Release build fails with SIGSEGV

[svend]

When building with the cargo build --release, the build fails with (signal: 11, SIGSEGV: Invalid memory reference). Building with cargo build (no --release flag) works. Here is the full output, along with the rust version:

ubuntu@host:~/syn$ git describe
0.8.0
ubuntu@host:~/syn$ cargo build --release --verbose
    Updating registry `https://github.com/rust-lang/crates.io-index`
   Compiling quote v0.2.0
     Running `rustc /home/ubuntu/.cargo/registry/src/github.com-1ecc6299db9ec823/quote-0.2.0/src/lib.rs --crate-name quote --crate-type lib -C opt-level=3 -C metadata=9442466506b24325 -C extra-filename=-9442466506b24325 --out-dir /home/ubuntu/syn/target/release/deps --emit=dep-info,link -L dependency=/home/ubuntu/syn/target/release/deps --cap-lints allow`
   Compiling syn v0.8.0 (file:///home/ubuntu/syn)
     Running `rustc src/lib.rs --crate-name syn --crate-type lib -C opt-level=3 --cfg feature=\"default\" --cfg feature=\"printing\" --cfg feature=\"parsing\" --cfg feature=\"quote\" -C metadata=977935f812d0e598 --out-dir /home/ubuntu/syn/target/release/deps --emit=dep-info,link -L dependency=/home/ubuntu/syn/target/release/deps --extern quote=/home/ubuntu/syn/target/release/deps/libquote-9442466506b24325.rlib`
error: Could not compile `syn`.

Caused by:
  Process didn't exit successfully: `rustc src/lib.rs --crate-name syn --crate-type lib -C opt-level=3 --cfg feature="default" --cfg feature="printing" --cfg feature="parsing" --cfg feature="quote" -C metadata=977935f812d0e598 --out-dir /home/ubuntu/syn/target/release/deps --emit=dep-info,link -L dependency=/home/ubuntu/syn/target/release/deps --extern quote=/home/ubuntu/syn/target/release/deps/libquote-9442466506b24325.rlib` (signal: 11, SIGSEGV: Invalid memory reference)
ubuntu@host:~/syn$ rustc --version --verbose
rustc 1.12.0 (3191fbae9 2016-09-23)
binary: rustc
commit-hash: 3191fbae9da539442351f883bdabcad0d72efcb6
commit-date: 2016-09-23
host: x86_64-unknown-linux-gnu
release: 1.12.0

[svend]

Building with rust 1.11.0 works. Let me know if I should file an issue with rust.

ubuntu@host:~/syn$ rustc --version --verbose
rustc 1.11.0 (9b21dcd6a 2016-08-15)
binary: rustc
commit-hash: 9b21dcd6a89f38e8ceccb2ede8c9027cb409f6e3
commit-date: 2016-08-15
host: x86_64-unknown-linux-gnu
release: 1.11.0
ubuntu@host:~/syn$ cargo build --release --verbose
    Updating registry `https://github.com/rust-lang/crates.io-index`
   Compiling quote v0.2.0
     Running `rustc /home/ubuntu/.cargo/registry/src/github.com-1ecc6299db9ec823/quote-0.2.0/src/lib.rs --crate-name quote --crate-type lib -C opt-level=3 -C metadata=9442466506b24325 -C extra-filename=-9442466506b24325 --out-dir /home/ubuntu/syn/target/release/deps --emit=dep-info,link -L dependency=/home/ubuntu/syn/target/release/deps -L dependency=/home/ubuntu/syn/target/release/deps --cap-lints allow`
   Compiling syn v0.8.0 (file:///home/ubuntu/syn)
     Running `rustc src/lib.rs --crate-name syn --crate-type lib -C opt-level=3 --cfg feature=\"quote\" --cfg feature=\"default\" --cfg feature=\"printing\" --cfg feature=\"parsing\" --out-dir /home/ubuntu/syn/target/release --emit=dep-info,link -L dependency=/home/ubuntu/syn/target/release -L dependency=/home/ubuntu/syn/target/release/deps --extern quote=/home/ubuntu/syn/target/release/deps/libquote-9442466506b24325.rlib`

[dtolnay]

Definitely a compiler bug.

It goes away with this commit 3a2ea4b so I have a lead.

[svend]

@dtolnay Thanks. I filed an issue before I read your response. It is here: rust-lang/rust#36875

[dtolnay]

Narrowed down further: e8b4e20.

[dtolnay]

I can't work on this right now but I will do my best to release a workaround later tonight.

[dtolnay]

I released a workaround in 0.8.1.

The following code triggered the bug:

pub fn str_chars(s: &str) -> Vec<char> {
    s.chars().collect()
}

The following workaround avoided the bug:

pub fn str_chars(s: &str) -> Vec<char> {
    let mut result = Vec::new();
    for ch in s.chars() {
        result.push(ch);
    }
    result
}