The ArgumentsDescriptor for zsuper depends on whether the surrounding method accepts kwargs

* And on ruby2_keywords, but that's not handled yet anywhere.

Author: eregon

src/main/java/org/truffleruby/language/supercall/SuperCallNode.java

@@ -52,15 +52,7 @@ public final Object execute(VirtualFrame frame) {
             callSuperMethodNode = insert(CallSuperMethodNode.create());
         }
 
-        final ArgumentsDescriptor actualDescriptor;
-
-        if (descriptor == null) {
-            actualDescriptor = RubyArguments.getDescriptor(frame);
-        } else {
-            actualDescriptor = descriptor;
-        }
-
-        return callSuperMethodNode.execute(frame, self, superMethod, actualDescriptor, superArguments, blockObject);
+        return callSuperMethodNode.execute(frame, self, superMethod, descriptor, superArguments, blockObject);
     }
 
     @Override

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

@@ -25,6 +25,9 @@
 import org.truffleruby.language.RubyNode;
 import org.truffleruby.language.RubyProcRootNode;
 import org.truffleruby.language.SourceIndexLength;
+import org.truffleruby.language.arguments.ArgumentsDescriptor;
+import org.truffleruby.language.arguments.EmptyArgumentsDescriptor;
+import org.truffleruby.language.arguments.KeywordArgumentsDescriptor;
 import org.truffleruby.language.arguments.MissingArgumentBehavior;
 import org.truffleruby.language.arguments.ReadPreArgumentNode;
 import org.truffleruby.language.arguments.ShouldDestructureNode;
@@ -485,12 +488,15 @@ public RubyNode visitZSuperNode(ZSuperParseNode node) {
         final ArgsParseNode argsNode = methodArgumentsTranslator.argsNode;
         final SequenceNode reloadSequence = (SequenceNode) reloadTranslator.visitArgsNode(argsNode);
 
+        final ArgumentsDescriptor descriptor = argsNode.hasKwargs()
+                ? KeywordArgumentsDescriptor.INSTANCE
+                : EmptyArgumentsDescriptor.INSTANCE;
         final RubyNode arguments = new ReadZSuperArgumentsNode(
                 reloadTranslator.getRestParameterIndex(),
                 reloadSequence.getSequence());
         final RubyNode block = executeOrInheritBlock(argumentsAndBlock.getBlock(), node);
 
-        RubyNode callNode = new SuperCallNode(arguments, block, null);
+        RubyNode callNode = new SuperCallNode(arguments, block, descriptor);
         callNode = wrapCallWithLiteralBlock(argumentsAndBlock, callNode);
 
         return withSourceSection(sourceSection, callNode);