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Comment by ericpauley | Hacker News Reader

It’s pretty common to type check interface implementations in Go using package-level casts.

I know, it is yet another language hack, just like the iota/const dance, instead of proper language constructs.

How is a package level interface check a “language hack”? They are straight forward and provide a user the same compile time guarantees as the Java implements keyword.

Because they are a workaround for what should be a language feature in first place, just like on ML languages to type check structural types.

What exactly isn’t a language feature? Or do you have issues with semantics?

    var _ Foo = (*Bar)(nil)

The statement asserts that Bar struct pointers are assignable to a Foo interface.

I do agree it’s not as clean looking as the Java implements keyword, but it’s already a fairly terse pattern and IMO the inconvenience does not justify introducing new language syntax.

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