Do not report SA1516 for two consecutive single line properties

Author: Matthias Baer

StyleCop.Analyzers/StyleCop.Analyzers.Test/LayoutRules/SA1516UnitTests.cs

@@ -32,7 +32,6 @@ public class Bar
         public string Test3;
 
         public string TestProperty1 { get; set; }
-
         public string TestProperty2 { get; set; }
         /// <summary>
         /// A summary.
@@ -149,7 +148,6 @@ class Foo { }
                 Diagnostic().WithLocation(2, 1),
                 Diagnostic().WithLocation(5, 1),
                 Diagnostic().WithLocation(12, 1),
-                Diagnostic().WithLocation(13, 1),
                 Diagnostic().WithLocation(18, 1),
                 Diagnostic().WithLocation(24, 1),
                 Diagnostic().WithLocation(29, 1),

StyleCop.Analyzers/StyleCop.Analyzers/LayoutRules/SA1516ElementsMustBeSeparatedByBlankLine.cs

@@ -345,34 +345,48 @@ private static void HandleMemberList(SyntaxNodeAnalysisContext context, SyntaxLi
 
                 if (!members[i - 1].ContainsDiagnostics && !members[i].ContainsDiagnostics)
                 {
-                    // Report if
-                    // the current declaration is not a field declaration
-                    // or the previous declaration is of different type
-                    // or the previous declaration spans across multiple lines
-                    //
-                    // Note that the order of checking is important, as the call to IsMultiLine requires a FieldDeclarationSyntax,
-                    // something that can only be guaranteed if the first two checks fail.
-                    if (!members[i].IsKind(SyntaxKind.FieldDeclaration)
-                        || !members[i - 1].IsKind(members[i].Kind())
-                        || IsMultiline((FieldDeclarationSyntax)members[i - 1]))
+                    // Don't report if
+                    // the previous declaration is of the same type
+                    // AND it is either
+                    // - a single line field declaration where the previous field is single line
+                    // or
+                    // - a single line property declaration where the previous property is single line
+                    if (members[i - 1].IsKind(members[i].Kind())
+                        && ((members[i].IsKind(SyntaxKind.FieldDeclaration)
+                             && !IsMultiline((FieldDeclarationSyntax)members[i])
+                             && !IsMultiline((FieldDeclarationSyntax)members[i - 1]))
+                            || (members[i].IsKind(SyntaxKind.PropertyDeclaration)
+                                && !IsMultiline((PropertyDeclarationSyntax)members[i])
+                                && !IsMultiline((PropertyDeclarationSyntax)members[i - 1]))))
                     {
-                        ReportIfThereIsNoBlankLine(context, members[i - 1], members[i]);
+                        continue;
                     }
+
+                    ReportIfThereIsNoBlankLine(context, members[i - 1], members[i]);
                 }
             }
         }
 
         private static bool IsMultiline(FieldDeclarationSyntax fieldDeclaration)
         {
-            var lineSpan = fieldDeclaration.GetLineSpan();
-            var attributeLists = fieldDeclaration.AttributeLists;
+            return IsMultiline(fieldDeclaration, fieldDeclaration.AttributeLists);
+        }
+
+        private static bool IsMultiline(PropertyDeclarationSyntax propertyDeclaration)
+        {
+            return IsMultiline(propertyDeclaration, propertyDeclaration.AttributeLists);
+        }
+
+        private static bool IsMultiline(MemberDeclarationSyntax memberDeclaration, SyntaxList<AttributeListSyntax> attributeLists)
+        {
+            var lineSpan = memberDeclaration.GetLineSpan();
 
             int startLine;
 
             // Exclude attributes when determining if a field declaration spans multiple lines
             if (attributeLists.Count > 0)
             {
-                var lastAttributeSpan = fieldDeclaration.SyntaxTree.GetLineSpan(attributeLists.Last().FullSpan);
+                var lastAttributeSpan = memberDeclaration.SyntaxTree.GetLineSpan(attributeLists.Last().FullSpan);
                 startLine = lastAttributeSpan.EndLinePosition.Line;
             }
             else