Clarify accepted types for Expression::AccessIndex
#1862
Merged
Conversation
This file contains 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
jimblandy
requested changes
Apr 25, 2022
src/lib.rs
Outdated
| /// Array access with a known index. | ||
| /// Access the same types as [`Access`] plus [`Struct`] with a known index. | ||
| /// | ||
| /// [`Array`]s must have a [`Constant`] size. |
There was a problem hiding this comment.
Is this true? I couldn't find code in the validator that would reject dynamically-sized arrays.
There was a problem hiding this comment.
The validator sets a bound of the size of the array if its size is constant, but sets it to !0 if it's not, which somehow evaluates to -1, making the bounds check always fail. At least in theory, I haven't explicitly tested this.
There was a problem hiding this comment.
It makes the compile time bounds check always succeed because !0 as a u32 is u32::MAX so no index is ever out of bounds. The code could be made easier to grok by using u32::MAX explicitly.
There was a problem hiding this comment.
(Agreed that the code is not as clear as it might be.)
Will I ever learn to run `cargo fmt` before pushing? The answer is probably yes, after this repeated embarrassment
jimblandy
approved these changes
Apr 26, 2022
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
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Outdated suggestions cannot be applied.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 docs for
AccessIndexonly note it can be used with arrays ("Array access with a known index.") and don't mention it can be used with structs or other types.This pull request documents the full list of types relative to those for
Expression::Access, which already have a more extensive blurb written about them.