Add analyzers for Regex.Match(...).Success and Regex.Matches(...).Count

src/NetAnalyzers/Core/AnalyzerReleases.Unshipped.md

@@ -4,5 +4,7 @@
 
 Rule ID | Category | Severity | Notes
 --------|----------|----------|-------
+CA1873 | Performance | Info | UseRegexMembers, [Documentation](https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1873)
+CA1874 | Performance | Info | UseRegexMembers, [Documentation](https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca1874)
 CA2023 | Reliability | Warning | LoggerMessageDefineAnalyzer, [Documentation](https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca2023)
 CA2024 | Reliability | Warning | DoNotUseEndOfStreamInAsyncMethods, [Documentation](https://learn.microsoft.com/dotnet/fundamentals/code-analysis/quality-rules/ca2024)

src/NetAnalyzers/Core/Microsoft.NetCore.Analyzers/MicrosoftNetCoreAnalyzersResources.resx

@@ -1376,6 +1376,30 @@
   <data name="UseEnvironmentCurrentManagedThreadIdFix" xml:space="preserve">
     <value>Use 'Environment.CurrentManagedThreadId'</value>
   </data>
+  <data name="UseRegexCountDescription" xml:space="preserve">
+    <value>'Regex.Count' is simpler and faster than 'Regex.Matches(...).Count'.</value>
+  </data>
+  <data name="UseRegexCountMessage" xml:space="preserve">
+    <value>Use 'Regex.Count' instead of 'Regex.Matches(...).Count'</value>
+  </data>
+  <data name="UseRegexCountTitle" xml:space="preserve">
+    <value>Use 'Regex.Count'</value>
+  </data>
+  <data name="UseRegexCountFix" xml:space="preserve">
+    <value>Use 'Regex.Count'</value>
+  </data>
+  <data name="UseRegexIsMatchDescription" xml:space="preserve">
+    <value>'Regex.IsMatch' is simpler and faster than 'Regex.Match(...).Success'.</value>
+  </data>
+  <data name="UseRegexIsMatchMessage" xml:space="preserve">
+    <value>Use 'Regex.IsMatch' instead of 'Regex.Match(...).Success'</value>
+  </data>
+  <data name="UseRegexIsMatchTitle" xml:space="preserve">
+    <value>Use 'Regex.IsMatch'</value>
+  </data>
+  <data name="UseRegexIsMatchFix" xml:space="preserve">
+    <value>Use 'Regex.IsMatch'</value>
+  </data>
   <data name="ThreadStaticOnNonStaticFieldDescription" xml:space="preserve">
     <value>'ThreadStatic' only affects static fields. When applied to instance fields, it has no impact on behavior.</value>
   </data>

