Ruby: Use "Receiver" instead of "Self" in flow summaries

Flow summaries use the "outside view", i.e., the call sites, so "receiver"
is better than "self", as the latter uses the "inside view", i.e. the callees.

Author: hvitved

ruby/ql/lib/codeql/ruby/dataflow/FlowSummary.qll

@@ -23,8 +23,8 @@ module SummaryComponent {
 
   predicate content = SC::content/1;
 
-  /** Gets a summary component that represents a `self` argument. */
-  SummaryComponent self() { result = argument(any(ParameterPosition pos | pos.isSelf())) }
+  /** Gets a summary component that represents a receiver. */
+  SummaryComponent receiver() { result = argument(any(ParameterPosition pos | pos.isSelf())) }
 
   /** Gets a summary component that represents a block argument. */
   SummaryComponent block() { result = argument(any(ParameterPosition pos | pos.isBlock())) }
@@ -67,8 +67,8 @@ module SummaryComponentStack {
 
   predicate argument = SCS::argument/1;
 
-  /** Gets a singleton stack representing a `self` argument. */
-  SummaryComponentStack self() { result = singleton(SummaryComponent::self()) }
+  /** Gets a singleton stack representing a receiver. */
+  SummaryComponentStack receiver() { result = singleton(SummaryComponent::receiver()) }
 
   /** Gets a singleton stack representing a block argument. */
   SummaryComponentStack block() { result = singleton(SummaryComponent::block()) }

ruby/ql/lib/codeql/ruby/dataflow/internal/FlowSummaryImplSpecific.qll

@@ -60,8 +60,8 @@ predicate summaryElement(DataFlowCallable c, string input, string output, string
  */
 bindingset[c]
 SummaryComponent interpretComponentSpecific(string c) {
-  c = "Self" and
-  result = FlowSummary::SummaryComponent::self()
+  c = "Receiver" and
+  result = FlowSummary::SummaryComponent::receiver()
   or
   c = "BlockArgument" and
   result = FlowSummary::SummaryComponent::block()