-- in.cue --
a: "foo"
"\(a)": b: c: d: e
e: 2

b: "bar"
X="\(b)": {
	a: 1
}
c: X

withError: {
    issue799: {key: int32} & {"\(1&2)": 123}
}
-- out/eval --
Errors:
invalid interpolation: conflicting values 2 and 1:
    ./in.cue:12:31

Result:
(_|_){
  // [eval]
  a: (string){ "foo" }
  e: (int){ 2 }
  b: (string){ "bar" }
  c: (struct){
    a: (int){ 1 }
  }
  withError: (_|_){
    // [eval]
    issue799: (_|_){
      // [eval] invalid interpolation: conflicting values 2 and 1:
      //     ./in.cue:12:31
      key: (int){ &(>=-2147483648, <=2147483647, int) }
    }
  }
  foo: (struct){
    b: (struct){
      c: (struct){
        d: (int){ 2 }
      }
    }
  }
  bar: (struct){
    a: (int){ 1 }
  }
}
-- out/compile --
--- in.cue
{
  a: "foo"
  "\(〈0;a〉)": {
    b: {
      c: {
        d: 〈3;e〉
      }
    }
  }
  e: 2
  b: "bar"
  "\(〈0;b〉)": {
    a: 1
  }
  c: 〈0;("\(〈0;b〉)")〉
  withError: {
    issue799: ({
      key: &(int, >=-2147483648, <=2147483647)
    } & {
      "\((1 & 2))": 123
    })
  }
}