Swift: Model Sequence.enumerated() as well.

Author: geoffw0

swift/ql/lib/codeql/swift/frameworks/StandardLibrary/Sequence.qll

@@ -50,6 +50,7 @@ private class SequenceSummaries extends SummaryModelCsv {
         ";Sequence;true;withContiguousStorageIfAvailable(_:);;;Argument[-1].CollectionElement;Argument[0].Parameter[0].CollectionElement;value",
         ";Sequence;true;withContiguousStorageIfAvailable(_:);;;Argument[0].ReturnValue;ReturnValue.OptionalSome;value",
         ";Sequence;true;forEach(_:);;;Argument[-1].CollectionElement;Argument[0].Parameter[0];value",
+        ";Sequence;true;enumerated();;;Argument[-1].CollectionElement;ReturnValue.CollectionElement.TupleElement[1];value",
         ";Sequence;true;makeIterator();;;Argument[-1].CollectionElement;ReturnValue.CollectionElement;value",
         ";Sequence;true;min();;;Argument[-1].CollectionElement;ReturnValue.OptionalSome;taint",
         ";Sequence;true;min(by:);;;Argument[-1].CollectionElement;ReturnValue.OptionalSome;taint",

swift/ql/test/library-tests/dataflow/taint/libraries/set.swift

@@ -34,7 +34,7 @@ func testSet(ix: Int) {
   }
   for (ix, elem) in taintedSet.enumerated() {
     sink(arg: ix)
-    sink(arg: elem) // $ MISSING: tainte=t1
+    sink(arg: elem) // $ tainted=t1
   }
   taintedSet.forEach {
     elem in