use some compound assignments

src/Polly/Caching/AsyncCacheSyntax.cs

@@ -68,7 +68,7 @@ public static AsyncCachePolicy CacheAsync(IAsyncCacheProvider cacheProvider, ITt
         if (ttlStrategy == null) throw new ArgumentNullException(nameof(ttlStrategy));
         if (cacheKeyStrategy == null) throw new ArgumentNullException(nameof(cacheKeyStrategy));
 
-        onCacheError = onCacheError ?? ((_, _, _) => { });
+        onCacheError ??= (_, _, _) => { };
         Action<Context, string> emptyDelegate = (_, _) => { };
 
         return new AsyncCachePolicy(cacheProvider, ttlStrategy, cacheKeyStrategy.GetCacheKey, emptyDelegate, emptyDelegate, emptyDelegate, onCacheError, onCacheError);
@@ -110,7 +110,7 @@ public static AsyncCachePolicy CacheAsync(IAsyncCacheProvider cacheProvider, ITt
         if (ttlStrategy == null) throw new ArgumentNullException(nameof(ttlStrategy));
         if (cacheKeyStrategy == null) throw new ArgumentNullException(nameof(cacheKeyStrategy));
 
-        onCacheError = onCacheError ?? ((_, _, _) => { });
+        onCacheError ??= (_, _, _) => { };
         Action<Context, string> emptyDelegate = (_, _) => { };
 
         return new AsyncCachePolicy(cacheProvider, ttlStrategy, cacheKeyStrategy, emptyDelegate, emptyDelegate, emptyDelegate, onCacheError, onCacheError);

src/Polly/Caching/AsyncCacheTResultSyntax.cs

@@ -417,7 +417,7 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(IAsyncCacheProvider<
     /// <exception cref="ArgumentNullException">cacheKeyStrategy</exception>
     public static AsyncCachePolicy<TResult> CacheAsync<TResult>(IAsyncCacheProvider<TResult> cacheProvider, ITtlStrategy ttlStrategy, ICacheKeyStrategy cacheKeyStrategy, Action<Context, string, Exception>? onCacheError = null)
     {
-        onCacheError = onCacheError ?? ((_, _, _) => { });
+        onCacheError ??= (_, _, _) => { };
 
         Action<Context, string> emptyDelegate = (_, _) => { };
 
@@ -440,7 +440,7 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(IAsyncCacheProvider<
     /// <exception cref="ArgumentNullException">cacheKeyStrategy</exception>
     public static AsyncCachePolicy<TResult> CacheAsync<TResult>(IAsyncCacheProvider<TResult> cacheProvider, ITtlStrategy<TResult> ttlStrategy, ICacheKeyStrategy cacheKeyStrategy, Action<Context, string, Exception>? onCacheError = null)
     {
-        onCacheError = onCacheError ?? ((_, _, _) => { });
+        onCacheError ??= (_, _, _) => { };
 
         Action<Context, string> emptyDelegate = (_, _) => { };
 
@@ -479,7 +479,7 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(IAsyncCacheProvider<
     /// <exception cref="ArgumentNullException">cacheKeyStrategy</exception>
     public static AsyncCachePolicy<TResult> CacheAsync<TResult>(IAsyncCacheProvider<TResult> cacheProvider, ITtlStrategy ttlStrategy, Func<Context, string> cacheKeyStrategy, Action<Context, string, Exception>? onCacheError = null)
     {
-        onCacheError = onCacheError ?? ((_, _, _) => { });
+        onCacheError ??= (_, _, _) => { };
 
         Action<Context, string> emptyDelegate = (_, _) => { };
 
@@ -502,7 +502,7 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(IAsyncCacheProvider<
     /// <exception cref="ArgumentNullException">cacheKeyStrategy</exception>
     public static AsyncCachePolicy<TResult> CacheAsync<TResult>(IAsyncCacheProvider<TResult> cacheProvider, ITtlStrategy<TResult> ttlStrategy, Func<Context, string> cacheKeyStrategy, Action<Context, string, Exception>? onCacheError = null)
     {
-        onCacheError = onCacheError ?? ((_, _, _) => { });
+        onCacheError ??= (_, _, _) => { };
 
         Action<Context, string> emptyDelegate = (_, _) => { };
 

src/Polly/Caching/CacheSyntax.cs

@@ -68,7 +68,7 @@ public static CachePolicy Cache(ISyncCacheProvider cacheProvider, ITtlStrategy t
         if (ttlStrategy == null) throw new ArgumentNullException(nameof(ttlStrategy));
         if (cacheKeyStrategy == null) throw new ArgumentNullException(nameof(cacheKeyStrategy));
 
