1 files changed, 30 insertions, 0 deletions
diff --git a/src/test/mir-opt/simplify_try.rs b/src/test/mir-opt/simplify_try.rs
new file mode 100644
index 000000000..15e351e7d
--- /dev/null
+++ b/src/test/mir-opt/simplify_try.rs
@@ -0,0 +1,30 @@
+// compile-flags: -Zunsound-mir-opts
+// EMIT_MIR simplify_try.try_identity.SimplifyArmIdentity.diff
+// EMIT_MIR simplify_try.try_identity.SimplifyBranchSame.after.mir
+// EMIT_MIR simplify_try.try_identity.SimplifyLocals.after.mir
+// EMIT_MIR simplify_try.try_identity.DestinationPropagation.diff
+
+
+fn into_result<T, E>(r: Result<T, E>) -> Result<T, E> {
+    r
+}
+
+fn from_error<T, E>(e: E) -> Result<T, E> {
+    Err(e)
+}
+
+// This was written to the `?` from `try_trait`, but `try_trait_v2` uses a different structure,
+// so the relevant desugar is copied inline in order to keep the test testing the same thing.
+// FIXME(#85133): while this might be useful for `r#try!`, it would be nice to have a MIR
+// optimization that picks up the `?` desugaring, as `SimplifyArmIdentity` does not.
+fn try_identity(x: Result<u32, i32>) -> Result<u32, i32> {
+    let y = match into_result(x) {
+        Err(e) => return from_error(From::from(e)),
+        Ok(v) => v,
+    };
+    Ok(y)
+}
+
+fn main() {
+    let _ = try_identity(Ok(0));
+}