From 2736a2a84f972baabe4012f890aaae14489af8d9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20K=C3=A5re=20Alsaker?= <john.kare.alsaker@gmail.com>
Date: Tue, 18 Mar 2025 22:30:43 +0100
Subject: [PATCH] Allow duplicates for side effect nodes

---
 compiler/rustc_query_system/src/dep_graph/serialized.rs | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/compiler/rustc_query_system/src/dep_graph/serialized.rs b/compiler/rustc_query_system/src/dep_graph/serialized.rs
index c96a58047723..f4b2cf631ed7 100644
--- a/compiler/rustc_query_system/src/dep_graph/serialized.rs
+++ b/compiler/rustc_query_system/src/dep_graph/serialized.rs
@@ -253,13 +253,16 @@ pub fn decode<D: Deps>(d: &mut MemDecoder<'_>, deps: &D) -> Arc<SerializedDepGra
 
         for (idx, node) in nodes.iter_enumerated() {
             if index[node.kind.as_usize()].insert(node.hash, idx).is_some() {
-                let name = deps.name(node.kind);
-                panic!(
+                // Side effect nodes can have duplicates
+                if node.kind != D::DEP_KIND_SIDE_EFFECT {
+                    let name = deps.name(node.kind);
+                    panic!(
                     "Error: A dep graph node ({name}) does not have an unique index. \
                      Running a clean build on a nightly compiler with `-Z incremental-verify-ich` \
                      can help narrow down the issue for reporting. A clean build may also work around the issue.\n
                      DepNode: {node:?}"
                 )
+                }
             }
         }