What that means is: I might call a function that tells me it will give me type X but instead it blows up. It's good that it blows up btw - that is the best thing a language with gradual typing can do for these cases. But it's not something I would be satisfied with.
Now, you can say that "blowing up" is part of any function anyways, but then my response would be that this severely hurts my ability to reason about how code will behave when run, so I'm giving up a huge benefit of a static type-system in general.
What that means is: I might call a function that tells me it will give me type X but instead it blows up. It's good that it blows up btw - that is the best thing a language with gradual typing can do for these cases. But it's not something I would be satisfied with.
Now, you can say that "blowing up" is part of any function anyways, but then my response would be that this severely hurts my ability to reason about how code will behave when run, so I'm giving up a huge benefit of a static type-system in general.