RS0046: Avoid Opt suffix in nullable-enabled code

src/Roslyn.Diagnostics.Analyzers/CSharp/CSharpAvoidOptSuffixForNullableEnableCode.cs

@@ -0,0 +1,47 @@
+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+using Analyzer.Utilities.Extensions;
+using Analyzer.Utilities.Lightup;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.Diagnostics;
+using Roslyn.Diagnostics.Analyzers;
+
+namespace Roslyn.Diagnostics.CSharp.Analyzers
+{
+    [DiagnosticAnalyzer(LanguageNames.CSharp)]
+    public sealed class CSharpAvoidOptSuffixForNullableEnableCode : AvoidOptSuffixForNullableEnableCode
+    {
+        public override void Initialize(AnalysisContext context)
+        {
+            context.EnableConcurrentExecution();
+            context.ConfigureGeneratedCodeAnalysis(GeneratedCodeAnalysisFlags.None);
+
+            context.RegisterSyntaxNodeAction(context =>
+            {
+                var parameter = (ParameterSyntax)context.Node;
+
+                if (parameter.Identifier.Text.EndsWith("Opt", System.StringComparison.Ordinal) &&
+                    context.SemanticModel.GetNullableContext(parameter.SpanStart).AnnotationsEnabled())
+                {
+                    context.ReportDiagnostic(parameter.Identifier.CreateDiagnostic(Rule));
+                }
+            }, SyntaxKind.Parameter);
+
+            context.RegisterSyntaxNodeAction(context =>
+            {
+                var fieldDeclaration = (FieldDeclarationSyntax)context.Node;
+
+                foreach (var variable in fieldDeclaration.Declaration.Variables)
+                {
+                    if (variable.Identifier.Text.EndsWith("Opt", System.StringComparison.Ordinal) &&
+                        context.SemanticModel.GetNullableContext(variable.SpanStart).AnnotationsEnabled())
+                    {
+                        context.ReportDiagnostic(variable.Identifier.CreateDiagnostic(Rule));
+                    }
+                }
+            }, SyntaxKind.FieldDeclaration);
+        }
+    }
+}

src/Roslyn.Diagnostics.Analyzers/Core/AnalyzerReleases.Unshipped.md

@@ -2,6 +2,7 @@
 Rule ID | Category | Severity | Notes
 --------|----------|----------|-------
 RS0040 | RoslynDiagnosticsReliability | Warning | DefaultableTypeShouldHaveDefaultableFieldsAnalyzer
+RS0042 | RoslynDiagnosticsDesign | Disabled | AvoidOptSuffixForNullableEnableCode
 
 ### Changed Rules
 Rule ID | New Category | New Severity | Old Category | Old Severity | Notes

src/Roslyn.Diagnostics.Analyzers/Core/AvoidOptSuffixForNullableEnableCode.cs

@@ -0,0 +1,30 @@
+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+using System.Collections.Immutable;
+using Analyzer.Utilities;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.Diagnostics;
+
+namespace Roslyn.Diagnostics.Analyzers
+{
+    public abstract class AvoidOptSuffixForNullableEnableCode : DiagnosticAnalyzer
+    {
+        private static readonly LocalizableString s_localizableTitle = new LocalizableResourceString(nameof(RoslynDiagnosticsAnalyzersResources.AvoidOptSuffixForNullableEnableCodeRuleIdTitle), RoslynDiagnosticsAnalyzersResources.ResourceManager, typeof(RoslynDiagnosticsAnalyzersResources));
+
+        private static readonly LocalizableString s_localizableMessage = new LocalizableResourceString(nameof(RoslynDiagnosticsAnalyzersResources.AvoidOptSuffixForNullableEnableCodeRuleIdMessage), RoslynDiagnosticsAnalyzersResources.ResourceManager, typeof(RoslynDiagnosticsAnalyzersResources));
+        private static readonly LocalizableString s_localizableDescription = new LocalizableResourceString(nameof(RoslynDiagnosticsAnalyzersResources.AvoidOptSuffixForNullableEnableCodeRuleIdDescription), RoslynDiagnosticsAnalyzersResources.ResourceManager, typeof(RoslynDiagnosticsAnalyzersResources));
+
+        internal static DiagnosticDescriptor Rule = new DiagnosticDescriptor(
+            RoslynDiagnosticIds.AvoidOptSuffixForNullableEnableCodeRuleId,
+            s_localizableTitle,
+            s_localizableMessage,
+            DiagnosticCategory.RoslynDiagnosticsDesign,
+            DiagnosticSeverity.Warning,
+            isEnabledByDefault: false,
+            description: s_localizableDescription,
+            helpLinkUri: null,
+            customTags: WellKnownDiagnosticTags.Telemetry);
+
+        public sealed override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics => ImmutableArray.Create(Rule);
+    }
+}

