Working

halo2_backend/Cargo.toml

@@ -9,7 +9,7 @@ authors = [
     "Privacy Scaling Explorations team",
 ]
 edition = "2021"
-rust-version = "1.66.0"
+rust-version = "1.70.0"
 description = """
 Halo2 backend implementation.  This package implements the halo2 proof system which includes setup (key generation), proving and verifying.
 """

halo2_debug/Cargo.toml

@@ -5,7 +5,7 @@ authors = [
     "Privacy Scaling Explorations team",
 ]
 edition = "2021"
-rust-version = "1.66.0"
+rust-version = "1.70.0"
 description = """
 Halo2 Debug.  This package contains utilities for debugging and testing within
 the halo2 ecosystem.

halo2_frontend/Cargo.toml

@@ -9,7 +9,7 @@ authors = [
     "Privacy Scaling Explorations team",
 ]
 edition = "2021"
-rust-version = "1.66.0"
+rust-version = "1.70.0"
 description = """
 Halo2 frontend implementation.  This package implements an API to write circuits, handles witness generation and contains the MockProver.
 """
@@ -38,9 +38,6 @@ halo2_middleware = { path = "../halo2_middleware" }
 # Developer tooling dependencies
 plotters = { version = "0.3.0", default-features = false, optional = true }
 tabbycat = { version = "0.1", features = ["attributes"], optional = true }
-once_cell = "1.19.0"
-parking_lot = "0.12.3"
-paste = "1.0.15"
 
 [dev-dependencies]
 proptest = "1"

halo2_frontend/src/circuit/table_layouter.rs

@@ -380,7 +380,7 @@ mod tests {
                 meta.lookup("", |cells| {
                     let a = cells.query_advice(a, Rotation::cur());
 
-                    vec![(a.clone(), table.0), (a, table.1)]
+                    vec![(a, table.0), (a, table.1)]
                 });
 
                 Self::Config { table }

halo2_frontend/src/dev.rs

@@ -184,7 +184,7 @@ impl<F: FieldFront> Mul<F> for Value<F> {
 /// use halo2_frontend::{
 ///     circuit::{Layouter, SimpleFloorPlanner, Value},
 ///     dev::{FailureLocation, MockProver, VerifyFailure},
-///     plonk::{circuit::Column, Circuit, ConstraintSystem, Error, Advice, Selector},
+///     plonk::{circuit::Column, Circuit, ConstraintSystem, Error, Advice, Selector, FieldFront},
 /// };
 /// use halo2_middleware::circuit::{Any, ColumnMid};
 /// use halo2_middleware::poly::Rotation;
@@ -206,7 +206,7 @@ impl<F: FieldFront> Mul<F> for Value<F> {
 ///     b: Value<u64>,
 /// }
 ///
-/// impl<F: PrimeField> Circuit<F> for MyCircuit {
+/// impl<F: FieldFront + From<u64>> Circuit<F> for MyCircuit {
 ///     type Config = MyConfig;
 ///     type FloorPlanner = SimpleFloorPlanner;
 ///     #[cfg(feature = "circuit-params")]
@@ -284,7 +284,7 @@ impl<F: FieldFront> Mul<F> for Value<F> {
 ///     MockProver::<Fp>::run(2, &circuit, vec![]).unwrap_err()
 /// });
 /// assert_eq!(
-///     result.unwrap_err().downcast_rF::<String>().unwrap(),
+///     result.unwrap_err().downcast_ref::<String>().unwrap(),
 ///     "n=4, minimum_rows=8, k=2"
 /// );
 /// ```
@@ -1376,13 +1376,10 @@ mod tests {
 
                     // If q is enabled, a must be in the table.
                     // When q is not enabled, lookup the default value instead.
-                    let not_q = Expression::Constant(Fp::one()) - q.clone();
+                    let not_q = Expression::Constant(Fp::one()) - q;
                     let default = Expression::Constant(Fp::from(2));
                     vec![
-                        (
-                            q.clone() * a.clone() + not_q.clone() * default.clone(),
-                            table,
-                        ),
+                        (q * a + not_q * default, table),
                         (q * a + not_q * default, advice_table),
                     ]
                 });
@@ -1540,7 +1537,7 @@ mod tests {
 
