Move to project-level usings

.github/copilot-instructions.md

@@ -89,6 +89,21 @@ src/
 │   └── Domain/                     # Test domain types using Bogus fakers
 ```
 
+## Usings and Namespaces
+
+**Do not add `using` directives to source files.** Every project has `ImplicitUsings` enabled and declares its namespaces as `<Using>` items: shared ones in `src/Directory.Build.props`, the rest in each csproj. If you need one that is not in scope, add it there rather than to the file.
+
+Four opt-in namespaces are the exception and **must** stay file-level:
+
+| Namespace | Why |
+|---|---|
+| `DynamicData.Alias` | Supplies `Select`, `Where` and `SelectMany` for changesets, so it changes what LINQ-looking code means. |
+| `DynamicData.PLinq` | Supplies `Filter`, `Transform` and `SubscribeMany` under the *same names* as the core operators, but parallel. |
+| `DynamicData.Aggregation` | Supplies `Count`, `Sum`, `Avg` and `Maximum`, which overlap Rx and LINQ names. |
+| `DynamicData.Experimental` | Unstable API. Opting in should be visible at the call site. |
+
+If globalising a namespace makes a name ambiguous, qualify the call site or add a global alias. Do not move the namespace back into the file. Already handled: `System.Reactive.Notification<T>` against `DynamicData.Internal.Notification<T>`, `Enumerable.ToHashSet` against `Kernel.EnumerableEx`, and `Person`, which the tests project aliases to the domain type so it wins over `Bogus.Person`.
+
 ## Operator Architecture Pattern
 
 Most operators follow the same two-part pattern:

src/Directory.Build.props

@@ -10,6 +10,7 @@
     <IsTestProject>$(MSBuildProjectName.Contains('Tests'))</IsTestProject>
     <IsBenchmarkProject>$(MSBuildProjectName.Contains('Benchmarks'))</IsBenchmarkProject>
     <DebugType>embedded</DebugType>
+    <ImplicitUsings>enable</ImplicitUsings>
     <Authors>Roland Pheasant</Authors>
     <Owners>Roland Pheasant</Owners>
     <Copyright>Copyright (c) Roland Pheasant 2011-$([System.DateTime]::Now.ToString(yyyy))</Copyright>
@@ -36,6 +37,19 @@
     <ContinuousIntegrationBuild>true</ContinuousIntegrationBuild>
   </PropertyGroup>
 
+  <!-- Namespaces used by every project. Project specific ones live in the csproj that needs them. -->
+  <ItemGroup>
+    <Using Include="DynamicData.Binding" />
+    <Using Include="DynamicData.Kernel" />
+    <Using Include="System.Collections.ObjectModel" />
+    <Using Include="System.ComponentModel" />
+    <Using Include="System.Reactive.Disposables" />
+    <Using Include="System.Reactive.Linq" />
+    <Using Include="System.Reactive.Subjects" />
+    <Using Include="System.Reflection" />
+    <Using Include="System.Runtime.CompilerServices" />
+  </ItemGroup>
+
   <PropertyGroup Condition="$(IsTestProject) OR $(IsBenchmarkProject)">
     <IsPackable>false</IsPackable>
     <CodeAnalysisRuleSet></CodeAnalysisRuleSet>

src/DynamicData.Benchmarks/Cache/DeliveryQueueBenchmarks.cs

@@ -1,17 +1,7 @@
-// Copyright (c) 2011-2025 Roland Pheasant. All rights reserved.
+// Copyright (c) 2011-2025 Roland Pheasant. All rights reserved.
 // Roland Pheasant licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for full license information.
 
-using System;
-using System.Linq;
-using System.Reactive.Linq;
-using System.Threading;
-using System.Threading.Tasks;
-
-using BenchmarkDotNet.Attributes;
-
-using DynamicData.Binding;
-
 namespace DynamicData.Benchmarks.Cache;
 
 /// <summary>

src/DynamicData.Benchmarks/Cache/DisposeMany_Cache.cs

@@ -2,10 +2,6 @@
 // Roland Pheasant licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for full license information.
