compiler nontermination after "error: bare CR not allowed in doc-comment"

[dwrensha]

$ rustc -vV
rustc 1.38.0-nightly (273f42b59 2019-07-21)
binary: rustc
commit-hash: 273f42b5964c29dda2c5a349dd4655529767b07f
commit-date: 2019-07-21
host: x86_64-unknown-linux-gnu
release: 1.38.0-nightly
LLVM version: 9.0


$ echo cyAgaS8vL2cNLyBydW4tcA0vLyBhIHNi | base64 --decode > main.rs

$ rustc main.rs
error: bare CR not allowed in doc-comment
 --> main.rs:1:9
  |
// a sbi///g
  |         ^

error: bare CR not allowed in doc-comment
 --> main.rs:1:12
  |
// a sbi///g
  |           ^

... and rustc keeps running until I kill it.

This bad behavior did not exist on the previous nightly. I hypothesize that it has to do with #59706 (cc @matklad).

This issue was found with the help of fuzz-rustc.

This issue has been assigned to @matklad via this comment.

[matklad]

Oh, excellent, thanks @dwrensha !

@rustbot claim