Implement UnwindSafe and RefUnwindSafe for Backtrace

Backtrace doesn't have visible mutable state.
rust-lang · Jul 31, 2023 · 0f06b07 · 0f06b07
1 parent 03b8b50
commit 0f06b07
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Showing 2 changed files with 9 additions and 1 deletion.
diff --git a/library/std/src/backtrace.rs b/library/std/src/backtrace.rs
@@ -92,6 +92,7 @@ use crate::backtrace_rs::{self, BytesOrWideString};
 use crate::env;
 use crate::ffi::c_void;
 use crate::fmt;
+use crate::panic::UnwindSafe;
 use crate::sync::atomic::{AtomicUsize, Ordering::Relaxed};
 use crate::sync::LazyLock;
 use crate::sys_common::backtrace::{lock, output_filename};
@@ -427,7 +428,7 @@ impl fmt::Display for Backtrace {
     }
 }
 
-type LazyResolve = impl (FnOnce() -> Capture) + Send + Sync;
+type LazyResolve = impl (FnOnce() -> Capture) + Send + Sync + UnwindSafe;
 
 fn lazy_resolve(mut capture: Capture) -> LazyResolve {
     move || {

diff --git a/library/std/src/backtrace/tests.rs b/library/std/src/backtrace/tests.rs
@@ -1,4 +1,5 @@
 use super::*;
+use crate::panic::{RefUnwindSafe, UnwindSafe};
 
 fn generate_fake_frames() -> Vec<BacktraceFrame> {
     vec![
@@ -91,3 +92,9 @@ fn test_frames() {
 
     assert!(iter.all(|(f, e)| format!("{f:#?}") == *e));
 }
+
+#[test]
+fn backtrace_unwind_safe() {
+    fn assert_unwind_safe<T: UnwindSafe + RefUnwindSafe>() {}
+    assert_unwind_safe::<Backtrace>();
+}