private async Task <Document> MakeParameterAsync(Document document, VariableDeclaratorSyntax typeDecl, CancellationToken cancellationToken)
{
var root = await document.GetSyntaxRootAsync(cancellationToken);
string varKeyword = string.Empty, varName = string.Empty;
//Predefined variable type (string, int, etc...)
var preDefType = typeDecl.Parent.ChildNodes().OfType <PredefinedTypeSyntax>().FirstOrDefault();
if (preDefType != null)
{
varKeyword = preDefType.Keyword.ToString();
var varDecl = typeDecl.Parent.ChildNodes().OfType <VariableDeclaratorSyntax>().FirstOrDefault();
varName = varDecl?.Identifier.ToString();
}
else //var
{
var identName = typeDecl.Parent.ChildNodes().OfType <IdentifierNameSyntax>().FirstOrDefault();
//Access the semantic model to determine actual type
var model = document.GetSemanticModelAsync().Result;
var type = model.GetTypeInfo(identName).Type;
varKeyword = type.ToMinimalDisplayString(model, typeDecl.SpanStart);
var varDecl = typeDecl.Parent.ChildNodes().OfType <VariableDeclaratorSyntax>().FirstOrDefault();
varName = varDecl?.Identifier.ToString();
}
MethodDeclarationSyntax mds = typeDecl.Ancestors().OfType <MethodDeclarationSyntax>().FirstOrDefault();
//Add the existing and new parameters
ParameterSyntax ps = SyntaxFactory.Parameter(SyntaxFactory.Identifier(string.Concat(varKeyword, " ", varName)));
var newList = SyntaxFactory.ParameterList(SyntaxFactory.SeparatedList <ParameterSyntax>().AddRange(
mds.ParameterList.ChildNodes().OfType <ParameterSyntax>()).Add(ps));
var methodNode = typeDecl.Ancestors().OfType <MethodDeclarationSyntax>().FirstOrDefault();
var variableNode = typeDecl.Parent.Parent;
var variableParentNode = typeDecl.Parent.Parent.Parent;
//Track the nodes we'll be using
var newRoot = root.TrackNodes(methodNode, variableNode, variableParentNode);
//Remode/replace the variable declaration
var trackedVariableParentNode = newRoot.GetCurrentNode(variableParentNode);
var trackedVariableNode = newRoot.GetCurrentNode(variableNode);
var newVariableParentNode = trackedVariableParentNode.RemoveNode(trackedVariableNode, SyntaxRemoveOptions.KeepNoTrivia);
newRoot = newRoot.ReplaceNode(trackedVariableParentNode, newVariableParentNode);
//Replace the method parameters
var trackedMethodNode = newRoot.GetCurrentNode(methodNode);
var newMethodNode = trackedMethodNode.ReplaceNode(trackedMethodNode.ParameterList, newList);
newRoot = newRoot.ReplaceNode(trackedMethodNode, newMethodNode);
return(document.WithSyntaxRoot(newRoot));
}
public override void VisitVariableDeclarator(VariableDeclaratorSyntax node)
{
if (node.Ancestors().Any(x => x is FunctionDefinitionSyntax))
CreateTag(node.Identifier, _classificationService.LocalVariableIdentifier);
else if (node.Ancestors().Any(x => x is TypeDefinitionSyntax))
CreateTag(node.Identifier, _classificationService.FieldIdentifier);
else
CreateTag(node.Identifier, _classificationService.GlobalVariableIdentifier);
base.VisitVariableDeclarator(node);
}
private async Task<Document> MakeParameterAsync(Document document, VariableDeclaratorSyntax typeDecl, CancellationToken cancellationToken)
{
var root = await document.GetSyntaxRootAsync(cancellationToken);
string varKeyword = string.Empty, varName = string.Empty;
//Predefined variable type (string, int, etc...)
