private static ArgumentAnalysisResult AnalyzeArgumentsForNormalFormNoNamedArguments(
ImmutableArray <ParameterSymbol> parameters,
AnalyzedArguments arguments,
bool isMethodGroupConversion,
bool isVararg
)
{
Debug.Assert(!parameters.IsDefault);
Debug.Assert(arguments != null);
Debug.Assert(arguments.Names.Count == 0);
// We simulate an additional non-optional parameter for a vararg method.
int parameterCount = parameters.Length + (isVararg ? 1 : 0);
int argumentCount = arguments.Arguments.Count;
// If there are no named arguments then analyzing the argument and parameter
// matching in normal form is simple: each argument corresponds exactly to
// the matching parameter, and if there are not enough arguments then the
// unmatched parameters had better all be optional. If there are too
// few parameters then one of the arguments has no matching parameter.
// Otherwise, everything is just right.
if (argumentCount < parameterCount)
{
for (
int parameterPosition = argumentCount;
parameterPosition < parameterCount;
++parameterPosition
)
{
if (
parameters.Length == parameterPosition ||
!CanBeOptional(parameters[parameterPosition], isMethodGroupConversion)
)
{
return(ArgumentAnalysisResult.RequiredParameterMissing(parameterPosition));
}
}
}
else if (parameterCount < argumentCount)
{
return(ArgumentAnalysisResult.NoCorrespondingParameter(parameterCount));
}
// A null map means that every argument in the argument list corresponds exactly to
// the same position in the formal parameter list.
return(ArgumentAnalysisResult.NormalForm(default(ImmutableArray <int>)));
}
private static ArgumentAnalysisResult AnalyzeArguments(
Symbol symbol,
AnalyzedArguments arguments,
bool isMethodGroupConversion,
bool expanded)
{
Debug.Assert((object)symbol != null);
Debug.Assert(arguments != null);
ImmutableArray <ParameterSymbol> parameters = symbol.GetParameters();
bool isVararg = symbol.GetIsVararg();
// The easy out is that we have no named arguments and are in normal form.
if (!expanded && arguments.Names.Count == 0)
{
return(AnalyzeArgumentsForNormalFormNoNamedArguments(parameters, arguments, isMethodGroupConversion, isVararg));
}
// We simulate an additional non-optional parameter for a vararg method.
int argumentCount = arguments.Arguments.Count;
int[] parametersPositions = null;
int? unmatchedArgumentIndex = null;
bool? unmatchedArgumentIsNamed = null;
// Try to map every argument position to a formal parameter position:
bool seenNamedParams = false;
bool seenOutOfPositionNamedArgument = false;
bool isValidParams = IsValidParams(symbol);
for (int argumentPosition = 0; argumentPosition < argumentCount; ++argumentPosition)
{
// We use -1 as a sentinel to mean that no parameter was found that corresponded to this argument.
bool isNamedArgument;
int parameterPosition = CorrespondsToAnyParameter(parameters, expanded, arguments, argumentPosition,
isValidParams, isVararg, out isNamedArgument, ref seenNamedParams, ref seenOutOfPositionNamedArgument) ?? -1;
if (parameterPosition == -1 && unmatchedArgumentIndex == null)
{
unmatchedArgumentIndex = argumentPosition;
unmatchedArgumentIsNamed = isNamedArgument;
}
if (parameterPosition != argumentPosition && parametersPositions == null)
{
parametersPositions = new int[argumentCount];
for (int i = 0; i < argumentPosition; ++i)
{
parametersPositions[i] = i;
}
}
if (parametersPositions != null)
{
parametersPositions[argumentPosition] = parameterPosition;
}
}
ParameterMap argsToParameters = new ParameterMap(parametersPositions, argumentCount);
// We have analyzed every argument and tried to make it correspond to a particular parameter.
// We must now answer the following questions:
//
// (1) Is there any named argument used out-of-position and followed by unnamed arguments?
// (2) Is there any argument without a corresponding parameter?
// (3) Was there any named argument that specified a parameter that was already
// supplied with a positional parameter?
// (4) Is there any non-optional parameter without a corresponding argument?
// (5) Is there any named argument that were specified twice?
//
// If the answer to any of these questions is "yes" then the method is not applicable.
// It is possible that the answer to any number of these questions is "yes", and so
// we must decide which error condition to prioritize when reporting the error,
// should we need to report why a given method is not applicable. We prioritize
// them in the given order.
// (1) Is there any named argument used out-of-position and followed by unnamed arguments?
int?badNonTrailingNamedArgument = CheckForBadNonTrailingNamedArgument(arguments, argsToParameters, parameters);
if (badNonTrailingNamedArgument != null)
{
return(ArgumentAnalysisResult.BadNonTrailingNamedArgument(badNonTrailingNamedArgument.Value));
}
// (2) Is there any argument without a corresponding parameter?
if (unmatchedArgumentIndex != null)
{
if (unmatchedArgumentIsNamed.Value)
{
return(ArgumentAnalysisResult.NoCorrespondingNamedParameter(unmatchedArgumentIndex.Value));
}
else
{
return(ArgumentAnalysisResult.NoCorrespondingParameter(unmatchedArgumentIndex.Value));
}
}
// (3) was there any named argument that specified a parameter that was already
// supplied with a positional parameter?
int?nameUsedForPositional = NameUsedForPositional(arguments, argsToParameters);
if (nameUsedForPositional != null)
{
return(ArgumentAnalysisResult.NameUsedForPositional(nameUsedForPositional.Value));
}
// (4) Is there any non-optional parameter without a corresponding argument?
int?requiredParameterMissing = CheckForMissingRequiredParameter(argsToParameters, parameters, isMethodGroupConversion, expanded);
if (requiredParameterMissing != null)
{
return(ArgumentAnalysisResult.RequiredParameterMissing(requiredParameterMissing.Value));
}
// __arglist cannot be used with named arguments (as it doesn't have a name)
if (arguments.Names.Any() && arguments.Names.Last() != null && isVararg)
{
return(ArgumentAnalysisResult.RequiredParameterMissing(parameters.Length));
}
// (5) Is there any named argument that were specified twice?
int?duplicateNamedArgument = CheckForDuplicateNamedArgument(arguments);
if (duplicateNamedArgument != null)
{
return(ArgumentAnalysisResult.DuplicateNamedArgument(duplicateNamedArgument.Value));
}
// We're good; this one might be applicable in the given form.
return(expanded ?
ArgumentAnalysisResult.ExpandedForm(argsToParameters.ToImmutableArray()) :
ArgumentAnalysisResult.NormalForm(argsToParameters.ToImmutableArray()));
}