From 3c1a68ee8f45dbb7361a2abe3808835d8a3b38ec Mon Sep 17 00:00:00 2001
From: Max Schaefer <max@semmle.com>
Date: Mon, 27 Jan 2020 12:05:48 +0000
Subject: [PATCH] Fix hash-consing of literals.

We shouldn't rely on the literal value given in the `literals` table, but use the exact value (where available) instead.
---
 ql/src/RedundantCode/Clones.qll | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/ql/src/RedundantCode/Clones.qll b/ql/src/RedundantCode/Clones.qll
index 48650674706..beccbb9d1ec 100644
--- a/ql/src/RedundantCode/Clones.qll
+++ b/ql/src/RedundantCode/Clones.qll
@@ -50,10 +50,16 @@ class HashableNode extends AstNode {
    * Gets the value of this AST node, or the empty string if it does not have one.
    */
   string getValue() {
-    literals(this, result, _)
-    or
-    not literals(this, _, _) and
-    result = ""
+    // for literals, get the exact value if available
+    if exists(this.(BasicLit).getExactValue())
+    then result = this.(BasicLit).getExactValue()
+    else
+      // for identifiers, get the name
+      if this instanceof Ident
+      then result = this.(Ident).getName()
+      else
+        // for everything else, give up
+        result = ""
   }
 
   /**