diff --git a/src/Microsoft.AspNet.Razor/Parser/CSharpCodeParser.cs b/src/Microsoft.AspNet.Razor/Parser/CSharpCodeParser.cs
index d8ffdcc661..a2290e42e6 100644
--- a/src/Microsoft.AspNet.Razor/Parser/CSharpCodeParser.cs
+++ b/src/Microsoft.AspNet.Razor/Parser/CSharpCodeParser.cs
@@ -149,7 +149,7 @@ namespace Microsoft.AspNet.Razor.Parser
                     var current = CurrentSymbol;
                     if (At(CSharpSymbolType.StringLiteral) && CurrentSymbol.Content.Length > 0 && CurrentSymbol.Content[0] == SyntaxConstants.TransitionCharacter)
                     {
-                        Tuple<CSharpSymbol, CSharpSymbol> split = Language.SplitSymbol(CurrentSymbol, 1, CSharpSymbolType.Transition);
+                        var split = Language.SplitSymbol(CurrentSymbol, 1, CSharpSymbolType.Transition);
                         current = split.Item1;
                         Context.Source.Position = split.Item2.Start.AbsoluteIndex;
                         NextToken();
diff --git a/src/Microsoft.AspNet.Razor/Parser/HtmlMarkupParser.Block.cs b/src/Microsoft.AspNet.Razor/Parser/HtmlMarkupParser.Block.cs
index 6df8333bf7..351db46641 100644
--- a/src/Microsoft.AspNet.Razor/Parser/HtmlMarkupParser.Block.cs
+++ b/src/Microsoft.AspNet.Razor/Parser/HtmlMarkupParser.Block.cs
@@ -316,7 +316,7 @@ namespace Microsoft.AspNet.Razor.Parser
                 var matched = RemoveTag(tags, tagName, tagStart);
 
                 if (tags.Count == 0 &&
-                    // Note tagName may contain a '!' escape character. This ensures </!text> doesn't match here. 
+                    // Note tagName may contain a '!' escape character. This ensures </!text> doesn't match here.
                     // </!text> tags are treated like any other escaped HTML end tag.
                     string.Equals(tagName, SyntaxConstants.TextTagName, StringComparison.OrdinalIgnoreCase) &&
                     matched)
@@ -491,7 +491,7 @@ namespace Microsoft.AspNet.Razor.Parser
         private void AttributePrefix(IEnumerable<HtmlSymbol> whitespace, IEnumerable<HtmlSymbol> nameSymbols)
         {
             // First, determine if this is a 'data-' attribute (since those can't use conditional attributes)
-            LocationTagged<string> name = nameSymbols.GetContent(Span.Start);
+            var name = nameSymbols.GetContent(Span.Start);
             var attributeCanBeConditional = !name.Value.StartsWith("data-", StringComparison.OrdinalIgnoreCase);
 
             // Accept the whitespace and name
@@ -507,7 +507,7 @@ namespace Microsoft.AspNet.Razor.Parser
             }
 
             // We now have the prefix: (i.e. '      foo="')
-            LocationTagged<string> prefix = Span.GetContent();
+            var prefix = Span.GetContent();
 
             if (attributeCanBeConditional)
             {
@@ -521,7 +521,7 @@ namespace Microsoft.AspNet.Razor.Parser
                 }
 
                 // Capture the suffix
-                LocationTagged<string> suffix = new LocationTagged<string>(string.Empty, CurrentLocation);
+                var suffix = new LocationTagged<string>(string.Empty, CurrentLocation);
                 if (quote != HtmlSymbolType.Unknown && At(quote))
                 {
                     suffix = CurrentSymbol.GetContent();
@@ -554,23 +554,45 @@ namespace Microsoft.AspNet.Razor.Parser
         {
             var prefixStart = CurrentLocation;
             var prefix = ReadWhile(sym => sym.Type == HtmlSymbolType.WhiteSpace || sym.Type == HtmlSymbolType.NewLine);
-            Accept(prefix);
 
             if (At(HtmlSymbolType.Transition))
             {
-                var valueStart = CurrentLocation;
-                PutCurrentBack();
-
-                // Output the prefix but as a null-span. DynamicAttributeBlockCodeGenerator will render it
-                Span.CodeGenerator = SpanCodeGenerator.Null;
-
-                // Dynamic value, start a new block and set the code generator
-                using (Context.StartBlock(BlockType.Markup))
+                if (NextIs(HtmlSymbolType.Transition))
                 {
-                    Context.CurrentBlock.CodeGenerator =
-                        new DynamicAttributeBlockCodeGenerator(prefix.GetContent(prefixStart), valueStart);
+                    // Wrapping this in a block so that the ConditionalAttributeCollapser doesn't rewrite it.
+                    using (Context.StartBlock(BlockType.Markup))
+                    {
+                        Accept(prefix);
 
-                    OtherParserBlock();
+                        // Render a single "@" in place of "@@".
+                        Span.CodeGenerator = new LiteralAttributeCodeGenerator(
+                            prefix.GetContent(prefixStart),
+                            new LocationTagged<string>(CurrentSymbol.GetContent(), CurrentLocation));
+                        AcceptAndMoveNext();
+                        Output(SpanKind.Markup, AcceptedCharacters.None);
+
+                        Span.CodeGenerator = SpanCodeGenerator.Null;
+                        AcceptAndMoveNext();
+                        Output(SpanKind.Markup, AcceptedCharacters.None);
+                    }
+                }
+                else
+                {
+                    Accept(prefix);
+                    var valueStart = CurrentLocation;
+                    PutCurrentBack();
+
+                    // Output the prefix but as a null-span. DynamicAttributeBlockCodeGenerator will render it
+                    Span.CodeGenerator = SpanCodeGenerator.Null;
+
+                    // Dynamic value, start a new block and set the code generator
+                    using (Context.StartBlock(BlockType.Markup))
+                    {
+                        Context.CurrentBlock.CodeGenerator =
+                            new DynamicAttributeBlockCodeGenerator(prefix.GetContent(prefixStart), valueStart);
+
+                        OtherParserBlock();
+                    }
                 }
             }
             else if (At(HtmlSymbolType.Text) &&
@@ -578,6 +600,8 @@ namespace Microsoft.AspNet.Razor.Parser
                      CurrentSymbol.Content[0] == '~' &&
                      NextIs(HtmlSymbolType.ForwardSlash))
             {
+                Accept(prefix);
+
                 // Virtual Path value
                 var valueStart = CurrentLocation;
                 VirtualPath();
@@ -587,6 +611,8 @@ namespace Microsoft.AspNet.Razor.Parser
             }
             else
             {
+                Accept(prefix);
+
                 // Literal value
                 // 'quote' should be "Unknown" if not quoted and symbols coming from the tokenizer should never have "Unknown" type.
                 var value = ReadWhile(sym =>
@@ -719,7 +745,7 @@ namespace Microsoft.AspNet.Razor.Parser
             Tuple<HtmlSymbol, SourceLocation> tag = Tuple.Create(tagName, _lastTagStart);
 
             if (tags.Count == 0 &&
-                // Note tagName may contain a '!' escape character. This ensures <!text> doesn't match here. 
+                // Note tagName may contain a '!' escape character. This ensures <!text> doesn't match here.
                 // <!text> tags are treated like any other escaped HTML start tag.
                 string.Equals(tag.Item1.Content, SyntaxConstants.TextTagName, StringComparison.OrdinalIgnoreCase))
             {
diff --git a/test/Microsoft.AspNet.Razor.Test/Framework/ParserTestBase.cs b/test/Microsoft.AspNet.Razor.Test/Framework/ParserTestBase.cs
index 8bf3b498d4..439d8643d2 100644
--- a/test/Microsoft.AspNet.Razor.Test/Framework/ParserTestBase.cs
+++ b/test/Microsoft.AspNet.Razor.Test/Framework/ParserTestBase.cs
@@ -277,15 +277,14 @@ namespace Microsoft.AspNet.Razor.Test.Framework
             // Evaluate the result
             var collector = new ErrorCollector();
 
