1 files changed, 7 insertions, 1 deletions
diff --git a/tvix/eval/src/chunk.rs b/tvix/eval/src/chunk.rs
index 5026cdb736..9f2fdf54dc 100644
--- a/tvix/eval/src/chunk.rs
+++ b/tvix/eval/src/chunk.rs
@@ -1,5 +1,5 @@
 use std::io::Write;
-use std::ops::Index;
+use std::ops::{Index, IndexMut};
 
 use crate::opcode::{CodeIdx, ConstantIdx, OpCode};
 use crate::value::Value;
@@ -51,6 +51,12 @@ impl Index<CodeIdx> for Chunk {
     }
 }
 
+impl IndexMut<CodeIdx> for Chunk {
+    fn index_mut(&mut self, index: CodeIdx) -> &mut Self::Output {
+        &mut self.code[index.0]
+    }
+}
+
 impl Chunk {
     pub fn push_op(&mut self, data: OpCode, span: codemap::Span) -> CodeIdx {
         let idx = self.code.len();