Use collection initializers

- Use C#12 collection initializers where relevant.
- Suppress false positives when using `TheoryData`.
- Remove some redundant code analysis suppressions.

src/Polly.Core/CircuitBreaker/CircuitBreakerManualControl.cs

@@ -9,8 +9,8 @@ namespace Polly.CircuitBreaker;
 public sealed class CircuitBreakerManualControl
 {
     private readonly object _lock = new();
-    private readonly HashSet<Func<ResilienceContext, Task>> _onIsolate = new();
-    private readonly HashSet<Func<ResilienceContext, Task>> _onReset = new();
+    private readonly HashSet<Func<ResilienceContext, Task>> _onIsolate = [];
+    private readonly HashSet<Func<ResilienceContext, Task>> _onReset = [];
     private bool _isolated;
 
     /// <summary>

src/Polly.Core/Hedging/Controller/HedgingExecutionContext.cs

@@ -10,8 +10,8 @@ internal sealed class HedgingExecutionContext<T> : IAsyncDisposable
 {
     public readonly record struct ExecutionInfo<TResult>(TaskExecution<T>? Execution, bool Loaded, Outcome<TResult>? Outcome);
 
-    private readonly List<TaskExecution<T>> _tasks = new();
-    private readonly List<TaskExecution<T>> _executingTasks = new();
+    private readonly List<TaskExecution<T>> _tasks = [];
+    private readonly List<TaskExecution<T>> _executingTasks = [];
     private readonly ObjectPool<TaskExecution<T>> _executionPool;
     private readonly TimeProvider _timeProvider;
     private readonly int _maxAttempts;

src/Polly.Core/PredicateBuilder.TResult.cs

@@ -6,7 +6,7 @@ namespace Polly;
 /// <typeparam name="TResult">The type of the result.</typeparam>
 public partial class PredicateBuilder<TResult>
 {
-    private readonly List<Predicate<Outcome<TResult>>> _predicates = new();
+    private readonly List<Predicate<Outcome<TResult>>> _predicates = [];
 
     /// <summary>
     /// Adds a predicate for handling exceptions of the specified type.

src/Polly.Core/Registry/ConfigureBuilderContext.cs

@@ -29,9 +29,9 @@ internal ConfigureBuilderContext(TKey strategyKey, string builderName, string? b
     /// </summary>
     internal string? BuilderInstanceName { get; }
 
-    internal List<CancellationToken> ReloadTokens { get; } = new();
+    internal List<CancellationToken> ReloadTokens { get; } = [];
 
-    internal List<Action> DisposeCallbacks { get; } = new();
+    internal List<Action> DisposeCallbacks { get; } = [];
 
     /// <summary>
     /// Reloads the pipeline when <paramref name="cancellationToken"/> is canceled.

src/Polly.Core/ResiliencePipelineBuilderBase.cs

@@ -1,5 +1,4 @@
 using System.ComponentModel;
-
 using System.ComponentModel.DataAnnotations;
 using System.Diagnostics.CodeAnalysis;
 using Polly.Telemetry;
@@ -19,7 +18,7 @@ namespace Polly;
 public abstract class ResiliencePipelineBuilderBase
 #pragma warning restore S1694 // An abstract class should have both abstract and concrete methods
 {
-    private readonly List<Entry> _entries = new();
+    private readonly List<Entry> _entries = [];
     private bool _used;
 
     private protected ResiliencePipelineBuilderBase()

src/Polly.Core/Utils/Pipeline/ReloadableComponent.cs

@@ -52,7 +52,7 @@ private void TryRegisterOnReload()
             return;
         }
 
