private static bool AssignedType(ISymbol symbol, SemanticModel semanticModel, CancellationToken cancellationToken, out ITypeSymbol memberType)
{
foreach (var reference in symbol.DeclaringSyntaxReferences)
{
var node = reference.GetSyntax(cancellationToken);
if (AssignmentExecutionWalker.SingleForSymbol(
symbol,
node.FirstAncestor <TypeDeclarationSyntax>(),
Search.TopLevel,
semanticModel,
cancellationToken,
out var assignment) &&
assignment.Right is IdentifierNameSyntax identifier)
{
var ctor = assignment.FirstAncestor <ConstructorDeclarationSyntax>();
if (ctor != null &&
ctor.ParameterList != null &&
ctor.ParameterList.Parameters.TryFirst(
p => p.Identifier.ValueText == identifier.Identifier.ValueText,
out var parameter))
{
memberType = semanticModel.GetDeclaredSymbolSafe(parameter, cancellationToken)?.Type;
return(true);
}
}
}
memberType = null;
return(false);
}
internal static bool TryGetAssignment(this BlockSyntax body, ISymbol symbol, SemanticModel semanticModel, CancellationToken cancellationToken, out AssignmentExpressionSyntax result)
{
result = null;
if (symbol == null)
{
return(false);
}
return(AssignmentExecutionWalker.FirstWith(symbol, body, Search.TopLevel, semanticModel, cancellationToken, out result));
}
/// <inheritdoc/>
protected override async Task RegisterCodeFixesAsync(DocumentEditorCodeFixContext context)
{
var syntaxRoot = await context.Document.GetSyntaxRootAsync(context.CancellationToken)
.ConfigureAwait(false);
foreach (var diagnostic in context.Diagnostics)
{
var node = syntaxRoot.FindNode(diagnostic.Location.SourceSpan);
if (node is IdentifierNameSyntax identifierName)
{
context.RegisterCodeFix(
"Throw if null.",
(editor, _) => editor.ReplaceNode(
node,
SyntaxFactory.ParseExpression($"{identifierName.Identifier.ValueText} ?? throw new System.ArgumentNullException(nameof({identifierName.Identifier.ValueText}))").WithSimplifiedNames()),
this.GetType(),
diagnostic);
}
else if (node is ParameterSyntax parameter)
{
var semanticModel = await context.Document.GetSemanticModelAsync(context.CancellationToken)
.ConfigureAwait(false);
var method = parameter.FirstAncestor <BaseMethodDeclarationSyntax>();
if (method != null)
{
using (var walker = AssignmentExecutionWalker.Borrow(method, Search.TopLevel, semanticModel, context.CancellationToken))
{
if (TryFirstAssignedWith(parameter, walker.Assignments, out var assignedValue))
{
context.RegisterCodeFix(
"Throw if null on first assignment.",
(editor, _) => editor.ReplaceNode(
assignedValue,
SyntaxFactory.ParseExpression($"{assignedValue.Identifier.ValueText} ?? throw new System.ArgumentNullException(nameof({assignedValue.Identifier.ValueText}))").WithSimplifiedNames()),
this.GetType(),
diagnostic);
}
else if (method.Body != null)
{
context.RegisterCodeFix(
"Add null check.",
(editor, _) => editor.ReplaceNode(
method.Body,
method.Body.InsertNodesBefore(
method.Body.Statements[0],
new[] { IfNullThrow(parameter.Identifier.ValueText) })),
this.GetType(),
diagnostic);
}
}
}
}
}
}
/// <inheritdoc/>
protected override async Task RegisterCodeFixesAsync(DocumentEditorCodeFixContext context)
{
var syntaxRoot = await context.Document.GetSyntaxRootAsync(context.CancellationToken)
.ConfigureAwait(false);
foreach (var diagnostic in context.Diagnostics)
{
var node = syntaxRoot.FindNode(diagnostic.Location.SourceSpan);
if (node is IdentifierNameSyntax identifierName)
{
context.RegisterCodeFix(
"Throw if null.",
(editor, _) => editor.ReplaceNode(
node,
SyntaxFactory.ParseExpression($"{identifierName.Identifier.ValueText} ?? throw new System.ArgumentNullException(nameof({identifierName.Identifier.ValueText}))").WithSimplifiedNames()),
this.GetType(),
diagnostic);
}
else if (node is ParameterSyntax parameter)
{