src/Roslyn.Diagnostics.Analyzers/Core/RoslynDiagnosticIds.cs

@@ -45,5 +45,6 @@ internal static class RoslynDiagnosticIds
         public const string RelaxTestNamingSuppressionRuleId = "RS0039";
         public const string DefaultableTypeShouldHaveDefaultableFieldsRuleId = "RS0040";
         public const string ObliviousPublicApiRuleId = "RS0041";
+        public const string AvoidOptSuffixForNullableEnableCodeRuleId = "RS0042";
     }
 }

src/Roslyn.Diagnostics.Analyzers/Core/RoslynDiagnosticsAnalyzersResources.resx

@@ -279,4 +279,13 @@
   <data name="DefaultableTypeShouldHaveDefaultableFieldsTitle" xml:space="preserve">
     <value>Defaultable types should have defaultable fields</value>
   </data>
+  <data name="AvoidOptSuffixForNullableEnableCodeRuleIdDescription" xml:space="preserve">
+    <value>Avoid the 'Opt' suffix in a nullable-enabled code.</value>
+  </data>
+  <data name="AvoidOptSuffixForNullableEnableCodeRuleIdMessage" xml:space="preserve">
+    <value>Avoid the 'Opt' suffix in a nullable-enabled code</value>
+  </data>
+  <data name="AvoidOptSuffixForNullableEnableCodeRuleIdTitle" xml:space="preserve">
+    <value>Avoid the 'Opt' suffix</value>
+  </data>
 </root>

src/Roslyn.Diagnostics.Analyzers/Core/xlf/RoslynDiagnosticsAnalyzersResources.cs.xlf

@@ -2,6 +2,21 @@
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
   <file datatype="xml" source-language="en" target-language="cs" original="../RoslynDiagnosticsAnalyzersResources.resx">
     <body>
+      <trans-unit id="AvoidOptSuffixForNullableEnableCodeRuleIdDescription">
+        <source>Avoid the 'Opt' suffix in a nullable-enabled code.</source>
+        <target state="new">Avoid the 'Opt' suffix in a nullable-enabled code.</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="AvoidOptSuffixForNullableEnableCodeRuleIdMessage">
+        <source>Avoid the 'Opt' suffix in a nullable-enabled code</source>
+        <target state="new">Avoid the 'Opt' suffix in a nullable-enabled code</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="AvoidOptSuffixForNullableEnableCodeRuleIdTitle">
+        <source>Avoid the 'Opt' suffix</source>
+        <target state="new">Avoid the 'Opt' suffix</target>
+        <note />
+      </trans-unit>
       <trans-unit id="DefaultableTypeShouldHaveDefaultableFieldsDescription">
         <source>Defaultable types should have defaultable fields</source>
         <target state="translated">Typy, které se dají nastavit jako výchozí, by měly mít pole, která se tak dají nastavit taky.</target>

src/Roslyn.Diagnostics.Analyzers/Core/xlf/RoslynDiagnosticsAnalyzersResources.de.xlf