src/NetAnalyzers/Core/Microsoft.NetCore.Analyzers/Runtime/UseRegexMembers.cs

@@ -0,0 +1,155 @@
+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the MIT license.  See License.txt in the project root for license information.
+
+using System.Collections.Immutable;
+using System.Linq;
+using Analyzer.Utilities;
+using Analyzer.Utilities.Extensions;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.Diagnostics;
+using Microsoft.CodeAnalysis.Operations;
+
+namespace Microsoft.NetCore.Analyzers.Runtime
+{
+    using static MicrosoftNetCoreAnalyzersResources;
+
+    /// <summary>
+    /// CA1873: <inheritdoc cref="UseRegexIsMatchMessage"/>
+    /// CA1874: <inheritdoc cref="UseRegexCountMessage"/>
+    /// </summary>
+    [DiagnosticAnalyzer(LanguageNames.CSharp, LanguageNames.VisualBasic)]
+    public sealed class UseRegexMembers : DiagnosticAnalyzer
+    {
+        internal const string RegexIsMatchRuleId = "CA1873";
+        internal const string RegexCountRuleId = "CA1874";
+
+        // Regex.Match(...).Success => Regex.IsMatch(...)
+        internal static readonly DiagnosticDescriptor UseRegexIsMatchRuleId = DiagnosticDescriptorHelper.Create(RegexIsMatchRuleId,
+            CreateLocalizableResourceString(nameof(UseRegexIsMatchTitle)),
+            CreateLocalizableResourceString(nameof(UseRegexIsMatchMessage)),
+            DiagnosticCategory.Performance,
+            RuleLevel.IdeSuggestion,
+            CreateLocalizableResourceString(nameof(UseRegexIsMatchDescription)),
+            isPortedFxCopRule: false,
+            isDataflowRule: false);
+
+        // Regex.Matches(...).Count => Regex.Count(...)
+        internal static readonly DiagnosticDescriptor UseRegexCountRuleId = DiagnosticDescriptorHelper.Create(RegexCountRuleId,
+            CreateLocalizableResourceString(nameof(UseRegexCountTitle)),
+            CreateLocalizableResourceString(nameof(UseRegexCountMessage)),
+            DiagnosticCategory.Performance,
+            RuleLevel.IdeSuggestion,
+            CreateLocalizableResourceString(nameof(UseRegexCountDescription)),
+            isPortedFxCopRule: false,
+            isDataflowRule: false);
+
+        public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics { get; } = ImmutableArray.Create(
+            UseRegexIsMatchRuleId,
+            UseRegexCountRuleId);
+
+        public override void Initialize(AnalysisContext context)
+        {
+            context.EnableConcurrentExecution();
+            context.ConfigureGeneratedCodeAnalysis(GeneratedCodeAnalysisFlags.None);
+            context.RegisterCompilationStartAction(context =>
+            {
+                // Require that Regex and supporting types exist.
+                if (!context.Compilation.TryGetOrCreateTypeByMetadataName(WellKnownTypeNames.SystemTextRegularExpressionsGroup, out var groupType) ||
+                    !context.Compilation.TryGetOrCreateTypeByMetadataName(WellKnownTypeNames.SystemTextRegularExpressionsMatchCollection, out var matchCollectionType) ||
+                    !context.Compilation.TryGetOrCreateTypeByMetadataName(WellKnownTypeNames.SystemTextRegularExpressionsRegex, out var regexType))
+                {
+                    return;
+                }
+
+                // Get the various members needed from Regex types.
+                var groupSuccessSymbol = groupType.GetMembers("Success").FirstOrDefault();
+                var matchCollectionCountSymbol = matchCollectionType.GetMembers("Count").FirstOrDefault();
+                var regexMatchSymbols = regexType.GetMembers("Match");
+                var regexMatchesSymbols = regexType.GetMembers("Matches");
+                var regexIsMatchSymbols = regexType.GetMembers("IsMatch");
+                var regexCountSymbols = regexType.GetMembers("Count");
+
+                // Ensure we have the required member symbols (Regex.Count is optional).
+                if (groupSuccessSymbol is null ||
+                    matchCollectionCountSymbol is null ||
+                    regexMatchSymbols.Length == 0 ||
+                    regexMatchesSymbols.Length == 0 ||
+                    regexIsMatchSymbols.Length == 0)
+                {
+                    return;
+                }
+
+                // Everything we're looking for is a property, so find all property references.
+                context.RegisterOperationAction(context =>
+                {
+                    var initialPropRef = (IPropertyReferenceOperation)context.Operation;
+
+                    // Regex.Match(...).Success. Look for Group.Success property access.
+                    if (SymbolEqualityComparer.Default.Equals(initialPropRef.Property, groupSuccessSymbol))
+                    {
+                        if (initialPropRef.Instance is IInvocationOperation regexMatchInvocation &&
+                            regexMatchSymbols.Contains(regexMatchInvocation.TargetMethod, SymbolEqualityComparer.Default) &&
+                            HasMatchingOverload(regexMatchInvocation.TargetMethod, regexIsMatchSymbols))
+                        {
+                            context.ReportDiagnostic(initialPropRef.CreateDiagnostic(UseRegexIsMatchRuleId));
+                        }
+                        else
+                        {
+                            return;
+                        }
+
+                        return;
+                    }
+
+                    // Regex.Matches(...).Count. Look for MatchCollection.Count property access.
+                    if (regexCountSymbols.Length != 0 &&
+                        SymbolEqualityComparer.Default.Equals(initialPropRef.Property, matchCollectionCountSymbol))
+                    {
+                        if (initialPropRef.Instance is IInvocationOperation regexMatchesInvocation &&
+                            regexMatchesSymbols.Contains(regexMatchesInvocation.TargetMethod, SymbolEqualityComparer.Default) &&
+                            HasMatchingOverload(regexMatchesInvocation.TargetMethod, regexCountSymbols))
+                        {
+                            context.ReportDiagnostic(initialPropRef.CreateDiagnostic(UseRegexCountRuleId));
+                        }
+
+                        return;
+                    }
+
+                    // Look in overloads to see whether any of the methods there have exactly the same parameters
+                    // by type as does the target method.
+                    static bool HasMatchingOverload(ISymbol target, ImmutableArray<ISymbol> overloads)
+                    {
+                        ImmutableArray<IParameterSymbol> targetParameters = target.GetParameters();
+                        foreach (ISymbol overload in overloads)
+                        {
+                            if (ParameterTypesMatch(targetParameters, overload.GetParameters()))
+                            {
+                                return true;
+                            }
+                        }
+
+                        return false;
+                    }
+
+                    // Checks whether the two lists of parameters have the same types in the same order.
+                    static bool ParameterTypesMatch(ImmutableArray<IParameterSymbol> left, ImmutableArray<IParameterSymbol> right)
+                    {
+                        if (left.Length != right.Length)
+                        {
+                            return false;
+                        }
+
+                        for (int i = 0; i < left.Length; i++)
+                        {
+                            if (!SymbolEqualityComparer.Default.Equals(left[i].Type, right[i].Type))
+                            {
+                                return false;
+                            }
+                        }
+
+                        return true;
+                    }
+                }, OperationKind.PropertyReference);
+            });
+        }
+    }
+}

