Change HTML in nested C# blocks to properly handle dots.

- Prior to this change adding a `.` after an implicit expression would result in compile errors due to Razor thinking the `.` was part of the C# (normally not the case).
- Added a code generation and unit tests to validate behavior.

#491

src/Microsoft.AspNet.Razor/Parser/CSharpCodeParser.cs

@@ -631,6 +631,11 @@ namespace Microsoft.AspNet.Razor.Parser
 
         private void ParseWithOtherParser(Action<ParserBase> parseAction)
         {
+            // When transitioning to the HTML parser we no longer want to act as if we're in a nested C# state.
+            // For instance, if <div>@hello.</div> is in a nested C# block we don't want the trailing '.' to be handled
+            // as C#; it should be handled as a period because it's wrapped in markup.
+            var wasNested = IsNested;
+            IsNested = false;
             using (PushSpanConfig())
             {
                 Context.SwitchActiveParser();
@@ -638,6 +643,7 @@ namespace Microsoft.AspNet.Razor.Parser
                 Context.SwitchActiveParser();
             }
             Initialize(Span);
+            IsNested = wasNested;
             NextToken();
         }
     }

test/Microsoft.AspNet.Razor.Test/CodeGenerators/CSharpRazorChunkGeneratorTest.cs

@@ -52,6 +52,7 @@ namespace Microsoft.AspNet.Razor.Test.Generator
         }
 
         [Theory]
+        [InlineData("NestedCSharp")]
         [InlineData("NullConditionalExpressions")]
         [InlineData("NestedCodeBlocks")]
         [InlineData("CodeBlock")]
@@ -75,6 +76,55 @@ namespace Microsoft.AspNet.Razor.Test.Generator
             RunTest(testType);
         }
 
+        [Fact]
+        public void CSharpChunkGeneratorCorrectlyGeneratesMappingsForNestedCSharp()
+        {
+            RunTest(
+                "NestedCSharp",
+                "NestedCSharp.DesignTime",
+                designTimeMode: true,
+                tabTest: TabTest.NoTabs,
+                expectedDesignTimePragmas: new List<LineMapping>
+                {
+                    BuildLineMapping(
+                        documentAbsoluteIndex: 2,
+                        documentLineIndex: 0,
+                        generatedAbsoluteIndex: 522,
+                        generatedLineIndex: 22,
+                        characterOffsetIndex: 2,
+                        contentLength: 6),
+                    BuildLineMapping(
+                        documentAbsoluteIndex: 9,
+                        documentLineIndex: 1,
+                        documentCharacterOffsetIndex: 5,
+                        generatedAbsoluteIndex: 598,
+                        generatedLineIndex: 29,
+                        generatedCharacterOffsetIndex: 4,
+                        contentLength: 53),
+                    BuildLineMapping(
+                        documentAbsoluteIndex: 82,
+                        documentLineIndex: 4,
+                        generatedAbsoluteIndex: 730,
+                        generatedLineIndex: 37,
+                        characterOffsetIndex: 13,
+                        contentLength: 16),
+                    BuildLineMapping(
+                        documentAbsoluteIndex: 115,
+                        documentLineIndex: 5,
+                        generatedAbsoluteIndex: 825,
+                        generatedLineIndex: 42,
+                        characterOffsetIndex: 14,
+                        contentLength: 7),
+                    BuildLineMapping(
+                        documentAbsoluteIndex: 122,
+                        documentLineIndex: 6,
+                        generatedAbsoluteIndex: 903,
+                        generatedLineIndex: 49,
+                        characterOffsetIndex: 5,
+                        contentLength: 2),
+                });
+        }
+
         [Fact]
         public void CSharpChunkGeneratorCorrectlyGeneratesMappingsForNullConditionalOperator()
         {

test/Microsoft.AspNet.Razor.Test/Parser/CSharp/CSharpBlockTest.cs

@@ -15,6 +15,31 @@ namespace Microsoft.AspNet.Razor.Test.Parser.CSharp
 {
     public class CSharpBlockTest : CsHtmlCodeParserTestBase
     {
+        [Fact]
+        public void ParseBlock_NestedCodeBlockWithMarkupSetsDotAsMarkup()
+        {
+            ParseBlockTest("if (true) { @if(false) { <div>@something.</div> } }",
+                new StatementBlock(
+                    Factory.Code("if (true) { ").AsStatement(),
+                    new StatementBlock(
+                        Factory.CodeTransition(),
+                        Factory.Code("if(false) {").AsStatement(),
+                        new MarkupBlock(
+                            Factory.Markup(" "),
+                            BlockFactory.MarkupTagBlock("<div>", AcceptedCharacters.None),
+                            Factory.EmptyHtml(),
+                            new ExpressionBlock(
+                                Factory.CodeTransition(),
+                                Factory.Code("something")
+                                    .AsImplicitExpression(CSharpCodeParser.DefaultKeywords, acceptTrailingDot: false)
+                                    .Accepts(AcceptedCharacters.NonWhiteSpace)),
+                            Factory.Markup("."),
+                            BlockFactory.MarkupTagBlock("</div>", AcceptedCharacters.None),
+                            Factory.Markup(" ").Accepts(AcceptedCharacters.None)),
+                        Factory.Code("}").AsStatement()),
+                    Factory.Code(" }").AsStatement()));
+        }
+
         [Fact]
         public void ParseBlockMethodThrowsArgNullExceptionOnNullContext()
         {

test/Microsoft.AspNet.Razor.Test/Parser/Html/HtmlDocumentTest.cs

@@ -16,6 +16,34 @@ namespace Microsoft.AspNet.Razor.Test.Parser.Html
     {
         private static readonly TestFile Nested1000 = TestFile.Create("TestFiles/nested-1000.html");
 
