Different stderr output in stable and nightly rust

[Frago9876543210]

TIL about Attribute::parse_args method and make usage of it in my crate. However, CI failed on beta and stable. Meanwhile nightly build is fine.

Look the at line number (4:10 and 4:9). Expected output for trybuild was generated on rustc 1.45.0-nightly (5fd2f06e9 2020-05-31) and also matches with lastest

EXPECTED:
┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
error: unexpected end of input, expected identifier

 --> $DIR/04-excepted-endian-identifier.rs:4:10

  |

4 | #[endian()]

  |          ^
┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈

ACTUAL OUTPUT:
┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
error: unexpected end of input, expected identifier

 --> $DIR/04-excepted-endian-identifier.rs:4:9

  |

4 | #[endian()]

  |         ^^
┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈

Link to CI

[dtolnay]

In general different compilers are free to produce different diagnostics. One can generally expect compiler diagnostics to improve over time.

Usually I run trybuild tests on a single toolchain only:
https://github.com/serde-rs/json/blob/4354fc3eb2232ee0ba9a9a23acce107a980a6dc0/tests/compiletest.rs#L1-L6

It would also be reasonable for a project to keep different expected output files for different toolchains but I have not found this valuable.