public static void AnalyzeIfStatement(SyntaxNodeAnalysisContext context)
{
var ifStatement = (IfStatementSyntax)context.Node;
if (ifStatement.IsSimpleIf() &&
!ifStatement.ContainsDiagnostics)
{
SyntaxList <StatementSyntax> statements;
if (ifStatement.TryGetContainingList(out statements) &&
!IsPartOfLazyInitialization(ifStatement, statements))
{
EqualsToNullExpression equalsToNull;
if (EqualsToNullExpression.TryCreate(ifStatement.Condition, out equalsToNull))
{
SimpleAssignmentStatement assignment;
if (SimpleAssignmentStatement.TryCreate(ifStatement.GetSingleStatementOrDefault(), out assignment) &&
SyntaxComparer.AreEquivalent(assignment.Left, equalsToNull.Left) &&
assignment.Right.IsSingleLine() &&
!ifStatement.SpanContainsDirectives())
{
int index = statements.IndexOf(ifStatement);
if (index > 0)
{
StatementSyntax previousStatement = statements[index - 1];
if (!previousStatement.ContainsDiagnostics &&
CanRefactor(previousStatement, ifStatement, equalsToNull.Left, ifStatement.Parent))
{
context.ReportDiagnostic(DiagnosticDescriptors.UseCoalesceExpression, previousStatement);
}
}
if (index < statements.Count - 1)
{
StatementSyntax nextStatement = statements[index + 1];
if (!nextStatement.ContainsDiagnostics)
{
MemberInvocationStatement memberInvocation;
if (MemberInvocationStatement.TryCreate(nextStatement, out memberInvocation) &&
SyntaxComparer.AreEquivalent(equalsToNull.Left, memberInvocation.Expression) &&
!ifStatement.Parent.ContainsDirectives(TextSpan.FromBounds(ifStatement.SpanStart, nextStatement.Span.End)))
{
context.ReportDiagnostic(DiagnosticDescriptors.InlineLazyInitialization, ifStatement);
}
}
}
}
}
}
}
}
private static void Analyze(SyntaxNodeAnalysisContext context, BinaryExpressionSyntax binaryExpression)
{
if (!binaryExpression.ContainsDiagnostics)
{
EqualsToNullExpression equalsToNull;
if (EqualsToNullExpression.TryCreate(binaryExpression, out equalsToNull) &&
IsUnconstrainedTypeParameter(context.SemanticModel.GetTypeSymbol(equalsToNull.Left, context.CancellationToken)) &&
!binaryExpression.SpanContainsDirectives())
{
context.ReportDiagnostic(DiagnosticDescriptors.UnconstrainedTypeParameterCheckedForNull, binaryExpression);
}
}
}
public static void AnalyzeIfStatement(SyntaxNodeAnalysisContext context)
{
var ifStatement = (IfStatementSyntax)context.Node;
if (ifStatement.IsSimpleIf() &&
!IsPartOfLazyInitialization(ifStatement))
{
EqualsToNullExpression equalsToNull;
if (EqualsToNullExpression.TryCreate(ifStatement.Condition, out equalsToNull))
{
SimpleAssignmentExpression assignment;
if (SimpleAssignmentExpression.TryCreate(ifStatement.GetSingleStatementOrDefault(), out assignment) &&
assignment.Left.IsEquivalentTo(equalsToNull.Left, topLevel: false) &&
assignment.Right.IsSingleLine() &&
!ifStatement.SpanContainsDirectives())
{
StatementSyntax fixableStatement = ifStatement;
SyntaxList <StatementSyntax> statements;
if (ifStatement.TryGetContainingList(out statements))
{
int index = statements.IndexOf(ifStatement);
if (index > 0)
{
StatementSyntax previousStatement = statements[index - 1];
if (CanRefactor(previousStatement, ifStatement, equalsToNull.Left, ifStatement.Parent))
{
fixableStatement = previousStatement;
}
}
}
context.ReportDiagnostic(DiagnosticDescriptors.UseCoalesceExpression, fixableStatement);
}
}
}
}
private static bool CanRefactor(SyntaxNodeAnalysisContext context, IfStatementSyntax ifStatement, ReturnStatementSyntax returnStatement)
{
SimpleIfStatementWithSingleStatement simpleIf;
if (SimpleIfStatementWithSingleStatement.TryCreate(ifStatement, out simpleIf))
{
EqualsToNullExpression equalsToNull;
if (EqualsToNullExpression.TryCreate(simpleIf.Condition, out equalsToNull))
{
IdentifierNameSyntax identifierName = GetIdentifierName(equalsToNull.Left);
if (identifierName != null)
{
SemanticModel semanticModel = context.SemanticModel;
CancellationToken cancellationToken = context.CancellationToken;
var fieldSymbol = semanticModel.GetSymbol(identifierName, cancellationToken) as IFieldSymbol;
if (fieldSymbol != null)
{
SimpleAssignmentStatement assignment;
if (SimpleAssignmentStatement.TryCreate(simpleIf.SingleStatement, out assignment))
{
string fieldName = identifierName.Identifier.ValueText;
return(assignment.Right.IsSingleLine() &&
IsBackingField(GetIdentifierName(assignment.Left), fieldName, fieldSymbol, semanticModel, cancellationToken) &&
IsBackingField(GetIdentifierName(returnStatement.Expression), fieldName, fieldSymbol, semanticModel, cancellationToken));
}
}
}
}
}
return(false);
}
