Swift: Permit data flow from generic arguments, rather than just pointers.

Author: geoffw0

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

@@ -211,9 +211,7 @@ private module Cached {
 private predicate modifiable(Argument arg) {
   arg.getExpr() instanceof InOutExpr
   or
-  arg.getExpr().getType() instanceof NominalType
-  or
-  arg.getExpr().getType() instanceof PointerType
+  arg.getExpr().getType() instanceof NominalOrBoundGenericNominalType
 }
 
 predicate modifiableParam(ParamDecl param) {

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

@@ -125,5 +125,5 @@ func testWritingPointerContainersInCalls(mpc: MyPointerContainer, mgpc: MyGeneri
   sink(arg: mpc.ptr.pointee) // $ tainted=114
 
   writeGenericPointerContainer(mgpc: mgpc)
-  sink(arg: mgpc.ptr.pointee) // $ MISSING: tainted=119
+  sink(arg: mgpc.ptr.pointee) // $ tainted=119
 }