C++: Make FlowVar::toString not use Expr::toString

jbj · jbj · commit 6122cdb424c2 · 2019-03-11T11:40:49.000+01:00
The `FlowVar::toString` predicate is purely a debugging aid, but
unfortunately it has to be `cached` because it's in a `cached` class.
Before this commit, it caused `Expr::toString` to be evaluated in full.
diff --git a/cpp/ql/src/semmle/code/cpp/dataflow/internal/FlowVar.qll b/cpp/ql/src/semmle/code/cpp/dataflow/internal/FlowVar.qll
@@ -269,15 +269,15 @@ module FlowVar_internal {
     override string toString() {
       exists(Expr e |
         this.definedByExpr(e, _) and
-        result = v +" := "+ e
+        result = "assignment to "+ v
       )
       or
       this.definedByInitialValue(_) and
       result = "initial value of "+ v
       or
       exists(Expr arg |
         this.definedByReference(arg) and
-        result = "ref def: "+ arg
+        result = "definition by reference of "+ v
       )
       or
       // impossible case
