Open
Conversation
The custom descriptors proposal is also at phase 3 and adds a notion of "exact" heap types. A heap type `(exact $foo)` is a subtype of `$foo`. The custom descriptors proposal refines existing instructions that produce new references like `struct.new $foo`, `array.new $foo`, and `ref.func $foo` to produce exact types rather than inexact types. Update the validation rules for the stack switching instructions accordingly. This does not need to be landed as long as custom descriptors has not reached phase 4, but it would be good to get eyes on the intersection of the two proposals early.
rossberg
reviewed
Apr 7, 2026
Member
rossberg
left a comment
rossberg
left a comment
There was a problem hiding this comment.
The changes look right to me.
| where: | ||
| - $e : [] -> [t*] | ||
| - $ct1 = cont [t1* (ref $ct2)] -> [t*] | ||
| - $ct1 = cont [t1* (ref null? (exact? $ct2))] -> [t*] |
Member
There was a problem hiding this comment.
The missing null? here looks like an inconsistency independent from exact types. Perhaps make a PR fixing it separately?
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
The custom descriptors proposal is also at phase 3 and adds a notion of "exact" heap types. A heap type
(exact $foo)is a subtype of$foo. The custom descriptors proposal refines existing instructions that produce new references likestruct.new $foo,array.new $foo, andref.func $footo produce exact types rather than inexact types. Update the validation rules for the stack switching instructions accordingly.This does not need to be landed as long as custom descriptors has not reached phase 4, but it would be good to get eyes on the intersection of the two proposals early.