Type identify rules

[Sze]

@zigo

In the following code, T1 != T2. But should they equal to each other?

Based on this post:

How does the compiler know two generic types are the same?

Misconception alert! In modern Zig, function memoization is purely an optimization: it does not impact language semantics and will not be a part of the language specification. Instead, the compiler determines whether types are equivalent by comparing two things: Where are the types declared in source code? What values do the type definitions “capture” – meaning, what is the value of any identifier used within the type’s definition but declared outside of it? Here’s a simple example: …

I think the answer is no.

There is a bit of wiggle room, you could argue that only the size of T should be depended upon and this shouldn’t be a full dependency on T itself, but as far as I know Zig currently doesn’t have such fine grained dependency tracking and instead just expects the programmer to write it in such a way, so that you don’t make your type depend on more than you intended.

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Or said another way, I think both behaviors are a reasonable thing to want based on use-case, so it seems reasonable to have a way to write each of them.