What is the difference between Go's type constraints and type assertions for enforcing constraints and checking types in Go programs?
Go's type constraints and type assertions are two different mechanisms that serve different purposes in Go programs.
Type constraints are used to restrict the set of types that a type parameter can accept. In Go, this is achieved through the use of interface types, where a type parameter can be constrained to implement certain methods or satisfy certain interface types. Type constraints help ensure that the generic code is well-typed and operates correctly for all types that it is instantiated with.
Type assertions, on the other hand, are used to check the dynamic type of a value at run-time. A type assertion allows a program to check whether an interface value contains a specific type, and to extract that value as that type. This can be useful for working with generic types, or for performing run-time type checks.
In summary, type constraints are used to restrict the set of types that a generic function or type can accept, while type assertions are used to check the dynamic type of a value at run-time.