-            // Link all the nodes
-            expectedRoot.LinkNodes();
-
             if (expectedRoot == null)
             {
                 Assert.Null(actualRoot);
             }
             else
             {
+                // Link all the nodes
+                expectedRoot.LinkNodes();
                 Assert.NotNull(actualRoot);
                 EvaluateSyntaxTreeNode(collector, actualRoot, expectedRoot);
                 if (collector.Success)
@@ -412,7 +411,7 @@ namespace Microsoft.AspNet.Razor.Test.Framework
                         actual.TagName,
                         actual.SelfClosing);
                 }
-                
+
                 var expectedAttributes = expected.Attributes.GetEnumerator();
                 var actualAttributes = actual.Attributes.GetEnumerator();
 
diff --git a/test/Microsoft.AspNet.Razor.Test/Parser/CSharp/CSharpBlockTest.cs b/test/Microsoft.AspNet.Razor.Test/Parser/CSharp/CSharpBlockTest.cs
index 49bf645ef7..054b1a9aca 100644
--- a/test/Microsoft.AspNet.Razor.Test/Parser/CSharp/CSharpBlockTest.cs
+++ b/test/Microsoft.AspNet.Razor.Test/Parser/CSharp/CSharpBlockTest.cs
@@ -7,6 +7,7 @@ using Microsoft.AspNet.Razor.Parser;
 using Microsoft.AspNet.Razor.Parser.SyntaxTree;
 using Microsoft.AspNet.Razor.Test.Framework;
 using Microsoft.AspNet.Razor.Text;
+using Microsoft.AspNet.Razor.Tokenizer;
 using Microsoft.AspNet.Razor.Tokenizer.Symbols;
 using Xunit;
 
@@ -704,8 +705,8 @@ catch(bar) { baz(); }", BlockType.Statement, SpanKind.Code);
                                     Factory.Markup("<a"),
                                     new MarkupBlock(
                                         new AttributeBlockCodeGenerator(
-                                            "href", 
-                                            new LocationTagged<string>(" href=\"", 183 + Environment.NewLine.Length * 5, 5, 30), 
+                                            "href",
+                                            new LocationTagged<string>(" href=\"", 183 + Environment.NewLine.Length * 5, 5, 30),
                                             new LocationTagged<string>("\"", 246 + Environment.NewLine.Length * 5, 5, 93)),
                                         Factory.Markup(" href=\"").With(SpanCodeGenerator.Null),
                                         new MarkupBlock(
@@ -736,6 +737,322 @@ catch(bar) { baz(); }", BlockType.Statement, SpanKind.Code);
                     Factory.Code("        }").AsStatement().Accepts(AcceptedCharacters.None)));
         }
 
