Fix analyzer RCS1264 (#1666)

Author: josefpihrt

ChangeLog.md

@@ -11,6 +11,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - [CLI] Add support for GitLab analyzer reports ([PR](https://github.com/dotnet/roslynator/pull/1633))
 
+### Fixed
+
+- Fix analyzer [RCS1264](https://josefpihrt.github.io/docs/roslynator/analyzers/RCS1264) ([PR](https://github.com/dotnet/roslynator/pull/1666))
+
 ## [4.13.1] - 2025-02-23
 
 ### Added

src/Analyzers/CSharp/Analysis/UseVarOrExplicitTypeAnalyzer.cs

@@ -43,7 +43,7 @@ private static void AnalyzeVariableDeclaration(SyntaxNodeAnalysisContext context
 
         if (style == TypeStyle.Implicit)
         {
-            if (CSharpTypeAnalysis.IsExplicitThatCanBeImplicit(variableDeclaration, context.SemanticModel, TypeAppearance.NotObvious, context.CancellationToken))
+            if (CSharpTypeAnalysis.IsExplicitThatCanBeImplicit(variableDeclaration, context.SemanticModel, context.CancellationToken))
                 ReportExplicitToImplicit(context, variableDeclaration.Type);
         }
         else if (style == TypeStyle.Explicit)

src/CSharp/CSharp/CSharpTypeAnalysis.cs

@@ -250,11 +250,13 @@ public static bool IsExplicitThatCanBeImplicit(
                 return IsTypeObvious(expression, typeSymbol, includeNullability: true, semanticModel, cancellationToken);
             case TypeAppearance.NotObvious:
                 return !IsTypeObvious(expression, typeSymbol, includeNullability: true, semanticModel, cancellationToken);
+            case TypeAppearance.None:
+                return GetEqualityComparer(includeNullability: true).Equals(
+                    typeSymbol,
+                    semanticModel.GetTypeSymbol(expression, cancellationToken));
+            default:
+                throw new InvalidOperationException($"Unknow enum value '{typeAppearance}'");
         }
-
-        Debug.Assert(typeAppearance == TypeAppearance.None, typeAppearance.ToString());
-
-        return true;
     }
 
     public static bool IsTypeObvious(ExpressionSyntax expression, SemanticModel semanticModel, CancellationToken cancellationToken)

src/Tests/Analyzers.Tests/RCS1264UseVarOrExplicitTypeTests.cs

@@ -38,6 +38,28 @@ object M()
 ", options: Options.AddConfigOption(ConfigOptionKeys.UseVar, ConfigOptionValues.UseVar_Always));
     }
 
+    [Fact, Trait(Traits.Analyzer, DiagnosticIdentifiers.UseVarOrExplicitType)]
+    public async Task Test_ObjectCreationExpression()
+    {
+        await VerifyDiagnosticAndFixAsync(@"
+class C
+{
+    void M()
+    {
+        [|string[]|] arr = new string[1];
+    }
+}
+", @"
+class C
+{
+    void M()
+    {
+        var arr = new string[1];
+    }
+}
+", options: Options.AddConfigOption(ConfigOptionKeys.UseVar, ConfigOptionValues.UseVar_Always));
+    }
+
     [Fact, Trait(Traits.Analyzer, DiagnosticIdentifiers.UseVarOrExplicitType)]
     public async Task Test_TupleExpression()
     {
@@ -177,16 +199,26 @@ class C
     }
 
     [Fact, Trait(Traits.Analyzer, DiagnosticIdentifiers.UseVarOrExplicitType)]
-    public async Task TestNoDiagnostic_ParseMethod()
+    public async Task TestDiagnostic_ParseMethod()
     {
-        await VerifyNoDiagnosticAsync(@"
+        await VerifyDiagnosticAndFixAsync(@"
+using System;
+
+class C
+{
+    void M()
+    {
+        [|TimeSpan|] timeSpan = TimeSpan.Parse(null);
+    }
+}
+", @"
 using System;
 
 class C
 {
     void M()
     {
-        TimeSpan timeSpan = TimeSpan.Parse(null);
+        var timeSpan = TimeSpan.Parse(null);
     }
 }
 ", options: Options.AddConfigOption(ConfigOptionKeys.UseVar, ConfigOptionValues.UseVar_Always));