src/NetAnalyzers/Core/Microsoft.NetCore.Analyzers/Runtime/UseRegexMembersFixer.cs

@@ -0,0 +1,81 @@
+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the MIT license.  See License.txt in the project root for license information.
+
+using System.Collections.Immutable;
+using System.Composition;
+using System.Linq;
+using System.Threading.Tasks;
+using Analyzer.Utilities;
+using Analyzer.Utilities.Extensions;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CodeActions;
+using Microsoft.CodeAnalysis.CodeFixes;
+using Microsoft.CodeAnalysis.Editing;
+using Microsoft.CodeAnalysis.Operations;
+
+namespace Microsoft.NetCore.Analyzers.Runtime
+{
+    using static MicrosoftNetCoreAnalyzersResources;
+
+    /// <summary>
+    /// CA1873: <inheritdoc cref="UseRegexIsMatchMessage"/>
+    /// CA1874: <inheritdoc cref="UseRegexCountMessage"/>
+    /// </summary>
+    [ExportCodeFixProvider(LanguageNames.CSharp, LanguageNames.VisualBasic), Shared]
+    public sealed class UseRegexMembersFixer : CodeFixProvider
+    {
+        public sealed override ImmutableArray<string> FixableDiagnosticIds { get; } = ImmutableArray.Create(
+            UseRegexMembers.RegexIsMatchRuleId,
+            UseRegexMembers.RegexCountRuleId);
+
+        public sealed override FixAllProvider GetFixAllProvider() => WellKnownFixAllProviders.BatchFixer;
+
+        public sealed override async Task RegisterCodeFixesAsync(CodeFixContext context)
+        {
+            Document doc = context.Document;
+            SemanticModel model = await doc.GetRequiredSemanticModelAsync(context.CancellationToken).ConfigureAwait(false);
+            SyntaxNode root = await doc.GetRequiredSyntaxRootAsync(context.CancellationToken).ConfigureAwait(false);
+
+            if (root.FindNode(context.Span, getInnermostNodeForTie: true) is SyntaxNode node &&
+                model.Compilation.TryGetOrCreateTypeByMetadataName(WellKnownTypeNames.SystemTextRegularExpressionsRegex, out var regexType) &&
+                model.GetOperation(node, context.CancellationToken) is IPropertyReferenceOperation operation &&
+                operation.Instance is IInvocationOperation regexCall)
+            {
+                string title, memberName;
+                switch (context.Diagnostics[0].Id)
+                {
+                    case UseRegexMembers.RegexIsMatchRuleId:
+                        title = UseRegexIsMatchFix;
+                        memberName = "IsMatch";
+                        break;
+
+                    case UseRegexMembers.RegexCountRuleId:
+                        title = UseRegexCountFix;
+                        memberName = "Count";
+                        break;
+
+                    default:
+                        RoslynDebug.Assert(false, $"Unknown id {context.Diagnostics[0].Id}");
+                        return;
+                }
+
+                context.RegisterCodeFix(
+                    CodeAction.Create(title,
+                    async cancellationToken =>
+                    {
+                        DocumentEditor editor = await DocumentEditor.CreateAsync(doc, cancellationToken).ConfigureAwait(false);
+
+                        var replacement = editor.Generator.InvocationExpression(  // swap in new method name, dropping the subsequent parameter access
+                            editor.Generator.MemberAccessExpression(
+                                regexCall.Instance?.Syntax ?? editor.Generator.TypeExpressionForStaticMemberAccess(regexType),
+                                memberName),
+                            regexCall.Arguments.Select(arg => arg.Syntax)); // use the exact same arguments
+
+                        editor.ReplaceNode(node, replacement.WithTriviaFrom(node));
+                        return editor.GetChangedDocument();
+                    },
+                    equivalenceKey: title),
+                    context.Diagnostics);
+            }
+        }
+    }
+}

src/NetAnalyzers/Core/Microsoft.NetCore.Analyzers/xlf/MicrosoftNetCoreAnalyzersResources.cs.xlf

