1 files changed, 36 insertions, 0 deletions
diff --git a/third_party/rust/anyhow/src/backtrace.rs b/third_party/rust/anyhow/src/backtrace.rs
new file mode 100644
index 0000000000..01e33cb237
--- /dev/null
+++ b/third_party/rust/anyhow/src/backtrace.rs
@@ -0,0 +1,36 @@
+#[cfg(backtrace)]
+pub(crate) use std::backtrace::Backtrace;
+
+#[cfg(not(backtrace))]
+pub(crate) enum Backtrace {}
+
+#[cfg(backtrace)]
+macro_rules! backtrace {
+    () => {
+        Some(Backtrace::capture())
+    };
+}
+
+#[cfg(not(backtrace))]
+macro_rules! backtrace {
+    () => {
+        None
+    };
+}
+
+#[cfg(backtrace)]
+macro_rules! backtrace_if_absent {
+    ($err:expr) => {
+        match $err.backtrace() {
+            Some(_) => None,
+            None => Some(Backtrace::capture()),
+        }
+    };
+}
+
+#[cfg(all(feature = "std", not(backtrace)))]
+macro_rules! backtrace_if_absent {
+    ($err:expr) => {
+        None
+    };
+}