Mutating immutable variable about v HOT 9 OPEN

It's a bug.

V doesn't have mutable types (&User vs mut &User).

The checker simply needs to improve to handle this. It already prohibits foo := mutable_ref.

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It's not a "feature", per se... it is simply the way things work, IMO.

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However, the code here isn't modifying User or &User. It is only modifying the mutable field inside User. That's why I said it is the way things work.

Creating an immutable reference does not change the mutability of the field.

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Thoughts @medvednikov @spytheman ?

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This is why pointers are so fraught...

Yes, rere returns an immutable pointer... to a struct with a mutable field. Modifying that field is perfectly valid.

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This is why pointers are so fraught...

Yes, rere returns an immutable pointer... to a struct with a mutable field. Modifying that field is perfectly valid.

so that's not a bug? it's a feature?

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I think it should not be possible to create a mutable reference to an immutable variable:

Same as

i := 0
mut ref := &i

Results in:

error: `i` is immutable, cannot have a mutable reference to it
   20 | 
   21 | i := 0
   22 | mut ref := &i
      |       

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However, the code here isn't modifying User or &User. It is only modifying the mutable field inside User. That's why I said it is the way things work.

Creating an immutable reference does not change the mutability of the field.

V immutable variable isn't JavaScript's const i guess. Fields and variable itself shouldn't be mutable if it's not declared as mut, am i right?

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Correct. "Immutable by default." This is opposite most other languages.

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