Emit error when using path-segment keyword as cfg pred

[mu001999]

Fixes #146968

Emit error CfgPredicateIdentifier if the word is path-segment keyword.

r? petrochenkov

[rustbot]

Some changes occurred in compiler/rustc_attr_parsing

cc @jdonszelmann

[petrochenkov]

Could you

• add similar test cases for some non path-segment keyword, like struct
• add test cases for --cfg on command line and make sure that they behave identically to cfg! and #[cfg].

After that we should be able to run crater on this.
@rustbot author

[rustbot]

Reminder, once the PR becomes ready for a review, use @rustbot ready.

[mu001999]

add test cases for --cfg on command line and make sure that they behave identically to cfg! and #[cfg]

--cfg will emit same error but will be suppressed because parse_cfg is called with ParseSess::with_fatal_emitter

[mu001999]

@rustbot ready

[petrochenkov]

add test cases for --cfg on command line and make sure that they behave identically to cfg! and #[cfg]

--cfg will emit same error but will be suppressed because parse_cfg is called with ParseSess::with_fatal_emitter

with_fatal_emitter doesn't suppress errors, it makes them fatal.
--cfg parsing has its own error reporting logic in fn parse_cfg in compiler\rustc_interface\src\interface.rs, and the new errors are not emitted there.
@rustbot author

[mu001999]

with_fatal_emitter doesn't suppress errors, it makes them fatal.

@petrochenkov I found with_fatal_emitter create dcx with FatalOnlyEmitter, see

rust/compiler/rustc_session/src/parse.rs

Lines 318 to 329 in a2db928

	pub fn with_fatal_emitter(locale_resources: Vec<&'static str>, fatal_note: String) -> Self {
	let translator = Translator::with_fallback_bundle(locale_resources, false);
	let sm = Arc::new(SourceMap::new(FilePathMapping::empty()));
	let fatal_emitter =
	Box::new(HumanEmitter::new(stderr_destination(ColorConfig::Auto), translator));
	let dcx = DiagCtxt::new(Box::new(FatalOnlyEmitter {
	fatal_emitter,
	fatal_note: Some(fatal_note),
	}))
	.disable_warnings();
	ParseSess::with_dcx(dcx, sm)
	}

and the comment of FatalOnlyEmitter and the impl of FatalOnlyEmitter::emit_diagnostic show only errors with diag.level == Level::Fatal can be emitted, see

rust/compiler/rustc_errors/src/emitter.rs

Lines 537 to 562 in 8155734

	/// An emitter that does nothing when emitting a non-fatal diagnostic.
	/// Fatal diagnostics are forwarded to `fatal_emitter` to avoid silent
	/// failures of rustc, as witnessed e.g. in issue #89358.
	pub struct FatalOnlyEmitter {
	pub fatal_emitter: Box<dyn Emitter + DynSend>,
	pub fatal_note: Option<String>,
	}
	impl Emitter for FatalOnlyEmitter {
	fn source_map(&self) -> Option<&SourceMap> {
	None
	}
	fn emit_diagnostic(&mut self, mut diag: DiagInner, registry: &Registry) {
	if diag.level == Level::Fatal {
	if let Some(fatal_note) = &self.fatal_note {
	diag.sub(Level::Note, fatal_note.clone(), MultiSpan::new());
	}
	self.fatal_emitter.emit_diagnostic(diag, registry);
	}
	}
	fn translator(&self) -> &Translator {
	self.fatal_emitter.translator()
	}
	}

[mu001999]

I have debug the logic in fn parse_cfg, and the err.emit is called in fact, but it is suppressed by the FatalOnlyEmitter.

[petrochenkov]

Ah, ok, "fatal emitter" means "fatal-only emitter".

In any case, the behavior is not correct.
I guess the assumption when using the fatal emitter was that we always reach the "expected key or key="value"" error at the bottom anyway, but that's not actually the case.
If we get to return (ident.name, meta_item.value_str()), then all the non-fatal errors are lost, which is incorrect.

[mu001999]

@rustbot ready

[petrochenkov]

So now we have to manually detect all recoverable parsing errors here, not just keywords instead of identifiers.
The set of recoverable errors is open, parser does much more recovery now than at the times of #64467, you can't catch them all manually.

If we don't want to remove the use of fatal-only emitter, then we need to set Recovery::Forbidden in the parser, then parse_meta_item will return Err on any syntactically invalid stuff instead of recovering.
Then the only remaining thing to check will be is_path_segment_keyword, like in rustc_attr_parsing.

[rustbot]

rustc_errors::emitter was changed

cc @Muscraft

[Urgau]

Note that this test and the change in behavior of --check-cfg was specifically added at the request of T-lang in the stabilization of #[cfg(true)]/#[cfg(false)] #138632 (comment)

[petrochenkov]

This PR will need to go through lang team too after a crater run.
(Similarly to other cases in this PR, this test case was accepted because --cfg parsing swallowed non-fatal parsing errors.)

[rustbot]

Some changes occurred in src/tools/clippy

cc @rust-lang/clippy

[mu001999]

@rustbot ready

[samueltardieu]

It looks like you removed some .32bit.stderr files from src/tools/clippy/tests/ui/ instead of renaming them.

