rustdoc: add #[allow(unused)] to every doctest

[QuietMisdreavus]

More information in #45750 - this is behavior that was documented but not actually implemented.

I also reordered how outer attributes are applied to doctests. Previously, attributes from #![doc(test(attr(...)))] would be applied after attributes from within the test itself, meaning if a doctest tried to override lints that would be set crate-wide, it wouldn't work at all. This gives a better scope of how lints can be applied.

Closes #45750

[rust-highfive]

r? @frewsxcv

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[QuietMisdreavus]

r? @GuillaumeGomez

[kennytm]

Some CI failures regarding playground.

The rustdoc/no-run-still-checks-lints.rs failure should be expected?

[01:00:27] failures:
[01:00:27] 
[01:00:27] ---- [rustdoc] rustdoc/playground-arg.rs stdout ----
[01:00:27] 	
[01:00:27] error: htmldocck failed!
[01:00:27] status: exit code: 1
[01:00:27] command: "/usr/bin/python2.7" "/checkout/src/etc/htmldocck.py" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc/playground-arg.stage2-x86_64-unknown-linux-gnu" "/checkout/src/test/rustdoc/playground-arg.rs"
[01:00:27] stdout:
[01:00:27] ------------------------------------------
[01:00:27] 
[01:00:27] ------------------------------------------
[01:00:27] stderr:
[01:00:27] ------------------------------------------
[01:00:27] 24: @matches check failed
[01:00:27] 	`XPATH PATTERN` did not match
[01:00:27] 	// @matches foo/index.html '//a[@class="test-arrow"][@href="https://example.com/?code=extern%20crate%20foo%3B%0Afn%20main()%20%7B%0Ause%20foo%3A%3Adummy%3B%0Adummy()%3B%0A%7D"]' "Run"
[01:00:27] 
[01:00:27] Encountered 1 errors
[01:00:27] 
[01:00:27] ------------------------------------------
[01:00:27] 
[01:00:27] thread '[rustdoc] rustdoc/playground-arg.rs' panicked at 'explicit panic', /checkout/src/tools/compiletest/src/runtest.rs:2497:8
[01:00:27] 
[01:00:27] ---- [rustdoc] rustdoc/playground.rs stdout ----
[01:00:27] 	
[01:00:27] error: htmldocck failed!
[01:00:27] status: exit code: 1
[01:00:27] command: "/usr/bin/python2.7" "/checkout/src/etc/htmldocck.py" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc/playground.stage2-x86_64-unknown-linux-gnu" "/checkout/src/test/rustdoc/playground.rs"
[01:00:27] stdout:
[01:00:27] ------------------------------------------
[01:00:27] 
[01:00:27] ------------------------------------------
[01:00:27] stderr:
[01:00:27] ------------------------------------------
[01:00:27] 37: @matches check failed
[01:00:27] 	`XPATH PATTERN` did not match
[01:00:27] 	// @matches foo/index.html '//a[@class="test-arrow"][@href="https://www.example.com/?code=fn%20main()%20%7B%0A%20%20%20%20println!(%22Hello%2C%20world!%22)%3B%0A%7D%0A"]' "Run"
[01:00:27] 38: @matches check failed
[01:00:27] 	`XPATH PATTERN` did not match
[01:00:27] 	// @matches foo/index.html '//a[@class="test-arrow"][@href="https://www.example.com/?code=fn%20main()%20%7B%0Aprintln!(%22Hello%2C%20world!%22)%3B%0A%7D"]' "Run"
[01:00:27] 39: @matches check failed
[01:00:27] 	`XPATH PATTERN` did not match
[01:00:27] 	// @matches foo/index.html '//a[@class="test-arrow"][@href="https://www.example.com/?code=%23!%5Bfeature(something)%5D%0A%0Afn%20main()%20%7B%0A%20%20%20%20println!(%22Hello%2C%20world!%22)%3B%0A%7D%0A&version=nightly"]' "Run"
[01:00:27] 
[01:00:27] Encountered 3 errors
[01:00:27] 
[01:00:27] ------------------------------------------
[01:00:27] 
[01:00:27] thread '[rustdoc] rustdoc/playground.rs' panicked at 'explicit panic', /checkout/src/tools/compiletest/src/runtest.rs:2497:8
[01:00:27] 
[01:00:27] 
[01:00:27] failures:
[01:00:27]     [rustdoc] rustdoc/no-run-still-checks-lints.rs
[01:00:27]     [rustdoc] rustdoc/playground-arg.rs
[01:00:27]     [rustdoc] rustdoc/playground.rs
[01:00:27] 
[01:00:27] test result: FAILED. 167 passed; 3 failed; 1 ignored; 0 measured; 0 filtered out

[QuietMisdreavus]

It looks like no-run-still-checks-lints.rs passed tests when it was supposed to fail, and that's because supplying #![allow(unused)] followed by #![deny(warnings)] still allows the unused group, because you didn't specifically re-enable it. I'll change that code to only add it if no #![doc(test(attr(...)))] were supplied.

As for the playground ones, it seems like the playground links also use this code to assemble the run links, so i'll need to update those tests to include the new attribute.

[QuietMisdreavus]

I've force-pushed to address the test failures.

[GuillaumeGomez]

Perfect, thanks!

@bors: r+

[bors]

📌 Commit ce2768a has been approved by GuillaumeGomez