Add analyzer 'Declare explicit/implicit type'

ChangeLog.md

@@ -12,6 +12,15 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Add analyzer "Add/remove blank line between switch sections" ([RCS0061](https://josefpihrt.github.io/docs/roslynator/analyzers/RCS0061)) ([PR](https://github.com/dotnet/roslynator/pull/1302))
   - Option (required): `roslynator_blank_line_between_switch_sections = include|omit|omit_after_block` 
   - Make analyzer [RCS0014](https://josefpihrt.github.io/docs/roslynator/analyzers/RCS0014) obsolete
+- Add analyzer "Declare explicit/implicit type" ([RCS1264](https://josefpihrt.github.io/docs/roslynator/analyzers/RCS1264)) ([PR](https://github.com/dotnet/roslynator/pull/1335))
+  - Required option: `roslynator_use_var = always | never | when_type_is_obvious` 
+  - This analyzer consolidates following analyzers (which are made obsolete):
+    - [RCS1008](https://josefpihrt.github.io/docs/roslynator/analyzers/RCS1008)
+    - [RCS1009](https://josefpihrt.github.io/docs/roslynator/analyzers/RCS1009)
+    - [RCS1010](https://josefpihrt.github.io/docs/roslynator/analyzers/RCS1010)
+    - [RCS1012](https://josefpihrt.github.io/docs/roslynator/analyzers/RCS1012)
+    - [RCS1176](https://josefpihrt.github.io/docs/roslynator/analyzers/RCS1176)
+    - [RCS1177](https://josefpihrt.github.io/docs/roslynator/analyzers/RCS1177)
 - Add code fix "Declare as nullable" ([PR](https://github.com/dotnet/roslynator/pull/1333))
   - Applicable to: `CS8600`, `CS8610`, `CS8765` and `CS8767`
 - Add option `roslynator_use_collection_expression = true|false` ([PR](https://github.com/dotnet/roslynator/pull/1325))

src/Analyzers.CodeFixes/CSharp/CodeFixes/UseExplicitTypeInsteadOfVarCodeFixProvider.cs

@@ -1,5 +1,6 @@
 // Copyright (c) .NET Foundation and Contributors. Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System;
 using System.Collections.Immutable;
 using System.Composition;
 using System.Diagnostics;
@@ -14,6 +15,7 @@
 
 namespace Roslynator.CSharp.CodeFixes;
 
+[Obsolete("Use code fix provider 'UseVarOrExplicitTypeCodeFixProvider' instead.")]
 [ExportCodeFixProvider(LanguageNames.CSharp, Name = nameof(UseExplicitTypeInsteadOfVarCodeFixProvider))]
 [Shared]
 public sealed class UseExplicitTypeInsteadOfVarCodeFixProvider : BaseCodeFixProvider

src/Analyzers.CodeFixes/CSharp/CodeFixes/UseExplicitTypeInsteadOfVarInForEachCodeFixProvider.cs

@@ -13,6 +13,7 @@
 
 namespace Roslynator.CSharp.CodeFixes;
 
+[Obsolete("Use code fix provider 'UseVarOrExplicitTypeCodeFixProvider' instead.")]
 [ExportCodeFixProvider(LanguageNames.CSharp, Name = nameof(UseExplicitTypeInsteadOfVarInForEachCodeFixProvider))]
 [Shared]
 public sealed class UseExplicitTypeInsteadOfVarInForEachCodeFixProvider : BaseCodeFixProvider

src/Analyzers.CodeFixes/CSharp/CodeFixes/UseVarInsteadOfExplicitTypeCodeFixProvider.cs

@@ -13,6 +13,7 @@
 
 namespace Roslynator.CSharp.CodeFixes;
 
