Fix compilation error

Author: MichaelRFairhurst

cpp/common/src/codingstandards/cpp/types/Compatible.qll

@@ -522,29 +522,3 @@ module FunctionDeclarationTypeEquivalence<
           .getType(), f2.getParameterDeclarationEntry(pragma[only_bind_into](i)).getType())
   }
 }
-
-/**
- * Convenience class to reduce the awkwardness of how `RoutineType` and `FunctionPointerIshType`
- * don't have a common ancestor.
- */
-private class FunctionType extends Type {
-  FunctionType() { this instanceof RoutineType or this instanceof FunctionPointerIshType }
-
-  Type getReturnType() {
-    result = this.(RoutineType).getReturnType() or
-    result = this.(FunctionPointerIshType).getReturnType()
-  }
-
-  Type getParameterType(int i) {
-    result = this.(RoutineType).getParameterType(i) or
-    result = this.(FunctionPointerIshType).getParameterType(i)
-  }
-}
-
-private class LeafType extends Type {
-  LeafType() {
-    not this instanceof DerivedType and
-    not this instanceof FunctionType and
-    not this instanceof FunctionType
-  }
-}