C#: Use the new shared classes for Source and Sink callables.

csharp/ql/lib/semmle/code/csharp/dataflow/internal/ExternalFlow.qll

@@ -431,20 +431,6 @@ Declaration interpretElement(
   )
 }
 
-/**
- * A callable where there exists a MaD sink model that applies to it.
- */
-class SinkCallable extends Callable {
-  SinkCallable() { SourceSinkInterpretationInput::sinkElement(this, _, _, _, _) }
-}
-
-/**
- * A callable where there exists a MaD source model that applies to it.
- */
-class SourceCallable extends Callable {
-  SourceCallable() { SourceSinkInterpretationInput::sourceElement(this, _, _, _, _) }
-}
-
 cached
 private module Cached {
   /**
@@ -651,3 +637,33 @@ private class NeutralCallableAdapter extends NeutralCallable {
 
   override predicate hasProvenance(Provenance provenance) { provenance = provenance_ }
 }
+
+/**
+ * A callable where there exists a MaD sink model that applies to it.
+ */
+private class SinkModelCallableAdapter extends SinkModelCallable {
+  private Provenance provenance;
+
+  SinkModelCallableAdapter() {
+    SourceSinkInterpretationInput::sinkElement(this, _, _, provenance, _)
+  }
+
+  override predicate hasProvenance(Provenance p) { provenance = p }
+}
+
+final class SinkCallable = SinkModelCallable;
+
+/**
+ * A callable where there exists a MaD source model that applies to it.
+ */
+private class SourceModelCallableAdapter extends SourceModelCallable {
+  private Provenance provenance;
+
+  SourceModelCallableAdapter() {
+    SourceSinkInterpretationInput::sourceElement(this, _, _, provenance, _)
+  }
+
+  override predicate hasProvenance(Provenance p) { provenance = p }
+}
+
+final class SourceCallable = SourceModelCallable;