collections/string-operator.cfa:251:1 error: Cannot choose between 2 alternatives for expression
Applying untyped:
  Name: ?=?
...to:
  Name: s
  Applying untyped:
    Name: ?*?
  ...to:
    Constant Expression ('a': char)
    ... with resolved type:
      char
    Constant Expression (3: signed int)
    ... with resolved type:
      signed int

 Alternatives are:
Cost ( 0, 0, 0, 2, 0, 0, 0, 1 ): Application of
      Variable Expression: ?=?: function
      ... with parameters
        reference to instance of struct string with body
        instance of struct string with body
      ... returning
        reference to instance of struct string with body

      ... with resolved type:
        pointer to function
        ... with parameters
          reference to instance of struct string with body
          instance of struct string with body
        ... returning
          reference to instance of struct string with body

      ... to arguments
      Generated Cast of:
        Variable Expression: s: instance of struct string with body
        ... with resolved type:
          instance of struct string with body
      ... to:
        reference to instance of struct string with body
      ... with resolved type:
        reference to instance of struct string with body
      Application of
        Variable Expression: ?*?: function
        ... with parameters
          char
          signed long long int
        ... returning
          instance of struct string with body

        ... with resolved type:
          pointer to function
          ... with parameters
            char
            signed long long int
          ... returning
            instance of struct string with body

        ... to arguments
        Constant Expression ('a': char)
        ... with resolved type:
          char
        Generated Cast of:
          Constant Expression (3: signed int)
          ... with resolved type:
            signed int
        ... to:
          signed long long int
        ... with resolved type:
          signed long long int

      ... with resolved type:
        instance of struct string with body

    ... with resolved type:
      reference to instance of struct string with body
  (types:
    reference to instance of struct string with body
  )
  Environment:

Cost ( 0, 0, 0, 2, 0, 0, 0, 1 ): Application of
      Variable Expression: ?=?: static inline function
      ... with parameters
        reference to instance of struct string with body
        signed int
      ... returning
        reference to instance of struct string with body

      ... with resolved type:
        pointer to function
        ... with parameters
          reference to instance of struct string with body
          signed int
        ... returning
          reference to instance of struct string with body

      ... to arguments
      Generated Cast of:
        Variable Expression: s: instance of struct string with body
        ... with resolved type:
          instance of struct string with body
      ... to:
        reference to instance of struct string with body
      ... with resolved type:
        reference to instance of struct string with body
      Application of
        Variable Expression: ?*?: function
        ... with parameters
          signed int
          signed int
        ... returning
          signed int

        ... with resolved type:
          pointer to function
          ... with parameters
            signed int
            signed int
          ... returning
            signed int

        ... to arguments
        Generated Cast of:
          Constant Expression ('a': char)
          ... with resolved type:
            char
        ... to:
          signed int
        ... with resolved type:
          signed int
        Constant Expression (3: signed int)
        ... with resolved type:
          signed int

      ... with resolved type:
        signed int

    ... with resolved type:
      reference to instance of struct string with body
  (types:
    reference to instance of struct string with body
  )
  Environment:


