How does Dart resolve mixin method conflicts and application order?

WHAT THIS TESTS: Your understanding of Dart's mixin composition model and linearization. The interviewer cares whether you know that Dart resolves name conflicts through an ordered superclass chain rather than through multiple inheritance semantics or compile-time errors. They want to see that you understand how the with clause mechanically builds a hierarchy.

A GOOD ANSWER COVERS: First, state that Dart does not throw a compile error when two mixins define the same method. Instead, it resolves the conflict by application order. Second, explain that Dart processes the with clause left-to-right. For extends S with M1, M2, M3, the compiler conceptually creates intermediate classes by applying M1 first, then M2 applied to that result, then M3 applied on top. This means the superclass chain from the concrete class upward is M3, then M2, then M1, then S. Third, clarify that because the rightmost mixin becomes the immediate superclass, its members shadow any identical members from earlier mixins. The last mixin wins. Fourth, note that the concrete class itself can declare the conflicting method to override every mixin. Fifth, mention that this linearization avoids the diamond problem because there is always a single unambiguous path up the hierarchy.

COMMON WRONG ANSWERS: Claiming the first mixin in the list wins instead of the last. Saying Dart emits a compile-time ambiguity error for overlapping mixin methods. Confusing this with Python's C3 MRO or C++ multiple inheritance. Describing mixins as textual copy-paste rather than superclass insertion. Suggesting you must use a special disambiguation syntax to pick a mixin implementation.

LIKELY FOLLOW-UPS: How do super calls propagate through a chain of mixins? What happens if a mixin and the superclass both define the same method? How does the on clause restrict which classes can use a mixin, and does that affect ordering? What changed in Dart's mixin implementation between Dart 2 and Dart 3?

ONE CONCRETE EXAMPLE: Imagine class NetworkClient extends Base with RetryMixin, CacheMixin. If both RetryMixin and CacheMixin define handleError, then NetworkClient sees CacheMixin.handleError because CacheMixin is applied last. If you reverse the order to with CacheMixin, RetryMixin, then RetryMixin wins. NetworkClient can still declare its own handleError to override both mixins and optionally call super.handleError to reach the next mixin in the chain.