More coercions: reserved ~> null : opt _#134
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I won’t believe in this system until we have a formal proof… anyways,
still finding holes.
Imagine the sender evolves as follows:
```
record {} <: record { foo : reserved }
```
and the receiver evolves (using fancy new opt field rules) as follows:
```
record {} :> record { foo : opt bool }
```
Both are allowed, so decoding must not fail. One way to fix that is to
add
```
(null : reserved) ~> null : opt <t>
```
to the rules.
nomeata
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|
@rossberg , did you have a chance to double check this? |
Contributor
|
I think you're right. |
chenyan-dfinity
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Nov 13, 2020
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I won’t believe in this system until we have a formal proof… anyways,
still finding holes.
Imagine the sender evolves as follows:
and the receiver evolves (using fancy new opt field rules) as follows:
Both are allowed, so coercion must not fail. One way to fix that is to
add
to the rules.