+        public static TheoryData BlockWithEscapedTransitionData
+        {
+            get
+            {
+                var factory = CreateDefaultSpanFactory();
+                var datetimeBlock = new ExpressionBlock(
+                    factory.CodeTransition(),
+                    factory.Code("DateTime.Now")
+                        .AsImplicitExpression(CSharpCodeParser.DefaultKeywords)
+                        .Accepts(AcceptedCharacters.NonWhiteSpace));
+
+                return new TheoryData<string, Block>
+                {
+                    {
+                        // Double transition in attribute value
+                        "{<span foo='@@' />}",
+                        CreateStatementBlock(
+                            new MarkupBlock(
+                                new MarkupTagBlock(
+                                    factory.Markup("<span"),
+                                    new MarkupBlock(
+                                        new AttributeBlockCodeGenerator("foo", new LocationTagged<string>(" foo='", 6, 0, 6), new LocationTagged<string>("'", 14, 0, 14)),
+                                        factory.Markup(" foo='").With(SpanCodeGenerator.Null),
+                                        new MarkupBlock(
+                                            factory.Markup("@").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 12, 0, 12), new LocationTagged<string>("@", 12, 0, 12))).Accepts(AcceptedCharacters.None),
+                                            factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                        factory.Markup("'").With(SpanCodeGenerator.Null)),
+                                    factory.Markup(" />").Accepts(AcceptedCharacters.None))))
+                    },
+                    {
+                        // Double transition at the end of attribute value
+                        "{<span foo='abc@@' />}",
+                        CreateStatementBlock(
+                            new MarkupBlock(
+                                new MarkupTagBlock(
+                                    factory.Markup("<span"),
+                                    new MarkupBlock(
+                                        new AttributeBlockCodeGenerator("foo", new LocationTagged<string>(" foo='", 6, 0, 6), new LocationTagged<string>("'", 17, 0, 17)),
+                                        factory.Markup(" foo='").With(SpanCodeGenerator.Null),
+                                        factory.Markup("abc").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 12, 0, 12), new LocationTagged<string>("abc", 12, 0, 12))),
+                                        new MarkupBlock(
+                                            factory.Markup("@").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 15, 0, 15), new LocationTagged<string>("@", 15, 0, 15))).Accepts(AcceptedCharacters.None),
+                                            factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                        factory.Markup("'").With(SpanCodeGenerator.Null)),
+                                factory.Markup(" />").Accepts(AcceptedCharacters.None))))
+                    },
+                    {
+                        // Double transition at the beginning attribute value
+                        "{<span foo='@@def' />}",
+                        CreateStatementBlock(
+                            new MarkupBlock(
+                                new MarkupTagBlock(
+                                    factory.Markup("<span"),
+                                    new MarkupBlock(
+                                        new AttributeBlockCodeGenerator("foo", new LocationTagged<string>(" foo='", 6, 0, 6), new LocationTagged<string>("'", 17, 0, 17)),
+                                        factory.Markup(" foo='").With(SpanCodeGenerator.Null),
+                                        new MarkupBlock(
+                                            factory.Markup("@").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 12, 0, 12), new LocationTagged<string>("@", 12, 0, 12))).Accepts(AcceptedCharacters.None),
+                                            factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                        factory.Markup("def").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 14, 0, 14), new LocationTagged<string>("def", 14, 0, 14))),
+                                        factory.Markup("'").With(SpanCodeGenerator.Null)),
+                                factory.Markup(" />").Accepts(AcceptedCharacters.None))))
+                    },
+                    {
+                        // Double transition in between attribute value
+                        "{<span foo='abc @@ def' />}",
+                        CreateStatementBlock(
+                            new MarkupBlock(
+                                new MarkupTagBlock(
+                                    factory.Markup("<span"),
+                                    new MarkupBlock(
+                                        new AttributeBlockCodeGenerator("foo", new LocationTagged<string>(" foo='", 6, 0, 6), new LocationTagged<string>("'", 22, 0, 22)),
+                                        factory.Markup(" foo='").With(SpanCodeGenerator.Null),
+                                        factory.Markup("abc").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 12, 0, 12), new LocationTagged<string>("abc", 12, 0, 12))),
+                                        new MarkupBlock(
+                                            factory.Markup(" @").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(" ", 15, 0, 15), new LocationTagged<string>("@", 16, 0, 16))).Accepts(AcceptedCharacters.None),
+                                            factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                        factory.Markup(" def").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(" ", 18, 0, 18), new LocationTagged<string>("def", 19, 0, 19))),
+                                        factory.Markup("'").With(SpanCodeGenerator.Null)),
+                                factory.Markup(" />").Accepts(AcceptedCharacters.None))))
+                    },
+                    {
+                        // Double transition with expression block
+                        "{<span foo='@@@DateTime.Now' />}",
+                        CreateStatementBlock(
+                            new MarkupBlock(
+                                new MarkupTagBlock(
+                                    factory.Markup("<span"),
+                                    new MarkupBlock(
+                                        new AttributeBlockCodeGenerator("foo", new LocationTagged<string>(" foo='", 6, 0, 6), new LocationTagged<string>("'", 27, 0, 27)),
+                                        factory.Markup(" foo='").With(SpanCodeGenerator.Null),
+                                        new MarkupBlock(
+                                            factory.Markup("@").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 12, 0, 12), new LocationTagged<string>("@", 12, 0, 12))).Accepts(AcceptedCharacters.None),
+                                            factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                        new MarkupBlock(
+                                            new DynamicAttributeBlockCodeGenerator(new LocationTagged<string>(string.Empty, 14, 0, 14), 14, 0, 14),
+                                            factory.EmptyHtml().With(SpanCodeGenerator.Null),
+                                            datetimeBlock),
+                                        factory.Markup("'").With(SpanCodeGenerator.Null)),
+                                factory.Markup(" />").Accepts(AcceptedCharacters.None))))
+                    },
+                    {
+                        "{<span foo='@DateTime.Now @@' />}",
+                        CreateStatementBlock(
+                            new MarkupBlock(
+                                new MarkupTagBlock(
+                                    factory.Markup("<span"),
+                                    new MarkupBlock(
+                                        new AttributeBlockCodeGenerator("foo", new LocationTagged<string>(" foo='", 6, 0, 6), new LocationTagged<string>("'", 28, 0, 28)),
+                                        factory.Markup(" foo='").With(SpanCodeGenerator.Null),
+                                        new MarkupBlock(
+                                            new DynamicAttributeBlockCodeGenerator(new LocationTagged<string>(string.Empty, 12, 0, 12), 12, 0, 12),
+                                            datetimeBlock),
+                                        new MarkupBlock(
+                                            factory.Markup(" @").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(" ", 25, 0, 25), new LocationTagged<string>("@", 26, 0, 26))).Accepts(AcceptedCharacters.None),
