Minor fix of compile error, fixes of clippy lints and trait bounds

Author: nu11ptr

src/convert.rs

@@ -353,7 +353,7 @@ impl<K, T> ResultContext<K, T> for Option<T> {
     }
 }
 
-impl<K: UniKind, K2: UniKind, T> ResultContext<K2, T> for UniResult<T, K> {
+impl<K: UniKind, K2, T> ResultContext<K2, T> for UniResult<T, K> {
     fn kind(self, kind: K2) -> UniResult<T, K2> {
         self.map_err(|err| err.kind(kind))
     }
@@ -402,7 +402,7 @@ impl<K: UniKind, K2: UniKind, T> ResultContext<K2, T> for UniResult<T, K> {
     }
 }
 
-impl<K2: UniKind, T> ResultContext<K2, T> for UniResult<T, dyn UniKind> {
+impl<K2, T> ResultContext<K2, T> for UniResult<T, dyn UniKind> {
     fn kind(self, kind: K2) -> UniResult<T, K2> {
         self.map_err(|err| err.kind(kind))
     }
@@ -450,7 +450,7 @@ impl<K2: UniKind, T> ResultContext<K2, T> for UniResult<T, dyn UniKind> {
     }
 }
 
-impl<C: 'static, K2: UniKind, T> ResultContext<K2, T> for UniResult<T, dyn UniKindCode<Code = C>> {
+impl<C: 'static, K2, T> ResultContext<K2, T> for UniResult<T, dyn UniKindCode<Code = C>> {
     fn kind(self, kind: K2) -> UniResult<T, K2> {
         self.map_err(|err| err.kind(kind))
     }
@@ -498,7 +498,7 @@ impl<C: 'static, K2: UniKind, T> ResultContext<K2, T> for UniResult<T, dyn UniKi
     }
 }
 
-impl<C: 'static, C2: 'static, K2: UniKind, T> ResultContext<K2, T>
+impl<C: 'static, C2: 'static, K2, T> ResultContext<K2, T>
     for UniResult<T, dyn UniKindCodes<Code = C, Code2 = C2>>
 {
     fn kind(self, kind: K2) -> UniResult<T, K2> {

src/error.rs

@@ -413,7 +413,7 @@ impl<C: 'static> UniError<dyn UniKindCode<Code = C>> {
     }
 
     /// Wraps the existing error with no additional context and a default kind.
-    pub fn kind_default<K2: UniKind>(self) -> UniError<K2>
+    pub fn kind_default<K2>(self) -> UniError<K2>
     where
         K2: Default,
     {

src/inner.rs

@@ -246,7 +246,7 @@ impl<K: UniKind + ?Sized> Display for UniErrorInner<K> {
 
         // *** Cause ***
         if let Some(cause) = &self.prev_cause() {
-            let cause = cause.to_string();
+            let cause = <Cause as alloc::string::ToString>::to_string(cause);
 
             if !cause.is_empty() {
                 if context_written || kind_context_written {