Ambiguity when combining tuple projection and string interpolation

[sungshik]

Describe the bug

An ambiguity may arise when tuple projection is combined with string interpolation.

To Reproduce

rascal>x = <"foo", "bar">;
tuple[str,str]: <"foo","bar">

rascal>"<x<0>>"
str: "foo"

rascal>"<x<1>>"
str: "bar"

rascal>"<x<0>><x<1>>"
Unexpected failure during parsing of current command: 
Ambiguous code (internal error), x<0>><x<1>

Expected behavior

rascal>"<x<0>><x<1>>"
str: "foobar"

I think the alternative the parser is considering is this:

"<x<0>><x<1>>"
  └─┘   └─┘    less-than:      x<0      x<1
       └───┘   unary tuple:           <(x<1)>
  └────────┘   insert-before: (x<0)>>(<(x<1)>)

This is not well-typed, but the parser doesn't mind.

Stack traces

org.rascalmpl.interpreter.asserts.Ambiguous: Ambiguous code (internal error), x<0>><x<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.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.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:1306)
        at org.rascalmpl.parser.gtd.SGTDBF.parse(SGTDBF.java:1245)
        at org.rascalmpl.parser.gtd.SGTDBF.parse(SGTDBF.java:1249)
        at org.rascalmpl.parser.gtd.SGTDBF.parse(SGTDBF.java:1261)
        at org.rascalmpl.interpreter.Evaluator.parseCommand(Evaluator.java:1052)
        at org.rascalmpl.interpreter.Evaluator.parseCommand(Evaluator.java:1042)
        at org.rascalmpl.repl.RascalInterpreterREPL.isStatementComplete(RascalInterpreterREPL.java:176)
        at org.rascalmpl.repl.BaseRascalREPL.handleInput(BaseRascalREPL.java:105)
        at org.rascalmpl.vscode.lsp.terminal.LSPTerminalREPL$1.handleInput(LSPTerminalREPL.java:233)
        at org.rascalmpl.repl.BaseREPL.handleInput(BaseREPL.java:179)
        at org.rascalmpl.repl.BaseREPL.run(BaseREPL.java:346)
        at org.rascalmpl.vscode.lsp.terminal.LSPTerminalREPL.main(LSPTerminalREPL.java:320)