Swift/C++: Use instanceof in more places

cpp/ql/lib/experimental/semmle/code/cpp/semantic/SemanticExprSpecific.qll

@@ -286,19 +286,7 @@ module SemanticExprConfig {
     )
   }
 
-  class Bound instanceof IRBound::Bound {
-    string toString() { result = super.toString() }
-
-    final Location getLocation() { result = super.getLocation() }
-  }
-
-  private class ValueNumberBound extends Bound {
-    IRBound::ValueNumberBound bound;
-
-    ValueNumberBound() { bound = this }
-
-    override string toString() { result = bound.toString() }
-  }
+  class Bound = IRBound::Bound;
 
   predicate zeroBound(Bound bound) { bound instanceof IRBound::ZeroBound }
 

cpp/ql/lib/experimental/semmle/code/cpp/semantic/analysis/SignAnalysisCommon.qll

@@ -33,23 +33,15 @@ abstract private class FlowSignDef extends SignDef {
 }
 
 /** An SSA definition whose sign is determined by the sign of that definitions source expression. */
-private class ExplicitSignDef extends FlowSignDef {
-  SemSsaExplicitUpdate update;
-
-  ExplicitSignDef() { update = this }
-
-  final override Sign getSign() { result = semExprSign(update.getSourceExpr()) }
+private class ExplicitSignDef extends FlowSignDef instanceof SemSsaExplicitUpdate {
+  final override Sign getSign() { result = semExprSign(super.getSourceExpr()) }
 }
 
 /** An SSA Phi definition, whose sign is the union of the signs of its inputs. */
-private class PhiSignDef extends FlowSignDef {
-  SemSsaPhiNode phi;
-
-  PhiSignDef() { phi = this }
-
+private class PhiSignDef extends FlowSignDef instanceof SemSsaPhiNode {
   final override Sign getSign() {
     exists(SemSsaVariable inp, SemSsaReadPositionPhiInputEdge edge |
-      edge.phiInput(phi, inp) and
+      edge.phiInput(this, inp) and
       result = semSsaSign(inp, edge)
     )
   }