Undefined

This checks items that are used but haven't been defined. It checks for:

• function calls
• parameter usage
• function local usage
• type use
• global usage
• memory usage
• table usage
• block label usage
• WasmGC struct field usage

Examples:

(module
  (func
    br 1)
  (func
    local.get 0
    call $not-defined)
  (func
    i32.const 0
    global.set $not-defined))