[mu001999]

It looks like you removed some .32bit.stderr files from src/tools/clippy/tests/ui/ instead of renaming them.

Good catch! Recovered. Seems the 32bit revision is not tested on both my device and CI 🤔

[bors]

☔ The latest upstream changes (presumably #147842) made this pull request unmergeable. Please resolve the merge conflicts.

[rustbot]

This PR was rebased onto a different master commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

[rust-log-analyzer]

The job aarch64-gnu-llvm-20-1 failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)

test [ui] tests/ui/cfg/expanded-cfg.rs ... ok
test [ui] tests/ui/cfg/disallowed-cli-cfgs.rs#windows_ ... ok
test [ui] tests/ui/cfg/disallowed-cli-cfgs.rs#unix_ ... ok
test [ui] tests/ui/cfg/nested-cfg-attr-conditional-compilation.rs ... ok
test [ui] tests/ui/cfg/path-kw-as-cfg-pred-cli-cfg.rs#cfg_crate ... ok
test [ui] tests/ui/cfg/path-kw-as-cfg-pred-cli-cfg.rs#cfg_priv ... ok
test [ui] tests/ui/cfg/path-kw-as-cfg-pred-cli-cfg.rs#cfg_raw_crate ... ok
test [ui] tests/ui/cfg/path-kw-as-cfg-pred-cli-cfg.rs#cfg_raw_self_lower ... ok
test [ui] tests/ui/cfg/path-kw-as-cfg-pred-cli-cfg.rs#cfg_raw_self_upper ... ok
test [ui] tests/ui/cfg/path-kw-as-cfg-pred-cli-cfg.rs#cfg_raw_super ... ok
test [ui] tests/ui/cfg/path-kw-as-cfg-pred-cli-cfg.rs#cfg_raw_underscore ... ok
test [ui] tests/ui/cfg/path-kw-as-cfg-pred-cli-cfg.rs#cfg_self_lower ... ok
test [ui] tests/ui/cfg/path-kw-as-cfg-pred-cli-cfg.rs#cfg_self_upper ... ok
test [ui] tests/ui/cfg/path-kw-as-cfg-pred-cli-cfg.rs#cfg_super ... ok
test [ui] tests/ui/cfg/path-kw-as-cfg-pred-cli-cfg.rs#cfg_struct ... ok
test [ui] tests/ui/cfg/path-kw-as-cfg-pred-cli-cfg.rs#cfg_underscore ... ok
test [ui] tests/ui/cfg/path-kw-as-cfg-pred-cli-check-cfg.rs#check_cfg_crate ... ok
test [ui] tests/ui/cfg/path-kw-as-cfg-pred-cli-check-cfg.rs#check_cfg_priv ... ok
test [ui] tests/ui/cfg/path-kw-as-cfg-pred-cli-check-cfg.rs#check_cfg_raw_crate ... ok
test [ui] tests/ui/cfg/path-kw-as-cfg-pred-cli-check-cfg.rs#check_cfg_raw_self_lower ... ok
test [ui] tests/ui/cfg/path-kw-as-cfg-pred-cli-check-cfg.rs#check_cfg_raw_self_upper ... ok
test [ui] tests/ui/cfg/path-kw-as-cfg-pred-cli-check-cfg.rs#check_cfg_raw_super ... ok
test [ui] tests/ui/cfg/path-kw-as-cfg-pred-cli-check-cfg.rs#check_cfg_raw_underscore ... ok
test [ui] tests/ui/cfg/path-kw-as-cfg-pred-cli-check-cfg.rs#check_cfg_self_upper ... ok
test [ui] tests/ui/cfg/path-kw-as-cfg-pred-cli-check-cfg.rs#check_cfg_self_lower ... ok
test [ui] tests/ui/cfg/path-kw-as-cfg-pred-cli-check-cfg.rs#check_cfg_struct ... ok
test [ui] tests/ui/cfg/path-kw-as-cfg-pred-cli-check-cfg.rs#check_cfg_super ... ok
test [ui] tests/ui/cfg/path-kw-as-cfg-pred-cli-check-cfg.rs#check_cfg_underscore ... ok
test [ui] tests/ui/cfg/path-kw-as-cfg-pred-cli-raw-allow.rs ... ok
test [ui] tests/ui/cfg/raw-true-false.rs ... ok
test [ui] tests/ui/cfg/path-kw-as-cfg-pred.rs ... FAILED
test [ui] tests/ui/check-cfg/allow-at-crate-level.rs ... ok
test [ui] tests/ui/check-cfg/allow-macro-cfg.rs ... ok
test [ui] tests/ui/check-cfg/allow-same-level.rs ... ok
test [ui] tests/ui/check-cfg/allow-upper-level.rs ... ok
test [ui] tests/ui/check-cfg/allow-top-level.rs ... ok
---
test [ui] tests/ui/zero-sized/zero-sized-btreemap-insert.rs ... ok

failures:

---- [ui] tests/ui/cfg/path-kw-as-cfg-pred.rs stdout ----
Saved the actual stderr to `/checkout/obj/build/aarch64-unknown-linux-gnu/test/ui/cfg/path-kw-as-cfg-pred/path-kw-as-cfg-pred.stderr`
diff of stderr:

