Adopt changes in Nodes.NumberedReferenceReadNode

Author: andrykonchin

spec/ruby/language/regexp/back-references_spec.rb

@@ -22,6 +22,15 @@
     $10.should == "0"
   end
 
+  it "returns nil for numbered variable with too large index" do
+    -> {
+      eval(<<~CODE).should == nil
+        "a" =~ /(.)/
+        eval('$4294967296')
+      CODE
+    }.should complain(/warning: ('|`)\$4294967296' is too big for a number variable, always nil/)
+  end
+
   it "will not clobber capture variables across threads" do
     cap1, cap2, cap3 = nil
     "foo" =~ /(o+)/

src/main/java/org/truffleruby/parser/YARPTranslator.java

@@ -2811,6 +2811,12 @@ public RubyNode visitNumberedParametersNode(Nodes.NumberedParametersNode node) {
 
     @Override
     public RubyNode visitNumberedReferenceReadNode(Nodes.NumberedReferenceReadNode node) {
+        // numbered references that are too large, e.g. $4294967296, are always `nil`
+        if (node.number == 0) {
+            final RubyNode rubyNode = new NilLiteralNode();
+            return assignPositionAndFlags(node, rubyNode);
+        }
+
         final RubyNode lastMatchNode = ReadGlobalVariableNodeGen.create("$~");
         final RubyNode rubyNode = new ReadMatchReferenceNodes.ReadNthMatchNode(lastMatchNode, node.number);