+[Obsolete("Use code fix provider 'UseVarOrExplicitTypeCodeFixProvider' instead.")]
 [ExportCodeFixProvider(LanguageNames.CSharp, Name = nameof(UseVarInsteadOfExplicitTypeCodeFixProvider))]
 [Shared]
 public sealed class UseVarInsteadOfExplicitTypeCodeFixProvider : BaseCodeFixProvider

src/Analyzers.CodeFixes/CSharp/CodeFixes/UseVarOrExplicitTypeCodeFixProvider.cs

@@ -0,0 +1,157 @@
+// Copyright (c) .NET Foundation and Contributors. Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Collections.Immutable;
+using System.Composition;
+using System.Diagnostics;
+using System.Threading.Tasks;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CodeActions;
+using Microsoft.CodeAnalysis.CodeFixes;
+using Microsoft.CodeAnalysis.CSharp;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Roslynator.CodeFixes;
+using Roslynator.CSharp;
+using static Roslynator.CSharp.CodeActionFactory;
+
+namespace Roslynator.CSharp.CodeFixes;
+
+[ExportCodeFixProvider(LanguageNames.CSharp, Name = nameof(UseVarOrExplicitTypeCodeFixProvider))]
+[Shared]
+public sealed class UseVarOrExplicitTypeCodeFixProvider : BaseCodeFixProvider
+{
+    public override ImmutableArray<string> FixableDiagnosticIds
+    {
+        get { return ImmutableArray.Create(DiagnosticIdentifiers.UseVarOrExplicitType); }
+    }
+
+    public override async Task RegisterCodeFixesAsync(CodeFixContext context)
+    {
+        SyntaxNode root = await context.GetSyntaxRootAsync().ConfigureAwait(false);
+
+        if (!TryFindFirstAncestorOrSelf(
+            root,
+            context.Span,
+            out SyntaxNode node,
+            predicate: f => f is TypeSyntax
+                || f.IsKind(
+                    SyntaxKind.VariableDeclaration,
+                    SyntaxKind.DeclarationExpression,
+                    SyntaxKind.ForEachStatement,
+                    SyntaxKind.ForEachVariableStatement,
+                    SyntaxKind.TupleExpression)))
+        {
+            return;
+        }
+
+        Document document = context.Document;
+        Diagnostic diagnostic = context.Diagnostics[0];
+
+        SemanticModel semanticModel = await context.GetSemanticModelAsync().ConfigureAwait(false);
+
+        if (node is TypeSyntax type)
+        {
+            if (type.IsVar)
+            {
+                if (node.IsParentKind(SyntaxKind.VariableDeclaration, SyntaxKind.ForEachStatement))
+                {
+                    node = node.Parent;
+                }
+                else if (node.IsParentKind(SyntaxKind.DeclarationExpression))
+                {
+                    node = node.Parent;
+
+                    if (node.IsParentKind(SyntaxKind.ForEachVariableStatement))
+                        node = node.Parent;
+                }
+            }
+            else
+            {
+                CodeAction codeAction = ChangeTypeToVar(document, type, equivalenceKey: GetEquivalenceKey(diagnostic, "ToImplicit"));
+                context.RegisterCodeFix(codeAction, diagnostic);
+                return;
+            }
+        }
+
+        switch (node)
+        {
+            case TupleExpressionSyntax tupleExpression:
+                {
+                    CodeAction codeAction = ChangeTypeToVar(document, tupleExpression, equivalenceKey: GetEquivalenceKey(diagnostic, "ToImplicit"));
+                    context.RegisterCodeFix(codeAction, diagnostic);
+                    break;
+                }
+            case VariableDeclarationSyntax variableDeclaration:
+                {
+                    ExpressionSyntax value = variableDeclaration.Variables[0].Initializer.Value;
+                    ITypeSymbol typeSymbol = semanticModel.GetTypeSymbol(value, context.CancellationToken);
+
+                    if (typeSymbol is null)
+                    {
+                        var localSymbol = semanticModel.GetDeclaredSymbol(variableDeclaration.Variables[0], context.CancellationToken) as ILocalSymbol;
