private static void AnalyzeIsExpression(SyntaxNodeAnalysisContext context)
{
var isExpression = (BinaryExpressionSyntax)context.Node;
IsExpressionInfo isExpressionInfo = SyntaxInfo.IsExpressionInfo(isExpression);
if (!isExpressionInfo.Success)
{
return;
}
ExpressionSyntax expression = isExpressionInfo.Expression;
var identifierName = expression as IdentifierNameSyntax;
if (identifierName == null)
{
if (expression.IsKind(SyntaxKind.SimpleMemberAccessExpression))
{
var memberAccess = (MemberAccessExpressionSyntax)expression;
if (memberAccess.Expression.IsKind(SyntaxKind.ThisExpression))
{
identifierName = memberAccess.Name as IdentifierNameSyntax;
}
}
if (identifierName == null)
{
return;
}
}
ExpressionSyntax left = isExpression.WalkUpParentheses();
SyntaxNode node = left.Parent;
if (node.ContainsDiagnostics)
{
return;
}
switch (node.Kind())
{
case SyntaxKind.LogicalAndExpression:
{
var logicalAnd = (BinaryExpressionSyntax)node;
if (left != logicalAnd.Left)
{
return;
}
ExpressionSyntax right = logicalAnd.Right;
if (right == null)
{
return;
}
SemanticModel semanticModel = context.SemanticModel;
CancellationToken cancellationToken = context.CancellationToken;
if (semanticModel.GetTypeSymbol(isExpressionInfo.Type, cancellationToken).IsNullableType())
{
return;
}
if (logicalAnd.Parent.IsInExpressionTree(semanticModel, cancellationToken))
{
return;
}
if (!IsFixable(right, identifierName, semanticModel, cancellationToken))
{
return;
}
DiagnosticHelpers.ReportDiagnostic(context, DiagnosticDescriptors.UsePatternMatchingInsteadOfIsAndCast, logicalAnd);
break;
}
case SyntaxKind.IfStatement:
{
var ifStatement = (IfStatementSyntax)node;
if (left != ifStatement.Condition)
{
return;
}
StatementSyntax statement = ifStatement.Statement;
if (statement == null)
{
return;
}
SemanticModel semanticModel = context.SemanticModel;
CancellationToken cancellationToken = context.CancellationToken;
if (semanticModel.GetTypeSymbol(isExpressionInfo.Type, cancellationToken).IsNullableType())
{
return;
}
if (!IsFixable(statement, identifierName, semanticModel, cancellationToken))
{
return;
}
DiagnosticHelpers.ReportDiagnostic(context, DiagnosticDescriptors.UsePatternMatchingInsteadOfIsAndCast, ifStatement.Condition);
break;
}
}
}
public static void AnalyzeWhereAndCast(SyntaxNodeAnalysisContext context, SimpleMemberInvocationExpressionInfo invocationInfo)
{
SimpleMemberInvocationExpressionInfo invocationInfo2 = SyntaxInfo.SimpleMemberInvocationExpressionInfo(invocationInfo.Expression);
if (!invocationInfo2.Success)
{
return;
}
ArgumentSyntax argument = invocationInfo2.Arguments.SingleOrDefault(shouldThrow: false);
if (argument == null)
{
return;
}
if (!string.Equals(invocationInfo2.NameText, "Where", StringComparison.Ordinal))
{
return;
}
SemanticModel semanticModel = context.SemanticModel;
CancellationToken cancellationToken = context.CancellationToken;
IMethodSymbol methodSymbol = semanticModel.GetReducedExtensionMethodInfo(invocationInfo.InvocationExpression, cancellationToken).Symbol;
if (methodSymbol == null)
{
return;
}
if (!SymbolUtility.IsLinqCast(methodSymbol, semanticModel))
{
return;
}
IMethodSymbol methodSymbol2 = semanticModel.GetReducedExtensionMethodInfo(invocationInfo2.InvocationExpression, cancellationToken).Symbol;
if (methodSymbol2 == null)
{
return;
}
if (!SymbolUtility.IsLinqWhere(methodSymbol2, semanticModel))
{
return;
}
IsExpressionInfo isExpressionInfo = SyntaxInfo.IsExpressionInfo(GetLambdaExpression(argument.Expression));
if (!isExpressionInfo.Success)
{
return;
}
TypeSyntax type2 = (invocationInfo.Name as GenericNameSyntax)?.TypeArgumentList?.Arguments.SingleOrDefault(shouldThrow: false);
if (type2 == null)
{
return;
}
ITypeSymbol typeSymbol = semanticModel.GetTypeSymbol(isExpressionInfo.Type, cancellationToken);
if (typeSymbol == null)
{
return;
}
ITypeSymbol typeSymbol2 = semanticModel.GetTypeSymbol(type2, cancellationToken);
if (!typeSymbol.Equals(typeSymbol2))
{
return;
}
TextSpan span = TextSpan.FromBounds(invocationInfo2.Name.SpanStart, invocationInfo.InvocationExpression.Span.End);
if (invocationInfo.InvocationExpression.ContainsDirectives(span))
{
return;
}
context.ReportDiagnostic(
DiagnosticDescriptors.SimplifyLinqMethodChain,
Location.Create(invocationInfo.InvocationExpression.SyntaxTree, span));
SyntaxNode GetLambdaExpression(ExpressionSyntax expression)
{
CSharpSyntaxNode body = (expression as LambdaExpressionSyntax)?.Body;
if (body?.Kind() == SyntaxKind.Block)
{
StatementSyntax statement = ((BlockSyntax)body).Statements.SingleOrDefault(shouldThrow: false);
if (statement?.Kind() == SyntaxKind.ReturnStatement)
{
var returnStatement = (ReturnStatementSyntax)statement;
return(returnStatement.Expression);
}
}
return(body);
}
}