Remove explicit type parameter requirement

Author: emlautarom1

crates/charon/src/expbackoff/mod.rs

@@ -73,31 +73,31 @@ where
     }
 }
 
+type Result<T> = std::result::Result<T, InvalidBackoff>;
+
+/// Error indicating an invalid backoff configuration.
+#[derive(Debug, thiserror::Error)]
+#[error("Invalid backoff configuration: {0}")]
+pub struct InvalidBackoff(&'static str);
+
 /// Builder pattern to create an [`ExponentialBackoff`] instance.
-pub struct ExponentialBackoffBuilder<R> {
+pub struct ExponentialBackoffBuilder<R = HasherRng> {
     base_delay: time::Duration,
     multiplier: f64,
     jitter: f64,
     max_delay: time::Duration,
     rng: R,
 }
 
-type Result<T> = std::result::Result<T, InvalidBackoff>;
-
-/// Error indicating an invalid backoff configuration.
-#[derive(Debug, thiserror::Error)]
-#[error("Invalid backoff configuration: {0}")]
-pub struct InvalidBackoff(&'static str);
-
-impl<R> ExponentialBackoffBuilder<R> {
+impl ExponentialBackoffBuilder {
     /// Backoff configuration with the default values specified at https://github.com/grpc/grpc/blob/master/doc/connection-backoff.md.
     ///
     /// This should be useful for callers who want to configure backoff with
     /// non-default values only for a subset of the options.
     ///
     /// Copied from [google.golang.org/grpc@v1.48.0/backoff/backoff.go]
-    pub fn default() -> ExponentialBackoffBuilder<HasherRng> {
-        ExponentialBackoffBuilder {
+    pub fn default() -> Self {
+        Self {
             base_delay: time::Duration::from_secs(1),
             multiplier: 1.6,
             jitter: 0.2,
@@ -107,16 +107,18 @@ impl<R> ExponentialBackoffBuilder<R> {
     }
 
     /// Common configuration for fast backoff.
-    pub fn fast_config() -> ExponentialBackoffBuilder<HasherRng> {
-        ExponentialBackoffBuilder {
+    pub fn fast_config() -> Self {
+        Self {
             base_delay: time::Duration::from_millis(100),
             multiplier: 1.6,
             jitter: 0.2,
             max_delay: time::Duration::from_secs(5),
             rng: HasherRng::default(),
         }
     }
+}
 
+impl<R> ExponentialBackoffBuilder<R> {
     /// Set the amount of time to backoff after the first failure.
     pub fn with_base_delay(mut self, delay: time::Duration) -> Self {
         self.base_delay = delay;
@@ -189,7 +191,7 @@ impl<R> ExponentialBackoffBuilder<R> {
 mod tests {
     use crate::expbackoff::ExponentialBackoffBuilder;
     use core::time::Duration;
-    use tower::util::rng::{HasherRng, Rng};
+    use tower::util::rng::Rng;
 
     struct Const(f64);
 
@@ -204,15 +206,15 @@ mod tests {
     }
 
     struct TestCase {
-        config: ExponentialBackoffBuilder<HasherRng>,
+        config: ExponentialBackoffBuilder,
         rng: f64,
         backoffs: Vec<Duration>,
     }
 
     #[test]
     fn default_config() {
         assert_test_case(TestCase {
-            config: ExponentialBackoffBuilder::<HasherRng>::default(),
+            config: ExponentialBackoffBuilder::default(),
             rng: 0.5,
             backoffs: vec![
                 Duration::from_secs(1),
@@ -235,7 +237,7 @@ mod tests {
     #[test]
     fn default_config_max_jitter() {
         assert_test_case(TestCase {
-            config: ExponentialBackoffBuilder::<HasherRng>::default(),
+            config: ExponentialBackoffBuilder::default(),
             rng: 1.0,
             backoffs: vec![
                 Duration::from_secs(1),
@@ -258,7 +260,7 @@ mod tests {
     #[test]
     fn fast() {
         assert_test_case(TestCase {
-            config: ExponentialBackoffBuilder::<HasherRng>::fast_config(),
+            config: ExponentialBackoffBuilder::fast_config(),
             rng: 0.5,
             backoffs: vec![
                 Duration::from_millis(100),