Avoid parser panics bubbling out to proc macros#158256
Open
Mark-Simulacrum wants to merge 1 commit into
Open
Conversation
rustbot
added
the
S-waiting-on-review
rustbot
added
the
T-compiler
Mark-Simulacrum
changed the title
cyrgani
reviewed
Jun 22, 2026
bjorn3
reviewed
Jun 22, 2026
Currently, rustc can emit a FatalError diagnostic during parsing of literals and tokenstreams. These are handled under the hood as a panic, which means that proc-macro code needed to catch_unwind if it wanted to fallibly parse some code. These still emit diagnostics, so in practice this isn't a full fix, but it at least makes the interface on the macro side a bit more uniform. This is primarily motivated by wasm proc macros which can't use catch_unwind and so this lets the test's output be the same with and without them.
Mark-Simulacrum
force-pushed
the
no-panic-pm-parsing
branch
from
39f2779 to
ca1224d
Compare
bjorn3
approved these changes
Jun 22, 2026
Member
|
@bors r+ |
Contributor
rust-bors
Bot
added
S-waiting-on-bors
rust-bors Bot
pushed a commit
that referenced
this pull request
Jun 23, 2026
…uwer Rollup of 16 pull requests Successful merges: - #156885 (Fix misattributed type inference error span for index expressions) - #157271 (simplify some `proc_macro` things) - #157883 (Remove strict invariant node_type on hir_type during ty privacy visit) - #157921 (trait solver: Resolve region vars in max universe) - #157960 (delegation: add support for infers in generics) - #158105 (Extract all instance shim variants into new `ShimKind` enum) - #158207 (Resolver: local/external split of `resolve_ident_in_module_non_globs_unadjusted` ) - #158279 (Follow goto and drop when linting unreachable code) - #157807 (don't ice on non-lifetime binders under `-Zassumptions-on-binders`) - #158020 (Update mingw-w64 C toolchain) - #158222 (format: ignore println newline in foreign format hints) - #158223 (Move target checking for #[lang] to the attribute parser) - #158252 (Use `cfg_select` in `std::os`) - #158257 ( fix escaping placeholder check in next solver normalization folder) - #158274 (triagebot: Stop pinging myself) - #158282 (slice_split_once: bounds check optimization note) Failed merges: - #158256 (Avoid parser panics bubbling out to proc macros)
This was referenced Jun 23, 2026
rust-bors Bot
pushed a commit
that referenced
this pull request
Jun 23, 2026
…uwer Rollup of 23 pull requests Successful merges: - #158315 (`rust-analyzer` subtree update) - #155739 (Add temporary scope to assert_eq and assert_ne) - #156885 (Fix misattributed type inference error span for index expressions) - #157271 (simplify some `proc_macro` things) - #157883 (Remove strict invariant node_type on hir_type during ty privacy visit) - #157921 (trait solver: Resolve region vars in max universe) - #157960 (delegation: add support for infers in generics) - #157983 (Lift the same-signature restriction for `extern "tail"`) - #158105 (Extract all instance shim variants into new `ShimKind` enum) - #158207 (Resolver: local/external split of `resolve_ident_in_module_non_globs_unadjusted` ) - #158279 (Follow goto and drop when linting unreachable code) - #157527 (Move derive tests into their dedicated folder) - #157807 (don't ice on non-lifetime binders under `-Zassumptions-on-binders`) - #158020 (Update mingw-w64 C toolchain) - #158222 (format: ignore println newline in foreign format hints) - #158223 (Move target checking for #[lang] to the attribute parser) - #158252 (Use `cfg_select` in `std::os`) - #158257 ( fix escaping placeholder check in next solver normalization folder) - #158263 (Only load the feature list once in the entire resolver) - #158274 (triagebot: Stop pinging myself) - #158282 (slice_split_once: bounds check optimization note) - #158300 (Improve unknown crate_type diagnostic suggestions) - #158304 (mailmap: update mu001999) Failed merges: - #158256 (Avoid parser panics bubbling out to proc macros)
rust-bors Bot
pushed a commit
that referenced
this pull request
Jun 24, 2026