+        [Fact]
+        public void ParseDocument_NestedCodeBlockWithMarkupSetsDotAsMarkup()
+        {
+            ParseDocumentTest("@if (true) { @if(false) { <div>@something.</div> } }",
+                new MarkupBlock(
+                    Factory.EmptyHtml(),
+                    new StatementBlock(
+                        Factory.CodeTransition(),
+                        Factory.Code("if (true) { ").AsStatement(),
+                        new StatementBlock(
+                            Factory.CodeTransition(),
+                            Factory.Code("if(false) {").AsStatement(),
+                            new MarkupBlock(
+                                Factory.Markup(" "),
+                                BlockFactory.MarkupTagBlock("<div>", AcceptedCharacters.None),
+                                Factory.EmptyHtml(),
+                                new ExpressionBlock(
+                                    Factory.CodeTransition(),
+                                    Factory.Code("something")
+                                        .AsImplicitExpression(CSharpCodeParser.DefaultKeywords, acceptTrailingDot: false)
+                                        .Accepts(AcceptedCharacters.NonWhiteSpace)),
+                                Factory.Markup("."),
+                                BlockFactory.MarkupTagBlock("</div>", AcceptedCharacters.None),
+                                Factory.Markup(" ").Accepts(AcceptedCharacters.None)),
+                            Factory.Code("}").AsStatement()),
+                        Factory.Code(" }").AsStatement())));
+        }
+
         [Fact]
         public void ParseDocumentMethodThrowsArgNullExceptionOnNullContext()
         {

test/Microsoft.AspNet.Razor.Test/TestFiles/CodeGenerator/Output/NestedCSharp.DesignTime.cs

@@ -0,0 +1,58 @@
+namespace TestOutput
+{
+    using System;
+    using System.Threading.Tasks;
+
+    public class NestedCSharp
+    {
+        private static object @__o;
+        private void @__RazorDesignTimeHelpers__()
+        {
+            #pragma warning disable 219
+            #pragma warning restore 219
+        }
+        #line hidden
+        public NestedCSharp()
+        {
+        }
+
+        #pragma warning disable 1998
+        public override async Task ExecuteAsync()
+        {
+#line 1 "NestedCSharp.cshtml"
+  
+    
+
+#line default
+#line hidden
+
+#line 2 "NestedCSharp.cshtml"
+    foreach (var result in (dynamic)Url)
+    {
+        
+
+#line default
+#line hidden
+
+#line 5 "NestedCSharp.cshtml"
+       __o = result.SomeValue;
+
+#line default
+#line hidden
+#line 6 "NestedCSharp.cshtml"
+              
+    }
+
+#line default
+#line hidden
+
+#line 7 "NestedCSharp.cshtml"
+     
+
+#line default
+#line hidden
+
+        }
+        #pragma warning restore 1998
+    }
+}

test/Microsoft.AspNet.Razor.Test/TestFiles/CodeGenerator/Output/NestedCSharp.cs

@@ -0,0 +1,59 @@
+#pragma checksum "NestedCSharp.cshtml" "{ff1816ec-aa5e-4d10-87f7-6f4963833460}" "2b9e8dcf7c08153c15ac84973938a7c0254f2369"
+namespace TestOutput
+{
+    using System;
+    using System.Threading.Tasks;
+
+    public class NestedCSharp
+    {
+        #line hidden
+        public NestedCSharp()
+        {
+        }
+
+        #pragma warning disable 1998
+        public override async Task ExecuteAsync()
+        {
+#line 1 "NestedCSharp.cshtml"
+  
+    
+
+#line default
+#line hidden
+
+#line 2 "NestedCSharp.cshtml"
+     foreach (var result in (dynamic)Url)
+    {
+
+#line default
+#line hidden
+
+            Instrumentation.BeginContext(54, 27, true);
+            WriteLiteral("        <div>\r\n            ");
+            Instrumentation.EndContext();
+            Instrumentation.BeginContext(82, 16, false);
+#line 5 "NestedCSharp.cshtml"
+       Write(result.SomeValue);
+
+#line default
+#line hidden
+            Instrumentation.EndContext();
+            Instrumentation.BeginContext(98, 19, true);
+            WriteLiteral(".\r\n        </div>\r\n");
+            Instrumentation.EndContext();
+#line 7 "NestedCSharp.cshtml"
+    }
+
+#line default
+#line hidden
+
+#line 7 "NestedCSharp.cshtml"
+     
+
+#line default
+#line hidden
+
+        }
+        #pragma warning restore 1998
+    }
+}

test/Microsoft.AspNet.Razor.Test/TestFiles/CodeGenerator/Source/NestedCSharp.cshtml

@@ -0,0 +1,8 @@
+@{
+    @foreach (var result in (dynamic)Url)
+    {
+        <div>
+            @result.SomeValue.
+        </div>
+    }
+}