Fixed SA1119CodeFix for preprocessor directives

Author: vweijsters

StyleCop.Analyzers/StyleCop.Analyzers.CodeFixes/MaintainabilityRules/SA1119CodeFixProvider.cs

@@ -67,8 +67,11 @@ private static SyntaxNode GetReplacement(ParenthesizedExpressionSyntax oldNode)
             var leadingTrivia = SyntaxFactory.TriviaList(oldNode.OpenParenToken.GetAllTrivia().Concat(oldNode.Expression.GetLeadingTrivia()));
             var trailingTrivia = oldNode.Expression.GetTrailingTrivia().AddRange(oldNode.CloseParenToken.GetAllTrivia());
 
+            // Workaround for Roslyn not handling elastic markers for directive trivia correctly.
+            var leadingSeparator = (oldNode.Parent is DirectiveTriviaSyntax) ? SyntaxFactory.Space : SyntaxFactory.ElasticMarker;
+
             return oldNode.Expression
-                .WithLeadingTrivia(leadingTrivia.Any() ? leadingTrivia : SyntaxFactory.TriviaList(SyntaxFactory.ElasticMarker))
+                .WithLeadingTrivia(leadingTrivia.Any() ? leadingTrivia : SyntaxFactory.TriviaList(leadingSeparator))
                 .WithTrailingTrivia(trailingTrivia.Any() ? trailingTrivia : SyntaxFactory.TriviaList(SyntaxFactory.ElasticMarker));
         }
 

StyleCop.Analyzers/StyleCop.Analyzers.Test/MaintainabilityRules/SA1119UnitTests.cs

@@ -1401,6 +1401,51 @@ public void Bar()
             await this.VerifyCSharpFixAsync(testCode, fixedCode).ConfigureAwait(false);
         }
 
+        /// <summary>
+        /// Verifies that a preprocessor statement with unnecessary parenthesis is handled correctly.
+        /// Regression test for #2069
+        /// </summary>
+        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
+        [Fact]
+        public async Task VerifyThatPreprocessorStatementIsHandledCorrectlyAsync()
+        {
+            string testCode = @"
+public class Program
+{
+    public static void Main(string[] args)
+    {
+#if(DEBUG)
+
+#endif
+
+    }
+}
+";
+
+            string fixedCode = @"
+public class Program
+{
+    public static void Main(string[] args)
+    {
+#if DEBUG
+
+#endif
+
+    }
+}
+";
+            DiagnosticResult[] expected =
+            {
+                this.CSharpDiagnostic(DiagnosticId).WithLocation(6, 4),
+                this.CSharpDiagnostic(ParenthesesDiagnosticId).WithLocation(6, 4),
+                this.CSharpDiagnostic(ParenthesesDiagnosticId).WithLocation(6, 10),
+            };
+
+            await this.VerifyCSharpDiagnosticAsync(testCode, expected, CancellationToken.None).ConfigureAwait(false);
+            await this.VerifyCSharpDiagnosticAsync(fixedCode, EmptyDiagnosticResults, CancellationToken.None).ConfigureAwait(false);
+            await this.VerifyCSharpFixAsync(testCode, fixedCode).ConfigureAwait(false);
+        }
+
         /// <inheritdoc/>
         protected override IEnumerable<DiagnosticAnalyzer> GetCSharpDiagnosticAnalyzers()
         {