DataFlow: Add some shared classes for Neutrals, Source and Sink callables.

shared/dataflow/codeql/dataflow/internal/FlowSummaryImpl.qll

@@ -270,6 +270,20 @@ module Make<
       NeutralSummaryCallable() { this.getKind() = "summary" }
     }
 
+    /**
+     * A callable that has a neutral source model.
+     */
+    class NeutralSourceCallable extends NeutralCallableFinal {
+      NeutralSourceCallable() { this.getKind() = "source" }
+    }
+
+    /**
+     * A callable that has a neutral sink model.
+     */
+    class NeutralSinkCallable extends NeutralCallableFinal {
+      NeutralSinkCallable() { this.getKind() = "sink" }
+    }
+
     /**
      * A callable that has a neutral model.
      */
@@ -1739,6 +1753,37 @@ module Make<
           )
         }
 
+        final private class SourceOrSinkElementFinal = SourceOrSinkElement;
+
+        bindingset[this]
+        private class SourceSinkModelCallableBase extends SourceOrSinkElementFinal {
+          /**
+           * Holds if there exists a manual model that applies to this.
+           */
+          final predicate hasManualModel() { any(Provenance p | this.hasProvenance(p)).isManual() }
+
+          /**
+           * Holds if this has provenance `p`.
+           */
+          abstract predicate hasProvenance(Provenance p);
+        }
+
+        /**
+         * A callable that has a source model.
+         */
+        abstract class SourceModelCallable extends SourceSinkModelCallableBase {
+          bindingset[this]
+          SourceModelCallable() { exists(this) }
+        }
+
+        /**
+         * A callable that has a sink model.
+         */
+        abstract class SinkModelCallable extends SourceSinkModelCallableBase {
+          bindingset[this]
+          SinkModelCallable() { exists(this) }
+        }
+
         /** A source or sink relevant for testing. */
         signature class RelevantSourceOrSinkElementSig extends SourceOrSinkElement {
           /** Gets the string representation of this callable used by `source/1` or `sink/1`. */