118 LL | #[cfg_attr(r#_, cfg(r#_))]
119    |                     ^^^
120 
- error: `cfg` predicate key must be an identifier
-   --> $DIR/path-kw-as-cfg-pred.rs:18:7
+ error[E0539]: malformed `cfg` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:18:1
123    |
124 LL | #[cfg(crate)]
-    |       ^^^^^
+    | ^^^^^^-----^^
+    | |     |
+    | |     expected a valid identifier here
+    | help: must be of the form: `#[cfg(predicate)]`
+    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>
126 
- error: `cfg` predicate key must be an identifier
-   --> $DIR/path-kw-as-cfg-pred.rs:20:7
+ error[E0539]: malformed `cfg` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:20:1
129    |
130 LL | #[cfg(super)]
-    |       ^^^^^
+    | ^^^^^^-----^^
+    | |     |
+    | |     expected a valid identifier here
+    | help: must be of the form: `#[cfg(predicate)]`
+    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>
132 
- error: `cfg` predicate key must be an identifier
-   --> $DIR/path-kw-as-cfg-pred.rs:22:7
+ error[E0539]: malformed `cfg` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:22:1
135    |
136 LL | #[cfg(self)]
-    |       ^^^^
+    | ^^^^^^----^^
+    | |     |
+    | |     expected a valid identifier here
+    | help: must be of the form: `#[cfg(predicate)]`
+    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>
138 
- error: `cfg` predicate key must be an identifier
-   --> $DIR/path-kw-as-cfg-pred.rs:24:7
+ error[E0539]: malformed `cfg` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:24:1
141    |
142 LL | #[cfg(Self)]
-    |       ^^^^
+    | ^^^^^^----^^
+    | |     |
+    | |     expected a valid identifier here
+    | help: must be of the form: `#[cfg(predicate)]`
+    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>
144 
- error: `cfg` predicate key must be an identifier
-   --> $DIR/path-kw-as-cfg-pred.rs:26:12
+ error[E0539]: malformed `cfg_attr` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:26:1
147    |
148 LL | #[cfg_attr(crate, path = "foo")]
-    |            ^^^^^
+    | ^^^^^^^^^^^-----^^^^^^^^^^^^^^^^
+    | |          |
+    | |          expected a valid identifier here
+    | help: must be of the form: `#[cfg_attr(predicate, attr1, attr2, ...)]`
+    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg_attr-attribute>
150 
- error: `cfg` predicate key must be an identifier
-   --> $DIR/path-kw-as-cfg-pred.rs:28:12
+ error[E0539]: malformed `cfg_attr` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:28:1
153    |
154 LL | #[cfg_attr(super, path = "foo")]
-    |            ^^^^^
+    | ^^^^^^^^^^^-----^^^^^^^^^^^^^^^^
+    | |          |
+    | |          expected a valid identifier here
+    | help: must be of the form: `#[cfg_attr(predicate, attr1, attr2, ...)]`
+    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg_attr-attribute>
156 
- error: `cfg` predicate key must be an identifier
-   --> $DIR/path-kw-as-cfg-pred.rs:30:12
+ error[E0539]: malformed `cfg_attr` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:30:1
159    |
160 LL | #[cfg_attr(self, path = "foo")]
-    |            ^^^^
+    | ^^^^^^^^^^^----^^^^^^^^^^^^^^^^
+    | |          |
+    | |          expected a valid identifier here
+    | help: must be of the form: `#[cfg_attr(predicate, attr1, attr2, ...)]`
+    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg_attr-attribute>
162 
- error: `cfg` predicate key must be an identifier
-   --> $DIR/path-kw-as-cfg-pred.rs:32:12
+ error[E0539]: malformed `cfg_attr` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:32:1
165    |
166 LL | #[cfg_attr(Self, path = "foo")]
-    |            ^^^^
+    | ^^^^^^^^^^^----^^^^^^^^^^^^^^^^
+    | |          |
+    | |          expected a valid identifier here
+    | help: must be of the form: `#[cfg_attr(predicate, attr1, attr2, ...)]`
+    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg_attr-attribute>
168 
- error: `cfg` predicate key must be an identifier
-   --> $DIR/path-kw-as-cfg-pred.rs:34:22
+ error[E0539]: malformed `cfg` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:34:18
171    |
172 LL | #[cfg_attr(true, cfg(crate))]
-    |                      ^^^^^
+    |                  ^^^^-----^
+    |                  |   |
+    |                  |   expected a valid identifier here
+    |                  help: must be of the form: `#[cfg(predicate)]`
+    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>
174 
- error: `cfg` predicate key must be an identifier
-   --> $DIR/path-kw-as-cfg-pred.rs:36:22
+ error[E0539]: malformed `cfg` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:36:18
177    |
178 LL | #[cfg_attr(true, cfg(super))]
-    |                      ^^^^^
+    |                  ^^^^-----^
+    |                  |   |
+    |                  |   expected a valid identifier here
+    |                  help: must be of the form: `#[cfg(predicate)]`
+    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>
180 
- error: `cfg` predicate key must be an identifier
-   --> $DIR/path-kw-as-cfg-pred.rs:38:22
+ error[E0539]: malformed `cfg` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:38:18
183    |
184 LL | #[cfg_attr(true, cfg(self))]
-    |                      ^^^^
+    |                  ^^^^----^
+    |                  |   |
+    |                  |   expected a valid identifier here
+    |                  help: must be of the form: `#[cfg(predicate)]`
+    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>
186 
- error: `cfg` predicate key must be an identifier
-   --> $DIR/path-kw-as-cfg-pred.rs:40:22
+ error[E0539]: malformed `cfg` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:40:18
189    |
190 LL | #[cfg_attr(true, cfg(Self))]
-    |                      ^^^^
+    |                  ^^^^----^
+    |                  |   |
+    |                  |   expected a valid identifier here
+    |                  help: must be of the form: `#[cfg(predicate)]`
+    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>
192 
193 error: expected identifier, found keyword `struct`
194   --> $DIR/path-kw-as-cfg-pred.rs:43:7

