IK
Size: a a a
2020 November 12
AV
А ну профиг
DB
А сколько шагов он пробует? Это захардкожено?
DB
При выводе инстанса
AV
Ты же значешь что делать если такой вопрос возникает?
DB
Я пытался лезть в код GHC, мне пока от него дурно
AV
Есть ответ проще
DB
Дока, понял
DB
Ща гляну
AV
10.8.3.5. Undecidable instances¶
Sometimes even the termination rules of Instance termination rules are too onerous. So GHC allows you to experiment with more liberal rules: if you use the experimental extension UndecidableInstances, both the Paterson Conditions and the Coverage Condition (described in Instance termination rules) are lifted. Termination is still ensured by having a fixed-depth recursion stack. If you exceed the stack depth you get a sort of backtrace, and the opportunity to increase the stack depth with -freduction-depth=⟨n⟩.
Sometimes even the termination rules of Instance termination rules are too onerous. So GHC allows you to experiment with more liberal rules: if you use the experimental extension UndecidableInstances, both the Paterson Conditions and the Coverage Condition (described in Instance termination rules) are lifted. Termination is still ensured by having a fixed-depth recursion stack. If you exceed the stack depth you get a sort of backtrace, and the opportunity to increase the stack depth with -freduction-depth=⟨n⟩.
AV
Ну я уже принёс
AV
Но схожить стоит, там вся конкретика