ExportAnalyzerAttribute: Simplify pattern matching and avoid multiple enumeration

ICSharpCode.ILSpyX/Analyzers/ExportAnalyzerAttribute.cs

@@ -39,8 +39,7 @@ namespace ICSharpCode.ILSpyX.Analyzers
 		{
 			foreach (var type in typeof(ExportAnalyzerAttribute).Assembly.GetTypes())
 			{
-				var exportAnalyzerAttribute = type.GetCustomAttribute(typeof(ExportAnalyzerAttribute), false) as ExportAnalyzerAttribute;
-				if (exportAnalyzerAttribute is not null)
+				if (type.GetCustomAttribute(typeof(ExportAnalyzerAttribute), false) is ExportAnalyzerAttribute exportAnalyzerAttribute)
 				{
 					yield return (exportAnalyzerAttribute, type);
 				}

ILSpy.Tests/Analyzers/ExportAnalyzerAttributeTests.cs

@@ -30,7 +30,9 @@ namespace ICSharpCode.ILSpy.Tests.Analyzers
 		[Test]
 		public void CollectAnalyzers()
 		{
-			var analyzerNames = ExportAnalyzerAttribute.GetAnnotatedAnalyzers().Select(analyzer => analyzer.AnalyzerType.Name);
+			var analyzerNames = ExportAnalyzerAttribute.GetAnnotatedAnalyzers()
+				.Select(analyzer => analyzer.AnalyzerType.Name)
+				.ToArray();
 			Assert.That(analyzerNames.Contains("AttributeAppliedToAnalyzer"));
 			Assert.That(analyzerNames.Contains("EventImplementedByAnalyzer"));
 			Assert.That(analyzerNames.Contains("MethodUsedByAnalyzer"));