Ruby: Use asCallable() to generate epsilon edges

Author: asgerf

ruby/ql/lib/codeql/ruby/ApiGraphs.qll

@@ -978,6 +978,12 @@ module API {
         pred = Impl::MkModuleInstanceUp(mod) and
         succ = getBackwardEndNode(mod.getOwnInstanceMethod("call"))
       )
+      or
+      // Step through callable wrappers like `proc` and `lambda` calls.
+      exists(DataFlow::Node node |
+        pred = getBackwardEndNode(node) and
+        succ = getBackwardStartNode(node.asCallable())
+      )
     }
 
     pragma[nomagic]

ruby/ql/test/library-tests/dataflow/api-graphs/VerifyApiGraphExpectations.expected

@@ -1,5 +1,3 @@
 failures
 testFailures
-| explicit-proc.rb:2:7:2:78 | # $ reachableFromSource=Member[Foo].Method[bar].Argument[0].Parameter[0] | Missing result:reachableFromSource=Member[Foo].Method[bar].Argument[0].Parameter[0] |
-| explicit-proc.rb:6:7:6:78 | # $ reachableFromSource=Member[Foo].Method[bar].Argument[0].Parameter[0] | Missing result:reachableFromSource=Member[Foo].Method[bar].Argument[0].Parameter[0] |
 | explicit-proc.rb:10:7:10:78 | # $ reachableFromSource=Member[Foo].Method[bar].Argument[0].Parameter[0] | Missing result:reachableFromSource=Member[Foo].Method[bar].Argument[0].Parameter[0] |