Почему в данном случае срабатывает неявный конструктор

Почему в данном случае срабатывает неявный конструктор, хотя он и помечен explicit?

необходимо преобразовать HugoCopy в Hugo, но конструктор копирования Hugo является explicit и поэтому неявное преобразование должно быть невозможно.

HugoCopy обратно в Hugo делается через operator Hugo const&()

Почему в данном случае срабатывает неявный конструктор, хотя он и помечен explicit?

the return statement initializes the glvalue result or prvalue result object of the (explicit or implicit) function call by copy-initialization (11.6) from the operand.

A constructor declared without the function-specifier explicit specifies a conversion from the types of its parameters (if any) to the type of its class. Such a constructor is called a converting constructor .
...
A non-explicit copy/move constructor (15.8) is a converting constructor.

For copy-initialization, the candidate functions are all the converting constructors (15.3.1) of that class.

почему на hoggy? Не нахожу перевода или значения данного слова.

как Вы смогли сделать так, что бы Ваш код сохранился для тех кто перейдёт по ссылке на онлайн компилятор?

Croessmah, в этом то и вопрос. Как?

Может у него и спросим? hoggy, выходи, дорогой.

по теме: не должно компиляццо.

в то время как в функциональном стиле - explisit работает нормально.

Дык и не компилится.

Потому что по правилам языка

clang собирает

однозначно эквивалентна

Не эквивалентна.

При возврате из функции для построения объекта типа Hugo необходимо неявно преобразовать HugoCopy в Hugo, но конструктор копирования Hugo является explicit и поэтому неявное преобразование должно быть невозможно.

If the destination type is a (possibly cv-qualified) class type:
(17.6.1) — If the initializer expression is a prvalue and the cv-unqualified version of the source type is the same class as the class of the destination, the initializer expression is used to initialize the destination object.
[ Example: T x = T(T(T())); calls the T default constructor to initialize x. — end example]
(17.6.2) — Otherwise, if the initialization is direct-initialization, or if it is copy-initialization where the cv-unqualified version of the source type is the same class as, or a derived class of, the class of the destination, constructors are considered.
The applicable constructors are enumerated ([over.match.ctor]), and the best one is chosen through overload resolution.
The constructor so selected is called to initialize the object, with the initializer expression or expression-list as its argument(s).
If no constructor applies, or the overload resolution is ambiguous, the initialization is ill-formed.
(17.6.3) — Otherwise (i.e., for the remaining copy-initialization cases), user-defined conversion sequences that can convert from the source type to the destination type or (when a conversion function is used) to a derived class thereof are enumerated as described in [over.match.copy], and the best one is chosen through overload resolution.
If the conversion cannot be done or is ambiguous, the initialization is ill-formed.
The function selected is called with the initializer expression as its argument; if the function is a constructor, the call is a prvalue of the cv-unqualified version of the destination type whose result object is initialized by the constructor.
The call is used to direct-initialize, according to the rules above, the object that is the destination of the copy-initialization.

1 Under the conditions specified in [dcl.init], as part of a copy-initialization of an object of class type, a user-defined conversion can be invoked to convert an initializer expression to the type of the object being initialized.
Overload resolution is used to select the user-defined conversion to be invoked.
[ Note: The conversion performed for indirect binding to a reference to a possibly cv-qualified class type is determined in terms of a corresponding non-reference copy-initialization. — end note]
Assuming that “cv1 T” is the type of the object being initialized, with T a class type, the candidate functions are selected as follows:

(1.1) The converting constructors of T are candidate functions.
(1.2) When the type of the initializer expression is a class type “cv S”, the non-explicit conversion functions of S and its base classes are considered.
When initializing a temporary object ([class.mem]) to be bound to the first parameter of a constructor where the parameter is of type “reference to possibly cv-qualified T” and the constructor is called with a single argument in the context of direct-initialization of an object of type “cv2 T”, explicit conversion functions are also considered.
Those that are not hidden within S and yield a type whose cv-unqualified version is the same type as T or is a derived class thereof are candidate functions.
Conversion functions that return “reference to X” return lvalues or xvalues, depending on the type of reference, of type X and are therefore considered to yield X for this process of selecting candidate functions.

2 In both cases, the argument list has one argument, which is the initializer expression.
[ Note: This argument will be compared against the first parameter of the constructors and against the implicit object parameter of the conversion functions. — end note]

The result of the call (which is the temporary for the constructor case) is then used to direct-initialize,
according to the rules above, the object that is the destination of the copy-initialization

по теме: не должно компиляццо.