private static void ApplyObserveEventMethodFix(
DocumentEditor editor,
AssignmentExpressionSyntax assignment,
MethodDeclarationSyntax methodDeclaration,
CancellationToken cancellationToken)
{
var usesArg = false;
if (methodDeclaration.ParameterList.Parameters.Any())
{
using (var pooled = IdentifierNameWalker.Borrow((SyntaxNode)methodDeclaration.Body ?? methodDeclaration.ExpressionBody))
{
foreach (var name in pooled.IdentifierNames)
{
if (name.Identifier.ValueText == methodDeclaration.ParameterList.Parameters[0].Identifier.ValueText)
{
if (methodDeclaration.ParameterList.Parameters.Count == 1)
{
usesArg = true;
continue;
}
return;
}
if (methodDeclaration.ParameterList.Parameters.Count == 2 &&
name.Identifier.ValueText == methodDeclaration.ParameterList.Parameters[1]
.Identifier.ValueText)
{
usesArg = true;
}
}
}
}
var eventSymbol = (IEventSymbol)editor.SemanticModel.GetSymbolSafe(assignment.Left, cancellationToken);
var observeSubscribe = GetObservableFromEventString(eventSymbol)
.Replace("HANDLERTYPE", eventSymbol.Type.ToMinimalDisplayString(editor.SemanticModel, assignment.SpanStart))
.Replace("ARGTYPE", ArgType(eventSymbol))
.Replace("LEFT", assignment.Left.ToString())
.Replace("LAMBDA", Lambda(methodDeclaration, usesArg));
editor.AddUsing(SystemReactiveLinq)
.ReplaceNode(
assignment,
SyntaxFactory.ParseExpression(observeSubscribe)
.WithTriviaFrom(assignment)
.WithSimplifiedNames()
.WithAdditionalAnnotations(Formatter.Annotation, Simplifier.Annotation));
if (methodDeclaration.ParameterList.Parameters.Count == 2)
{
editor.RemoveNode(methodDeclaration.ParameterList.Parameters[0]);
}
if (!usesArg &&
methodDeclaration.ParameterList.Parameters.Any())
{
editor.RemoveNode(methodDeclaration.ParameterList.Parameters.Last());
}
}
/// <inheritdoc/>
protected override async Task RegisterCodeFixesAsync(DocumentEditorCodeFixContext context)
{
var syntaxRoot = await context.Document.GetSyntaxRootAsync(context.CancellationToken)
.ConfigureAwait(false);
foreach (var diagnostic in context.Diagnostics)
{
if (syntaxRoot.TryFindNode(diagnostic, out AssignmentExpressionSyntax assignment))
{
if (assignment.Right is ParenthesizedLambdaExpressionSyntax lambda &&
lambda.Body != null)
{
using (var pooled = IdentifierNameWalker.Borrow(lambda.Body))
{
var usesArg = false;
foreach (var name in pooled.IdentifierNames)
{
if (name.Identifier.ValueText == lambda.ParameterList.Parameters[0]
.Identifier.ValueText)
{
return;
}
if (name.Identifier.ValueText == lambda.ParameterList.Parameters[1]
.Identifier.ValueText)
{
usesArg = true;
}
}
context.RegisterCodeFix(
"Observe.Event",
(editor, cancellationToken) => ApplyObserveEventLambdaFix(editor, assignment, usesArg, cancellationToken),
nameof(EventSubscriptionToObserveFix),
diagnostic);
}
}
if (assignment.Right is MemberAccessExpressionSyntax memberAccess)
{
var semanticModel = await context.Document.GetSemanticModelAsync(context.CancellationToken).ConfigureAwait(false);
if (semanticModel.GetSymbolSafe(memberAccess, context.CancellationToken) is IMethodSymbol method &&
method.DeclaredAccessibility == Accessibility.Private &&
method.DeclaringSyntaxReferences.Length == 1)
{
var methodDeclaration = (MethodDeclarationSyntax)method.DeclaringSyntaxReferences[0].GetSyntax(context.CancellationToken);
