Fix analyzer RCS1214

ChangeLog.md

@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Fix analyzer [RCS1182](https://josefpihrt.github.io/docs/roslynator/analyzers/RCS1182) ([PR](https://github.com/dotnet/roslynator/pull/1502))
 - Fix analyzer [RCS1198](https://josefpihrt.github.io/docs/roslynator/analyzers/RCS1198) ([PR](https://github.com/dotnet/roslynator/pull/1501))
+- Fix analyzer [RCS1214](https://josefpihrt.github.io/docs/roslynator/analyzers/RCS1214) ([PR](https://github.com/dotnet/roslynator/pull/1500))
 
 ## [4.12.4] - 2024-06-01
 

src/Analyzers/CSharp/Analysis/UnnecessaryInterpolatedStringAnalyzer.cs

@@ -60,7 +60,7 @@ private static void AnalyzeInterpolatedStringExpression(SyntaxNodeAnalysisContex
 
         if (ConvertInterpolatedStringToStringLiteralAnalysis.IsFixable(contents))
         {
-            if (IsFormattableString(context))
+            if (CheckConvertedType(context))
                 return;
 
             ReportDiagnostic(
@@ -87,7 +87,7 @@ private static void AnalyzeInterpolatedStringExpression(SyntaxNodeAnalysisContex
             if (!IsNonNullStringExpression(expression))
                 return;
 
-            if (IsFormattableString(context))
+            if (CheckConvertedType(context))
                 return;
 
             ReportDiagnostic(context, DiagnosticRules.UnnecessaryInterpolatedString, interpolatedString);
@@ -110,13 +110,15 @@ bool IsNonNullStringExpression(ExpressionSyntax expression)
                 && value is not null;
         }
 
-        static bool IsFormattableString(SyntaxNodeAnalysisContext context)
+        static bool CheckConvertedType(SyntaxNodeAnalysisContext context)
         {
-            return context
+            ITypeSymbol convertedType = context
                 .SemanticModel
                 .GetTypeInfo(context.Node, context.CancellationToken)
-                .ConvertedType?
-                .HasMetadataName(MetadataNames.System_FormattableString) == true;
+                .ConvertedType;
+
+            return convertedType?.HasMetadataName(MetadataNames.System_FormattableString) == true
+                || convertedType?.HasMetadataName(MetadataNames.System_MemoryExtensions_TryWriteInterpolatedStringHandler) == true;
         }
     }
 

src/Core/MetadataNames.cs

@@ -45,6 +45,7 @@ internal static class MetadataNames
     public static readonly MetadataName System_Linq_ImmutableArrayExtensions = MetadataName.Parse("System.Linq.ImmutableArrayExtensions");
     public static readonly MetadataName System_Linq_IOrderedEnumerable_T = MetadataName.Parse("System.Linq.IOrderedEnumerable`1");
     public static readonly MetadataName System_Linq_IQueryable_T = MetadataName.Parse("System.Linq.IQueryable`1");
+    public static readonly MetadataName System_MemoryExtensions_TryWriteInterpolatedStringHandler = MetadataName.Parse("System.MemoryExtensions+TryWriteInterpolatedStringHandler");
     public static readonly MetadataName System_NonSerializedAttribute = MetadataName.Parse("System.NonSerializedAttribute");
     public static readonly MetadataName System_ObsoleteAttribute = MetadataName.Parse("System.ObsoleteAttribute");
     public static readonly MetadataName System_ReadOnlySpan_T = MetadataName.Parse("System.ReadOnlySpan`1");

src/Tests/Analyzers.Tests/RCS1214UnnecessaryInterpolatedStringTests.cs

@@ -204,6 +204,24 @@ string Call(FormattableString s)
     }
 
 }
+""");
+    }
+
+    [Fact, Trait(Traits.Analyzer, DiagnosticIdentifiers.UnnecessaryInterpolatedString)]
+    public async Task TestNoDiagnostic_TryWriteInterpolatedStringHandler()
+    {
+        await VerifyNoDiagnosticAsync("""
+using System;
+using System.Globalization;
+
+class C
+{
+    public void M()
+    {
+        Span<char> bar = stackalloc char[1];
+        bar.TryWrite(CultureInfo.InvariantCulture, $"foo", out _);
+    }
+}
 """);
     }
 }