254 LL | #[cfg_attr(true, cfg(_))]
255    |                      ^ expected identifier, found reserved identifier
256 
- error: `cfg` predicate key must be an identifier
-   --> $DIR/path-kw-as-cfg-pred.rs:88:7
+ error[E0539]: malformed `cfg` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:88:1
259    |
260 LL | #[cfg(r#crate)]
-    |       ^^^^^^^
+    | ^^^^^^-------^^
+    | |     |
+    | |     expected a valid identifier here
+    | help: must be of the form: `#[cfg(predicate)]`
+    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>
262 
- error: `cfg` predicate key must be an identifier
-   --> $DIR/path-kw-as-cfg-pred.rs:91:7
+ error[E0539]: malformed `cfg` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:91:1
265    |
266 LL | #[cfg(r#super)]
-    |       ^^^^^^^
+    | ^^^^^^-------^^
+    | |     |
+    | |     expected a valid identifier here
+    | help: must be of the form: `#[cfg(predicate)]`
+    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>
268 
- error: `cfg` predicate key must be an identifier
-   --> $DIR/path-kw-as-cfg-pred.rs:94:7
+ error[E0539]: malformed `cfg` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:94:1
271    |
272 LL | #[cfg(r#self)]
-    |       ^^^^^^
+    | ^^^^^^------^^
+    | |     |
+    | |     expected a valid identifier here
+    | help: must be of the form: `#[cfg(predicate)]`
+    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>
274 
- error: `cfg` predicate key must be an identifier
-   --> $DIR/path-kw-as-cfg-pred.rs:97:7
+ error[E0539]: malformed `cfg` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:97:1
277    |
278 LL | #[cfg(r#Self)]
-    |       ^^^^^^
- 
- error: `cfg` predicate key must be an identifier
-   --> $DIR/path-kw-as-cfg-pred.rs:100:12
+    | ^^^^^^------^^
+    | |     |
+    | |     expected a valid identifier here
+    | help: must be of the form: `#[cfg(predicate)]`
283    |
- LL | #[cfg_attr(r#crate, cfg(r#crate))]
-    |            ^^^^^^^
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>
286 
- error: `cfg` predicate key must be an identifier
-   --> $DIR/path-kw-as-cfg-pred.rs:100:25
+ error[E0539]: malformed `cfg_attr` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:100:1
289    |
290 LL | #[cfg_attr(r#crate, cfg(r#crate))]
-    |                         ^^^^^^^
- 
- error: `cfg` predicate key must be an identifier
-   --> $DIR/path-kw-as-cfg-pred.rs:105:12
+    | ^^^^^^^^^^^-------^^^^^^^^^^^^^^^^
+    | |          |
+    | |          expected a valid identifier here
+    | help: must be of the form: `#[cfg_attr(predicate, attr1, attr2, ...)]`
295    |
- LL | #[cfg_attr(r#super, cfg(r#super))]
-    |            ^^^^^^^
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg_attr-attribute>
298 
- error: `cfg` predicate key must be an identifier
-   --> $DIR/path-kw-as-cfg-pred.rs:105:25
+ error[E0539]: malformed `cfg_attr` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:105:1
301    |
302 LL | #[cfg_attr(r#super, cfg(r#super))]
-    |                         ^^^^^^^
- 
- error: `cfg` predicate key must be an identifier
-   --> $DIR/path-kw-as-cfg-pred.rs:110:12
+    | ^^^^^^^^^^^-------^^^^^^^^^^^^^^^^
+    | |          |
+    | |          expected a valid identifier here
+    | help: must be of the form: `#[cfg_attr(predicate, attr1, attr2, ...)]`
307    |
- LL | #[cfg_attr(r#self, cfg(r#self))]
-    |            ^^^^^^
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg_attr-attribute>
310 
- error: `cfg` predicate key must be an identifier
-   --> $DIR/path-kw-as-cfg-pred.rs:110:24
+ error[E0539]: malformed `cfg_attr` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:110:1
313    |
314 LL | #[cfg_attr(r#self, cfg(r#self))]
-    |                        ^^^^^^
- 
- error: `cfg` predicate key must be an identifier
-   --> $DIR/path-kw-as-cfg-pred.rs:115:12
+    | ^^^^^^^^^^^------^^^^^^^^^^^^^^^
+    | |          |
+    | |          expected a valid identifier here
+    | help: must be of the form: `#[cfg_attr(predicate, attr1, attr2, ...)]`
319    |
- LL | #[cfg_attr(r#Self, cfg(r#Self))]
-    |            ^^^^^^
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg_attr-attribute>
322 
- error: `cfg` predicate key must be an identifier
-   --> $DIR/path-kw-as-cfg-pred.rs:115:24
+ error[E0539]: malformed `cfg_attr` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:115:1
325    |
326 LL | #[cfg_attr(r#Self, cfg(r#Self))]
-    |                        ^^^^^^
+    | ^^^^^^^^^^^------^^^^^^^^^^^^^^^
+    | |          |
+    | |          expected a valid identifier here
+    | help: must be of the form: `#[cfg_attr(predicate, attr1, attr2, ...)]`
+    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg_attr-attribute>
328 
- error: `cfg` predicate key must be an identifier
-   --> $DIR/path-kw-as-cfg-pred.rs:7:15
+ error[E0539]: malformed `cfg` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:7:9
331    |
332 LL |         #[cfg($crate)]
-    |               ^^^^^^
+    |         ^^^^^^------^^
+    |         |     |
+    |         |     expected a valid identifier here
+    |         help: must be of the form: `#[cfg(predicate)]`
334 ...
335 LL |     foo!();
336    |     ------ in this macro invocation