Rollup of 27 pull requests Successful merges: - #158315 (`rust-analyzer` subtree update) - #155739 (Add temporary scope to assert_eq and assert_ne) - #156885 (Fix misattributed type inference error span for index expressions) - #157271 (simplify some `proc_macro` things) - #157883 (Remove strict invariant node_type on hir_type during ty privacy visit) - #157921 (trait solver: Resolve region vars in max universe) - #157960 (delegation: add support for infers in generics) - #157983 (Lift the same-signature restriction for `extern "tail"`) - #158053 (Optimize network address parser) - #158105 (Extract all instance shim variants into new `ShimKind` enum) - #158207 (Resolver: local/external split of `resolve_ident_in_module_non_globs_unadjusted` ) - #158279 (Follow goto and drop when linting unreachable code) - #157527 (Move derive tests into their dedicated folder) - #157807 (don't ice on non-lifetime binders under `-Zassumptions-on-binders`) - #158020 (Update mingw-w64 C toolchain) - #158039 (c-variadic: test that we use equality up to free lifetimes) - #158222 (format: ignore println newline in foreign format hints) - #158223 (Move target checking for #[lang] to the attribute parser) - #158252 (Use `cfg_select` in `std::os`) - #158257 ( fix escaping placeholder check in next solver normalization folder) - #158263 (Only load the feature list once in the entire resolver) - #158267 (FromUtf8Error::into_utf8_lossy better example and suggest use) - #158274 (triagebot: Stop pinging myself) - #158282 (slice_split_once: bounds check optimization note) - #158300 (Improve unknown crate_type diagnostic suggestions) - #158304 (mailmap: update mu001999) - #158309 (Update `rustc-literal-escaper` version to `0.0.8`) Failed merges: - #158256 (Avoid parser panics bubbling out to proc macros)
JonathanBrouwer
added a commit
to JonathanBrouwer/rust
that referenced
this pull request
Jun 25, 2026
…g, r=bjorn3 Avoid parser panics bubbling out to proc macros Currently, rustc can emit a FatalError diagnostic during parsing of literals and tokenstreams. These are handled under the hood as a panic, which means that proc-macro code needed to catch_unwind if it wanted to fallibly parse some code. These still emit diagnostics, so in practice this isn't a full fix, but it at least makes the interface on the macro side a bit more uniform. The long-term fix should be to get rid of those FatalErrors (and in general all diagnostics that actually get emitted out during parsing, not just returned), but this seems like a reasonable improvement in the meantime. This is primarily motivated by wasm proc macros which can't use catch_unwind and so this lets the test's output be the same with and without them. r? bjorn3
JonathanBrouwer
added a commit
to JonathanBrouwer/rust
that referenced
this pull request
Jun 25, 2026
…g, r=bjorn3 Avoid parser panics bubbling out to proc macros Currently, rustc can emit a FatalError diagnostic during parsing of literals and tokenstreams. These are handled under the hood as a panic, which means that proc-macro code needed to catch_unwind if it wanted to fallibly parse some code. These still emit diagnostics, so in practice this isn't a full fix, but it at least makes the interface on the macro side a bit more uniform. The long-term fix should be to get rid of those FatalErrors (and in general all diagnostics that actually get emitted out during parsing, not just returned), but this seems like a reasonable improvement in the meantime. This is primarily motivated by wasm proc macros which can't use catch_unwind and so this lets the test's output be the same with and without them. r? bjorn3
rust-bors
Bot
added
the
S-waiting-on-author
Contributor
|
☔ The latest upstream changes (presumably #158342) made this pull request unmergeable. Please resolve the merge conflicts by rebasing. This pull request was unapproved. |
rust-bors
Bot
removed
the
S-waiting-on-bors
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
4 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.
Currently, rustc can emit a FatalError diagnostic during parsing of literals and tokenstreams. These are handled under the hood as a panic, which means that proc-macro code needed to catch_unwind if it wanted to fallibly parse some code. These still emit diagnostics, so in practice this isn't a full fix, but it at least makes the interface on the macro side a bit more uniform. The long-term fix should be to get rid of those FatalErrors (and in general all diagnostics that actually get emitted out during parsing, not just returned), but this seems like a reasonable improvement in the meantime.
This is primarily motivated by wasm proc macros which can't use catch_unwind and so this lets the test's output be the same with and without them.
r? bjorn3