Add configuration option to allow OfT suffix for generic types with any arity

docs/Rules/MA0048.md

@@ -42,11 +42,27 @@ class Foo<T> // compliant
 {
 }
 
+// filename: Foo`1.cs
+class Foo<T> // compliant
+{
+}
+
 // filename: Foo{TKey,TResult}.cs
 class Foo<TKey, TResult> // compliant
 {
 }
 
+// filename: FooOfT.cs
+class Foo<TKey, TResult> // non compliant (requires MA0048.allow_oft_for_all_generic_types = true)
+{
+}
+
+// filename: FooOfT.cs
+// .editorconfig: MA0048.allow_oft_for_all_generic_types = true
+class Foo<TKey, TResult> // compliant
+{
+}
+
 // filename: Foo{T}.cs
 class Foo<TKey, TResult> // non compliant
 {
@@ -76,6 +92,9 @@ MA0048.exclude_file_local_types = true
 # Only validate the first type in a file. default: false
 MA0048.only_validate_first_type = false
 
+# Allow "OfT" suffix for generic types with any arity (not just arity 1). default: false
+MA0048.allow_oft_for_all_generic_types = false
+
 # Ignore certain symbols. default: none
 # Pipe-separated list of wildcard patterns
 dotnet_diagnostic.MA0048.excluded_symbol_names = Foo*|T:MyNamespace.Bar

src/Meziantou.Analyzer/Rules/FileNameMustMatchTypeNameAnalyzer.cs

@@ -114,7 +114,7 @@ private static void AnalyzeSymbol(SymbolAnalysisContext context)
                     continue;
             }
 
-            if (symbol.Arity == 1)
+            if (symbol.Arity == 1 || (symbol.Arity > 1 && context.Options.GetConfigurationValue(location.SourceTree, Rule.Id + ".allow_oft_for_all_generic_types", defaultValue: false)))
             {
                 // TypeOfT
                 if (fileName.Equals((symbolName + "OfT").AsSpan(), StringComparison.OrdinalIgnoreCase))

tests/Meziantou.Analyzer.Test/Rules/FileNameMustMatchTypeNameAnalyzerTests.cs

@@ -89,6 +89,45 @@ class Test0<T>
               .ValidateAsync();
     }
 
+    [Fact]
+    public async Task DoesNotMatchFileName_GenericWithArityGreaterThan1UsingOfT_WithoutConfiguration()
+    {
+        await CreateProjectBuilder()
+              .WithSourceCode(fileName: "Test0OfT.cs", """
+                  class [||]Test0<T1, T2>
+                  {
+                  }
+                  """)
+              .ValidateAsync();
+    }
+
+    [Fact]
+    public async Task DoesMatchFileName_GenericWithArityGreaterThan1UsingOfT_WithConfiguration()
+    {
+        await CreateProjectBuilder()
+              .WithSourceCode(fileName: "Test0OfT.cs", """
+                  class Test0<T1, T2>
+                  {
+                  }
+                  """)
+              .AddAnalyzerConfiguration("MA0048.allow_oft_for_all_generic_types", "true")
+              .ValidateAsync();
+    }
+
+#if CSHARP11_OR_GREATER
+    [Fact]
+    public async Task DoesMatchFileName_RecordStructWithArityGreaterThan1UsingOfT_WithConfiguration()
+    {
+        await CreateProjectBuilder()
+              .WithSourceCode(fileName: "FooOfT.cs", """
+                  public record struct Foo<T1, T2>(T1 Key, T2 Value);
+                  """)
+              .WithLanguageVersion(Microsoft.CodeAnalysis.CSharp.LanguageVersion.CSharp11)
+              .AddAnalyzerConfiguration("MA0048.allow_oft_for_all_generic_types", "true")
+              .ValidateAsync();
+    }
+#endif
+
     [Fact]
     public async Task NestedTypeDoesMatchFileName_Ok()
     {