@@ -3148,6 +3148,46 @@ Obecné přetypování (IL unbox.any) používané sekvencí vrácenou metodou E
         <target state="translated">Velikost klíče algoritmu asymetrického šifrování {0} je menší než 2048. Použijte radši algoritmus RSA s velikostí klíče alespoň 2048, ECDH nebo ECDSA.</target>
         <note />
       </trans-unit>
+      <trans-unit id="UseRegexCountDescription">
+        <source>'Regex.Count' is simpler and faster than 'Regex.Matches(...).Count'.</source>
+        <target state="new">'Regex.Count' is simpler and faster than 'Regex.Matches(...).Count'.</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="UseRegexCountFix">
+        <source>Use 'Regex.Count'</source>
+        <target state="new">Use 'Regex.Count'</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="UseRegexCountMessage">
+        <source>Use 'Regex.Count' instead of 'Regex.Matches(...).Count'</source>
+        <target state="new">Use 'Regex.Count' instead of 'Regex.Matches(...).Count'</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="UseRegexCountTitle">
+        <source>Use 'Regex.Count'</source>
+        <target state="new">Use 'Regex.Count'</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="UseRegexIsMatchDescription">
+        <source>'Regex.IsMatch' is simpler and faster than 'Regex.Match(...).Success'.</source>
+        <target state="new">'Regex.IsMatch' is simpler and faster than 'Regex.Match(...).Success'.</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="UseRegexIsMatchFix">
+        <source>Use 'Regex.IsMatch'</source>
+        <target state="new">Use 'Regex.IsMatch'</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="UseRegexIsMatchMessage">
+        <source>Use 'Regex.IsMatch' instead of 'Regex.Match(...).Success'</source>
+        <target state="new">Use 'Regex.IsMatch' instead of 'Regex.Match(...).Success'</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="UseRegexIsMatchTitle">
+        <source>Use 'Regex.IsMatch'</source>
+        <target state="new">Use 'Regex.IsMatch'</target>
+        <note />
+      </trans-unit>
       <trans-unit id="UseSearchValuesCodeFixTitle">
         <source>Use 'SearchValues'</source>
         <target state="translated">Používat SearchValues</target>

src/NetAnalyzers/Core/Microsoft.NetCore.Analyzers/xlf/MicrosoftNetCoreAnalyzersResources.de.xlf

@@ -3148,6 +3148,46 @@ Erweiterungen und benutzerdefinierte Konvertierungen werden bei generischen Type
         <target state="translated">Die Schlüsselgröße des asymmetrischen Verschlüsselungsalgorithmus "{0}" beträgt weniger als 2048. Wechseln Sie stattdessen zu einer RSA-Verschlüsselung mit ECDH- oder ECDSA-Algorithmus mit einer Schlüsselgröße von mindestens 2048.</target>
         <note />
       </trans-unit>
+      <trans-unit id="UseRegexCountDescription">
+        <source>'Regex.Count' is simpler and faster than 'Regex.Matches(...).Count'.</source>
+        <target state="new">'Regex.Count' is simpler and faster than 'Regex.Matches(...).Count'.</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="UseRegexCountFix">
+        <source>Use 'Regex.Count'</source>
+        <target state="new">Use 'Regex.Count'</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="UseRegexCountMessage">
+        <source>Use 'Regex.Count' instead of 'Regex.Matches(...).Count'</source>
+        <target state="new">Use 'Regex.Count' instead of 'Regex.Matches(...).Count'</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="UseRegexCountTitle">
+        <source>Use 'Regex.Count'</source>
+        <target state="new">Use 'Regex.Count'</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="UseRegexIsMatchDescription">
+        <source>'Regex.IsMatch' is simpler and faster than 'Regex.Match(...).Success'.</source>
+        <target state="new">'Regex.IsMatch' is simpler and faster than 'Regex.Match(...).Success'.</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="UseRegexIsMatchFix">
+        <source>Use 'Regex.IsMatch'</source>
+        <target state="new">Use 'Regex.IsMatch'</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="UseRegexIsMatchMessage">
+        <source>Use 'Regex.IsMatch' instead of 'Regex.Match(...).Success'</source>
+        <target state="new">Use 'Regex.IsMatch' instead of 'Regex.Match(...).Success'</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="UseRegexIsMatchTitle">
+        <source>Use 'Regex.IsMatch'</source>
+        <target state="new">Use 'Regex.IsMatch'</target>
+        <note />
+      </trans-unit>
       <trans-unit id="UseSearchValuesCodeFixTitle">
         <source>Use 'SearchValues'</source>
         <target state="translated">"SearchValues" verwenden</target>