conversion-function-id: operator conversion-type-id
conversion-type-id: type-specifier-seq conversion-declaratoropt
conversion-declarator: ptr-operator conversion-declaratoropt
ctor-initializer: : mem-initializer-list
mem-initializer-list: mem-initializer ...opt mem-initializer-list , mem-initializer ...opt
mem-initializer: mem-initializer-id ( expression-listopt ) mem-initializer-id braced-init-list
mem-initializer-id: class-or-decltype identifier