+                                            factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                        factory.Markup("'").With(SpanCodeGenerator.Null)),
+                                factory.Markup(" />").Accepts(AcceptedCharacters.None))))
+                    },
+                    {
+                        "{<span foo='@DateTime.Now@@' />}",
+                        CreateStatementBlock(
+                            new MarkupBlock(
+                                new MarkupTagBlock(
+                                    factory.Markup("<span"),
+                                    new MarkupBlock(
+                                        new AttributeBlockCodeGenerator("foo", new LocationTagged<string>(" foo='", 6, 0, 6), new LocationTagged<string>("'", 27, 0, 27)),
+                                        factory.Markup(" foo='").With(SpanCodeGenerator.Null),
+                                        new MarkupBlock(
+                                            new DynamicAttributeBlockCodeGenerator(new LocationTagged<string>(string.Empty, 12, 0, 12), 12, 0, 12),
+                                            datetimeBlock),
+                                        new MarkupBlock(
+                                            factory.Markup("@").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 25, 0, 25), new LocationTagged<string>("@", 25, 0, 25))).Accepts(AcceptedCharacters.None),
+                                            factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                        factory.Markup("'").With(SpanCodeGenerator.Null)),
+                                factory.Markup(" />").Accepts(AcceptedCharacters.None))))
+                    },
+                    {
+                        "{<span foo='@(2+3)@@@DateTime.Now' />}",
+                        CreateStatementBlock(
+                            new MarkupBlock(
+                                new MarkupTagBlock(
+                                    factory.Markup("<span"),
+                                    new MarkupBlock(
+                                        new AttributeBlockCodeGenerator("foo", new LocationTagged<string>(" foo='", 6, 0, 6), new LocationTagged<string>("'", 33, 0, 33)),
+                                        factory.Markup(" foo='").With(SpanCodeGenerator.Null),
+                                        new MarkupBlock(
+                                            new DynamicAttributeBlockCodeGenerator(new LocationTagged<string>(string.Empty, 12, 0, 12), 12, 0, 12),
+                                            new ExpressionBlock(
+                                                factory.CodeTransition(),
+                                                factory.MetaCode("(").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None),
+                                                factory.Code("2+3").AsExpression(),
+                                                factory.MetaCode(")").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None))),
+                                        new MarkupBlock(
+                                            factory.Markup("@").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 18, 0, 18), new LocationTagged<string>("@", 18, 0, 18))).Accepts(AcceptedCharacters.None),
+                                            factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                        new MarkupBlock(
+                                            new DynamicAttributeBlockCodeGenerator(new LocationTagged<string>(string.Empty, 20, 0, 20), 20, 0, 20),
+                                            factory.EmptyHtml().With(SpanCodeGenerator.Null),
+                                            datetimeBlock),
+                                        factory.Markup("'").With(SpanCodeGenerator.Null)),
+                                factory.Markup(" />").Accepts(AcceptedCharacters.None))))
+                    },
+                    {
+                        "{<span foo='@@@(2+3)' />}",
+                        CreateStatementBlock(
+                            new MarkupBlock(
+                                new MarkupTagBlock(
+                                    factory.Markup("<span"),
+                                    new MarkupBlock(
+                                        new AttributeBlockCodeGenerator("foo", new LocationTagged<string>(" foo='", 6, 0, 6), new LocationTagged<string>("'", 20, 0, 20)),
+                                        factory.Markup(" foo='").With(SpanCodeGenerator.Null),
+                                        new MarkupBlock(
+                                            factory.Markup("@").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 12, 0, 12), new LocationTagged<string>("@", 12, 0, 12))).Accepts(AcceptedCharacters.None),
+                                            factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                        new MarkupBlock(
+                                            new DynamicAttributeBlockCodeGenerator(new LocationTagged<string>(string.Empty, 14, 0, 14), 14, 0, 14),
+                                            factory.EmptyHtml().With(SpanCodeGenerator.Null),
+                                            new ExpressionBlock(
+                                                factory.CodeTransition(),
+                                                factory.MetaCode("(").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None),
+                                                factory.Code("2+3").AsExpression(),
+                                                factory.MetaCode(")").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None))),
+                                        factory.Markup("'").With(SpanCodeGenerator.Null)),
+                                factory.Markup(" />").Accepts(AcceptedCharacters.None))))
+                    },
+                    {
+                        // Double transition with email in attribute value
+                        "{<span foo='abc@def.com @@' />}",
+                        CreateStatementBlock(
+                            new MarkupBlock(
+                                new MarkupTagBlock(
+                                    factory.Markup("<span"),
+                                    new MarkupBlock(
+                                        new AttributeBlockCodeGenerator("foo", new LocationTagged<string>(" foo='", 6, 0, 6), new LocationTagged<string>("'", 26, 0, 26)),
+                                        factory.Markup(" foo='").With(SpanCodeGenerator.Null),
+                                        factory.Markup("abc@def.com").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 12, 0, 12), new LocationTagged<string>("abc@def.com", 12, 0, 12))),
+                                        new MarkupBlock(
+                                            factory.Markup(" @").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(" ", 23, 0, 23), new LocationTagged<string>("@", 24, 0, 24))).Accepts(AcceptedCharacters.None),
+                                            factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                        factory.Markup("'").With(SpanCodeGenerator.Null)),
+                                factory.Markup(" />").Accepts(AcceptedCharacters.None))))
+                    },
+                    {
+                        "{<span foo='abc@@def.com @@' />}",
+                        CreateStatementBlock(
+                            new MarkupBlock(
+                                new MarkupTagBlock(
+                                    factory.Markup("<span"),
+                                    new MarkupBlock(
+                                        new AttributeBlockCodeGenerator("foo", new LocationTagged<string>(" foo='", 6, 0, 6), new LocationTagged<string>("'", 27, 0, 27)),
+                                        factory.Markup(" foo='").With(SpanCodeGenerator.Null),
+                                        factory.Markup("abc").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 12, 0, 12), new LocationTagged<string>("abc", 12, 0, 12))),
+                                        new MarkupBlock(
+                                            factory.Markup("@").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 15, 0, 15), new LocationTagged<string>("@", 15, 0, 15))).Accepts(AcceptedCharacters.None),
+                                            factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                        factory.Markup("def.com").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 17, 0, 17), new LocationTagged<string>("def.com", 17, 0, 17))),
+                                        new MarkupBlock(
