Extends a Class will make losing and corrupted types in a child class. · Issue #42541 · microsoft/TypeScript · GitHub

When we add types on properties base class, if a child class extends this base class, we will lost types and get corrupted behavior. Actually is seem affected by keyof T, i not tested all others types, but this one make coruptions. From

TSC2417 - Incorrectly extending other class (which is not the case) · Issue #18643 · microsoft/TypeScript · GitHub

Module not found when extending a class otherwise same code without extending no error · Issue #51260 · microsoft/TypeScript · GitHub

Support final classes (non-subclassable) · Issue #8306 · microsoft/ TypeScript · GitHub

this subclass inference problem · Issue #15615 · microsoft/TypeScript · GitHub

Support override keyword on class methods · Issue #2000 · microsoft/ TypeScript · GitHub

Support final classes (non-subclassable) · Issue #8306 · microsoft/ TypeScript · GitHub

Inherited typing for class property initializers · Issue #10570 · microsoft/ TypeScript · GitHub

BUG [TS2416]: Incorrect error reporting · Issue #42858 · microsoft/ TypeScript · GitHub

instanceof is broken when class extends Error type · Issue #13965 · microsoft/TypeScript · GitHub

Support override keyword on class methods · Issue #2000 · microsoft/ TypeScript · GitHub

Support override keyword on class methods · Issue #2000 · microsoft/ TypeScript · GitHub

Broken inferred recursive types · Issue #43817 · microsoft/TypeScript · GitHub

Mixin base requires explicit type in TS 4.3 due to recursively referencing itself when it doesn't · Issue #44284 · microsoft/TypeScript · GitHub