Switch to using RPITIT for to_base_prime_field_elements (#751)

* Switch to using RPITIT for `to_base_prime_field_elements` * Bump minimum Rust version to 1.75
arkworks-rs · Jun 19, 2024 · 9ce37d5 · 9ce37d5
1 parent 85d17f5
commit 9ce37d5
Show file tree

Hide file tree

Showing 5 changed files with 9 additions and 18 deletions.
diff --git a/Cargo.toml b/Cargo.toml
@@ -26,7 +26,7 @@ categories = ["cryptography"]
 include = ["Cargo.toml", "src", "README.md", "LICENSE-APACHE", "LICENSE-MIT", "doc/katex-header.html"]
 license = "MIT OR Apache-2.0"
 edition = "2021"
-rust-version = "1.70"
+rust-version = "1.75"
 
 [workspace.metadata.docs.rs]
 rustdoc-args = [ "--html-in-header katex-header.html" ]

diff --git a/ff/src/fields/mod.rs b/ff/src/fields/mod.rs
@@ -201,8 +201,6 @@ pub trait Field:
 {
     type BasePrimeField: PrimeField;
 
-    type BasePrimeFieldIter: Iterator<Item = Self::BasePrimeField>;
-
     /// Determines the algorithm for computing square roots.
     const SQRT_PRECOMP: Option<SqrtPrecomputation<Self>>;
 
@@ -219,7 +217,7 @@ pub trait Field:
     /// to `Self::BasePrimeField`.
     fn extension_degree() -> u64;
 
-    fn to_base_prime_field_elements(&self) -> Self::BasePrimeFieldIter;
+    fn to_base_prime_field_elements(&self) -> impl Iterator<Item = Self::BasePrimeField>;
 
     /// Convert a slice of base prime field elements into a field element.
     /// If the slice length != Self::extension_degree(), must return None.

diff --git a/ff/src/fields/models/cubic_extension.rs b/ff/src/fields/models/cubic_extension.rs
@@ -178,10 +178,8 @@ impl<P: CubicExtConfig> AdditiveGroup for CubicExtField<P> {
     }
 }
 
-type BaseFieldIter<P> = <<P as CubicExtConfig>::BaseField as Field>::BasePrimeFieldIter;
 impl<P: CubicExtConfig> Field for CubicExtField<P> {
     type BasePrimeField = P::BasePrimeField;
-    type BasePrimeFieldIter = Chain<BaseFieldIter<P>, Chain<BaseFieldIter<P>, BaseFieldIter<P>>>;
 
     const SQRT_PRECOMP: Option<SqrtPrecomputation<Self>> = P::SQRT_PRECOMP;
 
@@ -196,12 +194,11 @@ impl<P: CubicExtConfig> Field for CubicExtField<P> {
         Self::new(fe, P::BaseField::ZERO, P::BaseField::ZERO)
     }
 
-    fn to_base_prime_field_elements(&self) -> Self::BasePrimeFieldIter {
-        self.c0.to_base_prime_field_elements().chain(
-            self.c1
-                .to_base_prime_field_elements()
-                .chain(self.c2.to_base_prime_field_elements()),
-        )
+    fn to_base_prime_field_elements(&self) -> impl Iterator<Item = Self::BasePrimeField> {
+        self.c0
+            .to_base_prime_field_elements()
+            .chain(self.c1.to_base_prime_field_elements())
+            .chain(self.c2.to_base_prime_field_elements())
     }
 
     fn from_base_prime_field_elems(

diff --git a/ff/src/fields/models/fp/mod.rs b/ff/src/fields/models/fp/mod.rs
@@ -208,7 +208,6 @@ impl<P: FpConfig<N>, const N: usize> AdditiveGroup for Fp<P, N> {
 
 impl<P: FpConfig<N>, const N: usize> Field for Fp<P, N> {
     type BasePrimeField = Self;
-    type BasePrimeFieldIter = iter::Once<Self::BasePrimeField>;
 
     const SQRT_PRECOMP: Option<SqrtPrecomputation<Self>> = P::SQRT_PRECOMP;
     const ONE: Self = P::ONE;
@@ -221,7 +220,7 @@ impl<P: FpConfig<N>, const N: usize> Field for Fp<P, N> {
         elem
     }
 
-    fn to_base_prime_field_elements(&self) -> Self::BasePrimeFieldIter {
+    fn to_base_prime_field_elements(&self) -> impl Iterator<Item = Self::BasePrimeField> {
         iter::once(*self)
     }
 

diff --git a/ff/src/fields/models/quadratic_extension.rs b/ff/src/fields/models/quadratic_extension.rs
@@ -205,12 +205,9 @@ impl<P: QuadExtConfig> AdditiveGroup for QuadExtField<P> {
     }
 }
 
-type BaseFieldIter<P> = <<P as QuadExtConfig>::BaseField as Field>::BasePrimeFieldIter;
 impl<P: QuadExtConfig> Field for QuadExtField<P> {
     type BasePrimeField = P::BasePrimeField;
 
-    type BasePrimeFieldIter = Chain<BaseFieldIter<P>, BaseFieldIter<P>>;
-
     const SQRT_PRECOMP: Option<SqrtPrecomputation<Self>> = None;
 
     const ONE: Self = Self::new(P::BaseField::ONE, P::BaseField::ZERO);
@@ -224,7 +221,7 @@ impl<P: QuadExtConfig> Field for QuadExtField<P> {
         Self::new(fe, P::BaseField::ZERO)
     }
 
-    fn to_base_prime_field_elements(&self) -> Self::BasePrimeFieldIter {
+    fn to_base_prime_field_elements(&self) -> impl Iterator<Item = Self::BasePrimeField> {
         self.c0
             .to_base_prime_field_elements()
             .chain(self.c1.to_base_prime_field_elements())