+                                            factory.Markup(" @").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(" ", 24, 0, 24), new LocationTagged<string>("@", 25, 0, 25))).Accepts(AcceptedCharacters.None),
+                                            factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                        factory.Markup("'").With(SpanCodeGenerator.Null)),
+                                factory.Markup(" />").Accepts(AcceptedCharacters.None))))
+                    },
+                    {
+                        // Double transition in complex regex in attribute value
+                        @"{<span foo=""/^[a-z0-9!#$%&'*+\/=?^_`{|}~.-]+@@[a-z0-9]([a-z0-9-]*[a-z0-9])?\.([a-z0-9]([a-z0-9-]*[a-z0-9])?)*$/i"" />}",
+                        CreateStatementBlock(
+                            new MarkupBlock(
+                                new MarkupTagBlock(
+                                    factory.Markup("<span"),
+                                    new MarkupBlock(
+                                        new AttributeBlockCodeGenerator("foo", new LocationTagged<string>(" foo=\"", 6, 0, 6), new LocationTagged<string>("\"", 112, 0, 112)),
+                                        factory.Markup(" foo=\"").With(SpanCodeGenerator.Null),
+                                        factory.Markup(@"/^[a-z0-9!#$%&'*+\/=?^_`{|}~.-]+").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 12, 0, 12), new LocationTagged<string>(@"/^[a-z0-9!#$%&'*+\/=?^_`{|}~.-]+", 12, 0, 12))),
+                                        new MarkupBlock(
+                                            factory.Markup("@").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 44, 0, 44), new LocationTagged<string>("@", 44, 0, 44))).Accepts(AcceptedCharacters.None),
+                                            factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                        factory.Markup(@"[a-z0-9]([a-z0-9-]*[a-z0-9])?\.([a-z0-9]([a-z0-9-]*[a-z0-9])?)*$/i").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 46, 0, 46), new LocationTagged<string>(@"[a-z0-9]([a-z0-9-]*[a-z0-9])?\.([a-z0-9]([a-z0-9-]*[a-z0-9])?)*$/i", 46, 0, 46))),
+                                        factory.Markup("\"").With(SpanCodeGenerator.Null)),
+                                factory.Markup(" />").Accepts(AcceptedCharacters.None))))
+                    },
+                };
+            }
+        }
+
+        [Theory]
+        [MemberData(nameof(BlockWithEscapedTransitionData))]
+        public void ParseBlock_WithDoubleTransition_DoesNotThrow(string input, Block expected)
+        {
+            // Act & Assert
+            ParseBlockTest(input, expected);
+        }
+
+        [Fact]
+        public void ParseBlock_WithDoubleTransition_EndOfFile_Throws()
+        {
+            // Arrange
+            var expected = new StatementBlock(
+                Factory.MetaCode("{").Accepts(AcceptedCharacters.None),
+                new MarkupBlock(
+                    new MarkupTagBlock(
+                        Factory.Markup("<span"),
+                        new MarkupBlock(
+                        new AttributeBlockCodeGenerator("foo", new LocationTagged<string>(" foo='", 6, 0, 6), new LocationTagged<string>(string.Empty, 14, 0, 14)),
+                        Factory.Markup(" foo='").With(SpanCodeGenerator.Null),
+                        new MarkupBlock(
+                            Factory.Markup("@").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 12, 0, 12), new LocationTagged<string>("@", 12, 0, 12))).Accepts(AcceptedCharacters.None),
+                            Factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)))),
+                Factory.EmptyHtml()));
+            var expectedErrors = new RazorError[]
+            {
+                new RazorError(@"End of file or an unexpected character was reached before the ""span"" tag could be parsed.  Elements inside markup blocks must be complete. They must either be self-closing (""<br />"") or have matching end tags (""<p>Hello</p>"").  If you intended to display a ""<"" character, use the ""&lt;"" HTML entity.", new SourceLocation(1, 0, 1)),
+                new RazorError(@"The code block is missing a closing ""}"" character.  Make sure you have a matching ""}"" character for all the ""{"" characters within this block, and that none of the ""}"" characters are being interpreted as markup.", new SourceLocation(0, 0, 0)),
+            };
+
+            // Act & Assert
+            ParseBlockTest("{<span foo='@@", expected, expectedErrors);
+        }
+
+        [Fact]
+        public void ParseBlock_WithUnexpectedTransitionsInAttributeValue_Throws()
+        {
+            // Arrange
+            var expected = new StatementBlock(
+                Factory.MetaCode("{").Accepts(AcceptedCharacters.None),
+                new MarkupBlock(
+                    new MarkupTagBlock(
+                        Factory.Markup("<span"),
+                        new MarkupBlock(
+                        new AttributeBlockCodeGenerator("foo", new LocationTagged<string>(" foo='", 6, 0, 6), new LocationTagged<string>("'", 15, 0, 15)),
+                        Factory.Markup(" foo='").With(SpanCodeGenerator.Null),
+                        new MarkupBlock(
+                            new DynamicAttributeBlockCodeGenerator(new LocationTagged<string>(string.Empty, 12, 0, 12), 12, 0, 12),
+                            new ExpressionBlock(
+                                Factory.CodeTransition(),
+                                Factory.EmptyCSharp().AsImplicitExpression(CSharpCodeParser.DefaultKeywords).Accepts(AcceptedCharacters.NonWhiteSpace))),
+                        new MarkupBlock(
+                            new DynamicAttributeBlockCodeGenerator(new LocationTagged<string>(" ", 13, 0, 13), 13, 0, 13),
+                            Factory.Markup(" ").With(SpanCodeGenerator.Null),
+                            new ExpressionBlock(
+                                Factory.CodeTransition(),
+                                Factory.EmptyCSharp().AsImplicitExpression(CSharpCodeParser.DefaultKeywords).Accepts(AcceptedCharacters.NonWhiteSpace))),
+                        Factory.Markup("'").With(SpanCodeGenerator.Null)),
+                    Factory.Markup(" />").Accepts(AcceptedCharacters.None))),
+                Factory.EmptyCSharp().AsStatement(),
+                Factory.MetaCode("}").Accepts(AcceptedCharacters.None));
+            var expectedErrors = new RazorError[]
+            {
+                new RazorError(@"A space or line break was encountered after the ""@"" character.  Only valid identifiers, keywords, comments, ""("" and ""{"" are valid at the start of a code block and they must occur immediately following ""@"" with no space in between.", new SourceLocation(13, 0, 13)),
+                new RazorError(@"""' />}"" is not valid at the start of a code block.  Only identifiers, keywords, comments, ""("" and ""{"" are valid.", new SourceLocation(15, 0, 15)),
+            };
+
+            // Act & Assert
+            ParseBlockTest("{<span foo='@ @' />}", expected, expectedErrors);
+        }
+
         private void RunRazorCommentBetweenClausesTest(string preComment, string postComment, AcceptedCharacters acceptedCharacters = AcceptedCharacters.Any)
         {
             ParseBlockTest(preComment + "@* Foo *@ @* Bar *@" + postComment,
@@ -786,5 +1103,24 @@ catch(bar) { baz(); }", BlockType.Statement, SpanKind.Code);
                                    .Accepts(acceptedCharacters)),
                            errors);
         }
+
+        private static SpanFactory CreateDefaultSpanFactory()
+        {
+            return new SpanFactory
+            {
+                MarkupTokenizerFactory = doc => new HtmlTokenizer(doc),
+                CodeTokenizerFactory = doc => new CSharpTokenizer(doc)
+            };
+        }
+
+        private static StatementBlock CreateStatementBlock(MarkupBlock block)
+        {
+            var factory = CreateDefaultSpanFactory();
+            return new StatementBlock(
+                factory.MetaCode("{").Accepts(AcceptedCharacters.None),
+                block,
+                factory.EmptyCSharp().AsStatement(),
+                factory.MetaCode("}").Accepts(AcceptedCharacters.None));
+        }
     }
 }
diff --git a/test/Microsoft.AspNet.Razor.Test/Parser/CSharp/CSharpSectionTest.cs b/test/Microsoft.AspNet.Razor.Test/Parser/CSharp/CSharpSectionTest.cs
index 2f98aaf722..3adb784f5f 100644
--- a/test/Microsoft.AspNet.Razor.Test/Parser/CSharp/CSharpSectionTest.cs
+++ b/test/Microsoft.AspNet.Razor.Test/Parser/CSharp/CSharpSectionTest.cs
@@ -6,6 +6,8 @@ using Microsoft.AspNet.Razor.Generator;
 using Microsoft.AspNet.Razor.Parser;
 using Microsoft.AspNet.Razor.Parser.SyntaxTree;
 using Microsoft.AspNet.Razor.Test.Framework;
+using Microsoft.AspNet.Razor.Text;
+using Microsoft.AspNet.Razor.Tokenizer;
 using Xunit;
 
