如何从调用方法的 InvocationExpressionSyntax 节点获取 IMethodSymbol 或方法声明的语法节点？

Question

在我的分析器的实现中，我使用AnalyzeSymbol 方法：

public override void Initialize(AnalysisContext context)
{
  context.RegisterSymbolAction(AnalyzeSymbol, SymbolKind.Method);
}

private static void AnalyzeSymbol(SymbolAnalysisContext context)
{
  // here I look through the syntax of the method body in order to find invocations.
  var methodSymbol = context.Symbol as IMethodSymbol;
  var location = methodSymbol.Locations.FirstOrDefault();
  var methodNode = location.SourceTree.GetCompilationUnitRoot().FindNode(locati‌​on.SourceSpan);
  var blockNode = methodNode.ChildNodes().FirstOrDefault(s => s is BlockSyntax);
  var invocations = blockNode.DescendantNodes()
    .Select(s => s as InvocationExpressionSyntax)
    .Where(s => s != null)

  foreach(InvocationExpressionSyntax i in invocations i)
  {
    // look at the signature of the method which is invoked
    // in order to figure out if the arguments are attributed
  }
}

对于我找到的每个InvocationExpressionSyntax 节点，我需要检查在调用调用的声明方法的签名中声明参数的属性（即我的[ReadOnly] 属性，参见here）。据我了解，我需要以某种方式从InvocationExpressionSyntax 对象到相应的IMethodSymbol，但我不知道如何。不像FieldDeclarationSyntax，它有一个属性Declarations，通过它我得到一个IFieldSymbol，就像发布的here一样，InvocationExpressionSyntax没有，我尝试的以下代码为该符号产生null：

var model = context.Compilation.GetSemanticModel(ies.SyntaxTree);
var symbol = model.GetDeclaredSymbol(ies.Expression);

我做错了什么？

我的分析器应该分析的示例代码是：

void Foo()
{
  int i = 42;

  // coming from this InvocationExpressionSyntax node I want to find out that i is an parameter for an argument which has an [ReadOnly] attribute
  Bar(i);

  // coming from this InvocationExpressionSyntax node I want to find out that i is an parameter for an argument which has NOT an [ReadOnly] attribute
  Baz(i);
}

void Bar([ReadOnly] int i)
{
}

void Baz(int i)
{
}

Answer 1

您可以使用SymbolFinder 获取InvocationExpressionSyntax 的声明符号

Workspace workspace;
Workspace.TryGetWorkspace(location.SourceTree.GetText().Container, out workspace);
if (workspace != null)
{
    var invocMethodSymbol = model.GetSymbolInfo(ies.Expression).Symbol;
    // Await this task if you can
    var declarationMethodSymbol = SymbolFinder.FindSourceDefinitionAsync(invocMethodSymbol, workspace.CurrentSolution).Result;
}