-        onCacheError = onCacheError ?? ((_, _, _) => { });
+        onCacheError ??= (_, _, _) => { };
         Action<Context, string> emptyDelegate = (_, _) => { };
 
         return Cache(cacheProvider, ttlStrategy, cacheKeyStrategy.GetCacheKey, emptyDelegate, emptyDelegate, emptyDelegate, onCacheError, onCacheError);
@@ -110,7 +110,7 @@ public static CachePolicy Cache(ISyncCacheProvider cacheProvider, ITtlStrategy t
         if (ttlStrategy == null) throw new ArgumentNullException(nameof(ttlStrategy));
         if (cacheKeyStrategy == null) throw new ArgumentNullException(nameof(cacheKeyStrategy));
 
-        onCacheError = onCacheError ?? ((_, _, _) => { });
+        onCacheError ??= (_, _, _) => { };
         Action<Context, string> emptyDelegate = (_, _) => { };
 
         return Cache(cacheProvider, ttlStrategy, cacheKeyStrategy, emptyDelegate, emptyDelegate, emptyDelegate, onCacheError, onCacheError);

src/Polly/Caching/CacheTResultSyntax.cs

@@ -417,7 +417,7 @@ public static CachePolicy<TResult> Cache<TResult>(ISyncCacheProvider<TResult> ca
     /// <exception cref="ArgumentNullException">cacheKeyStrategy</exception>
     public static CachePolicy<TResult> Cache<TResult>(ISyncCacheProvider<TResult> cacheProvider, ITtlStrategy ttlStrategy, ICacheKeyStrategy cacheKeyStrategy, Action<Context, string, Exception>? onCacheError = null)
     {
-        onCacheError = onCacheError ?? ((_, _, _) => { });
+        onCacheError ??= (_, _, _) => { };
 
         Action<Context, string> emptyDelegate = (_, _) => { };
 
@@ -441,7 +441,7 @@ public static CachePolicy<TResult> Cache<TResult>(ISyncCacheProvider<TResult> ca
     /// <exception cref="ArgumentNullException">cacheKeyStrategy</exception>
     public static CachePolicy<TResult> Cache<TResult>(ISyncCacheProvider<TResult> cacheProvider, ITtlStrategy<TResult> ttlStrategy, ICacheKeyStrategy cacheKeyStrategy, Action<Context, string, Exception>? onCacheError = null)
     {
-        onCacheError = onCacheError ?? ((_, _, _) => { });
+        onCacheError ??= (_, _, _) => { };
 
         Action<Context, string> emptyDelegate = (_, _) => { };
 
@@ -481,7 +481,7 @@ public static CachePolicy<TResult> Cache<TResult>(ISyncCacheProvider<TResult> ca
     /// <exception cref="ArgumentNullException">cacheKeyStrategy</exception>
     public static CachePolicy<TResult> Cache<TResult>(ISyncCacheProvider<TResult> cacheProvider, ITtlStrategy ttlStrategy, Func<Context, string> cacheKeyStrategy, Action<Context, string, Exception>? onCacheError = null)
     {
-        onCacheError = onCacheError ?? ((_, _, _) => { });
+        onCacheError ??= (_, _, _) => { };
 
         Action<Context, string> emptyDelegate = (_, _) => { };
 
@@ -505,7 +505,7 @@ public static CachePolicy<TResult> Cache<TResult>(ISyncCacheProvider<TResult> ca
     /// <exception cref="ArgumentNullException">cacheKeyStrategy</exception>
     public static CachePolicy<TResult> Cache<TResult>(ISyncCacheProvider<TResult> cacheProvider, ITtlStrategy<TResult> ttlStrategy, Func<Context, string> cacheKeyStrategy, Action<Context, string, Exception>? onCacheError = null)
     {
-        onCacheError = onCacheError ?? ((_, _, _) => { });
+        onCacheError ??= (_, _, _) => { };
 
