rustc hanging indefinitely and using more and more memory

[yberreby]

When compiling a particular piece of code, rustc hangs and keeps allocating memory indefinitely. I noticed this because my computer suddenly started swapping, and I found out rustc was using around 6GB of memory and growing.

Here's the code that triggered the bug:

pub enum PrimaryExpr {
    Indexing(PrimaryExpr, Expression),
    Slicing(PrimaryExpr, Slice),
}

Yes, nothing else - no dependencies, no modules, nothing.

Trying to compile it triggers the bug (src/lib.rs contains only the above snippet):

$ cat src/lib.rs
pub enum PrimaryExpr {
    Indexing(PrimaryExpr, Expression),
    Slicing(PrimaryExpr, Slice),
}

$ rustc src/lib.rs
src/lib.rs:2:27: 2:37 error: type name `Expression` is undefined or not in scope [E0412]
src/lib.rs:2     Indexing(PrimaryExpr, Expression),
                                       ^~~~~~~~~~
src/lib.rs:2:27: 2:37 help: run `rustc --explain E0412` to see a detailed explanation
src/lib.rs:2:27: 2:37 help: no candidates by the name of `Expression` found in your project; maybe you misspelled the name or forgot to import an external crate?
src/lib.rs:3:26: 3:31 error: type name `Slice` is undefined or not in scope [E0412]
src/lib.rs:3     Slicing(PrimaryExpr, Slice),
                                      ^~~~~
src/lib.rs:3:26: 3:31 help: run `rustc --explain E0412` to see a detailed explanation
src/lib.rs:3:26: 3:31 help: you can import it into scope: `use std::raw::Slice;`.
error: main function not found

rustc reports the error normally, but instead of exiting afterward it stays alive and keeps allocating more memory until I manually kill it.

Meta

$ rustc --version -v
rustc 1.9.0-nightly (d5a91e6 2016-03-26)
binary: rustc
commit-hash: d5a91e6
commit-date: 2016-03-26
host: x86_64-apple-darwin
release: 1.9.0-nightly

[jonas-schievink]

Duplicate of #32326

[yberreby]

@jonas-schievink Indeed, thanks!