Random access node assignable throws ClassCastException

[jurgenvinju]

rascal>leesplank = "aap"("noot");
node: "aap"("noot")
rascal>leesplank[0] = "mies";
java.lang.ClassCastException: class io.usethesource.vallang.impl.persistent.Node cannot be cast to class io.usethesource.vallang.IConstructor (io.usethesource.vallang.impl.persistent.Node and io.usethesource.vallang.IConstructor are in unnamed module of loader 'app')
(internal error)
        at $shell$(|main://$shell$|)

java.lang.ClassCastException: class io.usethesource.vallang.impl.persistent.Node cannot be cast to class io.usethesource.vallang.IConstructor (io.usethesource.vallang.impl.persistent.Node and io.usethesource.vallang.IConstructor are in unnamed module of loader 'app')
        at org.rascalmpl.semantics.dynamic.Assignable$Subscript.assignment(Assignable.java:504)
        at org.rascalmpl.semantics.dynamic.Statement$Assignment.interpret(Statement.java:210)
        at org.rascalmpl.interpreter.Evaluator.eval(Evaluator.java:899)
        at org.rascalmpl.semantics.dynamic.Command$Statement.interpret(Command.java:125)
        at org.rascalmpl.interpreter.Evaluator.eval(Evaluator.java:1135)
        at org.rascalmpl.interpreter.Evaluator.eval(Evaluator.java:984)
        at org.rascalmpl.interpreter.Evaluator.eval(Evaluator.java:935)
        at org.rascalmpl.repl.RascalInterpreterREPL.evalStatement(RascalInterpreterREPL.java:135)
        at org.rascalmpl.repl.BaseRascalREPL.handleInput(BaseRascalREPL.java:107)
        at org.rascalmpl.shell.REPLRunner$1.handleInput(REPLRunner.java:57)
        at org.rascalmpl.repl.BaseREPL.handleInput(BaseREPL.java:179)
        at org.rascalmpl.repl.BaseREPL.run(BaseREPL.java:346)
        at org.rascalmpl.shell.REPLRunner.run(REPLRunner.java:91)
        at org.rascalmpl.shell.RascalShell.main(RascalShell.java:82)