Add NoUsingDeclaration analyzer (#195)

- Fix the test framework so that test cases can import System.Net
- Ignore SA1008
- Move StyleChecker.Refactoring.UnnecessaryUsing.Classes to
  StyleChecker.Refactoring
- Add GetTypeInfoSupplier(SemanticModelAnalysisContext) methods to
  SmaContextExtentions class
- Add GetFullNameWithoutNullability(ITypeSymbol) method to TypeSymbols
  class
- Add ToSymbol(VariableDeclaratorSyntax) to ISymbolizer interface

StyleChecker/StyleChecker.Test/Framework/Projects.cs

@@ -5,6 +5,8 @@ namespace StyleChecker.Test.Framework;
 using System.Collections.Immutable;
 using System.IO;
 using System.Linq;
+using System.Net;
+using System.Net.Sockets;
 using Maroontress.Extensions;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
@@ -39,7 +41,13 @@ public static IEnumerable<MetadataReference>
             /* Microsoft.CodeAnalysis */
             NewReference<Compilation>(),
             /* System.Runtime.Extensions */
-            NewReference<StringReader>()
+            NewReference<StringReader>(),
+            /* System.Net.Sockets */
+            NewReference<Socket>(),
+            /* System.Private.Url */
+            NewReference<Uri>(),
+            /* System.Net.Primitives */
+            NewReference<IPAddress>(),
         ];
 
     /// <summary>

StyleChecker/StyleChecker.Test/Refactoring/NoUsingDeclaration/AnalyzerTest.cs

@@ -0,0 +1,33 @@
+namespace StyleChecker.Test.Refactoring.NoUsingDeclaration;
+
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using StyleChecker.Refactoring.NoUsingDeclaration;
+using StyleChecker.Test.Framework;
+
+[TestClass]
+public sealed class AnalyzerTest : CodeFixVerifier
+{
+    public AnalyzerTest()
+        : base(new Analyzer(), new CodeFixer())
+    {
+    }
+
+    [TestMethod]
+    public void Okay()
+        => VerifyDiagnostic(ReadText("Okay"), Atmosphere.Default);
+
+    [TestMethod]
+    public void Code()
+    {
+        var code = ReadText("Code");
+        var fix = ReadText("CodeFix");
+        static Result Expected(Belief b)
+        {
+            return b.ToResult(
+                Analyzer.DiagnosticId,
+                $"Insert 'using' before '{b.Message}'.");
+        }
+
+        VerifyDiagnosticAndFix(code, Atmosphere.Default, Expected, fix);
+    }
+}

StyleChecker/StyleChecker.Test/Refactoring/NoUsingDeclaration/Code.cs

@@ -0,0 +1,47 @@
+#nullable enable
+namespace StyleChecker.Test.Refactoring.NoUsingDeclaration;
+
+using System;
+using System.IO;
+
+public sealed class Code
+{
+    public static void Main()
+    {
+        var i = new StreamReader("file.txt");
+    //@ ^var
+        StreamReader j = new("file.txt");
+    //@ ^StreamReader
+    }
+
+    public static void ExplicitTypeDeclarationsWithMultipleDeclarators()
+    {
+        StreamReader i1 = new StreamReader("1.txt"), i2 = new StreamReader("2.txt");
+    //@ ^StreamReader
+        StreamReader j1 = new StreamReader("1.txt"), j2 = new("2.txt");
+    //@ ^StreamReader
+        StreamReader k1 = new("1.txt"), k2 = new StreamReader("2.txt");
+    //@ ^StreamReader
+    }
+
+    public static void Using()
+    {
+        // StringReader 'i' does not need to be disposed
+        StringReader i = new("hello");
+        // IDisposable 'j' should be disposed
+        IDisposable j = new StringReader("world");
+    //@ ^IDisposable
+    }
+
+    public static void Nullable()
+    {
+        StreamReader? k = new StreamReader("file.txt");
+    //@ ^StreamReader?
+    }
+
+    public static void KeepTrivia()
+    {
+        /*foo*/ var i = new StreamReader("file.txt"); // bar
+        //@     ^var
+    }
+}

StyleChecker/StyleChecker.Test/Refactoring/NoUsingDeclaration/CodeFix.cs

@@ -0,0 +1,40 @@
+#nullable enable
+namespace StyleChecker.Test.Refactoring.NoUsingDeclaration;
+
+using System;
+using System.IO;
+
+public sealed class Code
+{
+    public static void Main()
+    {
+        using var i = new StreamReader("file.txt");
+        using StreamReader j = new("file.txt");
+    }
+
+    public static void ExplicitTypeDeclarationsWithMultipleDeclarators()
+    {
+        using StreamReader i1 = new StreamReader("1.txt"), i2 = new StreamReader("2.txt");
+        using StreamReader j1 = new StreamReader("1.txt"), j2 = new("2.txt");
+        using StreamReader k1 = new("1.txt"), k2 = new StreamReader("2.txt");
+    }
+
+    public static void Using()
+    {
+        // StringReader 'i' does not need to be disposed
+        StringReader i = new("hello");
+        // IDisposable 'j' should be disposed
+        using IDisposable j = new StringReader("world");
+    }
+
+    public static void Nullable()
+    {
+        using StreamReader? k = new StreamReader("file.txt");
+    }
+
+    public static void KeepTrivia()
+    {
+        /*foo*/
+        using var i = new StreamReader("file.txt"); // bar
+    }
+}

