C#: Provide some higher order methods for writing Locations to TRAP.

Author: michaelnebel

csharp/extractor/Semmle.Extraction.CSharp/Entities/Base/CachedSymbol.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
@@ -102,6 +103,22 @@ public virtual IEnumerable<Location> Locations
             }
         }
 
+        protected static void WriteLocationToTrap<T1>(Action<T1, Location> writeAction, T1 entity, Location l)
+        {
+            if (l is not EmptyLocation)
+            {
+                writeAction(entity, l);
+            }
+        }
+
+        protected static void WriteLocationsToTrap<T1>(Action<T1, Location> writeAction, T1 entity, IEnumerable<Location> locations)
+        {
+            foreach (var loc in locations)
+            {
+                WriteLocationToTrap(writeAction, entity, loc);
+            }
+        }
+
         /// <summary>
         /// Bind comments to this symbol.
         /// Comments are only bound to source declarations.

csharp/extractor/Semmle.Extraction.CSharp/Entities/Constructor.cs

@@ -29,10 +29,7 @@ public override void Populate(TextWriter trapFile)
             ContainingType!.PopulateGenerics();
 
             trapFile.constructors(this, Symbol.ContainingType.Name, ContainingType, (Constructor)OriginalDefinition);
-            if (Location is not EmptyLocation)
-            {
-                trapFile.constructor_location(this, Location);
-            }
+            WriteLocationToTrap(trapFile.constructor_location, this, Location);
 
             if (MakeSynthetic)
             {

csharp/extractor/Semmle.Extraction.CSharp/Entities/OrdinaryMethod.cs

@@ -45,13 +45,7 @@ public override void Populate(TextWriter trapFile)
 
             if (Context.ExtractLocation(Symbol))
             {
-                foreach (var l in Locations)
-                {
-                    if (l is not EmptyLocation)
-                    {
-                        trapFile.method_location(this, l);
-                    }
-                }
+                WriteLocationsToTrap(trapFile.method_location, this, Locations);
             }
 
             PopulateGenerics(trapFile);