feat: assert maximum bit size when creating a U128 from an integer

TomAFrench · TomAFrench · commit 7bae11985be1 · 2024-01-12T11:13:28.000Z
diff --git a/noir_stdlib/src/uint128.nr b/noir_stdlib/src/uint128.nr
@@ -116,6 +116,8 @@ impl U128 {
 
     pub fn from_integer<T>(i: T) -> U128 {
         let f = crate::as_field(i);
+        // Reject values which would overflow a u128
+        f.assert_max_bit_size(128);
         let lo = f as u64 as Field;
         let hi = (f-lo) / pow64;
         U128 {
@@ -289,4 +291,4 @@ impl Shr for U128 {
         }
         self / U128::from_integer(y)
     } 
-}
+}

Original file line number	Diff line number	Diff line change
`@@ -116,6 +116,8 @@ impl U128 {`
`116`	`116`
`117`	`117`	`pub fn from_integer<T>(i: T) -> U128 {`
`118`	`118`	`let f = crate::as_field(i);`
	`119`	`+ // Reject values which would overflow a u128`
	`120`	`+ f.assert_max_bit_size(128);`
`119`	`121`	`let lo = f as u64 as Field;`
`120`	`122`	`let hi = (f-lo) / pow64;`
`121`	`123`	`U128 {`
`@@ -289,4 +291,4 @@ impl Shr for U128 {`
`289`	`291`	`}`
`290`	`292`	`self / U128::from_integer(y)`
`291`	`293`	`}`
`292`		`-}`
	`294`	`+}`