rust/tests/ui/conditional-compilation/cfg-attr-empty-is-unused.rs

// Check that `#[cfg_attr($PREDICATE,)]` triggers the `unused_attribute` lint.

#![deny(unused)]

#[cfg_attr(FALSE,)] //~ ERROR `#[cfg_attr]` does not expand to any attributes
fn _f() {}

#[cfg_attr(not(FALSE),)] //~ ERROR `#[cfg_attr]` does not expand to any attributes
fn _g() {}

fn main() {}
Add test for linting on 'cfg_attr(,)'. 2019-06-22 05:12:26 -05:00			// Check that `#[cfg_attr($PREDICATE,)]` triggers the `unused_attribute` lint.

			`#![deny(unused)]`

Remove `Session.used_attrs` and move logic to `CheckAttrVisitor` Instead of updating global state to mark attributes as used, we now explicitly emit a warning when an attribute is used in an unsupported position. As a side effect, we are to emit more detailed warning messages (instead of just a generic "unused" message). `Session.check_name` is removed, since its only purpose was to mark the attribute as used. All of the callers are modified to use `Attribute.has_name` Additionally, `AttributeType::AssumedUsed` is removed - an 'assumed used' attribute is implemented by simply not performing any checks in `CheckAttrVisitor` for a particular attribute. We no longer emit unused attribute warnings for the `#[rustc_dummy]` attribute - it's an internal attribute used for tests, so it doesn't mark sense to treat it as 'unused'. With this commit, a large source of global untracked state is removed. 2021-07-29 12:00:41 -05:00			#[cfg_attr(FALSE,)] //~ ERROR `#[cfg_attr]` does not expand to any attributes
Add test for linting on 'cfg_attr(,)'. 2019-06-22 05:12:26 -05:00			`fn _f() {}`

Unify all the always-false cfgs under the `FALSE` cfg 2024-04-06 17:43:00 -05:00			#[cfg_attr(not(FALSE),)] //~ ERROR `#[cfg_attr]` does not expand to any attributes
Add test for linting on 'cfg_attr(,)'. 2019-06-22 05:12:26 -05:00			`fn _g() {}`

			`fn main() {}`