public static bool CanRefactor(
ForEachStatementSyntax forEachStatement,
SemanticModel semanticModel,
CancellationToken cancellationToken = default(CancellationToken))
{
if (forEachStatement == null)
{
throw new ArgumentNullException(nameof(forEachStatement));
}
if (semanticModel == null)
{
throw new ArgumentNullException(nameof(semanticModel));
}
ITypeSymbol typeSymbol = semanticModel.GetTypeSymbol(forEachStatement.Expression, cancellationToken);
if (typeSymbol?.IsErrorType() == false)
{
return(typeSymbol.IsString() ||
typeSymbol.IsArrayType() ||
SymbolUtility.FindGetItemMethodWithInt32Parameter(typeSymbol)?.IsAccessible(forEachStatement.SpanStart, semanticModel) == true);
}
return(false);
}
internal static void Analyze(SyntaxNodeAnalysisContext context, InvocationExpressionSyntax invocation, MemberAccessExpressionSyntax memberAccess)
{
SemanticModel semanticModel = context.SemanticModel;
CancellationToken cancellationToken = context.CancellationToken;
if (semanticModel
.GetExtensionMethodInfo(invocation, ExtensionMethodKind.Reduced, cancellationToken)
.IsLinqExtensionOfIEnumerableOfTWithoutParameters("First", allowImmutableArrayExtension: true))
{
ITypeSymbol typeSymbol = semanticModel.GetTypeSymbol(memberAccess.Expression, cancellationToken);
if (typeSymbol != null &&
(typeSymbol.IsArrayType() || SymbolUtility.FindGetItemMethodWithInt32Parameter(typeSymbol)?.IsAccessible(invocation.SpanStart, semanticModel) == true))
{
context.ReportDiagnostic(
DiagnosticDescriptors.UseElementAccessInsteadOfFirst,
memberAccess.Name);
}
}
}
private static async Task ProcessElementAtAsync(RefactoringContext context, InvocationExpressionSyntax invocation)
{
SemanticModel semanticModel = await context.GetSemanticModelAsync().ConfigureAwait(false);
if (invocation.ArgumentList?.Arguments.Count == 1 &&
semanticModel
.GetExtensionMethodInfo(invocation, ExtensionMethodKind.Reduced, context.CancellationToken)
.IsLinqElementAt(allowImmutableArrayExtension: true))
{
var memberAccess = (MemberAccessExpressionSyntax)invocation.Expression;
ITypeSymbol typeSymbol = semanticModel.GetTypeSymbol(memberAccess.Expression, context.CancellationToken);
if (typeSymbol != null &&
(typeSymbol.IsArrayType() || SymbolUtility.FindGetItemMethodWithInt32Parameter(typeSymbol)?.IsAccessible(invocation.SpanStart, semanticModel) == true))
{
context.RegisterRefactoring(
"Use [] instead of calling 'ElementAt'",
cancellationToken => RefactorAsync(context.Document, invocation, null, cancellationToken));
}
}
}
private static async Task ProcessFirstOrLastAsync(RefactoringContext context, InvocationExpressionSyntax invocation, string methodName)
{
if (invocation.ArgumentList.Arguments.Count == 0)
{
SemanticModel semanticModel = await context.GetSemanticModelAsync().ConfigureAwait(false);
if (semanticModel
.GetExtensionMethodInfo(invocation, ExtensionMethodKind.Reduced, context.CancellationToken)
.IsLinqExtensionOfIEnumerableOfTWithoutParameters(methodName, allowImmutableArrayExtension: true))
{
var memberAccess = (MemberAccessExpressionSyntax)invocation.Expression;
ITypeSymbol typeSymbol = semanticModel.GetTypeSymbol(memberAccess.Expression, context.CancellationToken);
if (typeSymbol != null &&
(typeSymbol.IsArrayType() || SymbolUtility.FindGetItemMethodWithInt32Parameter(typeSymbol)?.IsAccessible(invocation.SpanStart, semanticModel) == true))
{
string propertyName = GetCountOrLengthPropertyName(memberAccess.Expression, semanticModel, context.CancellationToken);
if (propertyName != null)
{
context.RegisterRefactoring(
$"Use [] instead of calling '{methodName}'",
cancellationToken =>
{
return(RefactorAsync(
context.Document,
invocation,
propertyName,
cancellationToken));
});
}
}
}
}
}