public static ImmutableArray <Diagnostic> GetDiagnostics(
SyntaxNode node,
SemanticModel model,
CancellationToken token)
{
var nullableParametersVisitor = new NullableParametersVisitor(model, token);
nullableParametersVisitor.Visit(node);
var nullableParameters = nullableParametersVisitor.NullableParameters;
var existingNullChecksVisitor = new ExistingNullChecksVisitor(model, token);
existingNullChecksVisitor.Visit(node);
var existingNullChecks = existingNullChecksVisitor.ExistingNullChecks;
var builder = ImmutableArray.CreateBuilder <Diagnostic>();
foreach (var nullableParameter in nullableParameters)
{
if (!existingNullChecks.Any(nullCheck => nullCheck.ParameterIndex == nullableParameter.Index))
{
var diagnostic = Diagnostic.Create(
Descriptor,
nullableParameter.Syntax.Identifier.GetLocation(),
properties: ImmutableDictionary <string, string?> .Empty.Add(
nameof(NullableParameter.Index),
nullableParameter.Index.ToString()));
builder.Add(diagnostic);
}
}
return(builder.ToImmutable());
}
private Document FixDiagnostics(
Document document,
ImmutableArray <Diagnostic> diagnostics,
SyntaxNode root,
SemanticModel model,
SyntaxNode node,
CancellationToken token)
{
var parameterIndexes = new List <int>();
foreach (var diagnostic in diagnostics)
{
if (diagnostic.Properties.TryGetValue(nameof(NullableParameter.Index), out string?index) &&
int.TryParse(index, out int parameterIndex))
{
parameterIndexes.Add(parameterIndex);
}
}
var nullableParametersVisitor = new NullableParametersVisitor(model, token);
nullableParametersVisitor.Visit(node);
var nullableParameters = nullableParametersVisitor.NullableParameters
.Where(x => parameterIndexes.Contains(x.Index))
.ToImmutableArray();
var addNullChecksRewriter = GetRewriter(document, model, nullableParameters, token);
var newNode = addNullChecksRewriter.Visit(node);
var newDocument = document.WithSyntaxRoot(root.ReplaceNode(node, newNode));
return(newDocument);
}
public override async Task RegisterCodeFixesAsync(CodeFixContext context)
{
var document = context.Document;
var token = context.CancellationToken;
var root = await document.GetSyntaxRootAsync(token);
if (root is null)
{
return;
}
var model = await document.GetSemanticModelAsync(token);
if (model is null)
{
return;
}
foreach (var diagnostic in context.Diagnostics)
{
if (diagnostic.Id != NullCheckAnalyzer.Id)
{
continue;
}
var node = root.FindNode(diagnostic.Location.SourceSpan)
.Ancestors()
.Where(node => node is BaseMethodDeclarationSyntax or LocalFunctionStatementSyntax)
.FirstOrDefault();
if (node is null)
{
continue;
}
if (!diagnostic.Properties.TryGetValue(nameof(NullableParameter.Index), out string?index) ||
!int.TryParse(index, out int parameterIndex))
{
continue;
}
var nullableParametersVisitor = new NullableParametersVisitor(model, token);
nullableParametersVisitor.Visit(node);
var nullableParameters = nullableParametersVisitor.NullableParameters;
var nullableParameter = nullableParameters.SingleOrDefault(x => x.Index == parameterIndex);
if (nullableParameter is null)
{
continue;
}
if (!ShouldRegisterCodeFix(nullableParameter))
{
continue;
}
// Add null check.
{
var codeAction = CodeAction.Create(
AddNullCheckTitle,
token =>
{
var newDocument = FixDiagnostic(document, nullableParameter, root, model, node, token);
return(Task.FromResult(newDocument));
},
equivalenceKey: AddNullCheckTitle);
context.RegisterCodeFix(codeAction, diagnostic);
}
// Add null checks.
var methodNullCheckDiagnostics = NullCheckAnalyzer.GetDiagnostics(node, model, token);
if (methodNullCheckDiagnostics.Length > 1)
{
var codeAction = CodeAction.Create(
AddNullChecksTitle,
token =>
{
var newDocument = FixDiagnostics(
document,
methodNullCheckDiagnostics,
root,
model,
node,
token);
return(Task.FromResult(newDocument));
},
equivalenceKey: AddNullChecksTitle);
context.RegisterCodeFix(codeAction, diagnostic);
}
}
}
