.github/workflows/ci.yml

@@ -27,7 +27,7 @@ jobs:
         rust: [1.56.0, stable, beta]
     timeout-minutes: 45
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@master
         with:
           toolchain: ${{matrix.rust}}
@@ -51,7 +51,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 45
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@nightly
         with:
           components: rust-src
@@ -82,7 +82,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 45
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@nightly
       - run: cargo generate-lockfile -Z minimal-versions
       - run: cargo check --locked
@@ -94,7 +94,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 45
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@nightly
         with:
           target: wasm32-unknown-unknown
@@ -108,7 +108,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 45
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@nightly
         with:
           components: rust-src
@@ -118,18 +118,16 @@ jobs:
         working-directory: fuzz
       - uses: dtolnay/install@honggfuzz
       - run: sudo apt-get install binutils-dev libunwind-dev
-        continue-on-error: true # https://github.com/dtolnay/proc-macro2/issues/387
       - run: cargo hfuzz build --no-default-features --features honggfuzz
         working-directory: fuzz
-        continue-on-error: true # https://github.com/dtolnay/proc-macro2/issues/387
 
   clippy:
     name: Clippy
     runs-on: ubuntu-latest
     if: github.event_name != 'pull_request'
     timeout-minutes: 45
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@nightly
         with:
           components: clippy, rust-src
@@ -143,7 +141,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 45
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@miri
       - run: cargo miri setup
       - run: cargo miri test
@@ -156,7 +154,7 @@ jobs:
     if: github.event_name != 'pull_request'
     timeout-minutes: 45
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: dtolnay/install@cargo-outdated
       - run: cargo outdated --workspace --exit-code 1
       - run: cargo outdated --manifest-path fuzz/Cargo.toml --exit-code 1

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "proc-macro2"
-version = "1.0.66" # remember to update html_root_url
+version = "1.0.67" # remember to update html_root_url
 authors = ["David Tolnay <dtolnay@gmail.com>", "Alex Crichton <alex@alexcrichton.com>"]
 autobenches = false
 categories = ["development-tools::procedural-macro-helpers"]

README.md

@@ -52,7 +52,7 @@ pub fn my_derive(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
 If parsing with [Syn], you'll use [`parse_macro_input!`] instead to propagate
 parse errors correctly back to the compiler when parsing fails.
 
-[`parse_macro_input!`]: https://docs.rs/syn/1.0/syn/macro.parse_macro_input.html
+[`parse_macro_input!`]: https://docs.rs/syn/2.0/syn/macro.parse_macro_input.html
 
 ## Unstable features
 

fuzz/Cargo.toml

@@ -9,9 +9,9 @@ publish = false
 cargo-fuzz = true
 
 [dependencies]
-afl = { version = "0.13", optional = true }
+afl = { version = "0.14", optional = true }
 honggfuzz = { version = "0.5", optional = true }
-libfuzzer-sys = { version = "0.4", optional = true }
+libfuzzer-sys = { version = "0.4.7", optional = true }
 proc-macro2 = { path = "..", default-features = false }
 
 [features]

fuzz/fuzz_targets/parse_token_stream.rs

@@ -43,7 +43,7 @@ fn main() {
 }
 
 #[cfg(feature = "libfuzzer")]
-libfuzzer_sys::fuzz_target!(|bytes: &[u8]| { do_fuzz(bytes) });
+libfuzzer_sys::fuzz_target!(|bytes: &[u8]| do_fuzz(bytes));
 
 #[cfg(feature = "afl")]
 fn main() {

src/lib.rs

@@ -55,7 +55,7 @@
 //! If parsing with [Syn], you'll use [`parse_macro_input!`] instead to
 //! propagate parse errors correctly back to the compiler when parsing fails.
 //!
-//! [`parse_macro_input!`]: https://docs.rs/syn/1.0/syn/macro.parse_macro_input.html
+//! [`parse_macro_input!`]: https://docs.rs/syn/2.0/syn/macro.parse_macro_input.html
 //!
 //! # Unstable features
 //!
@@ -86,7 +86,7 @@
 //! a different thread.
 
 // Proc-macro2 types in rustdoc of other crates get linked to here.
-#![doc(html_root_url = "https://docs.rs/proc-macro2/1.0.66")]
+#![doc(html_root_url = "https://docs.rs/proc-macro2/1.0.67")]
 #![cfg_attr(any(proc_macro_span, super_unstable), feature(proc_macro_span))]
 #![cfg_attr(super_unstable, feature(proc_macro_def_site))]
 #![cfg_attr(doc_cfg, feature(doc_cfg))]
@@ -98,6 +98,7 @@
     clippy::let_underscore_untyped,
     clippy::manual_assert,
     clippy::manual_range_contains,
+    clippy::missing_safety_doc,
     clippy::must_use_candidate,
     clippy::needless_doctest_main,
     clippy::new_without_default,
@@ -852,7 +853,7 @@ impl Debug for Punct {
 /// Rust keywords. Use `input.call(Ident::parse_any)` when parsing to match the
 /// behaviour of `Ident::new`.
 ///
-/// [`Parse`]: https://docs.rs/syn/1.0/syn/parse/trait.Parse.html
+/// [`Parse`]: https://docs.rs/syn/2.0/syn/parse/trait.Parse.html
 ///
 /// # Examples
 ///
@@ -943,7 +944,7 @@ impl Ident {
     /// Panics if the input string is neither a keyword nor a legal variable
     /// name. If you are not sure whether the string contains an identifier and
     /// need to handle an error case, use
-    /// <a href="https://docs.rs/syn/1.0/syn/fn.parse_str.html"><code
+    /// <a href="https://docs.rs/syn/2.0/syn/fn.parse_str.html"><code
     ///   style="padding-right:0;">syn::parse_str</code></a><code
     ///   style="padding-left:0;">::&lt;Ident&gt;</code>
     /// rather than `Ident::new`.

src/parse.rs

@@ -161,6 +161,10 @@ fn word_break(input: Cursor) -> Result<Cursor, Reject> {
     }
 }
 
+// Rustc's representation of a macro expansion error in expression position or
+// type position.
+const ERROR: &str = "(/*ERROR*/)";
+
 pub(crate) fn token_stream(mut input: Cursor) -> Result<TokenStream, LexError> {
     let mut trees = TokenStreamBuilder::new();
     let mut stack = Vec::new();
@@ -192,7 +196,7 @@ pub(crate) fn token_stream(mut input: Cursor) -> Result<TokenStream, LexError> {
         };
 
         if let Some(open_delimiter) = match first {
-            b'(' => Some(Delimiter::Parenthesis),
+            b'(' if !input.starts_with(ERROR) => Some(Delimiter::Parenthesis),
             b'[' => Some(Delimiter::Bracket),
             b'{' => Some(Delimiter::Brace),
             _ => None,
@@ -267,6 +271,10 @@ fn leaf_token(input: Cursor) -> PResult<TokenTree> {
         Ok((input, TokenTree::Punct(p)))
     } else if let Ok((input, i)) = ident(input) {
         Ok((input, TokenTree::Ident(i)))
+    } else if input.starts_with(ERROR) {
+        let rest = input.advance(ERROR.len());
+        let repr = crate::Literal::_new_fallback(Literal::_new(ERROR.to_owned()));
+        Ok((rest, TokenTree::Literal(repr)))
     } else {
         Err(Reject)
     }