diff --git a/pbjson-build/src/generator/message.rs b/pbjson-build/src/generator/message.rs
index 22e0f7d..467f095 100644
--- a/pbjson-build/src/generator/message.rs
+++ b/pbjson-build/src/generator/message.rs
@@ -89,7 +89,7 @@ fn write_field_empty_predicate<W: Write>(
         | (FieldType::Scalar(ScalarType::Bytes), FieldModifier::UseDefault) => {
             write!(writer, "!self.{}.is_empty()", member.rust_field_name())
         }
-        (_, FieldModifier::Optional) | (FieldType::Message(_), _) => {
+        (_, FieldModifier::Optional) | (FieldType::Message, _) => {
             write!(writer, "self.{}.is_some()", member.rust_field_name())
         }
         (FieldType::Scalar(ScalarType::F64), FieldModifier::UseDefault)
@@ -877,7 +877,7 @@ fn write_deserialize_field<W: Write>(
                     field.rust_type_name()
                 )?;
             }
-            FieldType::Message(_) => writeln!(
+            FieldType::Message => writeln!(
                 writer,
                 "map_.next_value::<::std::option::Option<_>>()?.map({}::{})",
                 resolver.rust_type(&one_of.path),
@@ -983,7 +983,7 @@ fn write_deserialize_field<W: Write>(
                 }
                 write!(writer, "{})", Indent(indent + 1))?;
             }
-            FieldType::Message(_) => match field.field_modifier {
+            FieldType::Message => match field.field_modifier {
                 FieldModifier::Repeated => {
                     // No explicit presence for repeated fields
                     write!(writer, "Some(map_.next_value()?)")?;
diff --git a/pbjson-build/src/lib.rs b/pbjson-build/src/lib.rs
index 912bbee..ce91cbd 100644
--- a/pbjson-build/src/lib.rs
+++ b/pbjson-build/src/lib.rs
@@ -80,7 +80,7 @@
 )]
 
 use prost_types::FileDescriptorProto;
-use std::io::{BufWriter, Error, ErrorKind, Result, Write};
+use std::io::{BufWriter, Error, Result, Write};
 use std::path::PathBuf;
 
 use crate::descriptor::{Descriptor, Package};
@@ -205,9 +205,7 @@ impl Builder {
     pub fn build<S: AsRef<str>>(&mut self, prefixes: &[S]) -> Result<()> {
         let mut output: PathBuf = self.out_dir.clone().map(Ok).unwrap_or_else(|| {
             std::env::var_os("OUT_DIR")
-                .ok_or_else(|| {
-                    Error::new(ErrorKind::Other, "OUT_DIR environment variable is not set")
-                })
+                .ok_or_else(|| Error::other("OUT_DIR environment variable is not set"))
                 .map(Into::into)
         })?;
         output.push("FILENAME");
diff --git a/pbjson-build/src/message.rs b/pbjson-build/src/message.rs
index 6f0e47a..d21406a 100644
--- a/pbjson-build/src/message.rs
+++ b/pbjson-build/src/message.rs
@@ -52,7 +52,7 @@ impl ScalarType {
 pub enum FieldType {
     Scalar(ScalarType),
     Enum(TypePath),
-    Message(TypePath),
+    Message,
     Map(ScalarType, Box<FieldType>),
 }
 
@@ -203,7 +203,7 @@ fn field_modifier(
         Label::Optional => match message.syntax {
             Syntax::Proto2 => FieldModifier::Optional,
             Syntax::Proto3 => match field_type {
-                FieldType::Message(_) => FieldModifier::Optional,
+                FieldType::Message => FieldModifier::Optional,
                 _ => FieldModifier::UseDefault,
             },
         },
@@ -245,7 +245,7 @@ fn resolve_type(descriptors: &DescriptorSet, type_name: &str) -> FieldType {
 
     match maybe_descriptor {
         Some((path, Descriptor::Enum(_))) => FieldType::Enum(path.clone()),
-        Some((path, Descriptor::Message(descriptor))) => match descriptor.is_map() {
+        Some((_path, Descriptor::Message(descriptor))) => match descriptor.is_map() {
             true => {
                 assert_eq!(descriptor.fields.len(), 2, "expected map to have 2 fields");
                 let key = &descriptor.fields[0];
@@ -263,7 +263,7 @@ fn resolve_type(descriptors: &DescriptorSet, type_name: &str) -> FieldType {
             }
             // Note: This may actually be a group but it is non-trivial to detect this,
             // they're deprecated, and pbjson doesn't need to be able to distinguish
-            false => FieldType::Message(path.clone()),
+            false => FieldType::Message,
         },
         None => panic!("failed to resolve type: {}", type_name),
     }
diff --git a/pbjson-types/descriptors.bin b/pbjson-types/descriptors.bin
index c3b3ed2..1b0a47b 100644
Binary files a/pbjson-types/descriptors.bin and b/pbjson-types/descriptors.bin differ
diff --git a/pbjson/src/lib.rs b/pbjson/src/lib.rs
index ea7828b..90de687 100644
--- a/pbjson/src/lib.rs
+++ b/pbjson/src/lib.rs
@@ -124,9 +124,11 @@ pub mod private {
         #[test]
         fn test_bytes() {
             for _ in 0..20 {
-                let mut rng = thread_rng();
-                let len = rng.gen_range(50..100);
-                let raw: Vec<_> = std::iter::from_fn(|| Some(rng.gen())).take(len).collect();
+                let mut rng = rand::rng();
+                let len = rng.random_range(50..100);
+                let raw: Vec<_> = std::iter::from_fn(|| Some(rng.random()))
+                    .take(len)
+                    .collect();
 
                 for config in [
                     base64::engine::general_purpose::STANDARD,
diff --git a/rust-toolchain.toml b/rust-toolchain.toml
index ba3f7e4..ff79a41 100644
--- a/rust-toolchain.toml
+++ b/rust-toolchain.toml
@@ -1,3 +1,3 @@
 [toolchain]
-channel = "1.74"
+channel = "1.91"
 components = ["rustfmt", "clippy"]