C#: add isParameterless predicate to Constructor class

Author: Jami Cogswell

csharp/ql/lib/semmle/code/csharp/Callable.qll

@@ -358,6 +358,9 @@ class Constructor extends DotNet::Constructor, Callable, Member, Attributable, @
     if this.isStatic() then result = this.getParameter(i) else result = this.getParameter(i - 1)
   }
 
+  /** Holds if this is a constructor without parameters. */
+  predicate isParameterless() { this.getNumberOfParameters() = 0 }
+
   override string getUndecoratedName() { result = ".ctor" }
 }
 

csharp/ql/src/utils/modelgenerator/internal/CaptureModelsSpecific.qll

@@ -30,11 +30,6 @@ private predicate isHigherOrder(CS::Callable api) {
   )
 }
 
-/** Holds if the given API is a constructor without parameters. */
-private predicate isParameterlessConstructor(CS::Callable api) {
-  api instanceof CS::Constructor and api.getNumberOfParameters() = 0
-}
-
 /**
  * Holds if it is relevant to generate models for `api`.
  */
@@ -44,7 +39,7 @@ private predicate isRelevantForModels(CS::Callable api) {
   not api instanceof CS::ConversionOperator and
   not api instanceof Util::MainMethod and
   not api instanceof CS::Destructor and
-  not isParameterlessConstructor(api)
+  not api.(CS::Constructor).isParameterless()
 }
 
 /**