From de0f1205671281679866e92edd9337a7416409e6 Mon Sep 17 00:00:00 2001
From: Josef Pihrt <josef.pihrt@outlook.com>
Date: Sun, 2 Feb 2020 15:53:19 +0100
Subject: [PATCH] Remove empty line between documentation comment and
 declaration (RCS1036)

---
 .../RemoveRedundantEmptyLineAnalyzer.cs       | 44 ++++++++++++++-----
 .../RCS1036RemoveRedundantEmptyLineTests.cs   | 23 ++++++++++
 2 files changed, 56 insertions(+), 11 deletions(-)

diff --git a/src/Analyzers/CSharp/Analysis/RemoveRedundantEmptyLineAnalyzer.cs b/src/Analyzers/CSharp/Analysis/RemoveRedundantEmptyLineAnalyzer.cs
index 279d34752f..7a031d9dfa 100644
--- a/src/Analyzers/CSharp/Analysis/RemoveRedundantEmptyLineAnalyzer.cs
+++ b/src/Analyzers/CSharp/Analysis/RemoveRedundantEmptyLineAnalyzer.cs
@@ -45,15 +45,15 @@ public override void Initialize(AnalysisContext context)
             context.RegisterSyntaxNodeAction(AnalyzeFixedStatement, SyntaxKind.FixedStatement);
 
             context.RegisterSyntaxNodeAction(AnalyzeAccessorList, SyntaxKind.AccessorList);
-
             context.RegisterSyntaxNodeAction(AnalyzeBlock, SyntaxKind.Block);
+            context.RegisterSyntaxNodeAction(AnalyzeSingleLineDocumentationCommentTrivia, SyntaxKind.SingleLineDocumentationCommentTrivia);
 
             context.RegisterSyntaxNodeAction(AnalyzeInitializer, SyntaxKind.ArrayInitializerExpression);
             context.RegisterSyntaxNodeAction(AnalyzeInitializer, SyntaxKind.CollectionInitializerExpression);
             context.RegisterSyntaxNodeAction(AnalyzeInitializer, SyntaxKind.ObjectInitializerExpression);
         }
 
-        public static void AnalyzeClassDeclaration(SyntaxNodeAnalysisContext context)
+        private static void AnalyzeClassDeclaration(SyntaxNodeAnalysisContext context)
         {
             var classDeclaration = (ClassDeclarationSyntax)context.Node;
 
@@ -64,7 +64,7 @@ public static void AnalyzeClassDeclaration(SyntaxNodeAnalysisContext context)
                 classDeclaration.CloseBraceToken);
         }
 
-        public static void AnalyzeStructDeclaration(SyntaxNodeAnalysisContext context)
+        private static void AnalyzeStructDeclaration(SyntaxNodeAnalysisContext context)
         {
             var structDeclaration = (StructDeclarationSyntax)context.Node;
 
@@ -75,7 +75,7 @@ public static void AnalyzeStructDeclaration(SyntaxNodeAnalysisContext context)
                 structDeclaration.CloseBraceToken);
         }
 
-        public static void AnalyzeInterfaceDeclaration(SyntaxNodeAnalysisContext context)
+        private static void AnalyzeInterfaceDeclaration(SyntaxNodeAnalysisContext context)
         {
             var interfaceDeclaration = (InterfaceDeclarationSyntax)context.Node;
 
@@ -86,7 +86,7 @@ public static void AnalyzeInterfaceDeclaration(SyntaxNodeAnalysisContext context
                 interfaceDeclaration.CloseBraceToken);
         }
 
-        public static void AnalyzeNamespaceDeclaration(SyntaxNodeAnalysisContext context)
+        private static void AnalyzeNamespaceDeclaration(SyntaxNodeAnalysisContext context)
         {
             var namespaceDeclaration = (NamespaceDeclarationSyntax)context.Node;
 
@@ -115,7 +115,7 @@ public static void AnalyzeNamespaceDeclaration(SyntaxNodeAnalysisContext context
                 AnalyzeEnd(context, members.Last(), namespaceDeclaration.CloseBraceToken);
         }
 
-        public static void AnalyzeSwitchStatement(SyntaxNodeAnalysisContext context)
+        private static void AnalyzeSwitchStatement(SyntaxNodeAnalysisContext context)
         {
             var switchStatement = (SwitchStatementSyntax)context.Node;
 