var preDefType = typeDecl.Parent.ChildNodes().OfType<PredefinedTypeSyntax>().FirstOrDefault();
if (preDefType != null)
{
varKeyword = preDefType.Keyword.ToString();
var varDecl = typeDecl.Parent.ChildNodes().OfType<VariableDeclaratorSyntax>().FirstOrDefault();
varName = varDecl?.Identifier.ToString();
}
else //var
{
var identName = typeDecl.Parent.ChildNodes().OfType<IdentifierNameSyntax>().FirstOrDefault();
//Access the semantic model to determine actual type
var model = document.GetSemanticModelAsync().Result;
var type = model.GetTypeInfo(identName).Type;
varKeyword = type.ToMinimalDisplayString(model, typeDecl.SpanStart);
var varDecl = typeDecl.Parent.ChildNodes().OfType<VariableDeclaratorSyntax>().FirstOrDefault();
varName = varDecl?.Identifier.ToString();
}
MethodDeclarationSyntax mds = typeDecl.Ancestors().OfType<MethodDeclarationSyntax>().FirstOrDefault();
//Add the existing and new parameters
ParameterSyntax ps = SyntaxFactory.Parameter(SyntaxFactory.Identifier(string.Concat(varKeyword, " ", varName)));
var newList = SyntaxFactory.ParameterList(SyntaxFactory.SeparatedList<ParameterSyntax>().AddRange(
mds.ParameterList.ChildNodes().OfType<ParameterSyntax>()).Add(ps));
var methodNode = typeDecl.Ancestors().OfType<MethodDeclarationSyntax>().FirstOrDefault();
var variableNode = typeDecl.Parent.Parent;
var variableParentNode = typeDecl.Parent.Parent.Parent;
//Track the nodes we'll be using
var newRoot = root.TrackNodes(methodNode, variableNode, variableParentNode);
//Remode/replace the variable declaration
var trackedVariableParentNode = newRoot.GetCurrentNode(variableParentNode);
var trackedVariableNode = newRoot.GetCurrentNode(variableNode);
var newVariableParentNode = trackedVariableParentNode.RemoveNode(trackedVariableNode, SyntaxRemoveOptions.KeepNoTrivia);
newRoot = newRoot.ReplaceNode(trackedVariableParentNode, newVariableParentNode);
//Replace the method parameters
var trackedMethodNode = newRoot.GetCurrentNode(methodNode);
var newMethodNode = trackedMethodNode.ReplaceNode(trackedMethodNode.ParameterList, newList);
newRoot = newRoot.ReplaceNode(trackedMethodNode, newMethodNode);
return document.WithSyntaxRoot(newRoot);
}
private static bool HasMutableUsagesInMethod(VariableDeclaratorSyntax parameter, ISymbol parameterSymbol,
SemanticModel semanticModel)
{
var methodSyntax = parameter?.Ancestors()?.FirstOrDefault(IsMethodLike);
if (methodSyntax == null)
{
return(false);
}
return(methodSyntax
.DescendantNodes()
.OfType <IdentifierNameSyntax>()
.Where(MatchesIdentifier)
.Any(IsMutatingUse));
bool IsMethodLike(SyntaxNode arg) =>
arg is BaseMethodDeclarationSyntax ||
arg is IndexerDeclarationSyntax ||
arg is AccessorDeclarationSyntax;
bool MatchesIdentifier(IdentifierNameSyntax id)
{
var symbol = semanticModel.GetSymbolInfo(id).Symbol;
return(Equals(parameterSymbol, symbol));
}
}
public override void VisitVariableDeclarator(VariableDeclaratorSyntax node)
{
if (node.Ancestors().Any(x => x is FunctionDefinitionSyntax))
{
CreateTag(node.Identifier, _classificationService.LocalVariableIdentifier);
}
else if (node.Ancestors().Any(x => x is TypeDefinitionSyntax))
{
CreateTag(node.Identifier, _classificationService.FieldIdentifier);
}
else
{
CreateTag(node.Identifier, _classificationService.GlobalVariableIdentifier);
}
base.VisitVariableDeclarator(node);
}
private static Diag GetDiagnostic(VariableDeclaratorSyntax syntax, ContractCategory contractCategory)
{
var fieldDeclarationSyntax = syntax?.Ancestors().OfType <FieldDeclarationSyntax>().FirstOrDefault();
if (fieldDeclarationSyntax?.AttributeLists.ContainsNotNullAttribute() != false)
{
return(null);
}
return(new Diag(fieldDeclarationSyntax.GetLocation(), syntax.ToString(), contractCategory));
}
private static bool HasMutableUsagesInMethod(VariableDeclaratorSyntax variable, ISymbol variableSymbol, SemanticModel semanticModel)
{
var methodSyntax = variable?.Ancestors()?.FirstOrDefault(IsMethodLike);
if (methodSyntax == null)
{
return(false);
}
return(methodSyntax
.DescendantNodes()
.OfType <IdentifierNameSyntax>()
.Where(MatchesIdentifier)
.Any(IsMutatingUse));
private static CompilationUnitSyntax AddInvariant(CompilationUnitSyntax root, SemanticModel semanticModel, [NotNull] VariableDeclaratorSyntax variableSyntax)
{
var classDeclaration = variableSyntax.Ancestors().OfType <ClassDeclarationSyntax>().FirstOrDefault();
var invariantMethod = classDeclaration?.ChildNodes()
.OfType <MethodDeclarationSyntax>()
