From d14cbc689a8494cff8de0dd908c556dc120ef3b3 Mon Sep 17 00:00:00 2001
From: chriseth <chris@ethereum.org>
Date: Thu, 20 Apr 2023 18:39:58 +0200
Subject: [PATCH] Detect duplicate labels.

---
 src/asm_compiler/mod.rs | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/asm_compiler/mod.rs b/src/asm_compiler/mod.rs
index 5f3e4e498..e0550cbb3 100644
--- a/src/asm_compiler/mod.rs
+++ b/src/asm_compiler/mod.rs
@@ -649,8 +649,11 @@ impl ASMPILConverter {
         self.code_lines
             .iter()
             .enumerate()
-            .filter_map(|(i, line)| line.label.as_ref().map(|l| (l.clone(), i)))
-            .collect()
+            .filter_map(|(i, line)| line.label.as_ref().map(|l| (l, i)))
+            .fold(HashMap::new(), |mut r, (l, i)| {
+                assert!(r.insert(l.clone(), i).is_none(), "Duplicate label: {l}");
+                r
+            })
     }
 
     /// Creates a pair of witness and fixed column and matches them in the lookup.