////////////////////////////////////////////////////////////////////////////////
// We need to rearange the method parameters so that the type of any specified named argument
// appears in the same place as the named argument. Consider the example below:
// Foo(int x = 4, string y = "", long l = 4)
// Foo(string y = "", string x="", long l = 5)
// and the call site:
// Foo(y:"a")
// After rearranging the parameter types we will have:
// (string, int, long) and (string, string, long)
// By rearranging the arguments as such we make sure that any specified named arguments appear in the same position for both
// methods and we also maintain the relative order of the other parameters (the type long appears after int in the above example)
private TypeArray RearrangeNamedArguments(TypeArray pta, MethPropWithInst mpwi,
CType pTypeThrough, ArgInfos args)
{
#if DEBUG
// We never have a named argument that is in a position in the argument
// list past the end of what would be the formal parameter list.
for (int i = pta.Count; i < args.carg; i++)
{
Debug.Assert(!(args.prgexpr[i] is ExprNamedArgumentSpecification));
}
#endif
// If we've no args we can skip. If the last argument isn't named then either we
// have no named arguments, and we can skip, or we have non-trailing named arguments
// and we MUST skip!
if (args.carg == 0 || !(args.prgexpr[args.carg - 1] is ExprNamedArgumentSpecification))
{
return(pta);
}
CType type = pTypeThrough != null ? pTypeThrough : mpwi.GetType();
CType[] typeList = new CType[pta.Count];
MethodOrPropertySymbol methProp = GroupToArgsBinder.FindMostDerivedMethod(GetSymbolLoader(), mpwi.MethProp(), type);
// We initialize the new type array with the parameters for the method.
for (int iParam = 0; iParam < pta.Count; iParam++)
{
typeList[iParam] = pta[iParam];
}
var prgexpr = args.prgexpr;
// We then go over the specified arguments and put the type for any named argument in the right position in the array.
for (int iParam = 0; iParam < args.carg; iParam++)
{
if (prgexpr[iParam] is ExprNamedArgumentSpecification named)
{
// We find the index of the type of the argument in the method parameter list and store that in a temp
int index = FindName(methProp.ParameterNames, named.Name);
CType tempType = pta[index];
// Starting from the current position in the type list up until the location of the type of the optional argument
// We shift types by one:
// before: (int, string, long)
// after: (string, int, long)
// We only touch the types between the current position and the position of the type we need to move
for (int iShift = iParam; iShift < index; iShift++)
{
typeList[iShift + 1] = typeList[iShift];
}
typeList[iParam] = tempType;
}
}
return(GetSymbolLoader().getBSymmgr().AllocParams(pta.Count, typeList));
}
////////////////////////////////////////////////////////////////////////////////
// We need to rearange the method parameters so that the type of any specified named argument
// appears in the same place as the named argument. Consider the example below:
// Foo(int x = 4, string y = "", long l = 4)
// Foo(string y = "", string x="", long l = 5)
// and the call site:
// Foo(y:"a")
// After rearanging the parameter types we will have:
// (string, int, long) and (string, string, long)
// By rearanging the arguments as such we make sure that any specified named arguments appear in the same position for both
// methods and we also maintain the relative order of the other parameters (the type long appears after int in the above example)
private TypeArray RearrangeNamedArguments(TypeArray pta, MethPropWithInst mpwi,
CType pTypeThrough, ArgInfos args)
{
if (!args.fHasExprs)
{
return(pta);
}
#if DEBUG
// We never have a named argument that is in a position in the argument
// list past the end of what would be the formal parameter list.
for (int i = pta.size; i < args.carg; i++)
{
Debug.Assert(!args.prgexpr[i].isNamedArgumentSpecification());
}
#endif
CType type = pTypeThrough != null ? pTypeThrough : mpwi.GetType();
CType[] typeList = new CType[pta.size];
MethodOrPropertySymbol methProp = GroupToArgsBinder.FindMostDerivedMethod(GetSymbolLoader(), mpwi.MethProp(), type);
// We initialize the new type array with the parameters for the method.
for (int iParam = 0; iParam < pta.size; iParam++)
{
typeList[iParam] = pta.Item(iParam);
}
// We then go over the specified arguments and put the type for any named argument in the right position in the array.
for (int iParam = 0; iParam < args.carg; iParam++)
{
EXPR arg = args.prgexpr[iParam];
if (arg.isNamedArgumentSpecification())
{
// We find the index of the type of the argument in the method parameter list and store that in a temp
int index = FindName(methProp.ParameterNames, arg.asNamedArgumentSpecification().Name);
CType tempType = pta.Item(index);
// Starting from the current position in the type list up until the location of the type of the optional argument
// We shift types by one:
// before: (int, string, long)
// after: (string, int, long)
// We only touch the types between the current position and the position of the type we need to move
for (int iShift = iParam; iShift < index; iShift++)
{
typeList[iShift + 1] = typeList[iShift];
}
typeList[iParam] = tempType;
}
}
return(GetSymbolLoader().getBSymmgr().AllocParams(pta.size, typeList));
}
////////////////////////////////////////////////////////////////////////////////
// Given a method group or indexer group, bind it to the arguments for an
// invocation. This method can change the arguments to bind with Extension
// Methods
private bool BindMethodGroupToArgumentsCore(out GroupToArgsBinderResult pResults, BindingFlag bindFlags, EXPRMEMGRP grp, ref EXPR args, int carg, bool bindingCollectionAdd, bool bHasNamedArgumentSpecifiers)
{
ArgInfos pargInfo = new ArgInfos {carg = carg};
FillInArgInfoFromArgList(pargInfo, args);
ArgInfos pOriginalArgInfo = new ArgInfos {carg = carg};
FillInArgInfoFromArgList(pOriginalArgInfo, args);
GroupToArgsBinder binder = new GroupToArgsBinder(this, bindFlags, grp, pargInfo, pOriginalArgInfo, bHasNamedArgumentSpecifiers, null/*atsDelegate*/);
bool retval = bindingCollectionAdd ? binder.BindCollectionAddArgs() : binder.Bind(true /*ReportErrors*/);
pResults = binder.GetResultsOfBind();
return retval;
}
////////////////////////////////////////////////////////////////////////////////
// Determine which method is better for the purposes of overload resolution.
