Fix MA0048 in case when first type is not first node (#785)

Author: FrediKats

src/Meziantou.Analyzer/Rules/FileNameMustMatchTypeNameAnalyzer.cs

@@ -86,6 +86,9 @@ private static void AnalyzeSymbol(SymbolAnalysisContext context)
                 var isFirstType = true;
                 foreach (var node in root.DescendantNodesAndSelf(descendIntoChildren: node => !IsTypeDeclaration(node)))
                 {
+                    if (!IsTypeDeclaration(node))
+                        continue;
+
                     if (node.SpanStart < symbolNode.SpanStart)
                     {
                         isFirstType = false;

tests/Meziantou.Analyzer.Test/Rules/FileNameMustMatchTypeNameAnalyzerTests.cs

@@ -247,6 +247,36 @@ struct Bar {}
               .ValidateAsync();
     }
 
+    [Fact]
+    public async Task MatchOnlyFirstType_TypeWithBlockScopedNamespaceDeclaration()
+    {
+        await CreateProjectBuilder()
+              .WithSourceCode(fileName: "Test0.cs", """
+                  namespace Sample
+                  {
+                      struct [||]Foo {}
+                      struct Bar {}
+                  }
+                  """)
+              .AddAnalyzerConfiguration("MA0048.only_validate_first_type", "true")
+              .ValidateAsync();
+    }
+
+#if CSHARP10_OR_GREATER
+    [Fact]
+    public async Task MatchOnlyFirstType_TypeWithFileScopedNamespaceDeclaration()
+    {
+        await CreateProjectBuilder()
+              .WithSourceCode(fileName: "Test0.cs", """
+                  namespace Sample;
+                  struct [||]Foo {}
+                  struct Bar {}
+                  """)
+              .AddAnalyzerConfiguration("MA0048.only_validate_first_type", "true")
+              .ValidateAsync();
+    }
+#endif
+
     [Theory]
     [InlineData("Sample")]
     [InlineData("T:MyNamespace.Sample")]