                     // If q is enabled, a must be in the table.
                     // When q is not enabled, lookup the default value instead.
-                    let not_q = Expression::Constant(Fp::one()) - q.clone();
+                    let not_q = Expression::Constant(Fp::one()) - q;
                     let default = Expression::Constant(Fp::from(2));
                     vec![(q * a + not_q * default, table)]
                 });

halo2_frontend/src/dev/gates.rs

@@ -29,7 +29,7 @@ struct Gate {
 /// use halo2_frontend::{
 ///     circuit::{Layouter, SimpleFloorPlanner},
 ///     dev::CircuitGates,
-///     plonk::{Circuit, ConstraintSystem, Error},
+///     plonk::{Circuit, ConstraintSystem, Error, FieldFront},
 /// };
 /// use halo2curves::pasta::pallas;
 ///

halo2_frontend/src/dev/tfp.rs

@@ -35,7 +35,7 @@ use crate::{
 /// use halo2_frontend::{
 ///     circuit::{floor_planner, Layouter, Value},
 ///     dev::TracingFloorPlanner,
-///     plonk::{Circuit, ConstraintSystem, Error},
+///     plonk::{Circuit, ConstraintSystem, Error, FieldFront},
 /// };
 ///
 /// # struct MyCircuit<F: FieldFront> {

halo2_frontend/src/plonk/circuit.rs

@@ -3,10 +3,13 @@ use crate::plonk::{Assigned, Error};
 use halo2_middleware::circuit::Any;
 use halo2_middleware::poly::Rotation;
 
+pub mod arena;
 pub mod compress_selectors;
 pub mod constraint_system;
 pub mod expression;
 
+pub use arena::FieldFront;
+
 pub use constraint_system::*;
 pub use expression::*;
 

halo2_frontend/src/plonk/circuit/arena.rs

@@ -0,0 +1,73 @@
+use super::ExprRef;
+use super::Expression;
+
+use halo2_middleware::ff::Field;
+
+/// A field that allows to store `Expression`s in an arena.
+pub trait FieldFront: Field {
+    // Since base trait is not referenciable, we need a way to access it.
+    // This is necessary to provide a way to transform fields from/to backend.
+    type Field: Field;
+
+    /// Transform FieldFront to Field
+    fn into_field(self) -> Self::Field;
+
+    /// Transform Field to FieldFront
+    fn into_fieldfront(f: Self::Field) -> Self;
+
+    /// Allocate a new expression to the arena.
+    fn alloc(expr: Expression<Self>) -> ExprRef<Self>;
+
+    /// Get an expression from the arena, panics if the reference is invalid.
+    fn get(ref_: &ExprRef<Self>) -> Expression<Self>;
+}
+
+#[derive(Default)]
+struct ExprArena<F: FieldFront>(Vec<Expression<F>>);
+
+impl<F: FieldFront> ExprArena<F> {
+    fn push(&mut self, expr: Expression<F>) -> crate::plonk::ExprRef<F> {
+        let index = self.0.len();
+        self.0.push(expr);
+        ExprRef(index, std::marker::PhantomData)
+    }
+    fn get(&self, ref_: crate::plonk::ExprRef<F>) -> &Expression<F> {
+        &self.0[ref_.0]
+    }
+}
+
+#[macro_export]
+macro_rules! expression_arena {
+    ($arena:ident, $field:ty) => {
+        fn $arena() -> &'static std::sync::RwLock<ExprArena<$field>> {
+            static LINES: std::sync::OnceLock<std::sync::RwLock<ExprArena<$field>>> =
+                std::sync::OnceLock::new();
+            LINES.get_or_init(|| std::sync::RwLock::new(ExprArena::default()))
+        }
+
+        impl $crate::plonk::FieldFront for $field {
+            type Field = $field;
+            fn into_field(self) -> Self::Field {
+                self
+            }
+            fn into_fieldfront(f: Self::Field) -> Self {
+                f
+            }
+            fn alloc(expr: $crate::plonk::Expression<Self>) -> $crate::plonk::ExprRef<Self> {
+                $arena().write().unwrap().push(expr)
+            }
+            fn get(ref_: &$crate::plonk::ExprRef<Self>) -> $crate::plonk::Expression<Self> {
+                *$arena().read().unwrap().get(*ref_)
+            }
+        }
+        impl From<$field> for $crate::plonk::ExprRef<$field> {
+            fn from(f: $field) -> Self {
+                $crate::plonk::FieldFront::alloc($crate::plonk::Expression::Constant(f))
+            }
+        }
+    };
+}
+
+// Field scalar arenas
+expression_arena!(arena_bn256_fr, halo2curves::bn256::Fr);
+expression_arena!(arena_pasta_fp, halo2curves::pasta::Fp);

