CODEWITHSUNDEEP
dart
A.A
A.A

Reputation: 4091

Dart TypeSafe - List and Iterable

In the following code , bar is a List but right side is a WhereIterable, As dart is a type safe language I have expected to have an error in Build time, but I have Uncaught Error: TypeError: Instance of 'WhereIterable<int>': type 'WhereIterable<int>' is not a subtype of type 'List<int>' error in Run time

void main() {
  final List<int> foo = [1, 2, 3];
  final List<int> bar = foo.where((e) => e > 1);
}

I know that adding .toList() fix error, My question is : Why we have no error in Compile/Build time?

Upvotes: 0

Views: 103

Answers (1)

Alex Radzishevsky
Alex Radzishevsky

Reputation: 3768

This is because dart implicitly casts Iterable to List. This is default behavior. In order to disable this one should turn of implicit casts in analyzer settings like this:

analyzer:
  strong-mode:
    implicit-casts: false

More information can be found here: https://dart.dev/guides/language/analysis-options#enabling-additional-type-checks and here: https://dart.dev/guides/language/type-system

Upvotes: 1

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