hakorune/tools/hako_check/rules/rule_duplicate_method.hako

// tools/hako_check/rules/rule_duplicate_method.hako — HC013: Duplicate Method
// Detect methods with the same name and arity defined multiple times in the same box.

using selfhost.shared.common.string_helpers as Str

static box RuleDuplicateMethodBox {
  method apply_ir(ir, path, out) {
    local boxes = ir.get("boxes")
    if boxes == null { return 0 }

    // Check each box for duplicate methods
    local bi = 0
    while bi < boxes.size() {
      local box_info = boxes.get(bi)
      if box_info == null { bi = bi + 1; continue }

      local box_name = box_info.get("name")
      if box_name == null { bi = bi + 1; continue }

      local methods = box_info.get("methods")
      if methods == null { bi = bi + 1; continue }

      // Track seen methods: {name/arity -> first_span}
      local seen = new MapBox()

      local mi = 0
      while mi < methods.size() {
        local method = methods.get(mi)
        if method == null { mi = mi + 1; continue }

        local name = method.get("name")
        local arity = method.get("arity")
        if name == null || arity == null { mi = mi + 1; continue }

        // Create signature: name/arity
        local sig = name + "/" + me._itoa(arity)

        // Check if already seen
        local first_span = seen.get(sig)
        if first_span != null {
          // Check if it's a [map/missing] error
          local first_span_str = first_span + ""
          if first_span_str.indexOf("[map/missing]") != 0 {
            // Duplicate detected!
            local span = method.get("span")
            local line = (span != null) ? span : 1
            out.push("[HC013] duplicate method definition: " + box_name + "." + sig + " at line " + me._itoa(line))
          } else {
            // First occurrence
            local span = method.get("span")
            seen.set(sig, span)
          }
        } else {
          // First occurrence
          local span = method.get("span")
          seen.set(sig, span)
        }

        mi = mi + 1
      }

      bi = bi + 1
    }
    return out.size()
  }

  _itoa(n) {
    local v = 0 + n
    if v == 0 { return "0" }
    local out = ""
    local digits = "0123456789"
    local tmp = ""
    while v > 0 {
      local d = v % 10
      tmp = digits.substring(d, d+1) + tmp
      v = v / 10
    }
    out = tmp
    return out
  }
}

static box RuleDuplicateMethodMain { method main(args) { return 0 } }