Negative numbers after ? seem to be ambiguous

[linuswagner]

rascal> ()[1] ? 1;
int: 1

but then with a negative number:

rascal> ()[1] ? -1;
Unexpected failure during parsing of current command: 
Ambiguous code (internal error), ()[1] ? -1
org.rascalmpl.interpreter.asserts.Ambiguous: Ambiguous code (internal error), ()[1] ? -1
        at org.rascalmpl.parser.uptr.UPTRNodeFactory.buildAmbiguityNode(UPTRNodeFactory.java:76)
        at org.rascalmpl.parser.uptr.UPTRNodeFactory.createAmbiguityNode(UPTRNodeFactory.java:85)
        at org.rascalmpl.parser.uptr.UPTRNodeFactory.createAmbiguityNode(UPTRNodeFactory.java:23)
        at org.rascalmpl.parser.gtd.result.out.SortContainerNodeFlattener.convertToUPTR(SortContainerNodeFlattener.java:183)
        at org.rascalmpl.parser.gtd.result.out.DefaultNodeFlattener.convert(DefaultNodeFlattener.java:63)
        at org.rascalmpl.parser.gtd.result.out.SortContainerNodeFlattener.buildAlternative(SortContainerNodeFlattener.java:90)
        at org.rascalmpl.parser.gtd.result.out.SortContainerNodeFlattener.gatherProduction(SortContainerNodeFlattener.java:65)
        at org.rascalmpl.parser.gtd.result.out.SortContainerNodeFlattener.gatherProduction(SortContainerNodeFlattener.java:71)
        at org.rascalmpl.parser.gtd.result.out.SortContainerNodeFlattener.gatherProduction(SortContainerNodeFlattener.java:71)
        at org.rascalmpl.parser.gtd.result.out.SortContainerNodeFlattener.gatherAlternatives(SortContainerNodeFlattener.java:53)
        at org.rascalmpl.parser.gtd.result.out.SortContainerNodeFlattener.convertToUPTR(SortContainerNodeFlattener.java:166)
        at org.rascalmpl.parser.gtd.result.out.DefaultNodeFlattener.convert(DefaultNodeFlattener.java:63)
        at org.rascalmpl.parser.gtd.result.out.SortContainerNodeFlattener.buildAlternative(SortContainerNodeFlattener.java:90)
        at org.rascalmpl.parser.gtd.result.out.SortContainerNodeFlattener.gatherProduction(SortContainerNodeFlattener.java:65)
        at org.rascalmpl.parser.gtd.result.out.SortContainerNodeFlattener.gatherAlternatives(SortContainerNodeFlattener.java:53)
        at org.rascalmpl.parser.gtd.result.out.SortContainerNodeFlattener.convertToUPTR(SortContainerNodeFlattener.java:166)
        at org.rascalmpl.parser.gtd.result.out.DefaultNodeFlattener.convert(DefaultNodeFlattener.java:63)
        at org.rascalmpl.parser.gtd.result.out.SortContainerNodeFlattener.buildAlternative(SortContainerNodeFlattener.java:90)
        at org.rascalmpl.parser.gtd.result.out.SortContainerNodeFlattener.gatherProduction(SortContainerNodeFlattener.java:65)
        at org.rascalmpl.parser.gtd.result.out.SortContainerNodeFlattener.gatherProduction(SortContainerNodeFlattener.java:71)
        at org.rascalmpl.parser.gtd.result.out.SortContainerNodeFlattener.gatherProduction(SortContainerNodeFlattener.java:71)
        at org.rascalmpl.parser.gtd.result.out.SortContainerNodeFlattener.gatherAlternatives(SortContainerNodeFlattener.java:53)
        at org.rascalmpl.parser.gtd.result.out.SortContainerNodeFlattener.convertToUPTR(SortContainerNodeFlattener.java:166)
        at org.rascalmpl.parser.gtd.result.out.DefaultNodeFlattener.convert(DefaultNodeFlattener.java:63)
        at org.rascalmpl.parser.gtd.result.out.DefaultNodeFlattener.convert(DefaultNodeFlattener.java:79)
        at org.rascalmpl.parser.gtd.SGTDBF.buildResult(SGTDBF.java:1297)
        at org.rascalmpl.parser.gtd.SGTDBF.parse(SGTDBF.java:1236)
        at org.rascalmpl.parser.gtd.SGTDBF.parse(SGTDBF.java:1240)
        at org.rascalmpl.parser.gtd.SGTDBF.parse(SGTDBF.java:1252)
        at org.rascalmpl.interpreter.Evaluator.parseCommand(Evaluator.java:1023)
        at org.rascalmpl.interpreter.Evaluator.parseCommand(Evaluator.java:1013)
        at org.rascalmpl.repl.RascalInterpreterREPL.isStatementComplete(RascalInterpreterREPL.java:174)
        at org.rascalmpl.repl.BaseRascalREPL.handleInput(BaseRascalREPL.java:105)
        at org.rascalmpl.vscode.lsp.terminal.LSPTerminalREPL$1.handleInput(LSPTerminalREPL.java:263)
        at org.rascalmpl.repl.BaseREPL.handleInput(BaseREPL.java:180)
        at org.rascalmpl.repl.BaseREPL.run(BaseREPL.java:347)
        at org.rascalmpl.vscode.lsp.terminal.LSPTerminalREPL.main(LSPTerminalREPL.java:345)

Using parenthesis disambiguates:

rascal> ()[1] ? (-1);
int: -1

[jurgenvinju]

Nice report. Thanks!