.FirstOrDefault(m => m.AttributeLists.ContainsAttribute("ContractInvariantMethod"));
if (invariantMethod == null)
{
return(root);
}
var statements = new [] { SyntaxFactory.ParseStatement($" Contract.Invariant({variableSyntax.Identifier.Text} != null);\r\n") };
return(root.ReplaceNode(invariantMethod, invariantMethod.AddBodyStatements(statements)));
}
public override SyntaxNode VisitVariableDeclarator(VariableDeclaratorSyntax node)
{
var id = node.Identifier.ValueText;
if (node.Ancestors().Any(anc => anc is FieldDeclarationSyntax))
{
return(base.VisitVariableDeclarator(node));
}
if (!identities.ContainsKey(id))
{
identities[id] = 1;
return(base.VisitVariableDeclarator(node));
}
++identities[id];
return(base.VisitVariableDeclarator(node.WithIdentifier(Identifier(id))));
}
private static IEnumerable <ConstructorDeclarationSyntax> GetConstructors(VariableDeclaratorSyntax fieldVariable)
{
var classDeclaration = fieldVariable.Ancestors().OfType <ClassDeclarationSyntax>().SingleOrDefault();
if (classDeclaration == null)
{
return(new List <ConstructorDeclarationSyntax>());
}
var constructors = classDeclaration.DescendantNodes().OfType <ConstructorDeclarationSyntax>();
var relevantConstructors = constructors.Where(x =>
x.Body
.DescendantNodes()
.OfType <IdentifierNameSyntax>()
.All(identifier => identifier.Identifier.Text != fieldVariable.Identifier.Text));
return(relevantConstructors);
}
private void Analyze(SyntaxNodeAnalysisContext context)
{
if (!IsCaseWeUnderstand(context.Node))
{
return;
}
// Collect some items we'll use repeatedly
if (context.Node.Parent != null)
{
VariableDeclaratorSyntax variableDeclaratorSyntax = context.Node.Parent.Parent as VariableDeclaratorSyntax;
if (variableDeclaratorSyntax != null)
{
BlockSyntax blockOfInterest = variableDeclaratorSyntax.Ancestors().OfType <BlockSyntax>().First();
var model = context.SemanticModel;
ISymbol ourSymbol = model.GetDeclaredSymbol(variableDeclaratorSyntax);
// Identify where y is first used (ie., MemberAccessExpression)
IdentifierNameSyntax identifierNameSyntax = GetFirstMemberAccess(ourSymbol, model, blockOfInterest);
if (identifierNameSyntax == null)
{
return;
}
if (!SameBlock(blockOfInterest, identifierNameSyntax))
{
return;
}
// Evaluate the code between (ie after) "y = x as yType" and "y.Foo" (ie before) to see if y is read (ie checked for null) or written to (ie rendering our check moot)
(StatementSyntax firstStatementOfAnalysis, int firstStatementOfAnalysisIndex) = GetStatement(blockOfInterest, variableDeclaratorSyntax, offset: 1);
(StatementSyntax lastStatementOfAnalysis, int lastStatementOfAnalysisIndex) = GetStatement(blockOfInterest, identifierNameSyntax, offset: -1);
if (lastStatementOfAnalysisIndex < firstStatementOfAnalysisIndex)
{
// There's nothing to analyze; they immediately used the symbol after the 'as'
// Before reporting an error, note common possibility that the situation could be:
// string y = obj as string;
// if (y != null && y.ToString() == @"")
// Ie there's nothing to analyze between the statements, but within the statement exists a check
if (firstStatementOfAnalysis is IfStatementSyntax ifStatementSyntax)
{
if (ifStatementSyntax.Condition.ToString().Contains(@"null"))
{
// There's an "if" statement with a likely null check of some kind in some order. Don't be too picky, just let it go to minimize risk of a false positive
return;
}
}
if (firstStatementOfAnalysis is WhileStatementSyntax whileStatementSyntax)
{
if (whileStatementSyntax.Condition.ToString().Contains(@"null"))
{
// There's an "if" statement with a likely null check of some kind in some order. Don't be too picky, just let it go to minimize risk of a false positive
return;
}
}
Report(context, identifierNameSyntax);
return;
}
bool ourSymbolIsReadOrWritten = false;
DataFlowAnalysis result = model.AnalyzeDataFlow(firstStatementOfAnalysis, lastStatementOfAnalysis);
if (result != null)
{
foreach (ISymbol assignedValue in result.ReadInside)
{
if (SymbolEqualityComparer.Default.Equals(assignedValue, ourSymbol))
{
// We shouldn't just be checking that we read our symbol; we should really see if it's checked for null
ourSymbolIsReadOrWritten = true;
break;
}
}
foreach (ISymbol assignedValue in result.WrittenInside)
{
if (SymbolEqualityComparer.Default.Equals(assignedValue, ourSymbol))
{
ourSymbolIsReadOrWritten = true;
break;
}
}
}
if (!ourSymbolIsReadOrWritten)
{
Report(context, identifierNameSyntax);
return;
}
}
}
}