ff: Add PrimeField: From<u64> constraint

pairing/src/bls12_381/fq.rs

@@ -456,7 +456,7 @@ pub struct Fq(FqRepr);
 
 #[test]
 fn test_b_coeff() {
-    assert_eq!(Fq::from_repr(FqRepr::from(4)).unwrap(), B_COEFF);
+    assert_eq!(Fq::from(4), B_COEFF);
 }
 
 #[test]
@@ -1586,7 +1586,7 @@ fn test_fq_is_valid() {
     assert!(!a.is_valid());
     a.0.sub_noborrow(&FqRepr::from(1));
     assert!(a.is_valid());
-    assert!(Fq(FqRepr::from(0)).is_valid());
+    assert!(Fq::from(0).is_valid());
     assert!(Fq(FqRepr([
         0xdf4671abd14dab3e,
         0xe2dc0c9f534fbd33,
@@ -2193,10 +2193,7 @@ fn test_fq_root_of_unity() {
     use ff::SqrtField;
 
     assert_eq!(Fq::S, 1);
-    assert_eq!(
-        Fq::multiplicative_generator(),
-        Fq::from_repr(FqRepr::from(2)).unwrap()
-    );
+    assert_eq!(Fq::multiplicative_generator(), Fq::from(2));
     assert_eq!(
         Fq::multiplicative_generator().pow_vartime([
             0xdcff7fffffffd555u64,
@@ -2225,9 +2222,7 @@ fn test_fq_ordering() {
     // FqRepr's ordering is well-tested, but we still need to make sure the Fq
     // elements aren't being compared in Montgomery form.
     for i in 0..100 {
-        assert!(
-            Fq::from_repr(FqRepr::from(i + 1)).unwrap() > Fq::from_repr(FqRepr::from(i)).unwrap()
-        );
+        assert!(Fq::from(i + 1) > Fq::from(i));
     }
 }
 

pairing/src/bls12_381/fq2.rs

@@ -364,7 +364,7 @@ fn test_fq2_squaring() {
         a.square(),
         Fq2 {
             c0: Fq::zero(),
-            c1: Fq::from_repr(FqRepr::from(2)).unwrap(),
+            c1: Fq::from(2),
         }
     ); // 2u
 

pairing/src/bls12_381/fr.rs

@@ -368,7 +368,7 @@ fn test_fr_is_valid() {
     assert!(!a.is_valid());
     a.0.sub_noborrow(&FrRepr::from(1));
     assert!(a.is_valid());
-    assert!(Fr(FrRepr::from(0)).is_valid());
+    assert!(Fr::from(0).is_valid());
     assert!(Fr(FrRepr([
         0xffffffff00000000,
         0x53bda402fffe5bfe,
@@ -961,10 +961,7 @@ fn test_fr_root_of_unity() {
     use ff::SqrtField;
 
     assert_eq!(Fr::S, 32);
-    assert_eq!(
-        Fr::multiplicative_generator(),
-        Fr::from_repr(FrRepr::from(7)).unwrap()
-    );
+    assert_eq!(Fr::multiplicative_generator(), Fr::from(7));
     assert_eq!(
         Fr::multiplicative_generator().pow_vartime([
             0xfffe5bfeffffffffu64,

pairing/src/bls12_381/tests/mod.rs

@@ -191,7 +191,7 @@ fn test_g1_uncompressed_invalid_vectors() {
         loop {
             let mut x3b = x.square();
             x3b.mul_assign(&x);
-            x3b.add_assign(&Fq::from_repr(FqRepr::from(4)).unwrap()); // TODO: perhaps expose coeff_b through API?
+            x3b.add_assign(&Fq::from(4)); // TODO: perhaps expose coeff_b through API?
 
             let y = x3b.sqrt();
             if y.is_some().into() {
@@ -331,8 +331,8 @@ fn test_g2_uncompressed_invalid_vectors() {
             let mut x3b = x.square();
             x3b.mul_assign(&x);
             x3b.add_assign(&Fq2 {
-                c0: Fq::from_repr(FqRepr::from(4)).unwrap(),
-                c1: Fq::from_repr(FqRepr::from(4)).unwrap(),
+                c0: Fq::from(4),
+                c1: Fq::from(4),
             }); // TODO: perhaps expose coeff_b through API?
 
             let y = x3b.sqrt();
@@ -428,7 +428,7 @@ fn test_g1_compressed_invalid_vectors() {
         loop {
             let mut x3b = x.square();
             x3b.mul_assign(&x);
-            x3b.add_assign(&Fq::from_repr(FqRepr::from(4)).unwrap()); // TODO: perhaps expose coeff_b through API?
+            x3b.add_assign(&Fq::from(4)); // TODO: perhaps expose coeff_b through API?
 
             if x3b.sqrt().is_some().into() {
                 x.add_assign(&Fq::one());
@@ -452,7 +452,7 @@ fn test_g1_compressed_invalid_vectors() {
         loop {
             let mut x3b = x.square();
             x3b.mul_assign(&x);
-            x3b.add_assign(&Fq::from_repr(FqRepr::from(4)).unwrap()); // TODO: perhaps expose coeff_b through API?
+            x3b.add_assign(&Fq::from(4)); // TODO: perhaps expose coeff_b through API?
 
             if x3b.sqrt().is_some().into() {
                 // We know this is on the curve, but it's likely not going to be in the correct subgroup.
@@ -558,8 +558,8 @@ fn test_g2_compressed_invalid_vectors() {
             let mut x3b = x.square();
             x3b.mul_assign(&x);
             x3b.add_assign(&Fq2 {
-                c0: Fq::from_repr(FqRepr::from(4)).unwrap(),
-                c1: Fq::from_repr(FqRepr::from(4)).unwrap(),
+                c0: Fq::from(4),
+                c1: Fq::from(4),
             }); // TODO: perhaps expose coeff_b through API?
 
             if x3b.sqrt().is_some().into() {
@@ -589,8 +589,8 @@ fn test_g2_compressed_invalid_vectors() {
             let mut x3b = x.square();
             x3b.mul_assign(&x);
             x3b.add_assign(&Fq2 {
-                c0: Fq::from_repr(FqRepr::from(4)).unwrap(),
-                c1: Fq::from_repr(FqRepr::from(4)).unwrap(),
+                c0: Fq::from(4),
+                c1: Fq::from(4),
             }); // TODO: perhaps expose coeff_b through API?
 
             if x3b.sqrt().is_some().into() {

pairing/src/tests/field.rs

@@ -119,7 +119,7 @@ pub fn from_str_tests<F: PrimeField>() {
             let n = rng.next_u64();
 
             let a = F::from_str(&format!("{}", n)).unwrap();
-            let b = F::from_repr(n.into()).unwrap();
+            let b = F::from(n);
 
             assert_eq!(a, b);
         }