From 680dfd41240b56dc44404c8d73b42c1661226a59 Mon Sep 17 00:00:00 2001
From: chriseth <chris@ethereum.org>
Date: Thu, 20 Apr 2023 23:06:52 +0200
Subject: [PATCH] Warn about duplicate labels (in riscv).

---
 src/riscv/parser.rs | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/riscv/parser.rs b/src/riscv/parser.rs
index 438a4058f..8e6a98db2 100644
--- a/src/riscv/parser.rs
+++ b/src/riscv/parser.rs
@@ -110,7 +110,12 @@ pub fn extract_label_offsets(statements: &[Statement]) -> BTreeMap<&str, usize>
             Statement::Label(l) => Some((l.as_str(), i)),
             Statement::Directive(_, _) | Statement::Instruction(_, _) => None,
         })
-        .collect()
+        .fold(BTreeMap::new(), |mut acc, (n, i)| {
+            if acc.insert(n, i).is_some() {
+                panic!("Duplicate label: {n}")
+            }
+            acc
+        })
 }
 
 pub fn referenced_labels(statement: &Statement) -> BTreeSet<&str> {