diff --git a/halo2_proofs/src/plonk/circuit.rs b/halo2_proofs/src/plonk/circuit.rs
index 59f2301bde..9d43aab734 100644
--- a/halo2_proofs/src/plonk/circuit.rs
+++ b/halo2_proofs/src/plonk/circuit.rs
@@ -1590,7 +1590,10 @@ pub struct LookupTracker<F: Field> {
     pub(crate) inputs: Vec<Vec<Expression<F>>>,
 }
 
-impl<F: Field> std::fmt::Debug for LookupTracker<F> where F: std::fmt::Debug {
+impl<F: Field> std::fmt::Debug for LookupTracker<F>
+where
+    F: std::fmt::Debug,
+{
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         f.debug_struct("LookupTracker")
             .field("table", &self.table)
diff --git a/halo2_proofs/src/plonk/prover.rs b/halo2_proofs/src/plonk/prover.rs
index 4ed6195ebc..15a97c8132 100644
--- a/halo2_proofs/src/plonk/prover.rs
+++ b/halo2_proofs/src/plonk/prover.rs
@@ -451,12 +451,15 @@ where
                 };
 
                 // Synthesize the circuit to obtain the witness and other information.
+
+                log::info!("create_proof synthesize phase {current_phase:?} begin");
                 ConcreteCircuit::FloorPlanner::synthesize(
                     &mut witness,
                     circuit,
                     config.clone(),
                     meta.constants.clone(),
                 )?;
+                log::info!("create_proof synthesize phase {current_phase:?} end");
 
                 #[cfg(feature = "phase-check")]
                 {
diff --git a/rust-toolchain b/rust-toolchain
index ee2d639b86..27c108be5c 100644
--- a/rust-toolchain
+++ b/rust-toolchain
@@ -1 +1 @@
-nightly-2023-08-12
\ No newline at end of file
+nightly-2023-12-03