WIP: Gate generating mod items in procedural macros
#50587
Closed
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
|
r? @eddyb (rust_highfive has picked a reviewer for you, use r? to override) |
rust-highfive
added
the
S-waiting-on-review
|
@bors: try |
|
@rust-lang/infra, could this be queued up for a check-only crater run? |
|
⌛ Trying commit bf3a1f146ad648bca69083a52dea192ba7a65e1f with merge d8c55432067be68f5e33e1472daddd580de55bca... |
|
@bors: try |
|
⌛ Trying commit 37b3c5e with merge d5fe9545473461c4b00b487ae07543b8d8646f3c... |
kennytm
added
the
S-waiting-on-crater
|
The job Click to expand the log.I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact |
|
☀️ Test successful - status-travis |
|
Crater run started. |
|
@alexcrichton |
|
Crater run finished: https://cargobomb-reports.s3.amazonaws.com/pr-50587/index.html. |
|
Alrighty-roo, thanks @Mark-Simulacrum! Definitely seems like we can't land this as-is, I'll file a follow-up. |
alexcrichton
added a commit
to alexcrichton/rust
that referenced
this pull request
May 18, 2018
This commit feature gates generating modules and macro definitions in procedural macro expansions. Custom derive is exempt from this check as it would be a large retroactive breaking change (rust-lang#50587). It's hoped that we can hopefully stem the bleeding to figure out a better solution here before opening up the floodgates. The restriction here is specifically targeted at surprising hygiene results [1] that result in non-"copy/paste" behavior. Hygiene and procedural macros is intended to be avoided as much as possible for Macros 1.2 by saying everything is "as if you copy/pasted the code", but modules and macros are sort of weird exceptions to this rule that aren't fully fleshed out. [1]: rust-lang#50504 (comment) cc rust-lang#50504
bors
added a commit
that referenced
this pull request
May 20, 2018
rustc: Disallow modules and macros in expansions This commit feature gates generating modules and macro definitions in procedural macro expansions. Custom derive is exempt from this check as it would be a large retroactive breaking change (#50587). It's hoped that we can hopefully stem the bleeding to figure out a better solution here before opening up the floodgates. The restriction here is specifically targeted at surprising hygiene results [1] that result in non-"copy/paste" behavior. Hygiene and procedural macros is intended to be avoided as much as possible for Macros 1.2 by saying everything is "as if you copy/pasted the code", but modules and macros are sort of weird exceptions to this rule that aren't fully fleshed out. [1]: #50504 (comment) cc #50504
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.
Discovered in #50504 the hygiene here is super questionable, so we'll likely want to gate this by default for procedural macros and procedural attributes for sure. This is a PR to evaluate the impact for procedural derive as well.