 namespace Microsoft.AspNet.Razor.Test.Parser.CSharp
@@ -443,5 +445,84 @@ namespace Microsoft.AspNet.Razor.Test.Parser.CSharp
                         Factory.MetaCode("}").Accepts(AcceptedCharacters.None)),
                     Factory.EmptyHtml()));
         }
+
+        public static TheoryData SectionWithEscapedTransitionData
+        {
+            get
+            {
+                var factory = CreateDefaultSpanFactory();
+
+                return new TheoryData<string, Block>
+                {
+                    {
+                        "@section s {<span foo='@@' />}",
+                        new MarkupBlock(
+                            factory.EmptyHtml(),
+                            new SectionBlock(new SectionCodeGenerator("s"),
+                                factory.CodeTransition(),
+                                factory.MetaCode("section s {")
+                                    .AutoCompleteWith(null, atEndOfSpan: true),
+                            new MarkupBlock(
+                                new MarkupTagBlock(
+                                    factory.Markup("<span"),
+                                    new MarkupBlock(
+                                        new AttributeBlockCodeGenerator("foo", new LocationTagged<string>(" foo='", 17, 0, 17), new LocationTagged<string>("'", 25, 0, 25)),
+                                        factory.Markup(" foo='").With(SpanCodeGenerator.Null),
+                                        new MarkupBlock(
+                                            factory.Markup("@").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 23, 0, 23), new LocationTagged<string>("@", 23, 0, 23))).Accepts(AcceptedCharacters.None),
+                                            factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                        factory.Markup("'").With(SpanCodeGenerator.Null)),
+                                factory.Markup(" />"))),
+                            factory.MetaCode("}").Accepts(AcceptedCharacters.None)),
+                            factory.EmptyHtml())
+                    },
+                    {
+                        "@section s {<span foo='@DateTime.Now @@' />}",
+                        new MarkupBlock(
+                            factory.EmptyHtml(),
+                            new SectionBlock(new SectionCodeGenerator("s"),
+                                factory.CodeTransition(),
+                                factory.MetaCode("section s {")
+                                    .AutoCompleteWith(null, atEndOfSpan: true),
+                            new MarkupBlock(
+                                new MarkupTagBlock(
+                                    factory.Markup("<span"),
+                                    new MarkupBlock(
+                                        new AttributeBlockCodeGenerator("foo", new LocationTagged<string>(" foo='", 17, 0, 17), new LocationTagged<string>("'", 39, 0, 39)),
+                                        factory.Markup(" foo='").With(SpanCodeGenerator.Null),
+                                        new MarkupBlock(
+                                            new DynamicAttributeBlockCodeGenerator(new LocationTagged<string>(string.Empty, 23, 0, 23), 23, 0, 23),
+                                            new ExpressionBlock(
+                                                factory.CodeTransition(),
+                                                factory.Code("DateTime.Now")
+                                                    .AsImplicitExpression(CSharpCodeParser.DefaultKeywords)
+                                                    .Accepts(AcceptedCharacters.NonWhiteSpace))),
+                                     new MarkupBlock(
+                                        factory.Markup(" @").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(" ", 36, 0, 36), new LocationTagged<string>("@", 37, 0, 37))).Accepts(AcceptedCharacters.None),
+                                        factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                    factory.Markup("'").With(SpanCodeGenerator.Null)),
+                                factory.Markup(" />"))),
+                            factory.MetaCode("}").Accepts(AcceptedCharacters.None)),
+                            factory.EmptyHtml())
+                    },
+                };
+            }
+        }
+
+        [Theory]
+        [MemberData(nameof(SectionWithEscapedTransitionData))]
+        public void ParseSectionBlock_WithDoubleTransition_DoesNotThrow(string input, Block expected)
+        {
+            ParseDocumentTest(input, expected);
+        }
+
+        private static SpanFactory CreateDefaultSpanFactory()
+        {
+            return new SpanFactory
+            {
+                MarkupTokenizerFactory = doc => new HtmlTokenizer(doc),
+                CodeTokenizerFactory = doc => new CSharpTokenizer(doc)
+            };
+        }
     }
 }
diff --git a/test/Microsoft.AspNet.Razor.Test/Parser/CSharp/CSharpTemplateTest.cs b/test/Microsoft.AspNet.Razor.Test/Parser/CSharp/CSharpTemplateTest.cs
index 3b8839ab6f..95d2ed8d98 100644
--- a/test/Microsoft.AspNet.Razor.Test/Parser/CSharp/CSharpTemplateTest.cs
+++ b/test/Microsoft.AspNet.Razor.Test/Parser/CSharp/CSharpTemplateTest.cs
@@ -3,9 +3,11 @@
 
