Nested EachOf results have extra expressions

Suppose I have a schema made of two EachOf expressions:

PREFIX schema: <http://schema.org/>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>

start={
  rdf:type [ schema:Person ],
  (
    schema:givenName xsd:string ,
    schema:familyName xsd:string
  ) *
}

... this parses into

{
  "type": "Schema",
  "start": {
    "type": "Shape",
    "expression": {
      "type": "EachOf",
      "expressions": [
        {
          "type": "TripleConstraint",
          "predicate": "http://www.w3.org/1999/02/22-rdf-syntax-ns#type",
          ...
        },
        {
          "type": "EachOf",
          "expressions": [
            {
              "type": "TripleConstraint",
              "predicate": "http://schema.org/givenName",
              ...
            },
            {
              "type": "TripleConstraint",
              "predicate": "http://schema.org/familyName",
              ...
            }
          ],
          "min": 0,
          "max": -1
        }
      ]
    }
  }
}

But if I validate against

<http://example.com/john> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://schema.org/Person> .
<http://example.com/john> <http://schema.org/givenName> "John" .
<http://example.com/john> <http://schema.org/familyName> "Doe" .

shex.js produces

{
  "type": "ShapeTest",
  "node": "http://example.com/john",
  "shape": {
    "term": "START"
  },
  "solution": {
    "type": "EachOfSolutions",
    "solutions": [
      {
        "type": "EachOfSolution",
        "expressions": [
          {
            "type": "TripleConstraintSolutions",
            "predicate": "http://www.w3.org/1999/02/22-rdf-syntax-ns#type",
            "solutions": [ { ... } ],
            "valueExpr": { .. }
          },
          {
            "type": "EachOfSolutions",
            "solutions": [
              {
                "type": "EachOfSolution",
                "expressions": [
                  {
                    "type": "TripleConstraintSolutions",
                    "predicate": "http://www.w3.org/1999/02/22-rdf-syntax-ns#type",
                    "solutions": [ { ... } ],
                    "valueExpr": { ... }
                  },
                  {
                    "type": "TripleConstraintSolutions",
                    "predicate": "http://schema.org/givenName",
                    "solutions": [ { ... } ],
                    "valueExpr": { ... }
                  },
                  {
                    "type": "TripleConstraintSolutions",
                    "predicate": "http://schema.org/familyName",
                    "solutions": [ { ... } ],
                    "valueExpr": { ... }
                  }
                ]
              }
            ],
            "min": 0,
            "max": -1
          }
        ]
      }
    ]
  }
}

The second EachOfSolution (the nested one) has an array of three expressions, where one is a TripleConstraintSolutions with predicate http://www.w3.org/1999/02/22-rdf-syntax-ns#type - which is copied/duplicated from the first EachOf expression (the outer / not nested one).

In fact the referenced objects are the same: result.solution.solutions[0].expressions[0] === result.solution.solutions[0].expressions[1].solutions[0].expressions[0].

If another solution to the nested EachOf is added - like validating against

<http://example.com/john> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://schema.org/Person> .
<http://example.com/john> <http://schema.org/givenName> "John" .
<http://example.com/john> <http://schema.org/familyName> "Doe" .
<http://example.com/john> <http://schema.org/givenName> "JOHN" .
<http://example.com/john> <http://schema.org/familyName> "DOE" .

then only the first nested EachOfSolution has three expressions, and the second nested EachOfSolution has just the two expected expressions.

Is this correct? I would have expected the expression tree in results to match the expression tree of the schema.

Complete demo code is here. Thanks again for all the work on ShEx! This isn't a critical bug for us or anything, just something I though I'd point out.

shexjs / shex.js

Nested EachOf results have extra expressions #70