@@ -128,7 +128,7 @@ public static void AnalyzeSwitchStatement(SyntaxNodeAnalysisContext context)
             }
         }
 
-        public static void AnalyzeTryStatement(SyntaxNodeAnalysisContext context)
+        private static void AnalyzeTryStatement(SyntaxNodeAnalysisContext context)
         {
             var tryStatement = (TryStatementSyntax)context.Node;
 
@@ -157,7 +157,7 @@ public static void AnalyzeTryStatement(SyntaxNodeAnalysisContext context)
             }
         }
 
-        public static void AnalyzeElseClause(SyntaxNodeAnalysisContext context)
+        private static void AnalyzeElseClause(SyntaxNodeAnalysisContext context)
         {
             var elseClause = (ElseClauseSyntax)context.Node;
 
@@ -344,7 +344,7 @@ private static void AnalyzeDeclaration(
             }
         }
 
-        public static void AnalyzeBlock(SyntaxNodeAnalysisContext context)
+        private static void AnalyzeBlock(SyntaxNodeAnalysisContext context)
         {
             var block = (BlockSyntax)context.Node;
 
@@ -361,7 +361,29 @@ public static void AnalyzeBlock(SyntaxNodeAnalysisContext context)
             }
         }
 
-        public static void AnalyzeInitializer(SyntaxNodeAnalysisContext context)
+        private static void AnalyzeSingleLineDocumentationCommentTrivia(SyntaxNodeAnalysisContext context)
+        {
+            var comment = (DocumentationCommentTriviaSyntax)context.Node;
+
+            if (comment is IStructuredTriviaSyntax structuredTrivia)
+            {
+                SyntaxTrivia trivia = structuredTrivia.ParentTrivia;
+                SyntaxTriviaList leadingTrivia = trivia.Token.LeadingTrivia;
+
+                int index = leadingTrivia.IndexOf(trivia);
+
+                if (index >= 0
+                    && index < leadingTrivia.Count - 1
+                    && leadingTrivia[index + 1].IsEndOfLineTrivia())
+                {
+                    DiagnosticHelpers.ReportDiagnostic(context,
+                        DiagnosticDescriptors.RemoveRedundantEmptyLine,
+                        leadingTrivia[index + 1].GetLocation());
+                }
+            }
+        }
+
+        private static void AnalyzeInitializer(SyntaxNodeAnalysisContext context)
         {
             var initializer = (InitializerExpressionSyntax)context.Node;
 
@@ -417,7 +439,7 @@ bool IsExpectedTrailingTrivia(SyntaxTriviaList triviaList)
             }
         }
 
-        public static void AnalyzeAccessorList(SyntaxNodeAnalysisContext context)
+        private static void AnalyzeAccessorList(SyntaxNodeAnalysisContext context)
         {
             var accessorList = (AccessorListSyntax)context.Node;
 
diff --git a/src/Tests/Analyzers.Tests/RCS1036RemoveRedundantEmptyLineTests.cs b/src/Tests/Analyzers.Tests/RCS1036RemoveRedundantEmptyLineTests.cs
index d2607039af..a61bf7a7d9 100644
--- a/src/Tests/Analyzers.Tests/RCS1036RemoveRedundantEmptyLineTests.cs
+++ b/src/Tests/Analyzers.Tests/RCS1036RemoveRedundantEmptyLineTests.cs
@@ -197,6 +197,29 @@ void M()
 ");
         }
 
+        [Fact, Trait(Traits.Analyzer, DiagnosticIdentifiers.RemoveRedundantEmptyLine)]
+        public async Task Test_EmptyLineAfterDocComment()
+        {
+            await VerifyDiagnosticAndFixAsync(@"
+class C
+{
+    /// <summary></summary>
+[|
+|]    void M()
+    {
+    }
+}
+", @"
+class C
+{
+    /// <summary></summary>
+    void M()
+    {
+    }
+}
+");
+        }
+
         [Fact, Trait(Traits.Analyzer, DiagnosticIdentifiers.RemoveRedundantEmptyLine)]
         public async Task TestNoDiagnostic_ObjectInitializer()
         {