Do not merge: check if sometimes we can't get snippets

Author: samueltardieu

clippy_utils/src/source.rs

@@ -514,8 +514,9 @@ fn snippet_with_applicability_sess<'a>(
 }
 
 /// Converts a span to a code snippet. Returns `None` if not available.
+#[allow(clippy::unnecessary_wraps)]
 pub fn snippet_opt(sess: &impl HasSession, span: Span) -> Option<String> {
-    sess.sess().source_map().span_to_snippet(span).ok()
+    Some(sess.sess().source_map().span_to_snippet(span).unwrap())
 }
 
 /// Converts a span (from a block) to a code snippet if available, otherwise use default.