Building diesel documentation fails

[weiznich]

After #52545 is fixed now, I've tried to build diesels documentation and failed with the following error:

 Documenting diesel v1.3.3 (/home/weiznich/Dokumente/rust/diesel/diesel)
error[E0275]: overflow evaluating the requirement `<&_ as insertable::Insertable<_>>::Values`
  |
  = help: consider adding a `#![recursion_limit="128"]` attribute to your crate
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `(&_, &_, &_, &_, &_)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `&(_, _, _, _, _)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `(&(_, _, _, _, _), &_, &_, &_, &_)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `&((_, _, _, _, _), _, _, _, _)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `(&((_, _, _, _, _), _, _, _, _), &_, &_, &_, &_)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `&(((_, _, _, _, _), _, _, _, _), _, _, _, _)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `(&(((_, _, _, _, _), _, _, _, _), _, _, _, _), &_, &_, &_, &_)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `&((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `(&((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), &_, &_, &_, &_)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `&(((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `(&(((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), &_, &_, &_, &_)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `&((((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `(&((((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), &_, &_, &_, &_)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `&(((((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `(&(((((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), &_, &_, &_, &_)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `&((((((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `(&((((((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), &_, &_, &_, &_)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `&(((((((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `(&(((((((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), &_, &_
, &_, &_)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `&((((((((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _,
_, _)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `(&((((((((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _,
 _, _), &_, &_, &_, &_)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `&(((((((((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _,
 _, _), _, _, _, _)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `(&(((((((((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _
, _, _), _, _, _, _), &_, &_, &_, &_)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `&((((((((((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _
, _, _), _, _, _, _), _, _, _, _)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `(&((((((((((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _,
_, _, _), _, _, _, _), _, _, _, _), &_, &_, &_, &_)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `&(((((((((((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _,
_, _, _), _, _, _, _), _, _, _, _), _, _, _, _)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `(&(((((((((((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _,
 _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), &_, &_, &_, &_)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `&((((((((((((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _,
 _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `(&((((((((((((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _
, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), &_, &_, &_, &_)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `&(((((((((((((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _
, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `(&(((((((((((((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _),
_, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), &_, &_, &_, &_)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `&((((((((((((((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _),
_, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `(&((((((((((((((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _),
 _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), &_, &_, &_, &_)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `&(((((((((((((((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _),
 _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `(&(((((((((((((((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _)
, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), &_, &_, &_, &_)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `&((((((((((((((((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _)
, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `(&((((((((((((((((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _
), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), &_, &_, &_, &_)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `&(((((((((((((((((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _
), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `(&(((((((((((((((((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _,
_), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), &_, &_, &_, &_)`
  = note: required because of the requirements on the impl of `insertable::Insertable<_>` for `&((((((((((((((((((((_, _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _,
_), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _), _, _, _, _)`
…

Note that a normal build of diesel succeeds and also all doc tests are passing.

rustc version: rustc 1.30.0-nightly (4591a24 2018-09-22)
rustdoc version: rustdoc 1.30.0-nightly (4591a24 2018-09-22)
diesel version: git master at commit 42d5b831

[Diggsey]

This breaks the documentation for all crates which depend on diesel too, unless you run with --no-deps 😦

[weiznich]

Is there anything I can do to help to debug/fix this?

[weiznich]

I've played a bit further around with this.
That strange thing is that it seems to depend on feature flags on diesel.
cargo +nightly doc --no-default-features and cargo +nightly doc --no-default-features --features "postgres" works fine.
Any of cargo +nightly doc --no-default-features --features "sqlite", cargo +nightly doc --no-default-features --features "mysql", cargo +nightly doc --no-default-features --features "with-deprecated" and cargo +nightly doc --no-default-features --features "32-column-tables" fails with the error posted above.
So given the structure of the diesel code base the feature with the smallest impact is "32-column-table" because it is used only in one place. This macro is used to implement various traits for tuples of different sizes. The number in the front indicates the number of tuple elements. Toying around with this has shown that documentation builds fine (if only this feature is passed) as long as we generate those impl for tuples up to 16 elements. For bigger tuples building the documentation fails. That seems strange.

[joelgallant]

Is this the same as #53122?

[weiznich]

Is this the same as #53122?

Seems to be the same underlying issue, but it should be noted that this happens for me on the 2015 edition. (So it is probably not dependent on the edition.)

Also a similar error occurs if someone tries to build diesel with cargo build --no-default-features --features "sqlite" on windows using the -gnu or the -msvc toolchain. Surprisingly this does not happen on linux. For me it seems to be quite strange that some trait resolution thing seems to be depended on the os used to compiling the crate in absent of any os specific impls.

[weiznich]

I've played around a bit more and tried to get cargo doc --no-default-features --features "with-deprecated" working on diesel. Turns out that removing some traits makes it building and documenting. I've no clue why, because those traits are not connected to Insertable that is mentioned in the error message in any way.
I'm totally willing to dig into this event deeper, but I've no idea where to look for what so it would be great if anyone is willing to provide some guidance for this.

[weiznich]

I've tried to play with cargo bisect-rustc to find the point where this error was introduced in rustdoc. (This happens also on released diesel (1.3.0) versions, where rustdoc was working at release time.)
This points to somewhere between 07-24 and 07-30 (Unfortunately there are no nightly's in between)

This results in the following commit range 5ed2b5120...a1e6bcb2085

Rustdoc related commits:

• fb0653e
• dab7151
• 46804ef
• 487e961

Blind guess without any future investigation: It is related to dab7151?

cc @GuillaumeGomez as author of that commit

[GuillaumeGomez]

It's very likely but it was supposed to be fixed by #54199.

cc @nikomatsakis

[weiznich]

@GuillaumeGomez This comment sounds that this also requires some changes in rustdoc. Are they already done?
Is there anything other I can do to help solving this?

(This is basically blocking diesel doing a release 😟 )

[GuillaumeGomez]

Ah indeed. Opening an issue to keep it in mind.

[GuillaumeGomez]

Opened #55197.

[GuillaumeGomez]

Unfortunately, as said in this comment, problem doesn't lie in rustdoc but still in rustc.

Or maybe I missed something else? cc @nikomatsakis

[nikomatsakis]

Sorry, missed these notifications. I will add to my list to investigate.

[emilyalbini]

This is a stable-to-stable regression: worked in 1.29.2 and broken in 1.30.0.