 
-using System;
-
-using BenchmarkDotNet.Attributes;
-
 namespace DynamicData.Benchmarks.Cache
 {
     [MemoryDiagnoser]

src/DynamicData.Benchmarks/Cache/EditDiff.cs

@@ -1,13 +1,4 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Reactive.Linq;
-
-using BenchmarkDotNet.Attributes;
-
-using DynamicData.Kernel;
-
-namespace DynamicData.Benchmarks.Cache;
+namespace DynamicData.Benchmarks.Cache;
 
 [MemoryDiagnoser]
 [MarkdownExporterAttribute.GitHub]

src/DynamicData.Benchmarks/Cache/ExpireAfter_Cache_ForSource.cs

@@ -1,12 +1,4 @@
-using System;
-using System.Collections.Immutable;
-using System.Linq;
-
-using BenchmarkDotNet.Attributes;
-
-using Bogus;
-
-namespace DynamicData.Benchmarks.Cache;
+namespace DynamicData.Benchmarks.Cache;
 
 [MemoryDiagnoser]
 [MarkdownExporterAttribute.GitHub]
@@ -79,7 +71,7 @@ public void RandomizedEditsAndExpirations()
     private void PerformRandomizedEdits(SourceCache<Item, int> source)
     {
         var randomizer = new Randomizer(1234567);
-        
+
         var nextItemIndex = 0;
 
         for (var i = 0; i < _editCount; ++i)

src/DynamicData.Benchmarks/Cache/ExpireAfter_Cache_ForStream.cs

@@ -1,13 +1,4 @@
-using System;
-using System.Collections.Immutable;
-using System.Linq;
-using System.Reactive.Subjects;
-
-using BenchmarkDotNet.Attributes;
-
-using Bogus;
-
-namespace DynamicData.Benchmarks.Cache;
+namespace DynamicData.Benchmarks.Cache;
 
 [MemoryDiagnoser]
 [MarkdownExporterAttribute.GitHub]

src/DynamicData.Benchmarks/Cache/FilterImmutable.cs

@@ -1,10 +1,4 @@
-using System;
-using System.Collections.Generic;
-using System.Reactive.Subjects;
-
-using BenchmarkDotNet.Attributes;
-
-namespace DynamicData.Benchmarks.Cache;
+namespace DynamicData.Benchmarks.Cache;
 
 [MemoryDiagnoser]
 [MarkdownExporterAttribute.GitHub]

src/DynamicData.Benchmarks/Cache/Filter_Cache_WithPredicateState.cs

@@ -1,13 +1,4 @@
-using System;
-using System.Collections.Immutable;
-using System.Linq;
-using System.Reactive.Subjects;
-
-using BenchmarkDotNet.Attributes;
-
-using Bogus;
-
-namespace DynamicData.Benchmarks.Cache;
+namespace DynamicData.Benchmarks.Cache;
 
 [MemoryDiagnoser]
 [MarkdownExporterAttribute.GitHub]
@@ -99,7 +90,6 @@ public Filter_Cache_WithPredicateState()
         }
         _changeSets = changeSets.MoveToImmutable();
 
-
         var predicateStates = ImmutableArray.CreateBuilder<int>(initialCapacity: 5_000);
         while (predicateStates.Count < predicateStates.Capacity)
             predicateStates.Add(randomizer.Int());
@@ -150,7 +140,7 @@ public static bool FilterByIdInclusionMask(
                 int     idInclusionMask,
                 Item    item)
             => ((item.Id & idInclusionMask) == 0) && item.IsIncluded;
-            
+
         public required int Id { get; init; }
 
         public bool IsIncluded { get; set; }

src/DynamicData.Benchmarks/Cache/SortAndBindChange.cs

@@ -1,12 +1,4 @@
-using System;
-using System.Collections.ObjectModel;
-using System.Linq;
-using System.Reactive.Disposables;
-using System.Reactive.Subjects;
-using BenchmarkDotNet.Attributes;
-using DynamicData.Binding;
-
-namespace DynamicData.Benchmarks.Cache;
+namespace DynamicData.Benchmarks.Cache;
 
 [MemoryDiagnoser]
 [MarkdownExporterAttribute.GitHub]
@@ -19,7 +11,6 @@ private record Item(string Name, int Id, int Ranking);
         .Ascending(i => i.Ranking)
         .ThenByAscending(i => i.Name);
 
-
     Subject<IChangeSet<Item, int>> _newSubject = new();
     Subject<IChangeSet<Item, int>> _newSubjectOptimised = new();
     Subject<IChangeSet<Item, int>> _oldSubject = new();
@@ -32,12 +23,9 @@ private record Item(string Name, int Id, int Ranking);
     private ReadOnlyObservableCollection<Item>? _oldList;
     private ReadOnlyObservableCollection<Item>? _oldListOptimised;
 
-
-
     [Params(10, 100, 1_000, 10_000, 50_000)]
     public int Count { get; set; }
 
-
     [GlobalSetup]
     public void SetUp()
     {
@@ -46,16 +34,15 @@ public void SetUp()
         _newSubject = new Subject<IChangeSet<Item, int>>();
         _newSubjectOptimised = new Subject<IChangeSet<Item, int>>();
 
-
-        _cleanUp = new CompositeDisposable  
+        _cleanUp = new CompositeDisposable
         (
             _newSubject.SortAndBind(out var newList, _comparer).Subscribe(),
             _newSubjectOptimised.SortAndBind(out var optimisedList, _comparer, new SortAndBindOptions
             {
                 InitialCapacity = Count,
                 UseBinarySearch = true
             }).Subscribe(),
-           
+
