diff --git a/field/src/extension/mod.rs b/field/src/extension/mod.rs
index 3586055e..bcf8537e 100644
--- a/field/src/extension/mod.rs
+++ b/field/src/extension/mod.rs
@@ -125,9 +125,9 @@ impl<F: Field> FieldExtension<1> for F {
 }
 
 /// Flatten the slice by sending every extension field element to its D-sized canonical representation.
-pub fn flatten<F: Field, const D: usize>(l: &[F::Extension]) -> Vec<F>
+pub fn flatten<F, const D: usize>(l: &[F::Extension]) -> Vec<F>
 where
-    F: Extendable<D>,
+    F: Field + Extendable<D>,
 {
     l.iter()
         .flat_map(|x| x.to_basefield_array().to_vec())
@@ -135,9 +135,9 @@ where
 }
 
 /// Batch every D-sized chunks into extension field elements.
-pub fn unflatten<F: Field, const D: usize>(l: &[F]) -> Vec<F::Extension>
+pub fn unflatten<F, const D: usize>(l: &[F]) -> Vec<F::Extension>
 where
-    F: Extendable<D>,
+    F: Field + Extendable<D>,
 {
     debug_assert_eq!(l.len() % D, 0);
     l.chunks_exact(D)
diff --git a/plonky2/src/hash/poseidon.rs b/plonky2/src/hash/poseidon.rs
index ae5a26c1..a7c76325 100644
--- a/plonky2/src/hash/poseidon.rs
+++ b/plonky2/src/hash/poseidon.rs
@@ -923,7 +923,7 @@ impl<F: RichField> AlgebraicHasher<F> for PoseidonHash {
 pub(crate) mod test_helpers {
     use super::*;
 
-    pub(crate) fn check_test_vectors<F: Field>(
+    pub(crate) fn check_test_vectors<F>(
         test_vectors: Vec<([u64; SPONGE_WIDTH], [u64; SPONGE_WIDTH])>,
     ) where
         F: Poseidon,
@@ -941,7 +941,7 @@ pub(crate) mod test_helpers {
         }
     }
 
-    pub(crate) fn check_consistency<F: Field>()
+    pub(crate) fn check_consistency<F>()
     where
         F: Poseidon,
     {
diff --git a/plonky2/src/iop/witness.rs b/plonky2/src/iop/witness.rs
index 40377aa3..85af6ca4 100644
--- a/plonky2/src/iop/witness.rs
+++ b/plonky2/src/iop/witness.rs
@@ -14,7 +14,7 @@ use crate::iop::ext_target::ExtensionTarget;
 use crate::iop::target::{BoolTarget, Target};
 use crate::iop::wire::Wire;
 use crate::plonk::circuit_data::{VerifierCircuitTarget, VerifierOnlyCircuitData};
-use crate::plonk::config::{AlgebraicHasher, GenericConfig, Hasher};
+use crate::plonk::config::{AlgebraicHasher, GenericConfig};
 use crate::plonk::proof::{Proof, ProofTarget, ProofWithPublicInputs, ProofWithPublicInputsTarget};
 
 pub trait WitnessWrite<F: Field> {
@@ -222,7 +222,7 @@ pub trait Witness<F: Field>: WitnessWrite<F> {
         }
     }
 
-    fn get_merkle_cap_target<H: Hasher<F>>(&self, cap_target: MerkleCapTarget) -> MerkleCap<F, H>
+    fn get_merkle_cap_target<H>(&self, cap_target: MerkleCapTarget) -> MerkleCap<F, H>
     where
         F: RichField,
         H: AlgebraicHasher<F>,