halo2_frontend/src/plonk/circuit/compress_selectors.rs

@@ -190,11 +190,11 @@ where
             // which is non-zero only on rows where `combination_assignment` is set to
             // `assigned_root`. In particular, rows set to 0 correspond to all selectors
             // being disabled.
-            let mut expression = query.clone();
+            let mut expression = query;
             let mut root = F::ONE;
             for _ in 0..combination_len {
                 if root != assigned_root {
-                    expression = expression * (Expression::Constant(root) - query.clone());
+                    expression = expression * (Expression::Constant(root) - query);
                 }
                 root += F::ONE;
             }

halo2_frontend/src/plonk/circuit/constraint_system.rs

@@ -709,7 +709,7 @@ impl<F: FieldFront> ConstraintSystem<F> {
                         assert!(!selector.is_simple());
                     }
 
-                    selector_replacements[selector.0].clone()
+                    selector_replacements[selector.0]
                 },
                 &|query| Expression::Fixed(query),
                 &|query| Expression::Advice(query),

halo2_frontend/src/plonk/circuit/expression.rs

@@ -1,3 +1,4 @@
+use super::arena::FieldFront;
 use crate::circuit::Region;
 use crate::plonk::circuit::{Advice, ColumnType, Fixed, Instance, VirtualCells};
 use crate::plonk::Error;
@@ -253,7 +254,7 @@ impl SealedPhase for ThirdPhase {
 /// row when required:
 /// ```
 /// use halo2_frontend::circuit::{Chip, Layouter, Value};
-/// use halo2_frontend::plonk::{Advice, Fixed, Error, Column, Selector};
+/// use halo2_frontend::plonk::{Advice, Fixed, Error, Column, Selector, FieldFront};
 /// use halo2_middleware::ff::Field;
 ///
 /// struct Config {
@@ -470,47 +471,16 @@ pub enum Expression<F: FieldFront> {
     Ref(ExprRef<F>),
 }
 
-// Arena context
-pub trait FieldFront: Field {
-    type Field: Field;
-    fn alloc(expr: Expression<Self>) -> ExprRef<Self>;
-    fn get(ref_: &ExprRef<Self>) -> Expression<Self>;
-    fn into_field(self) -> Self::Field;
-    fn into_field_fr(f: Self::Field) -> Self;
-}
-
 #[derive(Clone, Copy, Eq, PartialEq)]
-pub struct ExprRef<F>(usize, std::marker::PhantomData<F>);
-impl<F: FieldFront> Into<ExprRef<F>> for Expression<F> {
-    fn into(self) -> ExprRef<F> {
-        F::alloc(self)
-    }
-}
-
-#[allow(unused)]
-struct ArenaPool<F: FieldFront> {
-    expressions: Vec<Expression<F>>,
-}
-
-#[allow(unused)]
-impl<F: FieldFront> ArenaPool<F> {
-    fn new() -> Self {
-        Self {
-            expressions: Vec::new(),
-        }
-    }
-    fn push(&mut self, expr: Expression<F>) -> ExprRef<F> {
-        let index = self.expressions.len();
-        self.expressions.push(expr);
-        ExprRef(index, std::marker::PhantomData)
-    }
-    fn get(&self, ref_: ExprRef<F>) -> &Expression<F> {
-        &self.expressions[ref_.0]
+pub struct ExprRef<F>(pub(crate) usize, pub(crate) std::marker::PhantomData<F>);
+impl<F: FieldFront> From<Expression<F>> for ExprRef<F> {
+    fn from(val: Expression<F>) -> Self {
+        F::alloc(val)
     }
 }
 
