2 files changed, 23 insertions, 0 deletions
diff --git a/src/test/ui/feature-gates/feature-gate-custom_mir.rs b/src/test/ui/feature-gates/feature-gate-custom_mir.rs
new file mode 100644
index 00000000000..0126dde2f7d
--- /dev/null
+++ b/src/test/ui/feature-gates/feature-gate-custom_mir.rs
@@ -0,0 +1,12 @@
+#![feature(core_intrinsics)]
+
+extern crate core;
+
+#[custom_mir(dialect = "built")] //~ ERROR the `#[custom_mir]` attribute is just used for the Rust test suite
+pub fn foo(_x: i32) -> i32 {
+    0
+}
+
+fn main() {
+    assert_eq!(2, foo(2));
+}
diff --git a/src/test/ui/feature-gates/feature-gate-custom_mir.stderr b/src/test/ui/feature-gates/feature-gate-custom_mir.stderr
new file mode 100644
index 00000000000..3c149d30d82
--- /dev/null
+++ b/src/test/ui/feature-gates/feature-gate-custom_mir.stderr
@@ -0,0 +1,11 @@
+error[E0658]: the `#[custom_mir]` attribute is just used for the Rust test suite
+  --> $DIR/feature-gate-custom_mir.rs:5:1
+   |
+LL | #[custom_mir(dialect = "built")]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add `#![feature(custom_mir)]` to the crate attributes to enable
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0658`.