some changes to get unit tests to pass

Cargo.toml

@@ -10,7 +10,7 @@ edition = "2021"
 anyhow = { version = "1.0.40", default-features = false }
 itertools = { version = "0.10.0", default-features = false }
 num = { version = "0.4", default-features = false }
-plonky2 = { git = "https://github.com/mir-protocol/plonky2.git", default-features = false }
+plonky2 = { git = "https://github.com/mir-protocol/plonky2.git" }
 
 [dev-dependencies]
 plonky2 = { git = "https://github.com/mir-protocol/plonky2.git", default-features = false, features = ["gate_testing"] }

src/gates/add_many_u32.rs

@@ -92,7 +92,7 @@ impl, const D: usize> Gate for U32AddManyGate
     }
 
     fn serialize(&self, dst: &mut Vec<u8>) -> IoResult<()> {
-        dst.write_usize(self.num_addends);
+        dst.write_usize(self.num_addends)?;
         dst.write_usize(self.num_ops)
     }
 

src/serialization.rs

@@ -14,7 +14,6 @@ impl WriteU32 for Vec {
     }
 }
 
-#[cfg(feature = "std")]
 pub trait ReadU32 {
     fn read_target_u32(&mut self) -> IoResult<U32Target>;
 }