Merge pull request #2002 from sharwell/rm-duplicate-filtering

Remove duplicate filtering

Author: sharwell

StyleCop.Analyzers/StyleCop.Analyzers.CodeFixes/OrderingRules/UsingCodeFixProvider.cs

@@ -710,20 +710,7 @@ private List<UsingDirectiveSyntax> GenerateUsings(List<UsingDirectiveSyntax> usi
                         processedUsing = processedUsing.WithAdditionalAnnotations(FileHeaderStrippedAnnotation);
                     }
 
-                    // filter duplicate using declarations, preferring to keep the one with an alias
-                    var existingUsing = result.Find(u => string.Equals(u.Name.ToNormalizedString(), processedUsing.Name.ToNormalizedString(), StringComparison.Ordinal));
-                    if (existingUsing != null)
-                    {
-                        if (!existingUsing.HasNamespaceAliasQualifier() && processedUsing.HasNamespaceAliasQualifier())
-                        {
-                            result.Remove(existingUsing);
-                            result.Add(processedUsing);
-                        }
-                    }
-                    else
-                    {
-                        result.Add(processedUsing);
-                    }
+                    result.Add(processedUsing);
                 }
 
                 result.Sort(this.CompareUsings);

StyleCop.Analyzers/StyleCop.Analyzers.Test/OrderingRules/SA1210CombinedSystemDirectivesUnitTests.cs

@@ -138,6 +138,7 @@ namespace Food
 {
     using Food;
     using global::Food;
+    using global::Food;
     using global::System;
     using global::System.IO;
     using global::System.Linq;

StyleCop.Analyzers/StyleCop.Analyzers.Test/OrderingRules/SA1210UnitTests.cs

@@ -198,6 +198,7 @@ namespace Foo
     using corlib::System;
     using Foo;
     using global::Foo;
+    using global::Foo;
     using global::System;
     using global::System.IO;
     using global::System.Linq;

StyleCop.Analyzers/StyleCop.Analyzers.Test/OrderingRules/SA1211UnitTests.cs

@@ -196,6 +196,38 @@ public async Task TestPreprocessorDirectivesAsync()
             await this.VerifyCSharpFixAsync(testCode, fixedTestCode).ConfigureAwait(false);
         }
 
+        /// <summary>
+        /// Verifies that the analyzer will not combine using directives that refer to the same type. This is a
+        /// regression test for DotNetAnalyzers/StyleCopAnalyzers#2000.
+        /// </summary>
+        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
+        [Fact]
+        public async Task TestSameUsingWithDifferentAliasAsync()
+        {
+            string testCode = @"namespace NamespaceName
+{
+    using Func2 = System.Func<int>;
+    using Func1 = System.Func<int>;
+
+    internal delegate void DelegateName(Func1 arg1, Func2 arg2);
+}
+";
+            string fixedCode = @"namespace NamespaceName
+{
+    using Func1 = System.Func<int>;
+    using Func2 = System.Func<int>;
+
+    internal delegate void DelegateName(Func1 arg1, Func2 arg2);
+}
+";
+
+            var expected = this.CSharpDiagnostic().WithLocation(4, 5).WithArguments("Func1", "Func2");
+
+            await this.VerifyCSharpDiagnosticAsync(testCode, expected, CancellationToken.None).ConfigureAwait(false);
+            await this.VerifyCSharpDiagnosticAsync(fixedCode, EmptyDiagnosticResults, CancellationToken.None).ConfigureAwait(false);
+            await this.VerifyCSharpFixAsync(testCode, fixedCode, cancellationToken: CancellationToken.None).ConfigureAwait(false);
+        }
+
         /// <inheritdoc/>
         protected override IEnumerable<DiagnosticAnalyzer> GetCSharpDiagnosticAnalyzers()
         {