add auto-impl for primitive type

[GuillaumeGomez]

Part of #50431.

I have no clue how to test this though with the rustdoc test suite...

r? @QuietMisdreavus

[QuietMisdreavus]

If it's because you don't know how to force a primitive page to appear, you can do that by creating an empty module in a crate root and tagging it with #[doc(primitive = "i32")] (or some other primitive name). That will cause rustdoc to replace that mod with the corresponding primitive page. Then you can add your desired tests.

[GuillaumeGomez]

Seems more complicated than just doing this. I'll need to investigate further...

[QuietMisdreavus]

Some investigation today:

Only having a module tagged with #[doc(primitive = "i16")] will produce a page with nothing but whatever docs you tagged onto the module. Forcing rustdoc to include all_trait_implementations by re-exporting something from another crate (say, by pub use std::fs::File or the like) will pull in the necessary impls from core/std, which makes it load the auto-trait impls as well.

Strangely, this works for i16 but not bool. One thing i noticed between them is that bool has no inherent methods, only trait implementations. I wonder if that has something to do with it...

(EDIT: That "re-export something to pull in the traits" trick feels like a huge hack, but then again, pulling in primitives like this is also a bit of a hack, so i guess it balances out? 🤷‍♀️)

[QuietMisdreavus]

More discussion has uncovered that the "impl inlining" code uses this table to reference the list of primitives, which does not include an entry for bool. It does, however, include two entries for str, which means that there are two sets of auto-trait entries on that page. There's probably another set of lang-items we can use to pull the primitives we need out.

[rust-highfive]

The job x86_64-gnu-llvm-3.9 of your PR failed on Travis (raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

[00:04:51] travis_fold:start:tidy
travis_time:start:tidy
tidy check
[00:04:51] tidy error: /checkout/src/test/rustdoc/auto-impl-primitive.rs:14: line longer than 100 chars
[00:04:51] tidy error: /checkout/src/test/rustdoc/auto-impl-primitive.rs: missing trailing newline
[00:04:52] some tidy checks failed
[00:04:52] 
[00:04:52] 
[00:04:52] command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-tools-bin/tidy" "/checkout/src" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/cargo" "--no-vendor" "--quiet"
[00:04:52] 
[00:04:52] 
[00:04:52] failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test src/tools/tidy
[00:04:52] Build completed unsuccessfully in 0:01:46
[00:04:52] Build completed unsuccessfully in 0:01:46
[00:04:52] make: *** [tidy] Error 1
[00:04:52] Makefile:79: recipe for target 'tidy' failed

The command "stamp sh -x -c "$RUN_SCRIPT"" exited with 2.
travis_time:start:03f49506
$ date && (curl -fs --head https://google.com | grep ^Date: | sed 's/Date: //g' || true)

I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact @TimNN. (Feature Requests)

[QuietMisdreavus]

The last rebase only includes a test, it does not address the "no bool with two str" problem mentioned up-thread. I'm willing to land this with just tidy fixed (and if travis passes with the new test), but if that's the case i want to keep #50431 open to track that.

[GuillaumeGomez]

I'll fix tidy this evening.

[QuietMisdreavus]

@bors r+

[bors]

📌 Commit 564511e has been approved by QuietMisdreavus

[bors]

⌛ Testing commit 564511e with merge ba64edb...

[bors]

☀️ Test successful - status-appveyor, status-travis
Approved by: QuietMisdreavus
Pushing ba64edb to master...