Rollup merge of #91504 - cynecx:used_retain, r=nikic

`#[used(linker)]` attribute

See https://github.com/dtolnay/linkme/issues/41#issuecomment-927255631.

6 files changed, 79 insertions, 0 deletions

diff --git a/src/test/ui/attributes/used_with_arg.rs b/src/test/ui/attributes/used_with_arg.rs
new file mode 100644
index 00000000000..ad80ff53f0e
--- /dev/null
+++ b/src/test/ui/attributes/used_with_arg.rs
@@ -0,0 +1,19 @@
+#![feature(used_with_arg)]
+
+#[used(linker)]
+static mut USED_LINKER: [usize; 1] = [0];
+
+#[used(compiler)]
+static mut USED_COMPILER: [usize; 1] = [0];
+
+#[used(compiler)] //~ ERROR `used(compiler)` and `used(linker)` can't be used together
+#[used(linker)]
+static mut USED_COMPILER_LINKER2: [usize; 1] = [0];
+
+#[used(compiler)] //~ ERROR `used(compiler)` and `used(linker)` can't be used together
+#[used(linker)]
+#[used(compiler)]
+#[used(linker)]
+static mut USED_COMPILER_LINKER3: [usize; 1] = [0];
+
+fn main() {}
diff --git a/src/test/ui/attributes/used_with_arg.stderr b/src/test/ui/attributes/used_with_arg.stderr
new file mode 100644
index 00000000000..440e5c4a5a0
--- /dev/null
+++ b/src/test/ui/attributes/used_with_arg.stderr
@@ -0,0 +1,18 @@
+error: `used(compiler)` and `used(linker)` can't be used together
+  --> $DIR/used_with_arg.rs:9:1
+   |
+LL | #[used(compiler)]
+   | ^^^^^^^^^^^^^^^^^
+LL | #[used(linker)]
+   | ^^^^^^^^^^^^^^^
+
+error: `used(compiler)` and `used(linker)` can't be used together
+  --> $DIR/used_with_arg.rs:13:1
+   |
+LL | #[used(compiler)]
+   | ^^^^^^^^^^^^^^^^^
+LL | #[used(linker)]
+   | ^^^^^^^^^^^^^^^
+
+error: aborting due to 2 previous errors
+
diff --git a/src/test/ui/attributes/used_with_multi_args.rs b/src/test/ui/attributes/used_with_multi_args.rs
new file mode 100644
index 00000000000..2e17fcfd7a4
--- /dev/null
+++ b/src/test/ui/attributes/used_with_multi_args.rs
@@ -0,0 +1,6 @@
+#![feature(used_with_arg)]
+
+#[used(compiler, linker)] //~ expected `used`, `used(compiler)` or `used(linker)`
+static mut USED_COMPILER_LINKER: [usize; 1] = [0];
+
+fn main() {}
diff --git a/src/test/ui/attributes/used_with_multi_args.stderr b/src/test/ui/attributes/used_with_multi_args.stderr
new file mode 100644
index 00000000000..c93aafcfc7c
--- /dev/null
+++ b/src/test/ui/attributes/used_with_multi_args.stderr
@@ -0,0 +1,8 @@
+error: expected `used`, `used(compiler)` or `used(linker)`
+  --> $DIR/used_with_multi_args.rs:3:1
+   |
+LL | #[used(compiler, linker)]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/feature-gates/feature-gate-used_with_arg.rs b/src/test/ui/feature-gates/feature-gate-used_with_arg.rs
new file mode 100644
index 00000000000..1c8f01bdef1
--- /dev/null
+++ b/src/test/ui/feature-gates/feature-gate-used_with_arg.rs
@@ -0,0 +1,7 @@
+#[used(linker)] //~ ERROR `#[used(linker)]` is currently unstable
+static mut USED_LINKER: [usize; 1] = [0];
+
+#[used(compiler)] //~ ERROR `#[used(compiler)]` is currently unstable
+static mut USED_COMPILER: [usize; 1] = [0];
+
+fn main() {}
diff --git a/src/test/ui/feature-gates/feature-gate-used_with_arg.stderr b/src/test/ui/feature-gates/feature-gate-used_with_arg.stderr
new file mode 100644
index 00000000000..d115bf4e365
--- /dev/null
+++ b/src/test/ui/feature-gates/feature-gate-used_with_arg.stderr
@@ -0,0 +1,21 @@
+error[E0658]: `#[used(linker)]` is currently unstable
+  --> $DIR/feature-gate-used_with_arg.rs:1:1
+   |
+LL | #[used(linker)]
+   | ^^^^^^^^^^^^^^^
+   |
+   = note: see issue #93798 <https://github.com/rust-lang/rust/issues/93798> for more information
+   = help: add `#![feature(used_with_arg)]` to the crate attributes to enable
+
+error[E0658]: `#[used(compiler)]` is currently unstable
+  --> $DIR/feature-gate-used_with_arg.rs:4:1
+   |
+LL | #[used(compiler)]
+   | ^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #93798 <https://github.com/rust-lang/rust/issues/93798> for more information
+   = help: add `#![feature(used_with_arg)]` to the crate attributes to enable
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0658`.