More VB support for private field name rules

Author: jaredpar

src/Microsoft.DotNet.CodeFormatting.Tests/Rules/PrivateFieldNamingRuleTests.cs

@@ -165,6 +165,62 @@ Private _field As Integer
 
                 Verify(text, expected, runFormatter: false, languageName: LanguageNames.VisualBasic);
             }
+
+            [Fact]
+            public void ModuleFieldsAreShared()
+            {
+                var text = @"
+Module C
+    Private Field As Integer
+End Module";
+
+                var expected = @"
+Module C
+    Private s_field As Integer
+End Module";
+
+                Verify(text, expected, runFormatter: false, languageName: LanguageNames.VisualBasic);
+            }
+
+            [Fact]
+            public void MultipleDeclarations()
+            {
+                var text = @"
+Class C 
+    Private Field1, Field2 As Integer
+End Class";
+
+                var expected = @"
+Class C 
+    Private _field1,_field2 As Integer
+End Class";
+
+                Verify(text, expected, runFormatter: false, languageName: LanguageNames.VisualBasic);
+            }
+
+            [Fact]
+            public void FieldAndUse()
+            {
+                var text = @"
+Class C 
+    Private Field As Integer
+
+    Sub M()
+        Console.WriteLine(Field)
+    End Sub
+End Class";
+
+                var expected = @"
+Class C 
+    Private _field As Integer
+
+    Sub M()
+        Console.WriteLine(_field)
+    End Sub
+End Class";
+
+                Verify(text, expected, runFormatter: false, languageName: LanguageNames.VisualBasic);
+            }
         }
     }
 }

src/Microsoft.DotNet.CodeFormatting/Rules/PrivateFieldNamingRule.VisualBasic.cs

@@ -36,6 +36,7 @@ protected override SyntaxNode RemoveRenameAnnotations(SyntaxNode syntaxNode)
         private sealed class VisualBasicPrivateFieldAnnotationRewriter : VisualBasicSyntaxRewriter
         {
             private int _count;
+            private bool _inModule;
 
             internal static SyntaxNode AddAnnotations(SyntaxNode node, out int count)
             {
@@ -45,6 +46,20 @@ internal static SyntaxNode AddAnnotations(SyntaxNode node, out int count)
                 return newNode;
             }
 
+            public override SyntaxNode VisitModuleBlock(ModuleBlockSyntax node)
+            {
+                var savedInModule = _inModule;
+                try
+                {
+                    _inModule = true;
+                    return base.VisitModuleBlock(node);
+                }
+                finally
+                {
+                    _inModule = savedInModule;
+                }
+            }
+
             public override SyntaxNode VisitFieldDeclaration(FieldDeclarationSyntax node)
             {
                 bool isInstance;
@@ -75,7 +90,7 @@ public override SyntaxNode VisitFieldDeclaration(FieldDeclarationSyntax node)
                 return node.WithDeclarators(SyntaxFactory.SeparatedList(declarators));
             }
 
-            private static bool NeedsRewrite(FieldDeclarationSyntax fieldSyntax, out bool isInstance)
+            private bool NeedsRewrite(FieldDeclarationSyntax fieldSyntax, out bool isInstance)
             {
                 if (!IsPrivateField(fieldSyntax, out isInstance))
                 {
@@ -96,10 +111,10 @@ private static bool NeedsRewrite(FieldDeclarationSyntax fieldSyntax, out bool is
                 return false;
             }
 
-            private static bool IsPrivateField(FieldDeclarationSyntax node, out bool isInstance)
+            private bool IsPrivateField(FieldDeclarationSyntax node, out bool isInstance)
             {
                 var isPrivate = true;
-                isInstance = true;
+                isInstance = !_inModule;
 
                 foreach (var modifier in node.Modifiers)
                 {