Scala 3 opaque types provide encapsulation, type safety, abstraction, and semantic clarity. They allow defining abstract data types with controlled access to underlying representation.
Opaque types are useful when encapsulating type representation, ensuring type safety, creating new data types with hidden implementation details, and improving code readability with descriptive names.
In Domain-Driven Design and Functional Programming, defining custom types like EmailAddress instead of using plain types like String is a common practice. Opaque types facilitate such practices while enhancing clarity.
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