public static IMethodSymbol GetMethodSymbol([NotNull] this ArgumentSyntax argument, [NotNull] SemanticModel semanticModel)
{
Requires.NotNull(argument, nameof(argument));
Requires.NotNull(semanticModel, nameof(semanticModel));
var methodCallExpression = argument.GetInvocationExpression();
return(methodCallExpression.GetReferencedSymbol <IMethodSymbol>(semanticModel));
}
public static IParameterSymbol GetParameterSymbol([NotNull] this ArgumentSyntax argument, [NotNull] SemanticModel semanticModel)
{
Requires.NotNull(argument, nameof(argument));
Requires.NotNull(semanticModel, nameof(semanticModel));
var invocation = argument.GetInvocationExpression();
Requires.That(!(invocation as InvocationExpressionSyntax)?.IsNameOfOperator(semanticModel) ?? true,
"Cannot get parameter symbol for nameof operator.");
var methodSymbol = invocation.GetReferencedSymbol(semanticModel) as IMethodSymbol;
var propertySymbol = invocation.GetReferencedSymbol(semanticModel) as IPropertySymbol;
var parameterSymbols = methodSymbol?.Parameters ?? propertySymbol.Parameters;
// If this is a named argument, simply look up the parameter symbol by name.
if (argument.NameColon != null)
{
return(parameterSymbols.Single(parameter => parameter.Name == argument.NameColon.Name.Identifier.ValueText));
}
// Otherwise, get the corresponding invocation or object creation expression and match the argument.
var arguments = default(SeparatedSyntaxList <ArgumentSyntax>);
var invocationExpression = invocation as InvocationExpressionSyntax;
var objectCreationExpression = invocation as ObjectCreationExpressionSyntax;
var constructorInitializer = invocation as ConstructorInitializerSyntax;
var elementAccessExpression = invocation as ElementAccessExpressionSyntax;
var implicitElementAccessExpression = invocation as ImplicitElementAccessSyntax;
if (invocationExpression != null)
{
arguments = invocationExpression.ArgumentList.Arguments;
}
else if (objectCreationExpression != null)
{
arguments = objectCreationExpression.ArgumentList.Arguments;
}
else if (constructorInitializer != null)
{
arguments = constructorInitializer.ArgumentList.Arguments;
}
else if (elementAccessExpression != null)
{
arguments = elementAccessExpression.ArgumentList.Arguments;
}
else if (implicitElementAccessExpression != null)
{
arguments = implicitElementAccessExpression.ArgumentList.Arguments;
}
else
{
Assert.NotReached("Expected an invocation expression or an object creation expression.");
}
for (var i = 0; i < arguments.Count; ++i)
{
// If this is a method with a params parameter at the end, we might have more arguments than parameters. In that case,
// return the parameter symbol for the params parameter if the argument exceeds the parameter count.
if (i >= parameterSymbols.Length)
{
var lastParameter = parameterSymbols[methodSymbol.Parameters.Length - 1];
if (lastParameter.IsParams)
{
return(lastParameter);
}
Assert.NotReached("There are more arguments than parameters.");
}
if (arguments[i] == argument)
{
return(parameterSymbols[i]);
}
}
Assert.NotReached($"Unable to determine parameter symbol for argument '{argument}'.");
return(null);
}