@@ -2,6 +2,21 @@
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
   <file datatype="xml" source-language="en" target-language="de" original="../RoslynDiagnosticsAnalyzersResources.resx">
     <body>
+      <trans-unit id="AvoidOptSuffixForNullableEnableCodeRuleIdDescription">
+        <source>Avoid the 'Opt' suffix in a nullable-enabled code.</source>
+        <target state="new">Avoid the 'Opt' suffix in a nullable-enabled code.</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="AvoidOptSuffixForNullableEnableCodeRuleIdMessage">
+        <source>Avoid the 'Opt' suffix in a nullable-enabled code</source>
+        <target state="new">Avoid the 'Opt' suffix in a nullable-enabled code</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="AvoidOptSuffixForNullableEnableCodeRuleIdTitle">
+        <source>Avoid the 'Opt' suffix</source>
+        <target state="new">Avoid the 'Opt' suffix</target>
+        <note />
+      </trans-unit>
       <trans-unit id="DefaultableTypeShouldHaveDefaultableFieldsDescription">
         <source>Defaultable types should have defaultable fields</source>
         <target state="translated">Auf den Standard festlegbare Typen müssen auf den Standard festlegbare Felder aufweisen.</target>

src/Roslyn.Diagnostics.Analyzers/Core/xlf/RoslynDiagnosticsAnalyzersResources.es.xlf

@@ -2,6 +2,21 @@
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
   <file datatype="xml" source-language="en" target-language="es" original="../RoslynDiagnosticsAnalyzersResources.resx">
     <body>
+      <trans-unit id="AvoidOptSuffixForNullableEnableCodeRuleIdDescription">
+        <source>Avoid the 'Opt' suffix in a nullable-enabled code.</source>
+        <target state="new">Avoid the 'Opt' suffix in a nullable-enabled code.</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="AvoidOptSuffixForNullableEnableCodeRuleIdMessage">
+        <source>Avoid the 'Opt' suffix in a nullable-enabled code</source>
+        <target state="new">Avoid the 'Opt' suffix in a nullable-enabled code</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="AvoidOptSuffixForNullableEnableCodeRuleIdTitle">
+        <source>Avoid the 'Opt' suffix</source>
+        <target state="new">Avoid the 'Opt' suffix</target>
+        <note />
+      </trans-unit>
       <trans-unit id="DefaultableTypeShouldHaveDefaultableFieldsDescription">
         <source>Defaultable types should have defaultable fields</source>
         <target state="translated">Los tipos defaultable deben tener campos defaultable</target>

src/Roslyn.Diagnostics.Analyzers/Core/xlf/RoslynDiagnosticsAnalyzersResources.fr.xlf

@@ -2,6 +2,21 @@
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
   <file datatype="xml" source-language="en" target-language="fr" original="../RoslynDiagnosticsAnalyzersResources.resx">
     <body>
+      <trans-unit id="AvoidOptSuffixForNullableEnableCodeRuleIdDescription">
+        <source>Avoid the 'Opt' suffix in a nullable-enabled code.</source>
+        <target state="new">Avoid the 'Opt' suffix in a nullable-enabled code.</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="AvoidOptSuffixForNullableEnableCodeRuleIdMessage">
+        <source>Avoid the 'Opt' suffix in a nullable-enabled code</source>
+        <target state="new">Avoid the 'Opt' suffix in a nullable-enabled code</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="AvoidOptSuffixForNullableEnableCodeRuleIdTitle">
+        <source>Avoid the 'Opt' suffix</source>
+        <target state="new">Avoid the 'Opt' suffix</target>
+        <note />
+      </trans-unit>
       <trans-unit id="DefaultableTypeShouldHaveDefaultableFieldsDescription">
         <source>Defaultable types should have defaultable fields</source>
         <target state="translated">Les types par défaut doivent avoir des champs par défaut</target>

src/Roslyn.Diagnostics.Analyzers/Core/xlf/RoslynDiagnosticsAnalyzersResources.it.xlf

