C#: Re-factor containerContent into standalone predicate in DataFlow library.

java/ql/lib/semmle/code/java/dataflow/internal/DataFlowUtil.qll

@@ -256,6 +256,16 @@ class SyntheticFieldContent extends Content, TSyntheticFieldContent {
   override string toString() { result = s.toString() }
 }
 
+/**
+ * Holds if the the content `c` is a container.
+ */
+predicate containerContent(Content c) {
+  c instanceof ArrayContent or
+  c instanceof CollectionContent or
+  c instanceof MapKeyContent or
+  c instanceof MapValueContent
+}
+
 /**
  * A guard that validates some expression.
  *

java/ql/lib/semmle/code/java/dataflow/internal/TaintTrackingUtil.qll

@@ -54,7 +54,7 @@ private module Cached {
     FlowSummaryImpl::Private::Steps::summaryThroughStep(src, sink, false)
     or
     // Treat container flow as taint for the local taint flow relation
-    exists(DataFlow::Content c | containerContent(c) |
+    exists(DataFlow::Content c | DataFlow::containerContent(c) |
       readStep(src, c, sink) or
       storeStep(src, c, sink) or
       FlowSummaryImpl::Private::Steps::summaryGetterStep(src, c, sink) or
@@ -62,13 +62,6 @@ private module Cached {
     )
   }
 
-  private predicate containerContent(DataFlow::Content c) {
-    c instanceof DataFlow::ArrayContent or
-    c instanceof DataFlow::CollectionContent or
-    c instanceof DataFlow::MapKeyContent or
-    c instanceof DataFlow::MapValueContent
-  }
-
   /**
    * Holds if taint can flow in one local step from `src` to `sink` excluding
    * local data flow steps. That is, `src` and `sink` are likely to represent
@@ -87,7 +80,7 @@ private module Cached {
       not sink.getTypeBound() instanceof BoxedType and
       not sink.getTypeBound() instanceof NumberType and
       (
-        containerContent(f)
+        DataFlow::containerContent(f)
         or
         f instanceof TaintInheritingContent
       )

java/ql/src/utils/model-generator/ModelGeneratorUtilsSpecific.qll

@@ -122,21 +122,13 @@ predicate isRelevantTaintStep(DataFlow::Node node1, DataFlow::Node node2) {
       else any()
   )
   or
-  exists(DataFlow::Content f | storeStep(node1, f, node2) |
-    f instanceof DataFlow::ArrayContent or
-    f instanceof DataFlow::CollectionContent or
-    f instanceof DataFlow::MapKeyContent or
-    f instanceof DataFlow::MapValueContent
-  )
+  exists(DataFlow::Content f | storeStep(node1, f, node2) | DataFlow::containerContent(f))
 }
 
 predicate isRelevantContent(DataFlow::Content f) {
   isRelevantType(f.(DataFlow::FieldContent).getField().getType()) or
   isRelevantType(f.(DataFlow::FieldContent).getField().getType()) or
-  f instanceof DataFlow::ArrayContent or
-  f instanceof DataFlow::CollectionContent or
-  f instanceof DataFlow::MapKeyContent or
-  f instanceof DataFlow::MapValueContent
+  DataFlow::containerContent(f)
 }
 
 private string parameterAccess(Parameter p) {