C#: Refactor to re-use code to extract modifier tokens.

Author: michaelnebel

csharp/extractor/Semmle.Extraction.CSharp/SymbolExtensions.cs

@@ -68,19 +68,19 @@ public static string GetName(this ISymbol symbol, bool useMetadataName = false)
             return symbol.CanBeReferencedByName ? name : name.Substring(symbol.Name.LastIndexOf('.') + 1);
         }
 
+        private static IEnumerable<SyntaxToken> GetModifiers<T>(this ISymbol symbol, Func<T, IEnumerable<SyntaxToken>> getModifierTokens) =>
+            symbol.DeclaringSyntaxReferences
+                .Select(r => r.GetSyntax())
+                .OfType<T>()
+                .SelectMany(getModifierTokens);
+
         /// <summary>
         /// Gets the source-level modifiers belonging to this symbol, if any.
         /// </summary>
         public static IEnumerable<string> GetSourceLevelModifiers(this ISymbol symbol)
         {
-            var methodModifiers = symbol.DeclaringSyntaxReferences
-                .Select(r => r.GetSyntax())
-                .OfType<Microsoft.CodeAnalysis.CSharp.Syntax.BaseMethodDeclarationSyntax>()
-                .SelectMany(md => md.Modifiers);
-            var typeModifers = symbol.DeclaringSyntaxReferences
-                .Select(r => r.GetSyntax())
-                .OfType<Microsoft.CodeAnalysis.CSharp.Syntax.TypeDeclarationSyntax>()
-                .SelectMany(cd => cd.Modifiers);
+            var methodModifiers = symbol.GetModifiers<Microsoft.CodeAnalysis.CSharp.Syntax.BaseMethodDeclarationSyntax>(md => md.Modifiers);
+            var typeModifers = symbol.GetModifiers<Microsoft.CodeAnalysis.CSharp.Syntax.TypeDeclarationSyntax>(cd => cd.Modifiers);
             return methodModifiers.Concat(typeModifers).Select(m => m.Text);
         }
 
@@ -277,10 +277,8 @@ private static void BuildAssembly(IAssemblySymbol asm, EscapingTextWriter trapFi
             trapFile.Write("::");
         }
 
-        private static void BuildFunctionPointerTypeId(this IFunctionPointerTypeSymbol funptr, Context cx, EscapingTextWriter trapFile, ISymbol symbolBeingDefined)
-        {
+        private static void BuildFunctionPointerTypeId(this IFunctionPointerTypeSymbol funptr, Context cx, EscapingTextWriter trapFile, ISymbol symbolBeingDefined) =>
             BuildFunctionPointerSignature(funptr, trapFile, s => s.BuildOrWriteId(cx, trapFile, symbolBeingDefined));
-        }
 
         private static void BuildNamedTypeId(this INamedTypeSymbol named, Context cx, EscapingTextWriter trapFile, ISymbol symbolBeingDefined, bool constructUnderlyingTupleType)
         {
@@ -456,10 +454,8 @@ public static void BuildFunctionPointerSignature(IFunctionPointerTypeSymbol funp
             trapFile.Write('>');
         }
 
-        private static void BuildFunctionPointerTypeDisplayName(this IFunctionPointerTypeSymbol funptr, Context cx, TextWriter trapFile)
-        {
+        private static void BuildFunctionPointerTypeDisplayName(this IFunctionPointerTypeSymbol funptr, Context cx, TextWriter trapFile) =>
             BuildFunctionPointerSignature(funptr, trapFile, s => s.BuildDisplayName(cx, trapFile));
-        }
 
         private static void BuildNamedTypeDisplayName(this INamedTypeSymbol namedType, Context cx, TextWriter trapFile, bool constructUnderlyingTupleType)
         {