Fix SA1516 reporting location for top-level programs

Fixes #3242

Author: sharwell

StyleCop.Analyzers/StyleCop.Analyzers.Test.CSharp9/LayoutRules/SA1516CSharp9UnitTests.cs

@@ -3,9 +3,60 @@
 
 namespace StyleCop.Analyzers.Test.CSharp9.LayoutRules
 {
+    using System.Threading;
+    using System.Threading.Tasks;
+    using Microsoft.CodeAnalysis;
+    using Microsoft.CodeAnalysis.CSharp;
+    using Microsoft.CodeAnalysis.Testing;
     using StyleCop.Analyzers.Test.CSharp8.LayoutRules;
+    using Xunit;
+    using static StyleCop.Analyzers.Test.Verifiers.StyleCopCodeFixVerifier<
+        StyleCop.Analyzers.LayoutRules.SA1516ElementsMustBeSeparatedByBlankLine,
+        StyleCop.Analyzers.LayoutRules.SA1516CodeFixProvider>;
 
     public class SA1516CSharp9UnitTests : SA1516CSharp8UnitTests
     {
+        /// <summary>
+        /// Verifies that SA1516 is reported at the correct location in top-level programs.
+        /// </summary>
+        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
+        [Fact]
+        [WorkItem(3242, "https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3242")]
+        public async Task TestStatementSpacingInTopLevelProgramAsync()
+        {
+            var testCode = @"using System;
+using System.Threading;
+{|#0:return|} 0;
+";
+            var fixedCode = @"using System;
+using System.Threading;
+
+return 0;
+";
+
+            await new CSharpTest(LanguageVersion.CSharp9)
+            {
+                ReferenceAssemblies = ReferenceAssemblies.Net.Net50,
+                TestCode = testCode,
+                ExpectedDiagnostics =
+                {
+                    // /0/Test0.cs(3,1): warning SA1516: Elements should be separated by blank line
+                    Diagnostic().WithLocation(0),
+
+                    // /0/Test0.cs(3,1): warning SA1516: Elements should be separated by blank line
+                    Diagnostic().WithLocation(0),
+                },
+                FixedCode = fixedCode,
+                SolutionTransforms =
+                {
+                    (solution, projectId) =>
+                    {
+                        var project = solution.GetProject(projectId);
+                        var options = project.CompilationOptions;
+                        return solution.WithProjectCompilationOptions(projectId, options.WithOutputKind(OutputKind.ConsoleApplication));
+                    },
+                },
+            }.RunAsync(CancellationToken.None).ConfigureAwait(false);
+        }
     }
 }

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

@@ -366,10 +366,16 @@ private static Location GetDiagnosticLocation(SyntaxNode node)
                 return node.GetLeadingTrivia()[0].GetLocation();
             }
 
+            // Prefer the first token which is a direct child, but fall back to the first descendant token
             var firstToken = node.ChildTokens().FirstOrDefault();
+            if (firstToken.IsKind(SyntaxKind.None))
+            {
+                firstToken = node.GetFirstToken();
+            }
+
             if (firstToken != default)
             {
-                return node.ChildTokens().First().GetLocation();
+                return firstToken.GetLocation();
             }
 
             return Location.None;