@@ -2,6 +2,21 @@
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
   <file datatype="xml" source-language="en" target-language="it" original="../RoslynDiagnosticsAnalyzersResources.resx">
     <body>
+      <trans-unit id="AvoidOptSuffixForNullableEnableCodeRuleIdDescription">
+        <source>Avoid the 'Opt' suffix in a nullable-enabled code.</source>
+        <target state="new">Avoid the 'Opt' suffix in a nullable-enabled code.</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="AvoidOptSuffixForNullableEnableCodeRuleIdMessage">
+        <source>Avoid the 'Opt' suffix in a nullable-enabled code</source>
+        <target state="new">Avoid the 'Opt' suffix in a nullable-enabled code</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="AvoidOptSuffixForNullableEnableCodeRuleIdTitle">
+        <source>Avoid the 'Opt' suffix</source>
+        <target state="new">Avoid the 'Opt' suffix</target>
+        <note />
+      </trans-unit>
       <trans-unit id="DefaultableTypeShouldHaveDefaultableFieldsDescription">
         <source>Defaultable types should have defaultable fields</source>
         <target state="translated">I tipi defaultable devono avere campi defaultable</target>

src/Roslyn.Diagnostics.Analyzers/Core/xlf/RoslynDiagnosticsAnalyzersResources.ja.xlf

@@ -2,6 +2,21 @@
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
   <file datatype="xml" source-language="en" target-language="ja" original="../RoslynDiagnosticsAnalyzersResources.resx">
     <body>
+      <trans-unit id="AvoidOptSuffixForNullableEnableCodeRuleIdDescription">
+        <source>Avoid the 'Opt' suffix in a nullable-enabled code.</source>
+        <target state="new">Avoid the 'Opt' suffix in a nullable-enabled code.</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="AvoidOptSuffixForNullableEnableCodeRuleIdMessage">
+        <source>Avoid the 'Opt' suffix in a nullable-enabled code</source>
+        <target state="new">Avoid the 'Opt' suffix in a nullable-enabled code</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="AvoidOptSuffixForNullableEnableCodeRuleIdTitle">
+        <source>Avoid the 'Opt' suffix</source>
+        <target state="new">Avoid the 'Opt' suffix</target>
+        <note />
+      </trans-unit>
       <trans-unit id="DefaultableTypeShouldHaveDefaultableFieldsDescription">
         <source>Defaultable types should have defaultable fields</source>
         <target state="translated">既定に設定可能な型には、既定に設定可能なフィールドが必要です</target>

src/Roslyn.Diagnostics.Analyzers/Core/xlf/RoslynDiagnosticsAnalyzersResources.ko.xlf

@@ -2,6 +2,21 @@
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
   <file datatype="xml" source-language="en" target-language="ko" original="../RoslynDiagnosticsAnalyzersResources.resx">
     <body>
+      <trans-unit id="AvoidOptSuffixForNullableEnableCodeRuleIdDescription">
+        <source>Avoid the 'Opt' suffix in a nullable-enabled code.</source>
+        <target state="new">Avoid the 'Opt' suffix in a nullable-enabled code.</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="AvoidOptSuffixForNullableEnableCodeRuleIdMessage">
+        <source>Avoid the 'Opt' suffix in a nullable-enabled code</source>
+        <target state="new">Avoid the 'Opt' suffix in a nullable-enabled code</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="AvoidOptSuffixForNullableEnableCodeRuleIdTitle">
+        <source>Avoid the 'Opt' suffix</source>
+        <target state="new">Avoid the 'Opt' suffix</target>
+        <note />
+      </trans-unit>
       <trans-unit id="DefaultableTypeShouldHaveDefaultableFieldsDescription">
         <source>Defaultable types should have defaultable fields</source>
         <target state="translated">기본값 설정 가능 형식에는 기본값 설정 가능 필드가 있어야 합니다.</target>

src/Roslyn.Diagnostics.Analyzers/Core/xlf/RoslynDiagnosticsAnalyzersResources.pl.xlf