var semanticModel = await context.Document.GetSemanticModelAsync(context.CancellationToken)
.ConfigureAwait(false);
if (parameter.Parent is ParameterListSyntax parameterList &&
parameterList.Parent is BaseMethodDeclarationSyntax methodDeclaration)
{
using (var walker = AssignmentExecutionWalker.Borrow(methodDeclaration, Scope.Member, semanticModel, context.CancellationToken))
{
if (TryFirstAssignedWith(parameter, walker.Assignments, out var assignedValue))
{
context.RegisterCodeFix(
"Throw if null on first assignment.",
(editor, _) => editor.ReplaceNode(
assignedValue,
SyntaxFactory.ParseExpression($"{assignedValue.Identifier.ValueText} ?? throw new System.ArgumentNullException(nameof({assignedValue.Identifier.ValueText}))").WithSimplifiedNames()),
this.GetType(),
diagnostic);
}
else if (methodDeclaration.Body is BlockSyntax block)
{
context.RegisterCodeFix(
"Add null check.",
(editor, _) => editor.ReplaceNode(
block,
x => WithNullCheck(x, parameter)),
this.GetType(),
diagnostic);
}
}
}
}
}
}
private static bool IsInjected(FieldOrProperty member, TypeDeclarationSyntax typeDeclaration, SemanticModel semanticModel, CancellationToken cancellationToken)
{
using (var walker = AssignmentExecutionWalker.For(member.Symbol, typeDeclaration, Scope.Instance, semanticModel, cancellationToken))
{
foreach (var assignment in walker.Assignments)
{
if (assignment.TryFirstAncestorOrSelf <ConstructorDeclarationSyntax>(out _) &&
semanticModel.GetSymbolSafe(assignment.Right, cancellationToken) is IParameterSymbol)
{
return(true);
}
}
}
return(false);
}
internal static bool AssignsSymbolInSetter(IPropertySymbol property, ISymbol symbol, SemanticModel semanticModel, CancellationToken cancellationToken)
{
var setMethod = property?.SetMethod;
if (setMethod == null ||
setMethod.DeclaringSyntaxReferences.Length == 0)
{
return(false);
}
if (TryGetSetter(property, cancellationToken, out AccessorDeclarationSyntax setter))
{
if (AssignmentExecutionWalker.FirstForSymbol(symbol, setter, Search.Recursive, semanticModel, cancellationToken))
{
return(true);
}
}
return(false);
}
private static bool IsRedundantAssignment(ISymbol left, AssignmentExpressionSyntax assignment, SyntaxNodeAnalysisContext context)
{
if (left is IDiscardSymbol ||
assignment.TryFirstAncestor <ObjectCreationExpressionSyntax>(out _))
{
return(false);
}
if (assignment.TryFirstAncestor <MemberDeclarationSyntax>(out var member))
{
if (!(member is ConstructorDeclarationSyntax) &&
context.SemanticModel.TryGetType(assignment.Left, context.CancellationToken, out var type) &&
FieldOrProperty.TryCreate(left, out _))
{
if (type == KnownSymbol.Boolean ||
type.TypeKind == TypeKind.Enum)
{
return(false);
}
}
using (var walker = AssignmentExecutionWalker.For(left, member, Scope.Member, context.SemanticModel, context.CancellationToken))
{
foreach (var candidate in walker.Assignments)
{
if (candidate == assignment)
{
continue;
}
if (!MemberPath.Equals(candidate.Left, assignment.Left))
{
continue;
}
if (candidate.IsExecutedBefore(assignment) == ExecutedBefore.Yes)
{
if (left is IParameterSymbol parameter &&
parameter.RefKind == RefKind.Out &&
assignment.TryFirstAncestor <BlockSyntax>(out var assignmentBlock) &&
candidate.TryFirstAncestor <BlockSyntax>(out var candidateBlock) &&
(candidateBlock.Contains(assignmentBlock) ||
candidateBlock.Statements.Last() is ReturnStatementSyntax))
{
return(false);
}
using (var nameWalker = IdentifierNameWalker.Borrow(assignment.Right))
{
foreach (var name in nameWalker.IdentifierNames)
{
if (left.Name == name.Identifier.ValueText &&
context.SemanticModel.TryGetSymbol(
name,
context.CancellationToken,
out ISymbol symbol) &&
symbol.Equals(left))
{
return(false);
}
}
}
return(true);
}
}
}
}
return(false);
}