You can make "believe_me" assertions, which is incredibly useful when writing advanced (metaprogramming heavy) library code. The idea is to try and contain / and heavily test the small "unsafe" library part and isolate it from the rest of the code, then enjoy the advanced type transformations and checks in the "normal" application code.
For example, an SQL query builder library may internally do unchecked assertions about the type of the result row that a query transformation would produce (e.g. group_by), however assuming that part is correct, all application code using the query builder's group_by method would benefit from the correct row types being produced by `group_by` which can then be matched against the rest of the application code.
For example, an SQL query builder library may internally do unchecked assertions about the type of the result row that a query transformation would produce (e.g. group_by), however assuming that part is correct, all application code using the query builder's group_by method would benefit from the correct row types being produced by `group_by` which can then be matched against the rest of the application code.