337    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>
338    = note: this error originates in the macro `foo` (in Nightly builds, run with -Z macro-backtrace for more info)
339 
- error: `cfg` predicate key must be an identifier
-   --> $DIR/path-kw-as-cfg-pred.rs:9:20
+ error[E0539]: malformed `cfg_attr` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:9:9
342    |
343 LL |         #[cfg_attr($crate, path = "foo")]
-    |                    ^^^^^^
+    |         ^^^^^^^^^^^------^^^^^^^^^^^^^^^^
+    |         |          |
+    |         |          expected a valid identifier here
+    |         help: must be of the form: `#[cfg_attr(predicate, attr1, attr2, ...)]`
345 ...
346 LL |     foo!();
347    |     ------ in this macro invocation

348    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg_attr-attribute>
349    = note: this error originates in the macro `foo` (in Nightly builds, run with -Z macro-backtrace for more info)
350 
- error: `cfg` predicate key must be an identifier
-   --> $DIR/path-kw-as-cfg-pred.rs:11:30
+ error[E0539]: malformed `cfg` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:11:26
353    |
354 LL |         #[cfg_attr(true, cfg($crate))]
-    |                              ^^^^^^
+    |                          ^^^^------^
+    |                          |   |
+    |                          |   expected a valid identifier here
+    |                          help: must be of the form: `#[cfg(predicate)]`
356 ...
357 LL |     foo!();
358    |     ------ in this macro invocation

359    |
---
+ For more information about this error, try `rustc --explain E0539`.
441 

