public static void AnalyzeAsExpression(SyntaxNodeAnalysisContext context)
{
var binaryExpression = (BinaryExpressionSyntax)context.Node;
AsExpressionInfo info = SyntaxInfo.AsExpressionInfo(binaryExpression);
if (!info.Success)
{
return;
}
ITypeSymbol typeSymbol = context.SemanticModel.GetTypeSymbol(info.Type, context.CancellationToken);
if (typeSymbol?.IsErrorType() != false)
{
return;
}
Conversion conversion = context.SemanticModel.ClassifyConversion(info.Expression, typeSymbol);
if (!conversion.IsIdentity)
{
return;
}
context.ReportDiagnostic(
DiagnosticDescriptors.RemoveRedundantAsOperator,
Location.Create(binaryExpression.SyntaxTree, TextSpan.FromBounds(binaryExpression.OperatorToken.SpanStart, info.Type.Span.End)));
}
public static bool IsFixable(
BinaryExpressionSyntax binaryExpression,
SemanticModel semanticModel,
CancellationToken cancellationToken = default(CancellationToken))
{
AsExpressionInfo info = SyntaxInfo.AsExpressionInfo(binaryExpression);
if (!info.Success)
{
return(false);
}
ITypeSymbol typeSymbol = semanticModel.GetTypeSymbol(info.Type, cancellationToken);
if (typeSymbol == null)
{
return(false);
}
if (!semanticModel.IsExplicitConversion(info.Expression, typeSymbol))
{
return(false);
}
return(true);
}
private static Task <Document> RefactorAsync(
Document document,
LocalDeclarationStatementSyntax localDeclaration,
CancellationToken cancellationToken)
{
VariableDeclaratorSyntax variableDeclarator = localDeclaration
.Declaration
.Variables
.Single();
ExpressionSyntax expression = variableDeclarator
.Initializer
.Value
.WalkDownParentheses();
AsExpressionInfo asExpressionInfo = SyntaxInfo.AsExpressionInfo(expression);
PrefixUnaryExpressionSyntax newCondition = LogicalNotExpression(
ParenthesizedExpression(
IsPatternExpression(
asExpressionInfo.Expression,
DeclarationPattern(
asExpressionInfo.Type,
SingleVariableDesignation(variableDeclarator.Identifier)))));
StatementListInfo statementsInfo = SyntaxInfo.StatementListInfo(localDeclaration);
int index = statementsInfo.IndexOf(localDeclaration);
var ifStatement = (IfStatementSyntax)statementsInfo[index + 1];
SyntaxTriviaList leadingTrivia = statementsInfo.Parent
.DescendantTrivia(TextSpan.FromBounds(localDeclaration.SpanStart, ifStatement.SpanStart))
.ToSyntaxTriviaList()
.EmptyIfWhitespace();
leadingTrivia = localDeclaration.GetLeadingTrivia().AddRange(leadingTrivia);
StatementSyntax newStatement = ifStatement.Statement;
if (ifStatement.SingleNonBlockStatementOrDefault() is ReturnStatementSyntax returnStatement &&
returnStatement.Expression?.WalkDownParentheses() is IdentifierNameSyntax identifierName &&
string.Equals(identifierName.Identifier.ValueText, variableDeclarator.Identifier.ValueText, System.StringComparison.Ordinal))
{
newStatement = newStatement.ReplaceNode(returnStatement.Expression, NullLiteralExpression().WithTriviaFrom(returnStatement.Expression));
}
IfStatementSyntax newIfStatement = ifStatement
.WithCondition(newCondition.WithTriviaFrom(ifStatement.Condition))
.WithStatement(newStatement)
.WithLeadingTrivia(leadingTrivia)
.WithFormatterAnnotation();
SyntaxList <StatementSyntax> newStatements = statementsInfo.Statements.ReplaceRange(index, 2, newIfStatement);
return(document.ReplaceStatementsAsync(statementsInfo, newStatements, cancellationToken));
}
private static Task <Document> RefactorAsync(
Document document,
LocalDeclarationStatementSyntax localDeclaration,
CancellationToken cancellationToken)
{
VariableDeclaratorSyntax variableDeclarator = localDeclaration
.Declaration
.Variables
.Single();
ExpressionSyntax expression = variableDeclarator
.Initializer
.Value
.WalkDownParentheses();
AsExpressionInfo asExpressionInfo = SyntaxInfo.AsExpressionInfo(expression);
PrefixUnaryExpressionSyntax newCondition = LogicalNotExpression(
ParenthesizedExpression(
IsPatternExpression(
asExpressionInfo.Expression,
DeclarationPattern(
asExpressionInfo.Type,
SingleVariableDesignation(variableDeclarator.Identifier)))));
StatementListInfo statements = SyntaxInfo.StatementListInfo(localDeclaration);
int index = statements.IndexOf(localDeclaration);
var ifStatement = (IfStatementSyntax)statements[index + 1];
SyntaxTriviaList leadingTrivia = localDeclaration
.DescendantTrivia(TextSpan.FromBounds(localDeclaration.SpanStart, ifStatement.SpanStart))
.ToSyntaxTriviaList()
.EmptyIfWhitespace();
leadingTrivia = localDeclaration.GetLeadingTrivia().AddRange(leadingTrivia);
IfStatementSyntax newIfStatement = ifStatement