-        _tokenSource = CancellationTokenSource.CreateLinkedTokenSource(_reloadTokens.ToArray());
+        _tokenSource = CancellationTokenSource.CreateLinkedTokenSource([.. _reloadTokens]);
         _registration = _tokenSource.Token.Register(() =>
         {
             var context = ResilienceContextPool.Shared.Get().Initialize<VoidResult>(isSynchronous: true);
@@ -65,7 +65,7 @@ private void TryRegisterOnReload()
             }
             catch (Exception e)
             {
-                _reloadTokens = new List<CancellationToken>();
+                _reloadTokens = [];
                 _telemetry.Report(new(ResilienceEventSeverity.Error, ReloadFailedEvent), context, Outcome.FromException(e), new ReloadFailedArguments(e));
                 ResilienceContextPool.Shared.Return(context);
             }

src/Polly.Extensions/DependencyInjection/ConfigureResiliencePipelineRegistryOptions.cs

@@ -5,5 +5,5 @@ namespace Polly.DependencyInjection;
 internal sealed class ConfigureResiliencePipelineRegistryOptions<TKey>
     where TKey : notnull
 {
-    public List<Action<ResiliencePipelineRegistry<TKey>>> Actions { get; } = new();
+    public List<Action<ResiliencePipelineRegistry<TKey>>> Actions { get; } = [];
 }

src/Polly/AsyncPolicy.ExecuteOverloads.cs

@@ -10,7 +10,7 @@ public abstract partial class AsyncPolicy : PolicyBase, IAsyncPolicy
     /// <param name="action">The action to perform.</param>
     [DebuggerStepThrough]
     public Task ExecuteAsync(Func<Task> action) =>
-        ExecuteAsync((_, _) => action(), new Context(), DefaultCancellationToken, DefaultContinueOnCapturedContext);
+        ExecuteAsync((_, _) => action(), [], DefaultCancellationToken, DefaultContinueOnCapturedContext);
 
     /// <summary>
     ///     Executes the specified asynchronous action within the policy.
@@ -37,7 +37,7 @@ public Task ExecuteAsync(Func<Context, Task> action, Context context) =>
     /// <param name="cancellationToken">A cancellation token which can be used to cancel the action.  When a retry policy in use, also cancels any further retries.</param>
     [DebuggerStepThrough]
     public Task ExecuteAsync(Func<CancellationToken, Task> action, CancellationToken cancellationToken) =>
-        ExecuteAsync((_, ct) => action(ct), new Context(), cancellationToken, DefaultContinueOnCapturedContext);
+        ExecuteAsync((_, ct) => action(ct), [], cancellationToken, DefaultContinueOnCapturedContext);
 
     /// <summary>
     ///     Executes the specified asynchronous action within the policy.
@@ -68,7 +68,7 @@ public Task ExecuteAsync(Func<Context, CancellationToken, Task> action, Context
     /// <exception cref="InvalidOperationException">Please use asynchronous-defined policies when calling asynchronous ExecuteAsync (and similar) methods.</exception>
     [DebuggerStepThrough]
     public Task ExecuteAsync(Func<CancellationToken, Task> action, CancellationToken cancellationToken, bool continueOnCapturedContext) =>
-        ExecuteAsync((_, ct) => action(ct), new Context(), cancellationToken, continueOnCapturedContext);
+        ExecuteAsync((_, ct) => action(ct), [], cancellationToken, continueOnCapturedContext);
 
     /// <summary>
     ///     Executes the specified asynchronous action within the policy.
@@ -117,7 +117,7 @@ public async Task ExecuteAsync(Func<Context, CancellationToken, Task> action, Co
     /// <returns>The value returned by the action</returns>
     [DebuggerStepThrough]
     public Task<TResult> ExecuteAsync<TResult>(Func<Task<TResult>> action) =>
-        ExecuteAsync((_, _) => action(), new Context(), DefaultCancellationToken, DefaultContinueOnCapturedContext);
+        ExecuteAsync((_, _) => action(), [], DefaultCancellationToken, DefaultContinueOnCapturedContext);
 