// Better means: as least as good in all params, and better in at least one param.
// Better w/r to a param means is an ordering, from best down:
// 1) same type as argument
// 2) implicit conversion from argument to formal type
// Because of user defined conversion opers this relation is not transitive.
//
// If there is a tie because of identical signatures, the tie may be broken by the
// following rules:
// 1) If one is generic and the other isn't, the non-generic wins.
// 2) Otherwise if one is expanded (params) and the other isn't, the non-expanded wins.
// 3) Otherwise if one has more specific parameter types (at the declaration) it wins:
// This occurs if at least on parameter type is more specific and no parameter type is
// less specific.
//* A type parameter is less specific than a non-type parameter.
//* A constructed type is more specific than another constructed type if at least
// one type argument is more specific and no type argument is less specific than
// the corresponding type args in the other.
// 4) Otherwise if one has more modopts than the other does, the smaller number of modopts wins.
//
// Returns Left if m1 is better, Right if m2 is better, or Neither/Same
private BetterType WhichMethodIsBetter(
CandidateFunctionMember node1,
CandidateFunctionMember node2,
CType pTypeThrough,
ArgInfos args)
{
MethPropWithInst mpwi1 = node1.mpwi;
MethPropWithInst mpwi2 = node2.mpwi;
// Substitutions should have already been done on these!
TypeArray pta1 = RearrangeNamedArguments(node1.@params, mpwi1, pTypeThrough, args);
TypeArray pta2 = RearrangeNamedArguments(node2.@params, mpwi2, pTypeThrough, args);
// If the parameter types for both candidate methods are identical,
// use the tie breaking rules.
if (pta1 == pta2)
{
return(WhichMethodIsBetterTieBreaker(node1, node2, pTypeThrough, args));
}
// Otherwise, do a parameter-by-parameter comparison:
//
// Given an argument list A with a set of argument expressions {E1, ... En} and
// two applicable function members Mp and Mq with parameter types {P1,... Pn} and
// {Q1, ... Qn}, Mp is defined to be a better function member than Mq if:
//* for each argument the implicit conversion from Ex to Qx is not better than
// the implicit conversion from Ex to Px.
//* for at least one argument, the conversion from Ex to Px is better than the
// conversion from Ex to Qx.
BetterType betterMethod = BetterType.Neither;
CType type1 = pTypeThrough != null ? pTypeThrough : mpwi1.GetType();
CType type2 = pTypeThrough != null ? pTypeThrough : mpwi2.GetType();
MethodOrPropertySymbol methProp1 = GroupToArgsBinder.FindMostDerivedMethod(GetSymbolLoader(), mpwi1.MethProp(), type1);
MethodOrPropertySymbol methProp2 = GroupToArgsBinder.FindMostDerivedMethod(GetSymbolLoader(), mpwi2.MethProp(), type2);
List <Name> names1 = methProp1.ParameterNames;
List <Name> names2 = methProp2.ParameterNames;
for (int i = 0; i < args.carg; i++)
{
EXPR arg = args.fHasExprs ? args.prgexpr[i] : null;
CType argType = args.types[i];
CType p1 = pta1[i];
CType p2 = pta2[i];
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
// RUNTIME BINDER ONLY CHANGE
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
//
// We need to consider conversions from the actual runtime type
// since we could have private interfaces that we are converting
if (arg.RuntimeObjectActualType != null)
{
argType = arg.RuntimeObjectActualType;
}
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
// END RUNTIME BINDER ONLY CHANGE
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
BetterType betterConversion = WhichConversionIsBetter(arg, argType, p1, p2);
if (betterMethod == BetterType.Right && betterConversion == BetterType.Left)
{
betterMethod = BetterType.Neither;
break;
}
else if (betterMethod == BetterType.Left && betterConversion == BetterType.Right)
{
betterMethod = BetterType.Neither;
break;
}
else if (betterMethod == BetterType.Neither)
{
if (betterConversion == BetterType.Right || betterConversion == BetterType.Left)
{
betterMethod = betterConversion;
}
}
}
// We may have different sizes if we had optional parameters. If thats the case,
// the one with fewer parameters wins (ie less optional parameters) unless it is
// expanded. If so, the one with more parameters wins (ie option beats expanded).
if (pta1.Count != pta2.Count && betterMethod == BetterType.Neither)
{
if (node1.fExpanded && !node2.fExpanded)
{
return(BetterType.Right);
}
else if (node2.fExpanded && !node1.fExpanded)
{
return(BetterType.Left);
}
// Here, if both methods needed to use optionals to fill in the signatures,
// then we are ambiguous. Otherwise, take the one that didn't need any
// optionals.
if (pta1.Count == args.carg)
{
return(BetterType.Left);
}
else if (pta2.Count == args.carg)
{
return(BetterType.Right);
}
return(BetterType.Neither);
}
return(betterMethod);
}
