Recursive validObject does not work on formulas

[Dav-Ng]

Hi everyone,

I'm having an issue when validating an object recursively that contains a formula, an exception is thrown from Renjin:

org.renjin.eval.EvalException: object 'sloti' not found
	at org.renjin.sexp.Symbol.eval(Symbol.java:329)
	at org.renjin.sexp.Promise.doEval(Promise.java:87)
	at org.renjin.sexp.Promise.force(Promise.java:81)
	at org.renjin.sexp.Symbol.eval(Symbol.java:337)
	at org.renjin.sexp.Promise.doEval(Promise.java:87)
	at org.renjin.sexp.Promise.force(Promise.java:81)
	at org.renjin.primitives.R$primitive$identical.applyPromised(R$primitive$identical.java:27)
	at org.renjin.sexp.BuiltinFunction.apply(BuiltinFunction.java:100)
	at org.renjin.primitives.special.InternalFunction.apply(InternalFunction.java:46)
	at org.renjin.sexp.FunctionCall.eval(FunctionCall.java:80)
	at org.renjin.sexp.Closure.applyPromised(Closure.java:200)
	at org.renjin.sexp.Closure.apply(Closure.java:133)
	at org.renjin.primitives.special.RecallFunction.apply(RecallFunction.java:43)
	at org.renjin.sexp.FunctionCall.eval(FunctionCall.java:80)
	at org.renjin.sexp.Promise.doEval(Promise.java:87)
	at org.renjin.sexp.Promise.force(Promise.java:81)

Here is a simple code to reproduce the issue on either Java or R:
Java:
rEngine.eval("validObject(~1,complete=TRUE)");
R:
validObject(~1,complete=TRUE)

However, there is no issue when "complete" argument is omitted. Am I missing something?
The code works on GNU R 3.5.3 and returns TRUE. I'm using Renjin 3.5-beta76 in a Java project.

[perNyfelt]

This is just a comment to make it easier to investigate later (I dont have the time right now to look into this). The validObject code begins on line 429 here: https://github.com/bedatadriven/renjin/blob/master/packages/methods/R/SClasses.R
From a brief look at the code, I see no obvious reason why setting complete to true should cause this issue though.