-impl<F: FieldFront<Field = IF>, IF: Field> From<Expression<F>> for ExpressionMid<IF> {
-    fn from(val: Expression<F>) -> Self {
+impl<FF: FieldFront<Field = F>, F: Field> From<Expression<FF>> for ExpressionMid<F> {
+    fn from(val: Expression<FF>) -> Self {
         match val {
             Expression::Constant(c) => ExpressionMid::Constant(c.into_field()),
             Expression::Selector(_) => unreachable!(),
@@ -542,18 +512,20 @@ impl<F: FieldFront<Field = IF>, IF: Field> From<Expression<F>> for ExpressionMid
                 rotation,
             })),
             Expression::Challenge(c) => ExpressionMid::Var(VarMid::Challenge(c.into())),
-            Expression::Negated(e) => ExpressionMid::Negated(Box::new((F::get(&e)).into())),
-            Expression::Sum(lhs, rhs) => {
-                ExpressionMid::Sum(Box::new(F::get(&lhs).into()), Box::new(F::get(&rhs).into()))
-            }
-            Expression::Product(lhs, rhs) => {
-                ExpressionMid::Product(Box::new(F::get(&lhs).into()), Box::new(F::get(&rhs).into()))
-            }
+            Expression::Negated(e) => ExpressionMid::Negated(Box::new((FF::get(&e)).into())),
+            Expression::Sum(lhs, rhs) => ExpressionMid::Sum(
+                Box::new(FF::get(&lhs).into()),
+                Box::new(FF::get(&rhs).into()),
+            ),
+            Expression::Product(lhs, rhs) => ExpressionMid::Product(
+                Box::new(FF::get(&lhs).into()),
+                Box::new(FF::get(&rhs).into()),
+            ),
             Expression::Scaled(e, c) => ExpressionMid::Product(
-                Box::new(F::get(&e).into()),
+                Box::new(FF::get(&e).into()),
                 Box::new(ExpressionMid::Constant(c.into_field())),
             ),
-            Expression::Ref(ref_) => F::get(&ref_).into(),
+            Expression::Ref(ref_) => FF::get(&ref_).into(),
         }
     }
 }
@@ -1182,61 +1154,6 @@ impl<F: FieldFront> Product<Self> for Expression<F> {
     }
 }
 
-#[allow(non_camel_case_types)]
-pub struct ExprArena<F: FieldFront>(Vec<Expression<F>>);
-
-impl<F: FieldFront> ExprArena<F> {
-    pub fn new() -> Self {
-        Self(Vec::new())
-    }
-    pub fn push(&mut self, expr: Expression<F>) -> crate::plonk::ExprRef<F> {
-        let index = self.0.len();
-        self.0.push(expr);
-        ExprRef(index, std::marker::PhantomData)
-    }
-    pub fn get(&self, ref_: crate::plonk::ExprRef<F>) -> &Expression<F> {
-        &self.0[ref_.0]
-    }
-}
-
-#[macro_export]
-macro_rules! expression_arena {
-    ($arena:ident, $field:ty) => {
-        fn $arena() -> &'static std::sync::RwLock<ExprArena<$field>> {
-            static LINES: std::sync::OnceLock<std::sync::RwLock<ExprArena<$field>>> =
-                std::sync::OnceLock::new();
-            LINES.get_or_init(|| std::sync::RwLock::new(ExprArena::new()))
-        }
-
-        impl crate::plonk::FieldFront for $field {
-            type Field = $field;
-            fn into_field(self) -> Self::Field {
-                self
-            }
-            fn into_field_fr(f: Self::Field) -> Self {
-                f
-            }
-            fn alloc(expr: crate::plonk::Expression<Self>) -> crate::plonk::ExprRef<Self> {
-                $arena().write().unwrap().push(expr)
-            }
-            fn get(ref_: &crate::plonk::ExprRef<Self>) -> crate::plonk::Expression<Self> {
-                *$arena().read().unwrap().get(*ref_)
-            }
-        }
-
-        impl Into<crate::plonk::ExprRef<$field>> for $field {
-            fn into(self) -> crate::plonk::ExprRef<$field> {
-                crate::plonk::FieldFront::alloc(crate::plonk::Expression::Constant(self))
-            }
-        }
-    };
-}
-
-//#[cfg(test)]
-expression_arena!(arena_bn256_fr, halo2curves::bn256::Fr);
-expression_arena!(arena_bn256_fq, halo2curves::bn256::Fq);
-expression_arena!(arena_pasta_fp, halo2curves::pasta::Fp);
-
 #[cfg(test)]
 mod tests {
     use super::*;

halo2_middleware/Cargo.toml

@@ -9,7 +9,7 @@ authors = [
     "Privacy Scaling Explorations team",
 ]
 edition = "2021"
-rust-version = "1.66.0"
+rust-version = "1.70.0"
 description = """
 Halo2 middleware.  This package contains the types and traits required for the frontend-backend interaction.
 """