diff --git a/csharp/ql/src/semmle/code/csharp/Unification.qll b/csharp/ql/src/semmle/code/csharp/Unification.qll
index 77aeae0813a4..48256a59a29c 100644
--- a/csharp/ql/src/semmle/code/csharp/Unification.qll
+++ b/csharp/ql/src/semmle/code/csharp/Unification.qll
@@ -474,7 +474,8 @@ module Gvn {
         sourceDecl = any(GenericType t).getSourceDeclaration() and
         not sourceDecl instanceof PointerType and
         not sourceDecl instanceof NullableType and
-        not sourceDecl instanceof ArrayType
+        not sourceDecl instanceof ArrayType and
+        not sourceDecl instanceof TupleType
       }
 
     cached