Factor comparison into compatibleContents

Author: asgerf

ruby/ql/lib/codeql/ruby/typetracking/TypeTracker.qll

@@ -41,7 +41,7 @@ private module Cached {
       exists(TypeTrackerContentSet loadContents |
         step = LoadStep(pragma[only_bind_into](loadContents)) and
         tt = MkTypeTracker(hasCall, storeContents) and
-        storeContents.getAStoreContent() = loadContents.getAReadContent() and
+        compatibleContents(storeContents, loadContents) and
         result = noContentTypeTracker(hasCall)
       )
       or
@@ -76,7 +76,7 @@ private module Cached {
       exists(TypeTrackerContentSet storeContents |
         step = StoreStep(pragma[only_bind_into](storeContents)) and
         tbt = MkTypeBackTracker(hasReturn, loadContents) and
-        storeContents.getAStoreContent() = loadContents.getAReadContent() and
+        compatibleContents(storeContents, loadContents) and
         result = noContentTypeBackTracker(hasReturn)
       )
       or

ruby/ql/lib/codeql/ruby/typetracking/TypeTrackerSpecific.qll

@@ -15,17 +15,18 @@ class Node = DataFlowPublic::Node;
 
 class TypeTrackingNode = DataFlowPublic::LocalSourceNode;
 
-private newtype TOptionalTypeTrackerContent =
-  MkAttribute(string name) { name = any(Ast::SetterMethodCall c).getTargetName() } or
-  MkContent(DataFlowPublic::Content content) or
-  MkNoContent()
-
-class TypeTrackerContent = DataFlowPublic::Content;
-
 class TypeTrackerContentSet = DataFlowPublic::ContentSet;
 
 class OptionalTypeTrackerContentSet = DataFlowPublic::OptionalContentSet;
 
+/**
+ * Holds if a value stored with `storeContents` can be read back with `loadContents`.
+ */
+pragma[inline]
+predicate compatibleContents(TypeTrackerContentSet storeContents, TypeTrackerContentSet loadContents) {
+  storeContents.getAStoreContent() = loadContents.getAReadContent()
+}
+
 /** Gets the "no content set" value to use for a type tracker not inside any content. */
 OptionalTypeTrackerContentSet noContentSet() { result.isNoContentSet() }