C++: Use isAdditionalBarrier in the SqlTainted query.

cpp/ql/src/Security/CWE/CWE-089/SqlTainted.ql

@@ -27,6 +27,8 @@ class Configuration extends TaintTrackingConfiguration {
   override predicate isSink(Element tainted) {
     exists(SQLLikeFunction runSql | runSql.outermostWrapperFunctionCall(tainted, _))
   }
+
+  override predicate isAdditionalBarrier(Expr e) { e.getUnspecifiedType() instanceof IntegralType }
 }
 
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