Apply suggestions from code review

Co-authored-by: Taus <tausbn@github.com>

Author: yoff

python/ql/src/experimental/semmle/python/Concepts.qll

@@ -46,7 +46,7 @@ module SystemCommandExecution {
  * decompressing, decrypting, parsing etc.
  *
  * Doing so should normally preserve taint, but it can also be a problem
- * in itself, e.g. if it allows code execution or could result in deinal-of-service.
+ * in itself, e.g. if it allows code execution or could result in denial-of-service.
  *
  * Extend this class to refine existing API models. If you want to model new APIs,
  * extend `Decoding::Range` instead.
@@ -77,7 +77,7 @@ module Decoding {
    * decompressing, decrypting, parsing etc.
    *
    * Doing so should normally preserve taint, but it can also be a problem
-   * in itself, e.g. if it allows code execution or could result in deinal-of-service.
+   * in itself, e.g. if it allows code execution or could result in denial-of-service.
    *
    * Extend this class to model new APIs. If you want to refine existing API models,
    * extend `Decoding` instead.

python/ql/src/experimental/semmle/python/frameworks/Dill.qll

@@ -43,13 +43,14 @@ private module Dill {
  * See https://pypi.org/project/dill/ (which currently refers you
  * to https://docs.python.org/3/library/pickle.html#pickle.loads)
  */
-private class DillLoadsCall extends Decoding::Range {
-  DillLoadsCall() { this.asCfgNode().(CallNode).getFunction() = Dill::dill::loads().asCfgNode() }
+private class DillLoadsCall extends Decoding::Range, DataFlow::CfgNode {
+  override CallNode node;
+  DillLoadsCall() { node.getFunction() = Dill::dill::loads().asCfgNode() }
 
   override predicate unsafe() { any() }
 
   override DataFlow::Node getAnInput() {
-    result.asCfgNode() = this.asCfgNode().(CallNode).getArg(0)
+    result.asCfgNode() = node.getArg(0)
   }
 
   override DataFlow::Node getOutput() { result = this }