diff --git a/lang/src/son.rs b/lang/src/son.rs
index 7f7b2673..708554a4 100644
--- a/lang/src/son.rs
+++ b/lang/src/son.rs
@@ -24,6 +24,7 @@ use {
         fmt::{self, Debug, Display, Write},
         format_args as fa, mem,
         ops::{self, Range},
+        usize,
     },
     hashbrown::hash_map,
     hbbytecode::DisasmError,
@@ -2792,6 +2793,11 @@ impl<'a> Codegen<'a> {
                         }
                     }
 
+                    debug_assert_eq!(
+                        lexer::Lexer::new(&self.file().file[pos as usize..]).eat().kind,
+                        TokenKind::Return
+                    );
+
                     let ret = self.ci.nodes.new_node_nop(
                         ty::Id::VOID,
                         Kind::Return { file: self.ci.file },