 using System;
 using Microsoft.AspNet.Razor.Editor;
+using Microsoft.AspNet.Razor.Generator;
 using Microsoft.AspNet.Razor.Parser;
 using Microsoft.AspNet.Razor.Parser.SyntaxTree;
 using Microsoft.AspNet.Razor.Test.Framework;
+using Microsoft.AspNet.Razor.Text;
 using Microsoft.AspNet.Razor.Tokenizer.Symbols;
 using Xunit;
 
@@ -272,6 +274,49 @@ namespace Microsoft.AspNet.Razor.Test.Parser.CSharp
                            GetNestedTemplateError(69));
         }
 
+        [Fact]
+        public void ParseBlock_WithDoubleTransition_DoesNotThrow()
+        {
+            // Arrange
+            var testTemplateWithDoubleTransitionCode = " @<p foo='@@'>Foo #@item</p>";
+            var testTemplateWithDoubleTransition = new TemplateBlock(
+                new MarkupBlock(
+                    Factory.MarkupTransition(),
+                    new MarkupTagBlock(
+                        Factory.Markup("<p"),
+                        new MarkupBlock(
+                            new AttributeBlockCodeGenerator("foo", new LocationTagged<string>(" foo='", 46, 0, 46), new LocationTagged<string>("'", 54, 0, 54)),
+                            Factory.Markup(" foo='").With(SpanCodeGenerator.Null),
+                             new MarkupBlock(
+                                Factory.Markup("@").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 52, 0, 52), new LocationTagged<string>("@", 52, 0, 52))).Accepts(AcceptedCharacters.None),
+                                Factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                            Factory.Markup("'").With(SpanCodeGenerator.Null)),
+                        Factory.Markup(">").Accepts(AcceptedCharacters.None)),
+                    Factory.Markup("Foo #"),
+                    new ExpressionBlock(
+                        Factory.CodeTransition(),
+                        Factory.Code("item")
+                            .AsImplicitExpression(CSharpCodeParser.DefaultKeywords)
+                            .Accepts(AcceptedCharacters.NonWhiteSpace)
+                        ),
+                    new MarkupTagBlock(
+                        Factory.Markup("</p>").Accepts(AcceptedCharacters.None))
+                    )
+                );
+
+            var expected = new StatementBlock(
+                    Factory.MetaCode("{").Accepts(AcceptedCharacters.None),
+                    Factory.Code(" var foo = bar; Html.ExecuteTemplate(foo, ")
+                        .AsStatement()
+                        .AutoCompleteWith(autoCompleteString: null),
+                    testTemplateWithDoubleTransition,
+                    Factory.Code("); ").AsStatement(),
+                    Factory.MetaCode("}").Accepts(AcceptedCharacters.None));
+
+            // Act & Assert
+            ParseBlockTest("{ var foo = bar; Html.ExecuteTemplate(foo," + testTemplateWithDoubleTransitionCode + "); }", expected);
+        }
+
         private static RazorError GetNestedTemplateError(int characterIndex)
         {
             return new RazorError(RazorResources.ParseError_InlineMarkup_Blocks_Cannot_Be_Nested, new SourceLocation(characterIndex, 0, characterIndex));
diff --git a/test/Microsoft.AspNet.Razor.Test/Parser/Html/HtmlAttributeTest.cs b/test/Microsoft.AspNet.Razor.Test/Parser/Html/HtmlAttributeTest.cs
index 9cc349ae82..5f139cc6ed 100644
--- a/test/Microsoft.AspNet.Razor.Test/Parser/Html/HtmlAttributeTest.cs
+++ b/test/Microsoft.AspNet.Razor.Test/Parser/Html/HtmlAttributeTest.cs
@@ -206,6 +206,31 @@ namespace Microsoft.AspNet.Razor.Test.Parser.Html
                         Factory.Markup(" />"))));
         }
 
+        [Fact]
+        public void ConditionalAttributeCollapserDoesNotRewriteEscapedTransitions()
+        {
+            // Act
+            var results = ParseDocument("<span foo='@@' />");
+            var rewritingContext = new RewritingContext(results.Document, new ErrorSink());
+            new ConditionalAttributeCollapser(new HtmlMarkupParser().BuildSpan).Rewrite(rewritingContext);
+            var rewritten = rewritingContext.SyntaxTree;
+
+            // Assert
+            Assert.Equal(0, results.ParserErrors.Count());
+            EvaluateParseTree(rewritten,
+                new MarkupBlock(
+                    new MarkupTagBlock(
+                        Factory.Markup("<span"),
+                        new MarkupBlock(
+                            new AttributeBlockCodeGenerator("foo", new LocationTagged<string>(" foo='", 5, 0, 5), new LocationTagged<string>("'", 13, 0, 13)),
+                            Factory.Markup(" foo='").With(SpanCodeGenerator.Null),
+                            new MarkupBlock(
+                                Factory.Markup("@").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 11, 0, 11), new LocationTagged<string>("@", 11, 0, 11))).Accepts(AcceptedCharacters.None),
+                                Factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                            Factory.Markup("'").With(SpanCodeGenerator.Null)),
+                        Factory.Markup(" />"))));
+        }
+
         [Fact]
         public void ConditionalAttributesDoNotCreateExtraDataForEntirelyLiteralAttribute()
         {
diff --git a/test/Microsoft.AspNet.Razor.Test/Parser/Html/HtmlDocumentTest.cs b/test/Microsoft.AspNet.Razor.Test/Parser/Html/HtmlDocumentTest.cs
index 1902dfc5c7..ed797f121b 100644
--- a/test/Microsoft.AspNet.Razor.Test/Parser/Html/HtmlDocumentTest.cs
+++ b/test/Microsoft.AspNet.Razor.Test/Parser/Html/HtmlDocumentTest.cs
@@ -2,11 +2,13 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Collections.Generic;
 using Microsoft.AspNet.Razor.Generator;
 using Microsoft.AspNet.Razor.Parser;
 using Microsoft.AspNet.Razor.Parser.SyntaxTree;
 using Microsoft.AspNet.Razor.Test.Framework;
 using Microsoft.AspNet.Razor.Text;
+using Microsoft.AspNet.Razor.Tokenizer;
 using Xunit;
 
