Address review comments

java/ql/src/semmle/code/java/dataflow/internal/DataFlowDispatch.qll

@@ -4,21 +4,13 @@ private import DataFlowUtil
 private import semmle.code.java.dataflow.InstanceAccess
 private import semmle.code.java.dataflow.FlowSummary
 private import semmle.code.java.dispatch.VirtualDispatch as VirtualDispatch
-private import semmle.code.java.dataflow.internal.FlowSummaryImplSpecific
 
 private module DispatchImpl {
   /** Gets a viable implementation of the target of the given `Call`. */
   Callable viableCallable(Call c) {
     result = VirtualDispatch::viableCallable(c)
     or
-    result = c.getCallee().getSourceDeclaration() and
-    (
-      result instanceof SummarizedCallable
-      or
-      sourceElement(result, _, _)
-      or
-      sinkElement(result, _, _)
-    )
+    result.(SummarizedCallable) = c.getCallee().getSourceDeclaration()
   }
 
   /**

java/ql/src/semmle/code/java/dataflow/internal/FlowSummaryImpl.qll

@@ -712,8 +712,8 @@ module Private {
       exists(SourceOrSinkElement e |
         sourceElement(e, output, kind) and
         if outputNeedsReference(specLast(output))
-        then viableCallable(ref.asCall()) = any(InterpretNode n | n.asElement() = e).asCallable()
-        else ref.asElement() = e
+        then e = ref.getCallTarget()
+        else e = ref.asElement()
       )
     }
 
@@ -721,8 +721,8 @@ module Private {
       exists(SourceOrSinkElement e |
         sinkElement(e, input, kind) and
         if inputNeedsReference(specLast(input))
-        then viableCallable(ref.asCall()) = any(InterpretNode n | n.asElement() = e).asCallable()
-        else ref.asElement() = e
+        then e = ref.getCallTarget()
+        else e = ref.asElement()
       )
     }
 

java/ql/src/semmle/code/java/dataflow/internal/FlowSummaryImplSpecific.qll

@@ -125,6 +125,9 @@ class InterpretNode extends TInterpretNode {
   /** Gets the callable that this node corresponds to, if any. */
   DataFlowCallable asCallable() { result = this.asElement() }
 
+  /** Gets the target of this call, if any. */
+  Callable getCallTarget() { result = this.asCall().getCallee().getSourceDeclaration() }
+
   /** Gets a textual representation of this node. */
   string toString() {
     result = this.asElement().toString()