proc_macro::is_available() #71400
Merged
proc_macro::is_available() #71400
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
rust-highfive
added
the
S-waiting-on-review
dtolnay
added
A-macros
|
Reassigning per #71268 (comment) because @eddyb is occupied. |
|
LGTM, but it needs a tracking issue. FCP and official team approval can be done during stabilization. |
petrochenkov
added
S-waiting-on-author
3 tasks
|
@bors r=petrochenkov |
|
📌 Commit 3bd742f has been approved by |
bors
added
S-waiting-on-bors
bors
added a commit
to rust-lang-ci/rust
that referenced
this pull request
Apr 23, 2020
Rollup of 5 pull requests Successful merges: - rust-lang#71256 (Lint must_use on mem::replace) - rust-lang#71350 (Error code explanation extra check) - rust-lang#71369 (allow wasm32 compilation of librustc_data_structures/profiling.rs) - rust-lang#71400 (proc_macro::is_available()) - rust-lang#71440 (Implement `Copy` for `AllocErr`) Failed merges: r? @ghost
|
Seems fine, the panic=abort situation leaves us no other options. cc @mystor, who, IIRC, wanted a "default server" which would eliminate the need for |
|
Something like a fallback server could make |
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Outdated suggestions cannot be applied.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.
This PR adds
proc_macro::is_available() -> boolto determine whether proc_macro has been made accessible to the currently running program.The proc_macro crate is only intended for use inside the implementation of procedural macros. All the functions in the crate panic if invoked from outside of a procedural macro, such as from a build script or unit test or ordinary Rust binary.
Unfortunately those panics made it impossible for libraries that are designed to support both macro and non-macro use cases (e.g. Syn) to be used from binaries that are compiled with panic=abort. In panic=unwind mode we're able to attempt a proc macro call inside catch_unwind and use libproc_macro's result if it succeeds, otherwise fall back to a non-macro alternative implementation. But in panic=abort there was no way to determine which implementation needs to be used.
r? @eddyb
attn: @petrochenkov @adetaylor
ref: dtolnay/cxx#130