diff --git a/Cargo.lock b/Cargo.lock
index 92a6c3e976..1e924d92f4 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -903,6 +903,7 @@ dependencies = [
  "salsa",
  "salsa-macros",
  "serde",
+ "serde_derive",
  "smallvec",
  "span",
  "stdx",
diff --git a/crates/hir-ty/Cargo.toml b/crates/hir-ty/Cargo.toml
index e54a6190b4..238d1b08ae 100644
--- a/crates/hir-ty/Cargo.toml
+++ b/crates/hir-ty/Cargo.toml
@@ -19,6 +19,7 @@ arrayvec.workspace = true
 smallvec.workspace = true
 ena = "0.14.3"
 serde.workspace = true
+serde_derive.workspace = true
 either.workspace = true
 oorandom = "11.1.5"
 tracing = { workspace = true, features = ["attributes"] }
diff --git a/crates/hir-ty/src/next_solver/format_proof_tree.rs b/crates/hir-ty/src/next_solver/format_proof_tree.rs
index fa09cda234..59fb0d65c5 100644
--- a/crates/hir-ty/src/next_solver/format_proof_tree.rs
+++ b/crates/hir-ty/src/next_solver/format_proof_tree.rs
@@ -1,5 +1,5 @@
 use rustc_type_ir::{solve::GoalSource, solve::inspect::GoalEvaluation};
-use serde::{Deserialize, Serialize};
+use serde_derive::{Deserialize, Serialize};
 
 use crate::next_solver::infer::InferCtxt;
 use crate::next_solver::inspect::{InspectCandidate, InspectGoal};