context.RegisterCodeFix(
"Observe.Event",
(editor, cancellationToken) => ApplyObserveEventMethodFix(editor, assignment, methodDeclaration, cancellationToken),
nameof(EventSubscriptionToObserveFix),
diagnostic);
}
}
}
}
}
/// <inheritdoc/>
public override async Task RegisterCodeFixesAsync(CodeFixContext context)
{
var syntaxRoot = await context.Document.GetSyntaxRootAsync(context.CancellationToken)
.ConfigureAwait(false);
var semanticModel = await context.Document.GetSemanticModelAsync(context.CancellationToken)
.ConfigureAwait(false);
foreach (var diagnostic in context.Diagnostics)
{
var token = syntaxRoot.FindToken(diagnostic.Location.SourceSpan.Start);
if (string.IsNullOrEmpty(token.ValueText) ||
token.IsMissing)
{
continue;
}
var ctor = syntaxRoot.FindNode(diagnostic.Location.SourceSpan).FirstAncestorOrSelf <ConstructorDeclarationSyntax>();
var invocation = syntaxRoot.FindNode(diagnostic.Location.SourceSpan).FirstAncestorOrSelf <InvocationExpressionSyntax>();
if (ctor != null &&
invocation != null &&
invocation.Expression is MemberAccessExpressionSyntax memberAccess)
{
var condition = memberAccess.Expression;
var symbol = semanticModel.GetSymbolSafe(condition, context.CancellationToken);
if (symbol is IParameterSymbol parameter)
{
using (var pooled = IdentifierNameWalker.Borrow(ctor))
{
foreach (var name in pooled.IdentifierNames)
{
if (name.Identifier.ValueText == parameter.Name)
{
if (!condition.Contains(name))
{
return;
}
}
}
}
if (ctor.ParameterList.Parameters.TryFirst(p => p.Identifier.ValueText == parameter.Name, out ParameterSyntax parameterSyntax))
{
context.RegisterCodeFix(
CodeAction.Create(
"Inject negated.",
cancellationToken => ApplyInjectNegatedFixAsync(context, parameterSyntax, invocation, cancellationToken),
nameof(InjectNegatedCodeFix)),
diagnostic);
}
}
}
}
}
private static bool TryGetCanBeSlim(InvocationExpressionSyntax invocation, SyntaxNodeAnalysisContext context, out SyntaxNode path)
{
path = null;
var argument = invocation.FirstAncestor <ArgumentSyntax>();
if (argument != null)
{
if (argument.TryGetParameter(context.SemanticModel, context.CancellationToken, out var parameter) &&
parameter.Type == KnownSymbol.IObservableOfT)
{
if (parameter.Type is INamedTypeSymbol namedType &&
namedType.TypeArguments[0] == KnownSymbol.Object)
{
path = invocation.Expression is MemberAccessExpressionSyntax memberAccess
? (SyntaxNode)memberAccess.Name
: invocation;
return(true);
}
}
}
var parentInvocation = invocation.FirstAncestor <InvocationExpressionSyntax>();
if (parentInvocation != null)
{
var parentMethod = context.SemanticModel.GetSymbolSafe(parentInvocation, context.CancellationToken);
if (parentMethod == KnownSymbol.ObservableExtensions.Subscribe &&
parentInvocation.ArgumentList?.Arguments.TrySingle(out argument) == true)
{
if (argument.Expression is SimpleLambdaExpressionSyntax lambda)
{
using (var pooled = IdentifierNameWalker.Borrow(lambda.Body))
{
if (pooled.IdentifierNames.TryFirst(x => x.Identifier.ValueText == lambda.Parameter.Identifier.ValueText, out IdentifierNameSyntax _))
{
return(false);
}
path = invocation.Expression is MemberAccessExpressionSyntax memberAccess
? (SyntaxNode)memberAccess.Name
: invocation;
return(true);
}
}
}
}
return(false);
}