Swift: unify ArrayContent and CollectionContent

Author: Robert Marsh

swift/ql/lib/codeql/swift/dataflow/ExternalFlow.qll

@@ -497,9 +497,6 @@ predicate parseContent(AccessPathToken component, Content content) {
   or
   parseEnum(component, content)
   or
-  component.getName() = "ArrayElement" and
-  content instanceof Content::ArrayContent
-  or
   component.getName() = "CollectionElement" and
   content instanceof Content::CollectionContent
 }

swift/ql/lib/codeql/swift/dataflow/internal/DataFlowPrivate.qll

@@ -297,7 +297,6 @@ private module Cached {
     TFieldContent(FieldDecl f) or
     TTupleContent(int index) { exists(any(TupleExpr te).getElement(index)) } or
     TEnumContent(ParamDecl f) { exists(EnumElementDecl d | d.getAParam() = f) } or
-    TArrayContent() or
     TCollectionContent()
 }
 
@@ -842,7 +841,7 @@ predicate storeStep(Node node1, ContentSet c, Node node2) {
   exists(ArrayExpr arr |
     node1.asExpr() = arr.getAnElement() and
     node2.asExpr() = arr and
-    c.isSingleton(any(Content::ArrayContent ac))
+    c.isSingleton(any(Content::CollectionContent ac))
   )
   or
   // array assignment `a[n] = x`
@@ -851,7 +850,7 @@ predicate storeStep(Node node1, ContentSet c, Node node2) {
     node2.(PostUpdateNode).getPreUpdateNode().asExpr() = subscript.getBase() and
     subscript = assign.getDest() and
     subscript.getBase().getType() instanceof ArrayType and
-    c.isSingleton(any(Content::ArrayContent ac))
+    c.isSingleton(any(Content::CollectionContent ac))
   )
   or
   // creation of an optional via implicit wrapping keypath component
@@ -948,7 +947,7 @@ predicate readStep(Node node1, ContentSet c, Node node2) {
     (
       c.isSingleton(any(Content::FieldContent ct | ct.getField() = component.getDeclRef()))
       or
-      c.isSingleton(any(Content::ArrayContent ac)) and
+      c.isSingleton(any(Content::CollectionContent ac)) and
       component.isSubscript()
       or
       c instanceof OptionalSomeContentSet and
@@ -971,12 +970,7 @@ predicate readStep(Node node1, ContentSet c, Node node2) {
   exists(SubscriptExpr subscript |
     subscript.getBase() = node1.asExpr() and
     subscript = node2.asExpr() and
-    (
-      subscript.getBase().getType() instanceof ArrayType and
-      c.isSingleton(any(Content::ArrayContent ac))
-      or
       c.isSingleton(any(Content::CollectionContent ac))
-    )
   )
   or
   // read of a dictionary value via subscript operator
@@ -1099,7 +1093,7 @@ class DataFlowExpr = Expr;
  * precision. This disables adaptive access path precision for such access paths.
  */
 predicate forceHighPrecision(Content c) {
-  c instanceof Content::ArrayContent or c instanceof Content::CollectionContent
+  c instanceof Content::CollectionContent
 }
 
 /**

swift/ql/lib/codeql/swift/dataflow/internal/DataFlowPublic.qll

@@ -220,11 +220,6 @@ module Content {
     override string toString() { result = this.getSignature() }
   }
 
-  /** An element of an array at an unknown index */
-  class ArrayContent extends Content, TArrayContent {
-    override string toString() { result = "Array element" }
-  }
-
   /**
    * An element of a collection. This is a broad class including:
    *  - elements of collections, such as `Set<Element>`.

swift/ql/lib/codeql/swift/dataflow/internal/FlowSummaryImplSpecific.qll

@@ -129,11 +129,6 @@ private string getContentSpecific(ContentSet cs) {
     result = "EnumElement[" + c.getSignature() + "]"
   )
   or
-  exists(Content::ArrayContent c |
-    cs.isSingleton(c) and
-    result = "ArrayElement"
-  )
-  or
   exists(Content::CollectionContent c |
     cs.isSingleton(c) and
     result = "CollectionElement"