+
+                        if (localSymbol is not null)
+                        {
+                            typeSymbol = localSymbol.Type;
+                            value = value.WalkDownParentheses();
+
+                            Debug.Assert(
+                                value.IsKind(SyntaxKind.SimpleLambdaExpression, SyntaxKind.ParenthesizedLambdaExpression),
+                                value.Kind().ToString());
+
+                            if (value.IsKind(SyntaxKind.SimpleLambdaExpression, SyntaxKind.ParenthesizedLambdaExpression))
+                                typeSymbol = typeSymbol.WithNullableAnnotation(NullableAnnotation.NotAnnotated);
+                        }
+                        else
+                        {
+                            SyntaxDebug.Fail(variableDeclaration.Variables[0]);
+                            return;
+                        }
+                    }
+
+                    CodeAction codeAction = UseExplicitType(document, variableDeclaration.Type, typeSymbol, semanticModel, equivalenceKey: GetEquivalenceKey(diagnostic, "ToExplicit"));
+                    context.RegisterCodeFix(codeAction, diagnostic);
+                    break;
+                }
+            case DeclarationExpressionSyntax declarationExpression:
+                {
+                    ITypeSymbol typeSymbol = null;
+                    if (declarationExpression.Parent is AssignmentExpressionSyntax assignment)
+                    {
+                        typeSymbol = semanticModel.GetTypeSymbol(assignment.Right, context.CancellationToken);
+                    }
+                    else if (declarationExpression.Parent is ArgumentSyntax argument)
+                    {
+                        IParameterSymbol parameterSymbol = DetermineParameterHelper.DetermineParameter(argument, semanticModel, cancellationToken: context.CancellationToken);
+                        typeSymbol = parameterSymbol?.Type;
+                    }
+
+                    if (typeSymbol is null)
+                    {
+                        var localSymbol = semanticModel.GetDeclaredSymbol(declarationExpression.Designation, context.CancellationToken) as ILocalSymbol;
+                        typeSymbol = (localSymbol?.Type) ?? semanticModel.GetTypeSymbol(declarationExpression, context.CancellationToken);
+                    }
+
+                    CodeAction codeAction = UseExplicitType(document, declarationExpression.Type, typeSymbol, semanticModel, equivalenceKey: GetEquivalenceKey(diagnostic, "ToExplicit"));
+                    context.RegisterCodeFix(codeAction, diagnostic);
+                    break;
+                }
+            case ForEachStatementSyntax forEachStatement:
+                {
+                    ITypeSymbol typeSymbol = semanticModel.GetForEachStatementInfo((CommonForEachStatementSyntax)node).ElementType;
+
+                    CodeAction codeAction = UseExplicitType(document, forEachStatement.Type, typeSymbol, semanticModel, equivalenceKey: GetEquivalenceKey(diagnostic, "ToExplicit"));
+                    context.RegisterCodeFix(codeAction, diagnostic);
+                    break;
+                }
+            case ForEachVariableStatementSyntax forEachVariableStatement:
+                {
+                    var declarationExpression = (DeclarationExpressionSyntax)forEachVariableStatement.Variable;
+                    ITypeSymbol typeSymbol = semanticModel.GetForEachStatementInfo((CommonForEachStatementSyntax)node).ElementType;
+
+                    CodeAction codeAction = UseExplicitType(document, declarationExpression.Type, typeSymbol, semanticModel, equivalenceKey: GetEquivalenceKey(diagnostic, "ToExplicit"));
+                    context.RegisterCodeFix(codeAction, diagnostic);
+                    break;
+                }
+        }
+    }
+}

