGeneric = c1.TypeParameterCount > 0;
bool m2IsGeneric = c2.TypeParameterCount > 0;
if (m1IsGeneric && !m2IsGeneric)
{
return(2);
}
if (m2IsGeneric && !m1IsGeneric)
{
return(1);
}
// for params parameters: non-expanded calls are better
if (c1.IsExpanded && !c2.IsExpanded)
{
return(2);
}
if (c2.IsExpanded && !c1.IsExpanded)
{
return(1);
}
// if the number of parameters is different, the one with more parameters is better
// this occurs when only when both methods are expanded
if (c1.OriginalMethod.Parameters.Count > c2.OriginalMethod.Parameters.Count)
{
return(1);
}
if (c2.OriginalMethod.Parameters.Count > c1.OriginalMethod.Parameters.Count)
{
return(2);
}
IReturnType[] m1ParamTypes = new IReturnType[c1.Parameters.Count];
IReturnType[] m2ParamTypes = new IReturnType[c2.Parameters.Count];
for (int i = 0; i < m1ParamTypes.Length; i++)
{
m1ParamTypes[i] = c1.Parameters[i].ReturnType;
m2ParamTypes[i] = c2.Parameters[i].ReturnType;
}
return(GetMoreSpecific(m1ParamTypes, m2ParamTypes));
}
