Do not re-hash foreign spans.

1 files changed, 11 insertions, 0 deletions

diff --git a/src/test/incremental/mir-opt.rs b/src/test/incremental/mir-opt.rs
new file mode 100644
index 00000000000..5bd863439df
--- /dev/null
+++ b/src/test/incremental/mir-opt.rs
@@ -0,0 +1,11 @@
+// MIR optimizations can create expansions after the TyCtxt has been created.
+// This test verifies that those expansions can be decoded correctly.
+
+// revisions:rpass1 rpass2
+// compile-flags: -Z query-dep-graph -Z mir-opt-level=3
+
+fn main() {
+    if std::env::var("a").is_ok() {
+        println!("b");
+    }
+}