From b3cbdb5c1a5a1e75547d473ca59cfbdb182f2b50 Mon Sep 17 00:00:00 2001
From: Mathias Vorreiter Pedersen <mathiasvp@github.com>
Date: Wed, 24 Sep 2025 10:39:27 +0100
Subject: [PATCH] C++: Add QLDoc to TRange.

---
 cpp/ql/lib/semmle/code/cpp/controlflow/IRGuards.qll | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/cpp/ql/lib/semmle/code/cpp/controlflow/IRGuards.qll b/cpp/ql/lib/semmle/code/cpp/controlflow/IRGuards.qll
index d0f3de4fb3c..5765816e017 100644
--- a/cpp/ql/lib/semmle/code/cpp/controlflow/IRGuards.qll
+++ b/cpp/ql/lib/semmle/code/cpp/controlflow/IRGuards.qll
@@ -31,6 +31,12 @@ module GuardsInput implements SharedGuards::InputSig<Cpp::Location, Instruction,
   }
 
   private newtype TConstantValue =
+    // This is slightly abusing the shared guards library. Using
+    // `TRange(40, 50)` to model a constant expression in the program such as
+    // the literal "42" causes the shared guards library to make incorrect
+    // inferences.
+    // However, since we only use them to model `CaseConstant::asConstantValue`
+    // this does not cause any wrong inferences (at least for now).
     TRange(string minValue, string maxValue) {
       minValue != maxValue and
       exists(EdgeKind::caseEdge(minValue, maxValue))