.WithCondition(newCondition.WithTriviaFrom(ifStatement.Condition))
.WithLeadingTrivia(leadingTrivia);
StatementListInfo newStatements = statements.RemoveAt(index).ReplaceAt(index, newIfStatement);
return(document.ReplaceStatementsAsync(statements, newStatements, cancellationToken));
}
public static Task <Document> RefactorAsync(
Document document,
SyntaxNode node,
CancellationToken cancellationToken)
{
NullCheckExpressionInfo nullCheck = SyntaxInfo.NullCheckExpressionInfo(node);
AsExpressionInfo asExpressionInfo = SyntaxInfo.AsExpressionInfo(nullCheck.Expression);
ExpressionSyntax newNode = IsExpression(asExpressionInfo.Expression, asExpressionInfo.Type);
if (nullCheck.IsCheckingNull)
{
newNode = LogicalNotExpression(newNode.WithoutTrivia().Parenthesize()).WithTriviaFrom(newNode);
}
newNode = newNode
.Parenthesize()
.WithFormatterAnnotation();
return(document.ReplaceNodeAsync(node, newNode, cancellationToken));
}
private static void Analyze(SyntaxNodeAnalysisContext context, SyntaxNode node)
{
if (node.SpanContainsDirectives())
{
return;
}
NullCheckExpressionInfo nullCheck = SyntaxInfo.NullCheckExpressionInfo(node);
if (!nullCheck.Success)
{
return;
}
AsExpressionInfo asExpressionInfo = SyntaxInfo.AsExpressionInfo(nullCheck.Expression);
if (!asExpressionInfo.Success)
{
return;
}
DiagnosticHelpers.ReportDiagnostic(context, DiagnosticDescriptors.UseIsOperatorInsteadOfAsOperator, node);
}
private static void AnalyzeAsExpression(SyntaxNodeAnalysisContext context)
{
var asExpression = (BinaryExpressionSyntax)context.Node;
AsExpressionInfo asExpressionInfo = SyntaxInfo.AsExpressionInfo(asExpression);
if (!asExpressionInfo.Success)
{
return;
}
SingleLocalDeclarationStatementInfo localInfo = SyntaxInfo.SingleLocalDeclarationStatementInfo(asExpression);
if (!localInfo.Success)
{
return;
}
if (localInfo.Statement.SpanOrTrailingTriviaContainsDirectives())
{
return;
}
if (!(localInfo.Statement.NextStatement() is IfStatementSyntax ifStatement))
{
return;
}
if (!ifStatement.IsSimpleIf())
{
return;
}
if (ifStatement.SpanOrLeadingTriviaContainsDirectives())
{
return;
}
StatementSyntax statement = ifStatement.SingleNonBlockStatementOrDefault();
if (statement == null)
{
return;
}
if (!CSharpFacts.IsJumpStatement(statement.Kind()))
{
return;
}
NullCheckExpressionInfo nullCheck = SyntaxInfo.NullCheckExpressionInfo(ifStatement.Condition, NullCheckStyles.EqualsToNull | NullCheckStyles.IsNull);
if (!nullCheck.Success)
{
return;
}
if (!string.Equals(localInfo.IdentifierText, (nullCheck.Expression as IdentifierNameSyntax)?.Identifier.ValueText, StringComparison.Ordinal))
{
return;
}
if (!localInfo.Type.IsVar)
{
SemanticModel semanticModel = context.SemanticModel;
CancellationToken cancellationToken = context.CancellationToken;
ITypeSymbol typeSymbol = semanticModel.GetTypeSymbol(asExpressionInfo.Type, cancellationToken);
if (typeSymbol.IsNullableType())
{
return;
}
if (!SymbolEqualityComparer.Default.Equals(semanticModel.GetTypeSymbol(localInfo.Type, cancellationToken), typeSymbol))
{
return;
}
}
DiagnosticHelpers.ReportDiagnostic(context, DiagnosticDescriptors.UsePatternMatchingInsteadOfAsAndNullCheck, localInfo.Statement);
}
public static void AnalyzeAsExpression(SyntaxNodeAnalysisContext context)
{
var asExpression = (BinaryExpressionSyntax)context.Node;
AsExpressionInfo asExpressionInfo = SyntaxInfo.AsExpressionInfo(asExpression);
if (!asExpressionInfo.Success)
{
return;
}
SingleLocalDeclarationStatementInfo localInfo = SyntaxInfo.SingleLocalDeclarationStatementInfo(asExpression);
if (!localInfo.Success)
{
return;
}
if (localInfo.Statement.SpanOrTrailingTriviaContainsDirectives())
{
return;
}
if (!(localInfo.Statement.NextStatement() is IfStatementSyntax ifStatement))
{
return;
}
if (!ifStatement.IsSimpleIf())
{
return;
}
if (ifStatement.SpanOrLeadingTriviaContainsDirectives())
{
return;
}
StatementSyntax statement = ifStatement.SingleNonBlockStatementOrDefault();
if (statement == null)
{
return;
}
if (!CSharpFacts.IsJumpStatement(statement.Kind()))
{
return;
}
NullCheckExpressionInfo nullCheck = SyntaxInfo.NullCheckExpressionInfo(ifStatement.Condition, NullCheckStyles.EqualsToNull | NullCheckStyles.IsNull);
if (!nullCheck.Success)
{
return;
}
if (!string.Equals(localInfo.IdentifierText, (nullCheck.Expression as IdentifierNameSyntax)?.Identifier.ValueText, StringComparison.Ordinal))
{
return;
}
context.ReportDiagnostic(DiagnosticDescriptors.UsePatternMatchingInsteadOfAsAndNullCheck, localInfo.Statement);
}