From f8ace6ad4e18ff869563cfbad8efba95436e395e Mon Sep 17 00:00:00 2001
From: Tom Hvitved <hvitved@github.com>
Date: Tue, 5 Sep 2023 21:19:34 +0200
Subject: [PATCH] C#: Clear TRAP stack when calling `PopulateGenerics`

---
 .../Entities/Types/Type.cs                    | 55 ++++++++++---------
 csharp/extractor/Semmle.Extraction/Context.cs |  4 +-
 2 files changed, 31 insertions(+), 28 deletions(-)

diff --git a/csharp/extractor/Semmle.Extraction.CSharp/Entities/Types/Type.cs b/csharp/extractor/Semmle.Extraction.CSharp/Entities/Types/Type.cs
index 909b255871fd5..4f51ae74c936c 100644
--- a/csharp/extractor/Semmle.Extraction.CSharp/Entities/Types/Type.cs
+++ b/csharp/extractor/Semmle.Extraction.CSharp/Entities/Types/Type.cs
@@ -250,41 +250,44 @@ public void ExtractRecursive()
         /// </summary>
         public void PopulateGenerics()
         {
-            if (Symbol is null || !NeedsPopulation || !Context.ExtractGenerics(this))
-                return;
+            Context.PopulateLater(() =>
+            {
+                if (Symbol is null || !NeedsPopulation || !Context.ExtractGenerics(this))
+                    return;
 
-            var members = new List<ISymbol>();
+                var members = new List<ISymbol>();
 
-            foreach (var member in Symbol.GetMembers())
-                members.Add(member);
-            foreach (var member in Symbol.GetTypeMembers())
-                members.Add(member);
+                foreach (var member in Symbol.GetMembers())
+                    members.Add(member);
+                foreach (var member in Symbol.GetTypeMembers())
+                    members.Add(member);
 
-            // Mono extractor puts all BASE interface members as members of the current interface.
+                // Mono extractor puts all BASE interface members as members of the current interface.
 
-            if (Symbol.TypeKind == TypeKind.Interface)
-            {
-                foreach (var baseInterface in Symbol.Interfaces)
+                if (Symbol.TypeKind == TypeKind.Interface)
                 {
-                    foreach (var member in baseInterface.GetMembers())
-                        members.Add(member);
-                    foreach (var member in baseInterface.GetTypeMembers())
-                        members.Add(member);
+                    foreach (var baseInterface in Symbol.Interfaces)
+                    {
+                        foreach (var member in baseInterface.GetMembers())
+                            members.Add(member);
+                        foreach (var member in baseInterface.GetTypeMembers())
+                            members.Add(member);
+                    }
                 }
-            }
 
-            foreach (var member in members)
-            {
-                Context.CreateEntity(member);
-            }
+                foreach (var member in members)
+                {
+                    Context.CreateEntity(member);
+                }
 
-            if (Symbol.BaseType is not null)
-                Create(Context, Symbol.BaseType).PopulateGenerics();
+                if (Symbol.BaseType is not null)
+                    Create(Context, Symbol.BaseType).PopulateGenerics();
 
-            foreach (var i in Symbol.Interfaces)
-            {
-                Create(Context, i).PopulateGenerics();
-            }
+                foreach (var i in Symbol.Interfaces)
+                {
+                    Create(Context, i).PopulateGenerics();
+                }
+            }, preserveDuplicationKey: false);
         }
 
         public void ExtractRecursive(TextWriter trapFile, IEntity parent)
diff --git a/csharp/extractor/Semmle.Extraction/Context.cs b/csharp/extractor/Semmle.Extraction/Context.cs
index 6694757f0d837..a6442758daf23 100644
--- a/csharp/extractor/Semmle.Extraction/Context.cs
+++ b/csharp/extractor/Semmle.Extraction/Context.cs
@@ -153,9 +153,9 @@ internal void AddFreshLabel(Entity entity)
         /// Enqueue the given action to be performed later.
         /// </summary>
         /// <param name="toRun">The action to run.</param>
-        public void PopulateLater(Action a)
+        public void PopulateLater(Action a, bool preserveDuplicationKey = true)
         {
-            var key = GetCurrentTagStackKey();
+            var key = preserveDuplicationKey ? GetCurrentTagStackKey() : null;
             if (key is not null)
             {
                 // If we are currently executing with a duplication guard, then the same