1 files changed, 49 insertions, 0 deletions
diff --git a/src/tools/rustfmt/tests/source/cfg_if/lib.rs b/src/tools/rustfmt/tests/source/cfg_if/lib.rs
new file mode 100644
index 000000000..8b3bb304f
--- /dev/null
+++ b/src/tools/rustfmt/tests/source/cfg_if/lib.rs
@@ -0,0 +1,49 @@
+//! Run-time feature detection for the Rust standard library.
+//!
+//! To detect whether a feature is enabled in the system running the binary
+//! use one of the appropriate macro for the target:
+//!
+//! * `x86` and `x86_64`: [`is_x86_feature_detected`]
+//! * `arm`: [`is_arm_feature_detected`]
+//! * `aarch64`: [`is_aarch64_feature_detected`]
+//! * `mips`: [`is_mips_feature_detected`]
+//! * `mips64`: [`is_mips64_feature_detected`]
+//! * `powerpc`: [`is_powerpc_feature_detected`]
+//! * `powerpc64`: [`is_powerpc64_feature_detected`]
+
+#![unstable(feature = "stdsimd", issue = "27731")]
+#![feature(const_fn, staged_api, stdsimd, doc_cfg, allow_internal_unstable)]
+#![allow(clippy::shadow_reuse)]
+#![deny(clippy::missing_inline_in_public_items)]
+#![cfg_attr(target_os = "linux", feature(linkage))]
+#![cfg_attr(all(target_os = "freebsd", target_arch = "aarch64"), feature(asm))]
+#![cfg_attr(stdsimd_strict, deny(warnings))]
+#![cfg_attr(test, allow(unused_imports))]
+#![no_std]
+
+#[macro_use]
+extern crate cfg_if;
+
+cfg_if! {
+    if #[cfg(feature = "std_detect_file_io")] {
+        #[cfg_attr(test, macro_use(println))]
+        extern crate std;
+
+        #[allow(unused_imports)]
+        use std::{arch, fs, io, mem, sync};
+    } else {
+        #[cfg(test)]
+        #[macro_use(println)]
+        extern crate std;
+
+        #[allow(unused_imports)]
+        use core::{arch, mem, sync};
+    }
+}
+
+#[cfg(feature = "std_detect_dlsym_getauxval")]
+extern crate libc;
+
+#[doc(hidden)]
+#[unstable(feature = "stdsimd", issue = "27731")]
+pub mod detect;