Note: some mismatched output was normalized before being compared
-   --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:18:1
-   --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:20:1
-   --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:22:1
-   --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:24:1
-   --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:26:1
-   --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:28:1
-   --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:30:1
-   --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:32:1
-   --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:34:18
-   --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:36:18
-   --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:38:18
-   --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:40:18
-   --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:88:1
-   --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:91:1
-   --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:94:1
-   --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:97:1
-   --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:100:1
-   --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:105:1
-   --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:110:1
-   --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:115:1
-   --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:7:9
-   --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:9:9
-   --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:11:26
+ error[E0539]: malformed `cfg` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:18:1
+    | ^^^^^^-----^^
+    | |     |
+    | |     expected a valid identifier here
+    | help: must be of the form: `#[cfg(predicate)]`
+    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>
+ error[E0539]: malformed `cfg` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:20:1
+    | ^^^^^^-----^^
+    | |     |
+    | |     expected a valid identifier here
+    | help: must be of the form: `#[cfg(predicate)]`
+    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>
+ error[E0539]: malformed `cfg` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:22:1
+    | ^^^^^^----^^
+    | |     |
+    | |     expected a valid identifier here
+    | help: must be of the form: `#[cfg(predicate)]`
+    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>
+ error[E0539]: malformed `cfg` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:24:1
+    | ^^^^^^----^^
+    | |     |
+    | |     expected a valid identifier here
+    | help: must be of the form: `#[cfg(predicate)]`
+    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>
+ error[E0539]: malformed `cfg_attr` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:26:1
+    | ^^^^^^^^^^^-----^^^^^^^^^^^^^^^^
+    | |          |
+    | |          expected a valid identifier here
+    | help: must be of the form: `#[cfg_attr(predicate, attr1, attr2, ...)]`
+    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg_attr-attribute>
+ error[E0539]: malformed `cfg_attr` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:28:1
+    | ^^^^^^^^^^^-----^^^^^^^^^^^^^^^^
+    | |          |
+    | |          expected a valid identifier here
+    | help: must be of the form: `#[cfg_attr(predicate, attr1, attr2, ...)]`
+    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg_attr-attribute>
+ error[E0539]: malformed `cfg_attr` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:30:1
+    | ^^^^^^^^^^^----^^^^^^^^^^^^^^^^
+    | |          |
+    | |          expected a valid identifier here
+    | help: must be of the form: `#[cfg_attr(predicate, attr1, attr2, ...)]`
+    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg_attr-attribute>
+ error[E0539]: malformed `cfg_attr` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:32:1
+    | ^^^^^^^^^^^----^^^^^^^^^^^^^^^^
+    | |          |
+    | |          expected a valid identifier here
+    | help: must be of the form: `#[cfg_attr(predicate, attr1, attr2, ...)]`
+    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg_attr-attribute>
+ error[E0539]: malformed `cfg` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:34:18
+    |                  ^^^^-----^
+    |                  |   |
+    |                  |   expected a valid identifier here
+    |                  help: must be of the form: `#[cfg(predicate)]`
+    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>
+ error[E0539]: malformed `cfg` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:36:18
+    |                  ^^^^-----^
+    |                  |   |
+    |                  |   expected a valid identifier here
+    |                  help: must be of the form: `#[cfg(predicate)]`
+    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>
+ error[E0539]: malformed `cfg` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:38:18
+    |                  ^^^^----^
+    |                  |   |
+    |                  |   expected a valid identifier here
+    |                  help: must be of the form: `#[cfg(predicate)]`
+    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>
+ error[E0539]: malformed `cfg` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:40:18
+    |                  ^^^^----^
+    |                  |   |
+    |                  |   expected a valid identifier here
+    |                  help: must be of the form: `#[cfg(predicate)]`
+    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>
+ error[E0539]: malformed `cfg` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:88:1
+    | ^^^^^^-------^^
+    | |     |
+    | |     expected a valid identifier here
+    | help: must be of the form: `#[cfg(predicate)]`
+    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>
+ error[E0539]: malformed `cfg` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:91:1
+    | ^^^^^^-------^^
+    | |     |
+    | |     expected a valid identifier here
+    | help: must be of the form: `#[cfg(predicate)]`
+    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>
+ error[E0539]: malformed `cfg` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:94:1
+    | ^^^^^^------^^
+    | |     |
+    | |     expected a valid identifier here
+    | help: must be of the form: `#[cfg(predicate)]`
+    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>
+ error[E0539]: malformed `cfg` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:97:1
+    | ^^^^^^------^^
+    | |     |
+    | |     expected a valid identifier here
+    | help: must be of the form: `#[cfg(predicate)]`
+    |
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>
+ error[E0539]: malformed `cfg_attr` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:100:1
+    | ^^^^^^^^^^^-------^^^^^^^^^^^^^^^^
+    | |          |
+    | |          expected a valid identifier here
+    | help: must be of the form: `#[cfg_attr(predicate, attr1, attr2, ...)]`
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg_attr-attribute>
+ error[E0539]: malformed `cfg_attr` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:105:1
+    | ^^^^^^^^^^^-------^^^^^^^^^^^^^^^^
+    | |          |
+    | |          expected a valid identifier here
+    | help: must be of the form: `#[cfg_attr(predicate, attr1, attr2, ...)]`
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg_attr-attribute>
+ error[E0539]: malformed `cfg_attr` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:110:1
+    | ^^^^^^^^^^^------^^^^^^^^^^^^^^^
+    | |          |
+    | |          expected a valid identifier here
+    | help: must be of the form: `#[cfg_attr(predicate, attr1, attr2, ...)]`
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg_attr-attribute>
+ error[E0539]: malformed `cfg_attr` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:115:1
+    | ^^^^^^^^^^^------^^^^^^^^^^^^^^^
+    | |          |
+    | |          expected a valid identifier here
+    | help: must be of the form: `#[cfg_attr(predicate, attr1, attr2, ...)]`
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg_attr-attribute>
+ error[E0539]: malformed `cfg` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:7:9
+    |         ^^^^^^------^^
+    |         |     |
+    |         |     expected a valid identifier here
+    |         help: must be of the form: `#[cfg(predicate)]`
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>
+ error[E0539]: malformed `cfg_attr` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:9:9
+    |         ^^^^^^^^^^^------^^^^^^^^^^^^^^^^
+    |         |          |
+    |         |          expected a valid identifier here
+    |         help: must be of the form: `#[cfg_attr(predicate, attr1, attr2, ...)]`
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg_attr-attribute>
+ error[E0539]: malformed `cfg` attribute input
+   --> $DIR/path-kw-as-cfg-pred.rs:11:26
+    |                          ^^^^------^
+    |                          |   |
+    |                          |   expected a valid identifier here
+    |                          help: must be of the form: `#[cfg(predicate)]`
+    = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>
+ error: aborting due to 64 previous errors
+ For more information about this error, try `rustc --explain E0539`.


The actual stderr differed from the expected stderr
To update references, rerun the tests and pass the `--bless` flag
To only update this specific test, also pass `--test-args cfg/path-kw-as-cfg-pred.rs`

