diff --git a/crates/nu-cli/src/completions/command_completions.rs b/crates/nu-cli/src/completions/command_completions.rs
index c4dee0760..37417e3a2 100644
--- a/crates/nu-cli/src/completions/command_completions.rs
+++ b/crates/nu-cli/src/completions/command_completions.rs
@@ -81,6 +81,9 @@ impl CommandCompletion {
         match_algorithm: MatchAlgorithm,
     ) -> Vec<Suggestion> {
         let partial = working_set.get_span_contents(span);
+        if partial.is_empty() {
+            return Vec::new();
+        }
 
         let filter_predicate = |command: &[u8]| match_algorithm.matches_u8(command, partial);
 
diff --git a/crates/nu-protocol/src/engine/engine_state.rs b/crates/nu-protocol/src/engine/engine_state.rs
index d06c1e75f..d00032d5b 100644
--- a/crates/nu-protocol/src/engine/engine_state.rs
+++ b/crates/nu-protocol/src/engine/engine_state.rs
@@ -576,8 +576,7 @@ impl EngineState {
                 return &contents[(span.start - start)..(span.end - start)];
             }
         }
-
-        panic!("internal error: span missing in file contents cache")
+        &[0u8; 0]
     }
 
     pub fn get_config(&self) -> &Config {
@@ -1292,7 +1291,13 @@ impl<'a> StateWorkingSet<'a> {
         if permanent_end <= span.start {
             for (contents, start, finish) in &self.delta.file_contents {
                 if (span.start >= *start) && (span.end <= *finish) {
-                    return &contents[(span.start - start)..(span.end - start)];
+                    let begin = span.start - start;
+                    let mut end = span.end - start;
+                    if begin > end {
+                        end = *finish - permanent_end;
+                    }
+
+                    return &contents[begin..end];
                 }
             }
         } else {