Made SA1508 implementation more robust

Author: vweijsters

StyleCop.Analyzers/StyleCop.Analyzers.Test/LayoutRules/SA1508UnitTests.cs

@@ -6,6 +6,7 @@ namespace StyleCop.Analyzers.Test.LayoutRules
     using System.Collections.Generic;
     using System.Threading;
     using System.Threading.Tasks;
+    using Microsoft.CodeAnalysis;
     using Microsoft.CodeAnalysis.CodeFixes;
     using Microsoft.CodeAnalysis.Diagnostics;
     using StyleCop.Analyzers.LayoutRules;
@@ -832,6 +833,60 @@ public int TestProperty
             await this.VerifyCSharpFixAsync(testCode, fixedTestCode).ConfigureAwait(false);
         }
 
+        /// <summary>
+        /// Verifies that an invalid syntax will not crash the analyzer.
+        /// This is a regression test for #1534
+        /// </summary>
+        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
+        [Fact]
+        public async Task TestInvalidSyntaxAsync()
+        {
+            var testCode = @"namespace TestNamespace
+{
+    public class TestClass /
+    {
+    }
+}
+";
+
+            DiagnosticResult[] expected =
+            {
+                new DiagnosticResult
+                {
+                    Id = "CS1514",
+                    Severity = DiagnosticSeverity.Error,
+                    Locations = new[] { new DiagnosticResultLocation("Test0.cs", 3, 28) },
+                    Message = "{ expected"
+                },
+
+                new DiagnosticResult
+                {
+                    Id = "CS1513",
+                    Severity = DiagnosticSeverity.Error,
+                    Locations = new[] { new DiagnosticResultLocation("Test0.cs", 3, 28) },
+                    Message = "} expected"
+                },
+
+                new DiagnosticResult
+                {
+                    Id = "CS1022",
+                    Severity = DiagnosticSeverity.Error,
+                    Locations = new[] { new DiagnosticResultLocation("Test0.cs", 3, 28) },
+                    Message = "Type or namespace definition, or end-of-file expected"
+                },
+
+                new DiagnosticResult
+                {
+                    Id = "CS1022",
+                    Severity = DiagnosticSeverity.Error,
+                    Locations = new[] { new DiagnosticResultLocation("Test0.cs", 6, 1) },
+                    Message = "Type or namespace definition, or end-of-file expected"
+                }
+            };
+
+            await this.VerifyCSharpDiagnosticAsync(testCode, expected, CancellationToken.None).ConfigureAwait(false);
+        }
+
         /// <inheritdoc/>
         protected override IEnumerable<DiagnosticAnalyzer> GetCSharpDiagnosticAnalyzers()
         {

StyleCop.Analyzers/StyleCop.Analyzers/LayoutRules/SA1508ClosingCurlyBracketsMustNotBePrecededByBlankLine.cs

@@ -129,8 +129,10 @@ private static void AnalyzeCloseBrace(SyntaxNodeAnalysisContext context, SyntaxT
             var separatingTrivia = TriviaHelper.MergeTriviaLists(previousToken.TrailingTrivia, closeBraceToken.LeadingTrivia);
 
             // skip all leading whitespace for the close brace
+            // the index must be checked because two tokens can be more than two lines apart and
+            // still only be separated by whitespace trivia due to compilation errors
             var index = separatingTrivia.Count - 1;
-            while (separatingTrivia[index].IsKind(SyntaxKind.WhitespaceTrivia))
+            while (index >= 0 && separatingTrivia[index].IsKind(SyntaxKind.WhitespaceTrivia))
             {
                 index--;
             }