@@ -2,6 +2,21 @@
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
   <file datatype="xml" source-language="en" target-language="pl" original="../RoslynDiagnosticsAnalyzersResources.resx">
     <body>
+      <trans-unit id="AvoidOptSuffixForNullableEnableCodeRuleIdDescription">
+        <source>Avoid the 'Opt' suffix in a nullable-enabled code.</source>
+        <target state="new">Avoid the 'Opt' suffix in a nullable-enabled code.</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="AvoidOptSuffixForNullableEnableCodeRuleIdMessage">
+        <source>Avoid the 'Opt' suffix in a nullable-enabled code</source>
+        <target state="new">Avoid the 'Opt' suffix in a nullable-enabled code</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="AvoidOptSuffixForNullableEnableCodeRuleIdTitle">
+        <source>Avoid the 'Opt' suffix</source>
+        <target state="new">Avoid the 'Opt' suffix</target>
+        <note />
+      </trans-unit>
       <trans-unit id="DefaultableTypeShouldHaveDefaultableFieldsDescription">
         <source>Defaultable types should have defaultable fields</source>
         <target state="translated">Typy dopuszczające wartość domyślną powinny mieć pola z wartościami domyślnymi</target>

src/Roslyn.Diagnostics.Analyzers/Core/xlf/RoslynDiagnosticsAnalyzersResources.pt-BR.xlf

@@ -2,6 +2,21 @@
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
   <file datatype="xml" source-language="en" target-language="pt-BR" original="../RoslynDiagnosticsAnalyzersResources.resx">
     <body>
+      <trans-unit id="AvoidOptSuffixForNullableEnableCodeRuleIdDescription">
+        <source>Avoid the 'Opt' suffix in a nullable-enabled code.</source>
+        <target state="new">Avoid the 'Opt' suffix in a nullable-enabled code.</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="AvoidOptSuffixForNullableEnableCodeRuleIdMessage">
+        <source>Avoid the 'Opt' suffix in a nullable-enabled code</source>
+        <target state="new">Avoid the 'Opt' suffix in a nullable-enabled code</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="AvoidOptSuffixForNullableEnableCodeRuleIdTitle">
+        <source>Avoid the 'Opt' suffix</source>
+        <target state="new">Avoid the 'Opt' suffix</target>
+        <note />
+      </trans-unit>
       <trans-unit id="DefaultableTypeShouldHaveDefaultableFieldsDescription">
         <source>Defaultable types should have defaultable fields</source>
         <target state="translated">Os tipos usados como padrão devem ter campos usados como padrão</target>

src/Roslyn.Diagnostics.Analyzers/Core/xlf/RoslynDiagnosticsAnalyzersResources.ru.xlf

@@ -2,6 +2,21 @@
 <xliff xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.2" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
   <file datatype="xml" source-language="en" target-language="ru" original="../RoslynDiagnosticsAnalyzersResources.resx">
     <body>
+      <trans-unit id="AvoidOptSuffixForNullableEnableCodeRuleIdDescription">
+        <source>Avoid the 'Opt' suffix in a nullable-enabled code.</source>
+        <target state="new">Avoid the 'Opt' suffix in a nullable-enabled code.</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="AvoidOptSuffixForNullableEnableCodeRuleIdMessage">
+        <source>Avoid the 'Opt' suffix in a nullable-enabled code</source>
+        <target state="new">Avoid the 'Opt' suffix in a nullable-enabled code</target>
+        <note />
+      </trans-unit>
+      <trans-unit id="AvoidOptSuffixForNullableEnableCodeRuleIdTitle">
+        <source>Avoid the 'Opt' suffix</source>
+        <target state="new">Avoid the 'Opt' suffix</target>
+        <note />
+      </trans-unit>
       <trans-unit id="DefaultableTypeShouldHaveDefaultableFieldsDescription">
         <source>Defaultable types should have defaultable fields</source>
         <target state="translated">Типы, допускающие значения по умолчанию, должны иметь соответствующие поля.</target>