Description
On 7550cab I was seeing errors with cargo build
$ cargo build
Compiling opendp-ffi v0.1.0 (/Users/pdurbin/github/opendp/opendp/rust/opendp-ffi)
Compiling opendp v0.1.0 (/Users/pdurbin/github/opendp/opendp/rust/opendp)
error[E0391]: cycle detected when computing the bounds for type parameter `MO`
--> opendp/src/trans/count.rs:53:31
|
53 | where MO: CountByConstant<MO::Distance> + SensitivityMetric,
| ^^^^^^^^^^^^
|
= note: ...which again requires computing the bounds for type parameter `MO`, completing the cycle
note: cycle used when computing explicit predicates of `trans::count::make_count_by_categories`
--> opendp/src/trans/count.rs:53:31
|
53 | where MO: CountByConstant<MO::Distance> + SensitivityMetric,
| ^^^^^^^^^^^^
error: aborting due to previous error
For more information about this error, try `rustc --explain E0391`.
error: could not compile `opendp`
To learn more, run the command again with --verbose.
@Shoeboxam helped me figure out that my version of Rust was too old. Using rustup update I upgraded from Rust 1.51.0 to 1.53.0 (which is what GitHub Actions is using) and cargo build worked fine.
There are a few solutions we could take:
- Specify minimum version of Rust in the README or elsewhere.
- Have a troubleshooting doc that recommends upgrading Rust if compilation fails. (I hear SmartNoise has a nice troubleshooting doc.)