Nominal Types in WebAssembly

6 days ago

WebAssembly initially used structural type equality, where types with the same structure are considered equivalent.
Recursive type groups (`rec`) allow for nominal typing within a module by isolating types in their own equivalence classes.
The nominal typing proposal introduces `tag` for defining nominal types, but lacks subtyping and mutability.
Creating and checking nominal types involves exception handling mechanisms (`throw`, `try_table`, `catch`).
Nominal types can be shared between modules via type imports and exports.
The post humorously highlights the quirks of the nominal typing proposal in WebAssembly.

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