     /// <summary>
     ///     Executes the specified asynchronous action within the policy and returns the result.
@@ -149,7 +149,7 @@ public Task<TResult> ExecuteAsync<TResult>(Func<Context, Task<TResult>> action,
     /// <returns>The value returned by the action</returns>
     [DebuggerStepThrough]
     public Task<TResult> ExecuteAsync<TResult>(Func<CancellationToken, Task<TResult>> action, CancellationToken cancellationToken) =>
-        ExecuteAsync((_, ct) => action(ct), new Context(), cancellationToken, DefaultContinueOnCapturedContext);
+        ExecuteAsync((_, ct) => action(ct), [], cancellationToken, DefaultContinueOnCapturedContext);
 
     /// <summary>
     ///     Executes the specified asynchronous action within the policy and returns the result.
@@ -185,7 +185,7 @@ public Task<TResult> ExecuteAsync<TResult>(Func<Context, CancellationToken, Task
     /// <exception cref="InvalidOperationException">Please use asynchronous-defined policies when calling asynchronous ExecuteAsync (and similar) methods.</exception>
     [DebuggerStepThrough]
     public Task<TResult> ExecuteAsync<TResult>(Func<CancellationToken, Task<TResult>> action, CancellationToken cancellationToken, bool continueOnCapturedContext) =>
-        ExecuteAsync((_, ct) => action(ct), new Context(), cancellationToken, continueOnCapturedContext);
+        ExecuteAsync((_, ct) => action(ct), [], cancellationToken, continueOnCapturedContext);
 
     /// <summary>
     ///     Executes the specified asynchronous action within the policy and returns the result.
@@ -240,7 +240,7 @@ public async Task<TResult> ExecuteAsync<TResult>(Func<Context, CancellationToken
     /// <returns>The captured result</returns>
     [DebuggerStepThrough]
     public Task<PolicyResult> ExecuteAndCaptureAsync(Func<Task> action) =>
-        ExecuteAndCaptureAsync((_, _) => action(), new Context(), DefaultCancellationToken, DefaultContinueOnCapturedContext);
+        ExecuteAndCaptureAsync((_, _) => action(), [], DefaultCancellationToken, DefaultContinueOnCapturedContext);
 
     /// <summary>
     ///     Executes the specified asynchronous action within the policy and returns the captured result.
@@ -270,7 +270,7 @@ public Task<PolicyResult> ExecuteAndCaptureAsync(Func<Context, Task> action, Con
     /// <param name="cancellationToken">A cancellation token which can be used to cancel the action.  When a retry policy in use, also cancels any further retries.</param>
     [DebuggerStepThrough]
     public Task<PolicyResult> ExecuteAndCaptureAsync(Func<CancellationToken, Task> action, CancellationToken cancellationToken) =>
-        ExecuteAndCaptureAsync((_, ct) => action(ct), new Context(), cancellationToken, DefaultContinueOnCapturedContext);
+        ExecuteAndCaptureAsync((_, ct) => action(ct), [], cancellationToken, DefaultContinueOnCapturedContext);
 
     /// <summary>
     ///     Executes the specified asynchronous action within the policy and returns the captured result.
@@ -303,7 +303,7 @@ public Task<PolicyResult> ExecuteAndCaptureAsync(Func<Context, CancellationToken
     /// <exception cref="InvalidOperationException">Please use asynchronous-defined policies when calling asynchronous ExecuteAsync (and similar) methods.</exception>
     [DebuggerStepThrough]
     public Task<PolicyResult> ExecuteAndCaptureAsync(Func<CancellationToken, Task> action, CancellationToken cancellationToken, bool continueOnCapturedContext) =>
-        ExecuteAndCaptureAsync((_, ct) => action(ct), new Context(), cancellationToken, continueOnCapturedContext);
+        ExecuteAndCaptureAsync((_, ct) => action(ct), [], cancellationToken, continueOnCapturedContext);
 
