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mfaani/some-vs-some.md

Last active September 30, 2024 18:09
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`some Equatable` vs another `some Equatable`
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some-vs-some.md 
var a: some Equatable = 10
var c: some Equatable = 10
a = c // ERROR: Cannot assign value of type 'some Equatable' (type of 'c') to type 'some Equatable' (type of 'a')

You can't pass a different some Equatable to a. The compiler can't guarantee if a and c have identical underlying concrete types. Even though on the screen you can see c is an Int, to the compiler it's just some Equatable. It's NOT some Equatable_But_really_an_Int.

Because it's some Equatable then the compiler would be like, then 'What if c was "ten"? Let's just be safe an not allow it'

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