src/Analyzers.xml

@@ -1799,6 +1799,8 @@ else if (condition2)
   <Analyzer>
     <Id>RCS1008</Id>
     <Identifier>UseExplicitTypeInsteadOfVarWhenTypeIsNotObvious</Identifier>
+    <Status>Obsolete</Status>
+    <ObsoleteMessage>Use RCS1264 instead</ObsoleteMessage>
     <Title>Use explicit type instead of 'var' (when the type is not obvious)</Title>
     <MessageFormat>Use explicit type instead of 'var'</MessageFormat>
     <DefaultSeverity>Hidden</DefaultSeverity>
@@ -1814,6 +1816,8 @@ else if (condition2)
     <Id>RCS1009</Id>
     <Identifier>UseExplicitTypeInsteadOfVarInForEach</Identifier>
     <Title>Use explicit type instead of 'var' (foreach variable)</Title>
+    <Status>Obsolete</Status>
+    <ObsoleteMessage>Use RCS1264 instead</ObsoleteMessage>
     <MessageFormat>Use explicit type instead of 'var'</MessageFormat>
     <DefaultSeverity>Hidden</DefaultSeverity>
     <IsEnabledByDefault>false</IsEnabledByDefault>
@@ -1835,6 +1839,8 @@ foreach (var item in items)
   <Analyzer>
     <Id>RCS1010</Id>
     <Identifier>UseVarInsteadOfExplicitTypeWhenTypeIsObvious</Identifier>
+    <Status>Obsolete</Status>
+    <ObsoleteMessage>Use RCS1264 instead</ObsoleteMessage>
     <Title>Use 'var' instead of explicit type (when the type is obvious)</Title>
     <MessageFormat>Use 'var' instead of explicit type</MessageFormat>
     <DefaultSeverity>Hidden</DefaultSeverity>
@@ -1850,6 +1856,8 @@ foreach (var item in items)
   <Analyzer>
     <Id>RCS1012</Id>
     <Identifier>UseExplicitTypeInsteadOfVarWhenTypeIsObvious</Identifier>
+    <Status>Obsolete</Status>
+    <ObsoleteMessage>Use RCS1264 instead</ObsoleteMessage>
     <Title>Use explicit type instead of 'var' (when the type is obvious)</Title>
     <MessageFormat>Use explicit type instead of 'var'</MessageFormat>
     <DefaultSeverity>Hidden</DefaultSeverity>
@@ -5411,6 +5419,8 @@ else
   <Analyzer>
     <Id>RCS1176</Id>
     <Identifier>UseVarInsteadOfExplicitTypeWhenTypeIsNotObvious</Identifier>
+    <Status>Obsolete</Status>
+    <ObsoleteMessage>Use RCS1264 instead</ObsoleteMessage>
     <Title>Use 'var' instead of explicit type (when the type is not obvious)</Title>
     <MessageFormat>Use 'var' instead of explicit type</MessageFormat>
     <DefaultSeverity>Hidden</DefaultSeverity>
@@ -5425,6 +5435,8 @@ else
   <Analyzer>
     <Id>RCS1177</Id>
     <Identifier>UseVarInsteadOfExplicitTypeInForEach</Identifier>
+    <Status>Obsolete</Status>
+    <ObsoleteMessage>Use RCS1264 instead</ObsoleteMessage>
     <Title>Use 'var' instead of explicit type (in foreach)</Title>
     <MessageFormat>Use 'var' instead of explicit type</MessageFormat>
     <DefaultSeverity>Hidden</DefaultSeverity>
@@ -7633,6 +7645,17 @@ public string Foo(string bar)
       </Sample>
     </Samples>
   </Analyzer>
+  <Analyzer>
+    <Id>RCS1264</Id>
+    <Identifier>UseVarOrExplicitType</Identifier>
+    <Title>Use 'var' or explicit type</Title>
+    <MessageFormat>{0}</MessageFormat>
+    <DefaultSeverity>Info</DefaultSeverity>
+    <IsEnabledByDefault>false</IsEnabledByDefault>
+    <ConfigOptions>
+      <Option Key="use_var" IsRequired="true" />
+    </ConfigOptions>
+  </Analyzer>
   <Analyzer>
     <Id>RCS9001</Id>
     <Identifier>UsePatternMatching</Identifier>

src/Analyzers/CSharp/Analysis/UseExplicitTypeInsteadOfVarInForEachAnalyzer.cs

@@ -1,5 +1,6 @@
 // Copyright (c) .NET Foundation and Contributors. Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System;
 using System.Collections.Immutable;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
@@ -8,6 +9,7 @@
 
 namespace Roslynator.CSharp.Analysis;
 