error: 1 errors occurred comparing output.
status: exit status: 1
command: env -u RUSTC_LOG_COLOR RUSTC_ICE="0" RUST_BACKTRACE="short" "/checkout/obj/build/aarch64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs" "-Zthreads=1" "-Zsimulate-remapped-rust-src-base=/rustc/FAKE_PREFIX" "-Ztranslate-remapped-path-to-local-path=no" "-Z" "ignore-directory-in-diagnostics-source-blocks=/cargo" "-Z" "ignore-directory-in-diagnostics-source-blocks=/checkout/vendor" "--sysroot" "/checkout/obj/build/aarch64-unknown-linux-gnu/stage2" "--target=aarch64-unknown-linux-gnu" "--check-cfg" "cfg(test,FALSE)" "--error-format" "json" "--json" "future-incompat" "-Ccodegen-units=1" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "-Zwrite-long-types-to-disk=no" "-Cstrip=debuginfo" "--emit" "metadata" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/aarch64-unknown-linux-gnu/test/ui/cfg/path-kw-as-cfg-pred" "-A" "unused" "-A" "internal_features" "-A" "unused_parens" "-A" "unused_braces" "-Crpath" "-Cdebuginfo=0" "-Lnative=/checkout/obj/build/aarch64-unknown-linux-gnu/native/rust-test-helpers" "--edition=2024"
stdout: none
--- stderr -------------------------------
error: `crate` cannot be a raw identifier
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:70:10
   |
LL |     cfg!(r#crate); //~ ERROR `crate` cannot be a raw identifier
   |          ^^^^^^^

error: `super` cannot be a raw identifier
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:72:10
   |
LL |     cfg!(r#super); //~ ERROR `super` cannot be a raw identifier
   |          ^^^^^^^

error: `self` cannot be a raw identifier
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:74:10
   |
LL |     cfg!(r#self); //~ ERROR `self` cannot be a raw identifier
   |          ^^^^^^

error: `Self` cannot be a raw identifier
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:76:10
   |
LL |     cfg!(r#Self); //~ ERROR `Self` cannot be a raw identifier
   |          ^^^^^^

error: `_` cannot be a raw identifier
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:85:10
   |
LL |     cfg!(r#_); //~ ERROR `_` cannot be a raw identifier
   |          ^^^

error: `crate` cannot be a raw identifier
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:88:7
   |
LL | #[cfg(r#crate)] //~ ERROR `cfg` predicate key must be an identifier
   |       ^^^^^^^

error: `super` cannot be a raw identifier
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:91:7
   |
LL | #[cfg(r#super)] //~ ERROR `cfg` predicate key must be an identifier
   |       ^^^^^^^

error: `self` cannot be a raw identifier
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:94:7
   |
LL | #[cfg(r#self)] //~ ERROR `cfg` predicate key must be an identifier
   |       ^^^^^^

error: `Self` cannot be a raw identifier
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:97:7
   |
LL | #[cfg(r#Self)] //~ ERROR `cfg` predicate key must be an identifier
   |       ^^^^^^

error: `crate` cannot be a raw identifier
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:100:12
   |
LL | #[cfg_attr(r#crate, cfg(r#crate))] //~ ERROR `cfg` predicate key must be an identifier
   |            ^^^^^^^

error: `crate` cannot be a raw identifier
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:100:25
   |
LL | #[cfg_attr(r#crate, cfg(r#crate))] //~ ERROR `cfg` predicate key must be an identifier
   |                         ^^^^^^^

error: `super` cannot be a raw identifier
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:105:12
   |
LL | #[cfg_attr(r#super, cfg(r#super))] //~ ERROR `cfg` predicate key must be an identifier
   |            ^^^^^^^

error: `super` cannot be a raw identifier
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:105:25
   |
LL | #[cfg_attr(r#super, cfg(r#super))] //~ ERROR `cfg` predicate key must be an identifier
   |                         ^^^^^^^

error: `self` cannot be a raw identifier
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:110:12
   |
LL | #[cfg_attr(r#self, cfg(r#self))] //~ ERROR `cfg` predicate key must be an identifier
   |            ^^^^^^

error: `self` cannot be a raw identifier
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:110:24
   |
LL | #[cfg_attr(r#self, cfg(r#self))] //~ ERROR `cfg` predicate key must be an identifier
   |                        ^^^^^^

error: `Self` cannot be a raw identifier
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:115:12
   |
LL | #[cfg_attr(r#Self, cfg(r#Self))] //~ ERROR `cfg` predicate key must be an identifier
   |            ^^^^^^

error: `Self` cannot be a raw identifier
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:115:24
   |
LL | #[cfg_attr(r#Self, cfg(r#Self))] //~ ERROR `cfg` predicate key must be an identifier
   |                        ^^^^^^

error: `_` cannot be a raw identifier
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:125:7
   |
LL | #[cfg(r#_)] //~ ERROR `_` cannot be a raw identifier
   |       ^^^

error: `_` cannot be a raw identifier
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:131:12
   |
LL | #[cfg_attr(r#_, cfg(r#_))] //~ ERROR `_` cannot be a raw identifier
   |            ^^^

error: `_` cannot be a raw identifier
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:131:21
   |
LL | #[cfg_attr(r#_, cfg(r#_))] //~ ERROR `_` cannot be a raw identifier
   |                     ^^^

error[E0539]: malformed `cfg` attribute input
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:18:1
   |
LL | #[cfg(crate)] //~ ERROR `cfg` predicate key must be an identifier
   | ^^^^^^-----^^
   | |     |
   | |     expected a valid identifier here
   | help: must be of the form: `#[cfg(predicate)]`
   |
   = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>

error[E0539]: malformed `cfg` attribute input
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:20:1
   |
LL | #[cfg(super)] //~ ERROR `cfg` predicate key must be an identifier
   | ^^^^^^-----^^
   | |     |
   | |     expected a valid identifier here
   | help: must be of the form: `#[cfg(predicate)]`
   |
   = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>