StyleChecker/StyleChecker.Test/Refactoring/NoUsingDeclaration/Okay.cs

@@ -0,0 +1,113 @@
+#nullable enable
+namespace StyleChecker.Test.Refactoring.NoUsingDeclaration;
+
+using System;
+using System.IO;
+using System.Net.Sockets;
+
+public sealed class Okay
+{
+    private StreamReader? streamReader;
+
+    private TextWriter? SharedWriter { get; set; }
+
+    public void AssignedToFieldOrProperty()
+    {
+        // Replacing 'var' with 'using var' makes no sense.
+        var reader = new StreamReader("input.txt");
+        streamReader = reader;
+        var writer = new StreamWriter("output.txt");
+        SharedWriter = writer;
+    }
+
+    public static BufferedStream UsedAsAParameter()
+    {
+        // Replacing 'var' with 'using var' makes no sense.
+        var clientSocket = new Socket(
+            AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
+        var b = clientSocket.Connected;
+        var netStream = new NetworkStream(clientSocket, true);
+        var bufStream = new BufferedStream(netStream, 1024);
+        return bufStream;
+    }
+
+    // A factory method that returns a new IDisposable object.
+    public static Socket? Returned(Uri uri, int port)
+    {
+        // Replacing 'var' with 'using var' makes no sense.
+        var socket = new Socket(SocketType.Stream, ProtocolType.Tcp);
+        try
+        {
+            socket.Connect(uri.Host, port);
+            return socket;
+        }
+        catch (Exception)
+        {
+            socket.Dispose();
+        }
+        return null;
+    }
+
+    public static void Reassigned()
+    {
+        // Replacing 'var' with 'using var' causes an error CS1656.
+        var i = new StreamReader("file.txt");
+        Console.WriteLine(i.ReadLine());
+        i = new StreamReader("another.txt");
+        Console.WriteLine(i.ReadLine());
+    }
+
+    public static Action Captured()
+    {
+        var i = new StreamWriter("file.txt");
+        return () =>
+        {
+            i.WriteLine("hello");
+        };
+    }
+
+    public static void Main()
+    {
+        using var i = new StreamReader("file.txt");
+        // StringReader does not need to be disposed.
+        var j = new StringReader("hello");
+    }
+
+    public static void ExplicitTypeDeclarations()
+    {
+        using StreamReader i = new("file.txt");
+        using IDisposable j = new StringReader("world");
+    }
+
+    public static void Nullable()
+    {
+        using StreamReader? k = new StreamReader("file.txt");
+    }
+
+    public static void NotNewOperator()
+    {
+        var out1 = Console.Out;
+        TextWriter out2 = Console.Out;
+        var file1 = NewStreamReader("file.txt");
+        StreamReader? file2 = NewStreamReader("file.txt");
+    }
+
+    private static StreamReader? NewStreamReader(string path)
+    {
+        try
+        {
+            return new StreamReader(path);
+        }
+        catch (IOException)
+        {
+            return null;
+        }
+    }
+
+    private static void Loophole()
+    {
+        var (r1, r2) = (new StreamReader("1"), new StreamReader("2"));
+        TextReader[] array = [new StreamReader("1")];
+        var anotherArray = new[] { new StreamReader("1") };
+    }
+}

StyleChecker/StyleChecker.Test/StyleChecker.Test.csproj

@@ -45,6 +45,9 @@
     <Compile Remove="Refactoring\EqualsNull\Okay.cs" />
     <Compile Remove="Refactoring\NotOneShotInitialization\Code.cs" />
     <Compile Remove="Refactoring\NotOneShotInitialization\Okay.cs" />
+    <Compile Remove="Refactoring\NoUsingDeclaration\Code.cs" />
+    <Compile Remove="Refactoring\NoUsingDeclaration\CodeFix.cs" />
+    <Compile Remove="Refactoring\NoUsingDeclaration\Okay.cs" />
     <Compile Remove="Refactoring\StinkyBooleanExpression\Code.cs" />
     <Compile Remove="Refactoring\StinkyBooleanExpression\CodeFix.cs" />
     <Compile Remove="Refactoring\StinkyBooleanExpression\Okay.cs" />
@@ -255,6 +258,15 @@
     <Content Include="Refactoring\NotOneShotInitialization\Okay.cs">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </Content>
+    <Content Include="Refactoring\NoUsingDeclaration\CodeFix.cs">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </Content>
+    <Content Include="Refactoring\NoUsingDeclaration\Code.cs">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </Content>
+    <Content Include="Refactoring\NoUsingDeclaration\Okay.cs">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </Content>
     <Content Include="Refactoring\StinkyBooleanExpression\CodeFix.cs">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </Content>

StyleChecker/StyleChecker/.editorconfig

@@ -29,3 +29,6 @@ dotnet_diagnostic.SA1013.severity = none
 
 # SA1012: Opening braces should be spaced correctly
 dotnet_diagnostic.SA1012.severity = none
+
+# SA1008: Opening parenthesis should be spaced correctly
+dotnet_diagnostic.SA1008.severity = none

StyleChecker/StyleChecker/Refactoring/UnnecessaryUsing/Classes.cs → StyleChecker/StyleChecker/Refactoring/Classes.cs

@@ -1,4 +1,4 @@
-namespace StyleChecker.Refactoring.UnnecessaryUsing;
+namespace StyleChecker.Refactoring;
 
 using System.Collections.Immutable;
 using System.IO;

StyleChecker/StyleChecker/Refactoring/ISymbolizer.cs

@@ -283,4 +283,15 @@ public interface ISymbolizer
     /// The symbol representing the query range variable.
     /// </returns>
     IRangeVariableSymbol? ToSymbol(QueryContinuationSyntax node);
+
+    /// <summary>
+    /// Gets the symbol corresponding to the specified variable declarator.
+    /// </summary>
+    /// <param name="node">
+    /// The variable declarator.
+    /// </param>
+    /// <returns>
+    /// The symbol representing the variable.
+    /// </returns>
+    ISymbol? ToSymbol(VariableDeclaratorSyntax node);
 }