CODEWITHSUNDEEP
classinheritancedartstatic-typing
Zacharias Georgiou
Zacharias Georgiou

Reputation: 1

Dart: Why does the following code compiles in strong mode?

void main(){
  new C(new A()); // This gives no warning or error
  new D(new A()); // This gives an error

}
class A{}

class B extends A{}

class C {
  B b;
  C(A bb){    this.b = bb;   }
}

class D {  
  B b; 
  D(this.b); 
}

In both statements in main function I give as a parameter an instance of type A. If I am not wrong both statements should give an error or warning in Strong mode, however only the second gives an error: Type check failed: new A()(A) is not of type B

Image showing the code compiled from https://dartpad.dartlang.org/

I just started learning dart language and I couldn't find in the documentation an explanation for this case. Does anybody know why this is happening?

Upvotes: 0

Views: 84

Answers (1)

Alexandre Ardhuin
Alexandre Ardhuin

Reputation: 76233

It looks like you made a typo in your C constructor. Do you mean:

class C {
  B b;
  C(B/*not A*/ bb){    this.b = bb;   }
}

Upvotes: 1

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