Java: Re-factor NeutralCallable to include all neutrals and introduce NeutralSummaryCallable.

java/ql/src/Metrics/Summaries/GeneratedVsManualCoverageQuery.qll

@@ -45,12 +45,10 @@ private int getNumApis(string package, string apiSubset) {
 
 /** Holds if the given `callable` belongs to the specified `apiSubset`. */
 private predicate callableSubset(Callable callable, string apiSubset) {
-  apiSubset in ["topJdkApis", "allApis"] and
-  (
-    if apiSubset = "topJdkApis"
-    then exists(TopJdkApi topJdkApi | callable = topJdkApi.asCallable())
-    else apiSubset = "allApis"
-  )
+  apiSubset = "topJdkApis" and
+  callable instanceof TopJdkApi
+  or
+  apiSubset = "allApis"
 }
 
 /**

java/ql/src/Metrics/Summaries/TopJdkApis.qll

@@ -287,16 +287,19 @@ predicate hasApiName(Callable c, string apiName) {
 }
 
 /** A top JDK API. */
-class TopJdkApi extends SummarizedCallableBase {
+class TopJdkApi extends Callable {
   TopJdkApi() {
+    this.isSourceDeclaration() and
     exists(string apiName |
-      hasApiName(this.asCallable(), apiName) and
+      hasApiName(this, apiName) and
       topJdkApiName(apiName)
     )
   }
 
   /** Holds if this API has a manual summary model. */
-  private predicate hasManualSummary() { this.(SummarizedCallable).hasManualModel() }
+  private predicate hasManualSummary() {
+    exists(SummarizedCallable sc | sc.asCallable() = this and sc.hasManualModel())
+  }
 
   /** Holds if this API has a manual neutral model. */
   private predicate hasManualNeutral() {

java/ql/src/Telemetry/ExternalApi.qll

@@ -79,7 +79,7 @@ class ExternalApi extends Callable {
 
   /** Holds if this API is a known neutral. */
   pragma[nomagic]
-  predicate isNeutral() { this = any(FlowSummaryImpl::Public::NeutralCallable nsc).asCallable() }
+  predicate isNeutral() { this instanceof FlowSummaryImpl::Public::NeutralCallable }
 
   /**
    * Holds if this API is supported by existing CodeQL libraries, that is, it is either a