         Action<Context, string> emptyDelegate = (_, _) => { };
 

src/Polly/CircuitBreaker/AdvancedCircuitController.cs

@@ -82,7 +82,7 @@ public override void OnActionFailure(DelegateResult<TResult> outcome, Context co
                     var healthCount = _metrics.GetHealthCount_NeedsLock();
 
                     int throughput = healthCount.Total;
-                    if (throughput >= _minimumThroughput && ((double)healthCount.Failures) / throughput >= _failureThreshold)
+                    if (throughput >= _minimumThroughput && (double)healthCount.Failures / throughput >= _failureThreshold)
                     {
                         Break_NeedsLock(context);
                     }

src/Polly/CircuitBreaker/RollingHealthMetrics.cs

@@ -65,7 +65,7 @@ private void ActualiseCurrentMetric_NeedsLock()
             _windows.Enqueue(_currentWindow);
         }
 
-        while (_windows.Count > 0 && (now - _windows.Peek().StartedAt >= _samplingDuration))
+        while (_windows.Count > 0 && now - _windows.Peek().StartedAt >= _samplingDuration)
             _windows.Dequeue();
     }
 }

src/Polly/ExceptionPredicates.cs

@@ -9,7 +9,7 @@ public class ExceptionPredicates
 
     internal void Add(ExceptionPredicate predicate)
     {
-        _predicates = _predicates ?? new List<ExceptionPredicate>(); // The ?? pattern here is sufficient; only a deliberately contrived example would lead to the same PolicyBuilder instance being used in a multi-threaded way to define policies simultaneously on multiple threads.
+        _predicates ??= new List<ExceptionPredicate>(); // The ?? pattern here is sufficient; only a deliberately contrived example would lead to the same PolicyBuilder instance being used in a multi-threaded way to define policies simultaneously on multiple threads.
 
         _predicates.Add(predicate);
     }

src/Polly/PolicyBuilder.OrSyntax.cs

@@ -34,7 +34,7 @@ public PolicyBuilder Or<TException>(Func<TException, bool> exceptionPredicate) w
     /// <returns>The PolicyBuilder instance, for fluent chaining.</returns>
     public PolicyBuilder OrInner<TException>() where TException : Exception
     {
-        ExceptionPredicates.Add((HandleInner(ex => ex is TException)));
+        ExceptionPredicates.Add(HandleInner(ex => ex is TException));
         return this;
     }
 
@@ -160,7 +160,7 @@ public PolicyBuilder<TResult> Or<TException>(Func<TException, bool> exceptionPre
     /// <returns>The PolicyBuilder instance, for fluent chaining.</returns>
     public PolicyBuilder<TResult> OrInner<TException>() where TException : Exception
     {
-        ExceptionPredicates.Add((PolicyBuilder.HandleInner(ex => ex is TException)));
+        ExceptionPredicates.Add(PolicyBuilder.HandleInner(ex => ex is TException));
         return this;
     }
 

src/Polly/RateLimit/LockFreeTokenBucketRateLimiter.cs

@@ -69,13 +69,13 @@ public LockFreeTokenBucketRateLimiter(TimeSpan onePer, long bucketCapacity)
                 // Passing addNextTokenAtTicks merits one token
                 1 +
                 // And any whole token tick intervals further each merit another.
-                (-ticksTillAddNextToken / addTokenTickInterval);
+                -ticksTillAddNextToken / addTokenTickInterval;
 
             // We mustn't exceed bucket capacity though.
             long tokensToAdd = Math.Min(bucketCapacity, tokensMissedAdding);
 
             // Work out when tokens would next be due to be added, if we add these tokens.
-            long newAddNextTokenAtTicks = currentAddNextTokenAtTicks + (tokensToAdd * addTokenTickInterval);
+            long newAddNextTokenAtTicks = currentAddNextTokenAtTicks + tokensToAdd * addTokenTickInterval;
             // But if we were way overdue refilling the bucket (there was inactivity for a while), that value would be out-of-date: the next time we add tokens must be at least addTokenTickInterval from now.
             newAddNextTokenAtTicks = Math.Max(newAddNextTokenAtTicks, now + addTokenTickInterval);
 

src/Polly/ResultPredicates.cs

@@ -9,7 +9,7 @@ public class ResultPredicates<TResult>
 
     internal void Add(ResultPredicate<TResult> predicate)
     {
-        _predicates = _predicates ?? new List<ResultPredicate<TResult>>(); // The ?? pattern here is sufficient; only a deliberately contrived example would lead to the same PolicyBuilder instance being used in a multi-threaded way to define policies simultaneously on multiple threads.
+        _predicates ??= new List<ResultPredicate<TResult>>(); // The ?? pattern here is sufficient; only a deliberately contrived example would lead to the same PolicyBuilder instance being used in a multi-threaded way to define policies simultaneously on multiple threads.
 
         _predicates.Add(predicate);
     }