Use synthetic fields to improve taint precision

java/ql/test/library-tests/frameworks/android/slice/test.ql

@@ -7,3 +7,12 @@ class SliceValueFlowConf extends DefaultValueFlowConf {
     super.isSource(source) or source instanceof RemoteFlowSource
   }
 }
+
+class SliceTaintFlowConf extends DefaultTaintFlowConf {
+  override predicate allowImplicitRead(DataFlow::Node node, DataFlow::Content c) {
+    super.allowImplicitRead(node, c)
+    or
+    isSink(node) and
+    c.(DataFlow::SyntheticFieldContent).getField() = "androidx.slice.Slice.action"
+  }
+}