     /// <summary>
     ///     Executes the specified asynchronous action within the policy and returns the captured result.
@@ -352,7 +352,7 @@ public async Task<PolicyResult> ExecuteAndCaptureAsync(Func<Context, Cancellatio
     /// <returns>The captured result</returns>
     [DebuggerStepThrough]
     public Task<PolicyResult<TResult>> ExecuteAndCaptureAsync<TResult>(Func<Task<TResult>> action) =>
-        ExecuteAndCaptureAsync((_, _) => action(), new Context(), DefaultCancellationToken, DefaultContinueOnCapturedContext);
+        ExecuteAndCaptureAsync((_, _) => action(), [], DefaultCancellationToken, DefaultContinueOnCapturedContext);
 
     /// <summary>
     /// Executes the specified asynchronous action within the policy and returns the result.
@@ -386,7 +386,7 @@ public Task<PolicyResult<TResult>> ExecuteAndCaptureAsync<TResult>(Func<Context,
     /// <returns>The captured result</returns>
     [DebuggerStepThrough]
     public Task<PolicyResult<TResult>> ExecuteAndCaptureAsync<TResult>(Func<CancellationToken, Task<TResult>> action, CancellationToken cancellationToken) =>
-        ExecuteAndCaptureAsync((_, ct) => action(ct), new Context(), cancellationToken, DefaultContinueOnCapturedContext);
+        ExecuteAndCaptureAsync((_, ct) => action(ct), [], cancellationToken, DefaultContinueOnCapturedContext);
 
     /// <summary>
     ///     Executes the specified asynchronous action within the policy and returns the result.
@@ -424,7 +424,7 @@ public Task<PolicyResult<TResult>> ExecuteAndCaptureAsync<TResult>(Func<Context,
     /// <exception cref="InvalidOperationException">Please use asynchronous-defined policies when calling asynchronous ExecuteAsync (and similar) methods.</exception>
     [DebuggerStepThrough]
     public Task<PolicyResult<TResult>> ExecuteAndCaptureAsync<TResult>(Func<CancellationToken, Task<TResult>> action, CancellationToken cancellationToken, bool continueOnCapturedContext) =>
-        ExecuteAndCaptureAsync((_, ct) => action(ct), new Context(), cancellationToken, continueOnCapturedContext);
+        ExecuteAndCaptureAsync((_, ct) => action(ct), [], cancellationToken, continueOnCapturedContext);
 
     /// <summary>
     ///     Executes the specified asynchronous action within the policy and returns the result.

src/Polly/AsyncPolicy.TResult.ExecuteOverloads.cs

@@ -11,7 +11,7 @@ public abstract partial class AsyncPolicy<TResult> : IAsyncPolicy<TResult>
     /// <returns>The value returned by the action</returns>
     [DebuggerStepThrough]
     public Task<TResult> ExecuteAsync(Func<Task<TResult>> action) =>
-        ExecuteAsync((_, _) => action(), new Context(), CancellationToken.None, DefaultContinueOnCapturedContext);
+        ExecuteAsync((_, _) => action(), [], CancellationToken.None, DefaultContinueOnCapturedContext);
 
     /// <summary>
     ///     Executes the specified asynchronous action within the policy and returns the result.
@@ -41,7 +41,7 @@ public Task<TResult> ExecuteAsync(Func<Context, Task<TResult>> action, Context c
     /// <returns>The value returned by the action</returns>
     [DebuggerStepThrough]
     public Task<TResult> ExecuteAsync(Func<CancellationToken, Task<TResult>> action, CancellationToken cancellationToken) =>
-        ExecuteAsync((_, ct) => action(ct), new Context(), cancellationToken, DefaultContinueOnCapturedContext);
+        ExecuteAsync((_, ct) => action(ct), [], cancellationToken, DefaultContinueOnCapturedContext);
 