error[E0539]: malformed `cfg` attribute input
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:22:1
   |
LL | #[cfg(self)] //~ ERROR `cfg` predicate key must be an identifier
   | ^^^^^^----^^
   | |     |
   | |     expected a valid identifier here
   | help: must be of the form: `#[cfg(predicate)]`
   |
   = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>

error[E0539]: malformed `cfg` attribute input
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:24:1
   |
LL | #[cfg(Self)] //~ ERROR `cfg` predicate key must be an identifier
   | ^^^^^^----^^
   | |     |
   | |     expected a valid identifier here
   | help: must be of the form: `#[cfg(predicate)]`
   |
   = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>

error[E0539]: malformed `cfg_attr` attribute input
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:26:1
   |
LL | #[cfg_attr(crate, path = "foo")] //~ ERROR `cfg` predicate key must be an identifier
   | ^^^^^^^^^^^-----^^^^^^^^^^^^^^^^
   | |          |
   | |          expected a valid identifier here
   | help: must be of the form: `#[cfg_attr(predicate, attr1, attr2, ...)]`
   |
   = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg_attr-attribute>

error[E0539]: malformed `cfg_attr` attribute input
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:28:1
   |
LL | #[cfg_attr(super, path = "foo")] //~ ERROR `cfg` predicate key must be an identifier
   | ^^^^^^^^^^^-----^^^^^^^^^^^^^^^^
   | |          |
   | |          expected a valid identifier here
   | help: must be of the form: `#[cfg_attr(predicate, attr1, attr2, ...)]`
   |
   = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg_attr-attribute>

error[E0539]: malformed `cfg_attr` attribute input
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:30:1
   |
LL | #[cfg_attr(self, path = "foo")] //~ ERROR `cfg` predicate key must be an identifier
   | ^^^^^^^^^^^----^^^^^^^^^^^^^^^^
   | |          |
   | |          expected a valid identifier here
   | help: must be of the form: `#[cfg_attr(predicate, attr1, attr2, ...)]`
   |
   = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg_attr-attribute>

error[E0539]: malformed `cfg_attr` attribute input
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:32:1
   |
LL | #[cfg_attr(Self, path = "foo")] //~ ERROR `cfg` predicate key must be an identifier
   | ^^^^^^^^^^^----^^^^^^^^^^^^^^^^
   | |          |
   | |          expected a valid identifier here
   | help: must be of the form: `#[cfg_attr(predicate, attr1, attr2, ...)]`
   |
   = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg_attr-attribute>

error[E0539]: malformed `cfg` attribute input
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:34:18
   |
LL | #[cfg_attr(true, cfg(crate))] //~ ERROR `cfg` predicate key must be an identifier
   |                  ^^^^-----^
   |                  |   |
   |                  |   expected a valid identifier here
   |                  help: must be of the form: `#[cfg(predicate)]`
   |
   = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>

error[E0539]: malformed `cfg` attribute input
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:36:18
   |
LL | #[cfg_attr(true, cfg(super))] //~ ERROR `cfg` predicate key must be an identifier
   |                  ^^^^-----^
   |                  |   |
   |                  |   expected a valid identifier here
   |                  help: must be of the form: `#[cfg(predicate)]`
   |
   = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>

error[E0539]: malformed `cfg` attribute input
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:38:18
   |
LL | #[cfg_attr(true, cfg(self))] //~ ERROR `cfg` predicate key must be an identifier
   |                  ^^^^----^
   |                  |   |
   |                  |   expected a valid identifier here
   |                  help: must be of the form: `#[cfg(predicate)]`
   |
   = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>

error[E0539]: malformed `cfg` attribute input
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:40:18
   |
LL | #[cfg_attr(true, cfg(Self))] //~ ERROR `cfg` predicate key must be an identifier
   |                  ^^^^----^
   |                  |   |
   |                  |   expected a valid identifier here
   |                  help: must be of the form: `#[cfg(predicate)]`
   |
   = note: for more information, visit <https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute>

error: expected identifier, found keyword `struct`
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:43:7
   |
LL | #[cfg(struct)] //~ ERROR expected identifier, found keyword
   |       ^^^^^^ expected identifier, found keyword

error: expected identifier, found reserved keyword `priv`
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:45:7
   |
LL | #[cfg(priv)] //~ ERROR expected identifier, found reserved keyword `priv`
   |       ^^^^ expected identifier, found reserved keyword

error: expected identifier, found reserved identifier `_`
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:47:7
   |
LL | #[cfg(_)] //~ ERROR expected identifier, found reserved identifier `_`
   |       ^ expected identifier, found reserved identifier

error: expected identifier, found keyword `struct`
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:49:12
   |
LL | #[cfg_attr(struct, path = "foo")] //~ ERROR expected identifier, found keyword
   |            ^^^^^^ expected identifier, found keyword
   |
help: escape `struct` to use it as an identifier
   |
LL | #[cfg_attr(r#struct, path = "foo")] //~ ERROR expected identifier, found keyword
   |            ++

error: expected identifier, found reserved keyword `priv`
##[error]  --> /checkout/tests/ui/cfg/path-kw-as-cfg-pred.rs:51:12