Don't unwrap the result of `span_to_snippet`

It can return `Err` due to macros being expanded across crates or
files.

1 files changed, 7 insertions, 0 deletions

diff --git a/src/test/ui/borrowck/move-error-snippets-ext.rs b/src/test/ui/borrowck/move-error-snippets-ext.rs
new file mode 100644
index 00000000000..c77f6c8276e
--- /dev/null
+++ b/src/test/ui/borrowck/move-error-snippets-ext.rs
@@ -0,0 +1,7 @@
+// ignore-test
+
+macro_rules! aaa {
+    ($c:ident) => {{
+        let a = $c;
+    }}
+}