     /// <summary>
     ///     Executes the specified asynchronous action within the policy and returns the result.
@@ -53,7 +53,7 @@ public Task<TResult> ExecuteAsync(Func<CancellationToken, Task<TResult>> action,
     /// <exception cref="InvalidOperationException">Please use asynchronous-defined policies when calling asynchronous ExecuteAsync (and similar) methods.</exception>
     [DebuggerStepThrough]
     public Task<TResult> ExecuteAsync(Func<CancellationToken, Task<TResult>> action, CancellationToken cancellationToken, bool continueOnCapturedContext) =>
-        ExecuteAsync((_, ct) => action(ct), new Context(), cancellationToken, continueOnCapturedContext);
+        ExecuteAsync((_, ct) => action(ct), [], cancellationToken, continueOnCapturedContext);
 
     /// <summary>
     ///     Executes the specified asynchronous action within the policy and returns the result.
@@ -127,7 +127,7 @@ public async Task<TResult> ExecuteAsync(Func<Context, CancellationToken, Task<TR
     /// <returns>The captured result</returns>
     [DebuggerStepThrough]
     public Task<PolicyResult<TResult>> ExecuteAndCaptureAsync(Func<Task<TResult>> action) =>
-        ExecuteAndCaptureAsync((_, _) => action(), new Context(), CancellationToken.None, DefaultContinueOnCapturedContext);
+        ExecuteAndCaptureAsync((_, _) => action(), [], CancellationToken.None, DefaultContinueOnCapturedContext);
 
     /// <summary>
     /// Executes the specified asynchronous action within the policy and returns the result.
@@ -158,7 +158,7 @@ public Task<PolicyResult<TResult>> ExecuteAndCaptureAsync(Func<Context, Task<TRe
     /// <returns>The captured result</returns>
     [DebuggerStepThrough]
     public Task<PolicyResult<TResult>> ExecuteAndCaptureAsync(Func<CancellationToken, Task<TResult>> action, CancellationToken cancellationToken) =>
-        ExecuteAndCaptureAsync((_, ct) => action(ct), new Context(), cancellationToken, DefaultContinueOnCapturedContext);
+        ExecuteAndCaptureAsync((_, ct) => action(ct), [], cancellationToken, DefaultContinueOnCapturedContext);
 
     /// <summary>
     ///     Executes the specified asynchronous action within the policy and returns the result.
@@ -170,7 +170,7 @@ public Task<PolicyResult<TResult>> ExecuteAndCaptureAsync(Func<CancellationToken
     /// <exception cref="InvalidOperationException">Please use asynchronous-defined policies when calling asynchronous ExecuteAsync (and similar) methods.</exception>
     [DebuggerStepThrough]
     public Task<PolicyResult<TResult>> ExecuteAndCaptureAsync(Func<CancellationToken, Task<TResult>> action, CancellationToken cancellationToken, bool continueOnCapturedContext) =>
-        ExecuteAndCaptureAsync((_, ct) => action(ct), new Context(), cancellationToken, continueOnCapturedContext);
+        ExecuteAndCaptureAsync((_, ct) => action(ct), [], cancellationToken, continueOnCapturedContext);
 
     /// <summary>
     ///     Executes the specified asynchronous action within the policy and returns the result.

src/Polly/Context.Dictionary.cs

@@ -11,7 +11,7 @@ public partial class Context : IDictionary<string, object>, IDictionary, IReadOn
 
     private Dictionary<string, object> wrappedDictionary;
 
-    private Dictionary<string, object> WrappedDictionary => wrappedDictionary ?? (wrappedDictionary = new Dictionary<string, object>());
+    private Dictionary<string, object> WrappedDictionary => wrappedDictionary ?? (wrappedDictionary = []);
 
     /// <summary>
     /// Initializes a new instance of the <see cref="Context"/> class, with the specified <paramref name="operationKey" /> and the supplied <paramref name="contextData"/>.

src/Polly/ExceptionPredicates.cs

@@ -9,7 +9,7 @@ public class ExceptionPredicates
 
     internal void Add(ExceptionPredicate predicate)
     {
-        _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 ??= []; // 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);
     }