Update SA1121 and SA1404 to detect global using aliases

#3594

StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp10/MaintainabilityRules/SA1404CSharp10UnitTests.cs

@@ -3,9 +3,57 @@
 
 namespace StyleCop.Analyzers.Test.CSharp10.MaintainabilityRules
 {
+    using System.Threading;
+    using System.Threading.Tasks;
+    using StyleCop.Analyzers.MaintainabilityRules;
     using StyleCop.Analyzers.Test.CSharp9.MaintainabilityRules;
+    using Xunit;
+    using static StyleCop.Analyzers.Test.Verifiers.StyleCopCodeFixVerifier<
+        StyleCop.Analyzers.MaintainabilityRules.SA1404CodeAnalysisSuppressionMustHaveJustification,
+        StyleCop.Analyzers.MaintainabilityRules.SA1404CodeFixProvider>;
 
     public class SA1404CSharp10UnitTests : SA1404CSharp9UnitTests
     {
+        [Fact]
+        public async Task TestUsingNameChangeInGlobalUsingInAnotherFileAsync()
+        {
+            var testCode1 = @"
+global using MySuppressionAttribute = System.Diagnostics.CodeAnalysis.SuppressMessageAttribute;";
+
+            var testCode2 = @"
+public class Foo
+{
+    [[|MySuppression(null, null)|]]
+    public void Bar()
+    {
+
+    }
+}";
+
+            var fixedCode2 = @"
+public class Foo
+{
+    [MySuppression(null, null, Justification = """ + SA1404CodeAnalysisSuppressionMustHaveJustification.JustificationPlaceholder + @""")]
+    public void Bar()
+    {
+
+    }
+}";
+
+            var test = new CSharpTest
+            {
+                RemainingDiagnostics =
+                {
+                    Diagnostic().WithLocation("/0/Test1.cs", 4, 32),
+                },
+                NumberOfIncrementalIterations = 2,
+                NumberOfFixAllIterations = 2,
+            };
+            test.TestState.Sources.Add(testCode1);
+            test.TestState.Sources.Add(testCode2);
+            test.FixedState.Sources.Add(testCode1);
+            test.FixedState.Sources.Add(fixedCode2);
+            await test.RunAsync(CancellationToken.None).ConfigureAwait(false);
+        }
     }
 }

StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp10/ReadabilityRules/SA1121CSharp10UnitTests.cs

@@ -42,5 +42,31 @@ class Bar
                 FixedCode = newSource,
             }.RunAsync(CancellationToken.None).ConfigureAwait(false);
         }
+
+        [Fact]
+        public async Task TestUsingNameChangeInGlobalUsingInAnotherFileAsync()
+        {
+            var source1 = @"
+global using MyDouble = System.Double;";
+
+            var oldSource2 = @"
+class TestClass
+{
+    private [|MyDouble|] x;
+}";
+
+            var newSource2 = @"
+class TestClass
+{
+    private double x;
+}";
+
+            var test = new CSharpTest();
+            test.TestState.Sources.Add(source1);
+            test.TestState.Sources.Add(oldSource2);
+            test.FixedState.Sources.Add(source1);
+            test.FixedState.Sources.Add(newSource2);
+            await test.RunAsync(CancellationToken.None).ConfigureAwait(false);
+        }
     }
 }

StyleCop.Analyzers/StyleCop.Analyzers/Helpers/SyntaxTreeHelpers.cs

@@ -33,7 +33,10 @@ public static ConcurrentDictionary<SyntaxTree, bool> GetOrCreateUsingAliasCache(
             Compilation cachedCompilation;
             if (!cache.Item1.TryGetTarget(out cachedCompilation) || cachedCompilation != compilation)
             {
-                var replacementCache = Tuple.Create(new WeakReference<Compilation>(compilation), new ConcurrentDictionary<SyntaxTree, bool>());
+                var containsGlobalUsingAlias = ContainsGlobalUsingAliasNoCache(compilation);
+                var replacementDictionary = containsGlobalUsingAlias ? null : new ConcurrentDictionary<SyntaxTree, bool>();
+                var replacementCache = Tuple.Create(new WeakReference<Compilation>(compilation), replacementDictionary);
+
                 while (true)
                 {
                     var prior = Interlocked.CompareExchange(ref usingAliasCache, replacementCache, cache);
@@ -79,6 +82,12 @@ internal static bool ContainsUsingAlias(this SyntaxTree tree, ConcurrentDictiona
                 return false;
             }
 
+            if (cache == null)
+            {
+                // NOTE: This happens if any syntax tree in the compilation contains a global using alias
+                return true;
+            }
+
             bool result;
             if (cache.TryGetValue(tree, out result))
             {
@@ -96,5 +105,18 @@ private static bool ContainsUsingAliasNoCache(SyntaxTree tree)
 
             return nodes.OfType<UsingDirectiveSyntax>().Any(x => x.Alias != null);
         }
+
+        private static bool ContainsGlobalUsingAliasNoCache(Compilation compilation)
+        {
+            return compilation.SyntaxTrees.Any(ContainsGlobalUsingAliasNoCache);
+        }
+
+        private static bool ContainsGlobalUsingAliasNoCache(SyntaxTree tree)
+        {
+            var nodes = tree.GetRoot().DescendantNodes(node => node.IsKind(SyntaxKind.CompilationUnit) || node.IsKind(SyntaxKind.NamespaceDeclaration) || node.IsKind(SyntaxKindEx.FileScopedNamespaceDeclaration));
+
+            var relevantNodes = nodes.OfType<UsingDirectiveSyntax>().ToArray();
+            return relevantNodes.Any(x => x.Alias != null && !x.GlobalKeyword().IsKind(SyntaxKind.None));
+        }
     }
 }

StyleCop.Analyzers/StyleCop.Analyzers/Lightup/UsingDirectiveSyntaxExtensions.cs

@@ -0,0 +1,31 @@
+// Copyright (c) Tunnel Vision Laboratories, LLC. All Rights Reserved.
+// Licensed under the MIT License. See LICENSE in the project root for license information.
+
+namespace StyleCop.Analyzers.Lightup
+{
+    using System;
+    using Microsoft.CodeAnalysis;
+    using Microsoft.CodeAnalysis.CSharp.Syntax;
+
+    internal static class UsingDirectiveSyntaxExtensions
+    {
+        private static readonly Func<UsingDirectiveSyntax, SyntaxToken> GlobalKeywordAccessor;
+        private static readonly Func<UsingDirectiveSyntax, SyntaxToken, UsingDirectiveSyntax> WithGlobalKeywordAccessor;
+
+        static UsingDirectiveSyntaxExtensions()
+        {
+            GlobalKeywordAccessor = LightupHelpers.CreateSyntaxPropertyAccessor<UsingDirectiveSyntax, SyntaxToken>(typeof(UsingDirectiveSyntax), nameof(GlobalKeyword));
+            WithGlobalKeywordAccessor = LightupHelpers.CreateSyntaxWithPropertyAccessor<UsingDirectiveSyntax, SyntaxToken>(typeof(UsingDirectiveSyntax), nameof(GlobalKeyword));
+        }
+
+        public static SyntaxToken GlobalKeyword(this UsingDirectiveSyntax syntax)
+        {
+            return GlobalKeywordAccessor(syntax);
+        }
+
+        public static UsingDirectiveSyntax WithGlobalKeyword(this UsingDirectiveSyntax syntax, SyntaxToken globalKeyword)
+        {
+            return WithGlobalKeywordAccessor(syntax, globalKeyword);
+        }
+    }
+}