             _oldSubject.Sort(_comparer).Bind(out var oldList).Subscribe(),
             _oldSubjectOptimised.Sort(_comparer, SortOptimisations.ComparesImmutableValuesOnly).Bind(out var oldOptimisedList).Subscribe()
         );
@@ -65,8 +52,6 @@ public void SetUp()
         _oldList = oldList;
         _oldListOptimised = oldOptimisedList;
 
-
-
         var changeSet = new ChangeSet<Item, int>(Count);
         foreach (var i in Enumerable.Range(1, Count))
         {
@@ -84,7 +69,6 @@ public void SetUp()
     [Benchmark(Baseline = true)]
     public void Old() => RunTest(_oldSubject, _oldList!);
 
-
     [Benchmark]
     public void OldOptimized() => RunTest(_oldSubjectOptimised, _oldListOptimised!);
 
@@ -94,7 +78,6 @@ public void SetUp()
     [Benchmark]
     public void NewOptimized() => RunTest(_newSubjectOptimised, _newListOptimised!);
 
-
     void RunTest(Subject<IChangeSet<Item, int>> subject, ReadOnlyObservableCollection<Item> list)
     {
         var original = list[Count / 2];
@@ -106,6 +89,5 @@ void RunTest(Subject<IChangeSet<Item, int>> subject, ReadOnlyObservableCollectio
         });
     }
 
-
     public void Dispose() => _cleanUp?.Dispose();
-}
+}

src/DynamicData.Benchmarks/Cache/SortAndBindInitial.cs

@@ -1,11 +1,4 @@
-using BenchmarkDotNet.Attributes;
-using System;
-using System.Linq;
-using System.Reactive.Disposables;
-using System.Reactive.Subjects;
-using DynamicData.Binding;
-
-namespace DynamicData.Benchmarks.Cache;
+namespace DynamicData.Benchmarks.Cache;
 
 [MemoryDiagnoser]
 [MarkdownExporterAttribute.GitHub]
@@ -17,7 +10,6 @@ private record Item(string Name, int Id, int Ranking);
 
     private readonly SortExpressionComparer<Item> _comparer = SortExpressionComparer<Item>.Ascending(i => i.Ranking).ThenByAscending(i => i.Name);
 
-
     Subject<IChangeSet<Item, int>> _newSubject = new();
     Subject<IChangeSet<Item, int>> _newSubjectOptimised = new();
     Subject<IChangeSet<Item, int>> _oldSubject = new();
@@ -26,11 +18,9 @@ private record Item(string Name, int Id, int Ranking);
     private IDisposable? _cleanUp;
     private ChangeSet<Item, int>? _changeSet;
 
-
     [Params(10, 100, 1_000, 10_000, 50_000)]
     public int Count { get; set; }
 
-
     [GlobalSetup]
     public void SetUp()
     {
@@ -63,7 +53,6 @@ public void SetUp()
         );
     }
 
-
     [Benchmark(Baseline = true)]
     public void Old() => _oldSubject.OnNext(_changeSet!);
 
@@ -76,6 +65,5 @@ public void SetUp()
     [Benchmark]
     public void NewOptimized() => _newSubjectOptimised.OnNext(_changeSet!);
 
-
     public void Dispose() => _cleanUp?.Dispose();
-}
+}

src/DynamicData.Benchmarks/Cache/SourceCache.cs

@@ -2,11 +2,6 @@
 // Roland Pheasant licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for full license information.
 
-using System.Linq;
-
-using BenchmarkDotNet.Attributes;
-using BenchmarkDotNet.Jobs;
-
 namespace DynamicData.Benchmarks.Cache
 {
     public class BenchmarkItem

src/DynamicData.Benchmarks/Cache/StatelessFiltering.cs

@@ -1,10 +1,4 @@
-using System;
-using System.Collections.Generic;
-using System.Reactive.Subjects;
-
-using BenchmarkDotNet.Attributes;
-
-namespace DynamicData.Benchmarks.Cache;
+namespace DynamicData.Benchmarks.Cache;
 
 [MemoryDiagnoser]
 [MarkdownExporterAttribute.GitHub]

src/DynamicData.Benchmarks/Cache/StatelessTransforming.cs

@@ -1,11 +1,4 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Reactive.Subjects;
-
-using BenchmarkDotNet.Attributes;
-
-namespace DynamicData.Benchmarks.Cache;
+namespace DynamicData.Benchmarks.Cache;
 
 [MemoryDiagnoser]
 [MarkdownExporterAttribute.GitHub]

src/DynamicData.Benchmarks/Cache/ToObservableChangeSet_Cache.cs

@@ -1,12 +1,4 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Reactive.Subjects;
-
-using BenchmarkDotNet.Attributes;
-using BenchmarkDotNet.Columns;
-
-namespace DynamicData.Benchmarks.Cache;
+namespace DynamicData.Benchmarks.Cache;
 
 [MemoryDiagnoser]
 [MarkdownExporterAttribute.GitHub]

src/DynamicData.Benchmarks/Cache/TransformImmutable.cs

@@ -1,11 +1,4 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Reactive.Subjects;
-
-using BenchmarkDotNet.Attributes;
-
-namespace DynamicData.Benchmarks.Cache;
+namespace DynamicData.Benchmarks.Cache;
 
 [MemoryDiagnoser]
 [MarkdownExporterAttribute.GitHub]

src/DynamicData.Benchmarks/Cache/TransformMany.cs

@@ -1,11 +1,4 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Reactive.Linq;
-
-using BenchmarkDotNet.Attributes;
-
-namespace DynamicData.Benchmarks.Cache;
+namespace DynamicData.Benchmarks.Cache;
 
 [MemoryDiagnoser]
 [MarkdownExporterAttribute.GitHub]