use customized field conversion

Author: jialinli98

vlayer/ethereum/circuits/lib/src/slot.nr

@@ -1,5 +1,5 @@
 use dep::bignum::U256;
-use dep::ethereum::{misc::types::Bytes32, uint256::{from, from_field, into}};
+use dep::ethereum::{misc::types::Bytes32, uint256::{from, into}};
 use dep::keccak256::keccak256;
 
 global STORAGE_KEY_HASH_INPUT_LENGTH: u32 = 64;
@@ -16,16 +16,21 @@ pub(crate) fn dynamic_array(slot: U256, size: Field, index: Field) -> U256 {
     dynamic_array_with_precalculated_slot(start, size, index)
 }
 
+fn field_to_u256(f: Field) -> U256 {
+    let bytes = f.to_be_bytes();
+    from(bytes)
+}
+
 pub(crate) fn dynamic_array_with_precalculated_slot(slot: U256, size: Field, index: Field) -> U256 {
-    let product = from_field(size * index);
+    // TODO: use from_field() instead of field_to_u256()
+    let product = field_to_u256(size * index);
     let sum = slot + product;
-    // TODO: Uncomment this when we have a way to check for overflows in the circuit without getting brillig errors
-    // assert(sum >= slot, "Attempt to add with overflow");
+    assert(sum >= slot, "Attempt to add with overflow");
     sum
 }
 
 pub(crate) fn struct_slot(slot: U256, offset: Field) -> U256 {
-    let sum = slot + from_field(offset);
-    // assert(sum >= slot, "Attempt to add with overflow");
+    let sum = slot + field_to_u256(offset);
+    assert(sum >= slot, "Attempt to add with overflow");
     sum
 }

vlayer/ethereum/circuits/lib/src/slot_test.nr

@@ -87,11 +87,11 @@ mod dynamic_array {
         assert_eq(expected_slot, dynamic_array(slot, 2, 7));
     }
 
-    // #[test(should_fail_with = "Attempt to add with overflow")]
-    // fn fail_overflow() {
-    //     let slot = from_field(6);
-    //     let _ = dynamic_array(slot, 2, MAX_FIELD_VALUE);
-    // }
+    #[test(should_fail_with = "Attempt to add with overflow")]
+    fn fail_overflow() {
+        let slot = from_field(6);
+        let _ = dynamic_array(slot, 2, MAX_FIELD_VALUE);
+    }
 }
 
 mod dynamic_array_with_precalculated_slot {
@@ -121,11 +121,11 @@ mod dynamic_array_with_precalculated_slot {
         assert_eq(expected_slot, dynamic_array_with_precalculated_slot(slot, 10, 1_000_000_000));
     }
 
-    // #[test(should_fail_with = "Attempt to add with overflow")]
-    // fn fail_overflow() {
-    //     let slot = from([0xfe; 32]);
-    //     let _ = dynamic_array_with_precalculated_slot(slot, 2, MAX_FIELD_VALUE);
-    // }
+    #[test(should_fail_with = "Attempt to add with overflow")]
+    fn fail_overflow() {
+        let slot = from([0xfe; 32]);
+        let _ = dynamic_array_with_precalculated_slot(slot, 2, MAX_FIELD_VALUE);
+    }
 }
 
 mod struct_slot {
@@ -142,9 +142,9 @@ mod struct_slot {
         assert_eq(expected_slot, struct_slot(slot, 256));
     }
 
-    // #[test(should_fail_with = "Attempt to add with overflow")]
-    // fn overflow() {
-    //     let slot = from([0xff; 32]);
-    //     let _ = struct_slot(slot, 256);
-    // }
+    #[test(should_fail_with = "Attempt to add with overflow")]
+    fn overflow() {
+        let slot = from([0xff; 32]);
+        let _ = struct_slot(slot, 256);
+    }
 }