+[Obsolete("Use analyzer 'UseVarOrExplicitTypeAnalyzer' instead.")]
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
 public sealed class UseExplicitTypeInsteadOfVarInForEachAnalyzer : BaseDiagnosticAnalyzer
 {

src/Analyzers/CSharp/Analysis/UseExplicitTypeInsteadOfVarWhenTypeIsNotObviousAnalyzer.cs

@@ -1,5 +1,6 @@
 // Copyright (c) .NET Foundation and Contributors. Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System;
 using System.Collections.Immutable;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
@@ -8,6 +9,7 @@
 
 namespace Roslynator.CSharp.Analysis;
 
+[Obsolete("Use analyzer 'UseVarOrExplicitTypeAnalyzer' instead.")]
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
 public sealed class UseExplicitTypeInsteadOfVarWhenTypeIsNotObviousAnalyzer : BaseDiagnosticAnalyzer
 {

src/Analyzers/CSharp/Analysis/UseExplicitTypeInsteadOfVarWhenTypeIsObviousAnalyzer.cs

@@ -1,5 +1,6 @@
 // Copyright (c) .NET Foundation and Contributors. Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System;
 using System.Collections.Immutable;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
@@ -8,6 +9,7 @@
 
 namespace Roslynator.CSharp.Analysis;
 
+[Obsolete("Use analyzer 'UseVarOrExplicitTypeAnalyzer' instead.")]
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
 public sealed class UseExplicitTypeInsteadOfVarWhenTypeIsObviousAnalyzer : BaseDiagnosticAnalyzer
 {

src/Analyzers/CSharp/Analysis/UseVarInsteadOfExplicitTypeInForEachAnalyzer.cs

@@ -1,5 +1,6 @@
 // Copyright (c) .NET Foundation and Contributors. Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System;
 using System.Collections.Immutable;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
@@ -8,6 +9,7 @@
 
 namespace Roslynator.CSharp.Analysis;
 
+[Obsolete("Use analyzer 'UseVarOrExplicitTypeAnalyzer' instead.")]
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
 public sealed class UseVarInsteadOfExplicitTypeInForEachAnalyzer : BaseDiagnosticAnalyzer
 {

src/Analyzers/CSharp/Analysis/UseVarInsteadOfExplicitTypeWhenTypeIsNotObviousAnalyzer.cs

@@ -1,5 +1,6 @@
 // Copyright (c) .NET Foundation and Contributors. Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System;
 using System.Collections.Immutable;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
@@ -8,6 +9,7 @@
 
 namespace Roslynator.CSharp.Analysis;
 
+[Obsolete("Use analyzer 'UseVarOrExplicitTypeAnalyzer' instead.")]
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
 public sealed class UseVarInsteadOfExplicitTypeWhenTypeIsNotObviousAnalyzer : BaseDiagnosticAnalyzer
 {

src/Analyzers/CSharp/Analysis/UseVarInsteadOfExplicitTypeWhenTypeIsObviousAnalyzer.cs

@@ -1,5 +1,6 @@
 // Copyright (c) .NET Foundation and Contributors. Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System;
 using System.Collections.Immutable;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
@@ -8,6 +9,7 @@
 
 namespace Roslynator.CSharp.Analysis;
 
+[Obsolete("Use analyzer 'UseVarOrExplicitTypeAnalyzer' instead.")]
 [DiagnosticAnalyzer(LanguageNames.CSharp)]
 public sealed class UseVarInsteadOfExplicitTypeWhenTypeIsObviousAnalyzer : BaseDiagnosticAnalyzer
 {