 namespace Microsoft.AspNet.Razor.Test.Parser.Html
@@ -281,5 +283,302 @@ namespace Microsoft.AspNet.Razor.Test.Parser.Html
             var content = Nested1000.ReadAllText();
             ParseDocument(content);
         }
+
+        public static TheoryData BlockWithEscapedTransitionData
+        {
+            get
+            {
+                var factory = CreateDefaultSpanFactory();
+                var datetimeBlock = new ExpressionBlock(
+                    factory.CodeTransition(),
+                    factory.Code("DateTime.Now")
+                        .AsImplicitExpression(CSharpCodeParser.DefaultKeywords)
+                        .Accepts(AcceptedCharacters.NonWhiteSpace));
+
+                return new TheoryData<string, Block>
+                {
+                    {
+                        // Double transition in attribute value
+                        "<span foo='@@' />",
+                        new MarkupBlock(
+                            new MarkupTagBlock(
+                                factory.Markup("<span"),
+                                new MarkupBlock(
+                                    new AttributeBlockCodeGenerator("foo", new LocationTagged<string>(" foo='", 5, 0, 5), new LocationTagged<string>("'", 13, 0, 13)),
+                                    factory.Markup(" foo='").With(SpanCodeGenerator.Null),
+                                    new MarkupBlock(
+                                        factory.Markup("@").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 11, 0, 11), new LocationTagged<string>("@", 11, 0, 11))).Accepts(AcceptedCharacters.None),
+                                        factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                    factory.Markup("'").With(SpanCodeGenerator.Null)),
+                                factory.Markup(" />")))
+                    },
+                    {
+                        // Double transition at the end of attribute value
+                        "<span foo='abc@@' />",
+                        new MarkupBlock(
+                            new MarkupTagBlock(
+                                factory.Markup("<span"),
+                                new MarkupBlock(
+                                    new AttributeBlockCodeGenerator("foo", new LocationTagged<string>(" foo='", 5, 0, 5), new LocationTagged<string>("'", 16, 0, 16)),
+                                    factory.Markup(" foo='").With(SpanCodeGenerator.Null),
+                                    factory.Markup("abc").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 11, 0, 11), new LocationTagged<string>("abc", 11, 0, 11))),
+                                    new MarkupBlock(
+                                        factory.Markup("@").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 14, 0, 14), new LocationTagged<string>("@", 14, 0, 14))).Accepts(AcceptedCharacters.None),
+                                        factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                    factory.Markup("'").With(SpanCodeGenerator.Null)),
+                                factory.Markup(" />")))
+                    },
+                    {
+                        // Double transition at the beginning of attribute value
+                        "<span foo='@@def' />",
+                        new MarkupBlock(
+                            new MarkupTagBlock(
+                                factory.Markup("<span"),
+                                new MarkupBlock(
+                                    new AttributeBlockCodeGenerator("foo", new LocationTagged<string>(" foo='", 5, 0, 5), new LocationTagged<string>("'", 16, 0, 16)),
+                                    factory.Markup(" foo='").With(SpanCodeGenerator.Null),
+                                    new MarkupBlock(
+                                        factory.Markup("@").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 11, 0, 11), new LocationTagged<string>("@", 11, 0, 11))).Accepts(AcceptedCharacters.None),
+                                        factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                    factory.Markup("def").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 13, 0, 13), new LocationTagged<string>("def", 13, 0, 13))),
+                                    factory.Markup("'").With(SpanCodeGenerator.Null)),
+                                factory.Markup(" />")))
+                    },
+                    {
+                        // Double transition in between attribute value
+                        "<span foo='abc @@ def' />",
+                        new MarkupBlock(
+                            new MarkupTagBlock(
+                                factory.Markup("<span"),
+                                new MarkupBlock(
+                                    new AttributeBlockCodeGenerator("foo", new LocationTagged<string>(" foo='", 5, 0, 5), new LocationTagged<string>("'", 21, 0, 21)),
+                                    factory.Markup(" foo='").With(SpanCodeGenerator.Null),
+                                    factory.Markup("abc").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 11, 0, 11), new LocationTagged<string>("abc", 11, 0, 11))),
+                                    new MarkupBlock(
+                                        factory.Markup(" @").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(" ", 14, 0, 14), new LocationTagged<string>("@", 15, 0, 15))).Accepts(AcceptedCharacters.None),
+                                        factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                    factory.Markup(" def").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(" ", 17, 0, 17), new LocationTagged<string>("def", 18, 0, 18))),
+                                    factory.Markup("'").With(SpanCodeGenerator.Null)),
+                                factory.Markup(" />")))
+                    },
+                    {
+                        // Double transition with expression block
+                        "<span foo='@@@DateTime.Now' />",
+                        new MarkupBlock(
+                            new MarkupTagBlock(
+                                factory.Markup("<span"),
+                                new MarkupBlock(
+                                    new AttributeBlockCodeGenerator("foo", new LocationTagged<string>(" foo='", 5, 0, 5), new LocationTagged<string>("'", 26, 0, 26)),
+                                    factory.Markup(" foo='").With(SpanCodeGenerator.Null),
+                                    new MarkupBlock(
+                                        factory.Markup("@").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 11, 0, 11), new LocationTagged<string>("@", 11, 0, 11))).Accepts(AcceptedCharacters.None),
+                                        factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                    new MarkupBlock(
+                                        new DynamicAttributeBlockCodeGenerator(new LocationTagged<string>(string.Empty, 13, 0, 13), 13, 0, 13),
+                                        factory.EmptyHtml().With(SpanCodeGenerator.Null),
+                                        datetimeBlock),
+                                    factory.Markup("'").With(SpanCodeGenerator.Null)),
+                                factory.Markup(" />")))
+                    },
+                    {
+                        "<span foo='@DateTime.Now @@' />",
+                        new MarkupBlock(
+                            new MarkupTagBlock(
+                                factory.Markup("<span"),
+                                new MarkupBlock(
+                                    new AttributeBlockCodeGenerator("foo", new LocationTagged<string>(" foo='", 5, 0, 5), new LocationTagged<string>("'", 27, 0, 27)),
+                                    factory.Markup(" foo='").With(SpanCodeGenerator.Null),
+                                    new MarkupBlock(
+                                        new DynamicAttributeBlockCodeGenerator(new LocationTagged<string>(string.Empty, 11, 0, 11), 11, 0, 11),
+                                        datetimeBlock),
+                                    new MarkupBlock(
+                                        factory.Markup(" @").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(" ", 24, 0, 24), new LocationTagged<string>("@", 25, 0, 25))).Accepts(AcceptedCharacters.None),
+                                        factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                    factory.Markup("'").With(SpanCodeGenerator.Null)),
+                                factory.Markup(" />")))
+                    },
+                    {
+                        "<span foo='@(2+3)@@@DateTime.Now' />",
+                        new MarkupBlock(
+                            new MarkupTagBlock(
+                                factory.Markup("<span"),
+                                new MarkupBlock(
+                                    new AttributeBlockCodeGenerator("foo", new LocationTagged<string>(" foo='", 5, 0, 5), new LocationTagged<string>("'", 32, 0, 32)),
+                                    factory.Markup(" foo='").With(SpanCodeGenerator.Null),
+                                    new MarkupBlock(
+                                        new DynamicAttributeBlockCodeGenerator(new LocationTagged<string>(string.Empty, 11, 0, 11), 11, 0, 11),
+                                        new ExpressionBlock(
+                                            factory.CodeTransition(),
+                                            factory.MetaCode("(").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None),
+                                            factory.Code("2+3").AsExpression(),
+                                            factory.MetaCode(")").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None))),
+                                    new MarkupBlock(
+                                        factory.Markup("@").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 17, 0, 17), new LocationTagged<string>("@", 17, 0, 17))).Accepts(AcceptedCharacters.None),
+                                        factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                    new MarkupBlock(
+                                        new DynamicAttributeBlockCodeGenerator(new LocationTagged<string>(string.Empty, 19, 0, 19), 19, 0, 19),
+                                        factory.EmptyHtml().With(SpanCodeGenerator.Null),
+                                        datetimeBlock),
+                                    factory.Markup("'").With(SpanCodeGenerator.Null)),
+                            factory.Markup(" />")))
+                    },
+                    {
+                        "<span foo='@@@(2+3)' />",
+                        new MarkupBlock(
+                            new MarkupTagBlock(
+                                factory.Markup("<span"),
+                                new MarkupBlock(
+                                    new AttributeBlockCodeGenerator("foo", new LocationTagged<string>(" foo='", 5, 0, 5), new LocationTagged<string>("'", 19, 0, 19)),
+                                    factory.Markup(" foo='").With(SpanCodeGenerator.Null),
+                                    new MarkupBlock(
+                                        factory.Markup("@").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 11, 0, 11), new LocationTagged<string>("@", 11, 0, 11))).Accepts(AcceptedCharacters.None),
+                                        factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                    new MarkupBlock(
+                                        new DynamicAttributeBlockCodeGenerator(new LocationTagged<string>(string.Empty, 13, 0, 13), 13, 0, 13),
+                                        factory.EmptyHtml().With(SpanCodeGenerator.Null),
+                                        new ExpressionBlock(
+                                            factory.CodeTransition(),
+                                            factory.MetaCode("(").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None),
+                                            factory.Code("2+3").AsExpression(),
+                                            factory.MetaCode(")").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None))),
+                                    factory.Markup("'").With(SpanCodeGenerator.Null)),
+                            factory.Markup(" />")))
+                    },
+                    {
+                        "<span foo='@DateTime.Now@@' />",
+                        new MarkupBlock(
+                            new MarkupTagBlock(
+                                factory.Markup("<span"),
+                                new MarkupBlock(
+                                    new AttributeBlockCodeGenerator("foo", new LocationTagged<string>(" foo='", 5, 0, 5), new LocationTagged<string>("'", 26, 0, 26)),
+                                    factory.Markup(" foo='").With(SpanCodeGenerator.Null),
+                                    new MarkupBlock(
+                                        new DynamicAttributeBlockCodeGenerator(new LocationTagged<string>(string.Empty, 11, 0, 11), 11, 0, 11),
+                                        datetimeBlock),
+                                    new MarkupBlock(
+                                        factory.Markup("@").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 24, 0, 24), new LocationTagged<string>("@", 24, 0, 24))).Accepts(AcceptedCharacters.None),
+                                        factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                    factory.Markup("'").With(SpanCodeGenerator.Null)),
+                                factory.Markup(" />")))
+                    },
+                    {
+                        // Double transition with email in attribute value
+                        "<span foo='abc@def.com @@' />",
+                        new MarkupBlock(
+                            new MarkupTagBlock(
+                                factory.Markup("<span"),
+                                new MarkupBlock(
+                                    new AttributeBlockCodeGenerator("foo", new LocationTagged<string>(" foo='", 5, 0, 5), new LocationTagged<string>("'", 25, 0, 25)),
+                                    factory.Markup(" foo='").With(SpanCodeGenerator.Null),
+                                    factory.Markup("abc@def.com").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 11, 0, 11), new LocationTagged<string>("abc@def.com", 11, 0, 11))),
+                                    new MarkupBlock(
+                                        factory.Markup(" @").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(" ", 22, 0, 22), new LocationTagged<string>("@", 23, 0, 23))).Accepts(AcceptedCharacters.None),
+                                        factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                    factory.Markup("'").With(SpanCodeGenerator.Null)),
+                                factory.Markup(" />")))
+                    },
+                    {
+                        "<span foo='abc@@def.com @@' />",
+                        new MarkupBlock(
+                            new MarkupTagBlock(
+                                factory.Markup("<span"),
+                                new MarkupBlock(
+                                    new AttributeBlockCodeGenerator("foo", new LocationTagged<string>(" foo='", 5, 0, 5), new LocationTagged<string>("'", 26, 0, 26)),
+                                    factory.Markup(" foo='").With(SpanCodeGenerator.Null),
+                                    factory.Markup("abc").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 11, 0, 11), new LocationTagged<string>("abc", 11, 0, 11))),
+                                    new MarkupBlock(
+                                        factory.Markup("@").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 14, 0, 14), new LocationTagged<string>("@", 14, 0, 14))).Accepts(AcceptedCharacters.None),
+                                        factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                    factory.Markup("def.com").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 16, 0, 16), new LocationTagged<string>("def.com", 16, 0, 16))),
+                                    new MarkupBlock(
+                                        factory.Markup(" @").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(" ", 23, 0, 23), new LocationTagged<string>("@", 24, 0, 24))).Accepts(AcceptedCharacters.None),
+                                        factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                    factory.Markup("'").With(SpanCodeGenerator.Null)),
+                                factory.Markup(" />")))
+                    },
+                    {
+                        // Double transition before end of file
+                        "<span foo='@@",
+                        new MarkupBlock(
+                            new MarkupTagBlock(
+                                factory.Markup("<span"),
+                                new MarkupBlock(
+                                    new AttributeBlockCodeGenerator("foo", new LocationTagged<string>(" foo='", 5, 0, 5), new LocationTagged<string>(string.Empty, 13, 0, 13)),
+                                    factory.Markup(" foo='").With(SpanCodeGenerator.Null),
+                                    new MarkupBlock(
+                                        factory.Markup("@").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 11, 0, 11), new LocationTagged<string>("@", 11, 0, 11))).Accepts(AcceptedCharacters.None),
+                                        factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)))),
+                            factory.EmptyHtml())
+                    },
+                    {
+                        // Double transition in complex regex in attribute value
+                        @"<span foo=""/^[a-z0-9!#$%&'*+\/=?^_`{|}~.-]+@@[a-z0-9]([a-z0-9-]*[a-z0-9])?\.([a-z0-9]([a-z0-9-]*[a-z0-9])?)*$/i"" />",
+                        new MarkupBlock(
+                            new MarkupTagBlock(
+                                factory.Markup("<span"),
+                                new MarkupBlock(
+                                    new AttributeBlockCodeGenerator("foo", new LocationTagged<string>(" foo=\"", 5, 0, 5), new LocationTagged<string>("\"", 111, 0, 111)),
+                                    factory.Markup(" foo=\"").With(SpanCodeGenerator.Null),
+                                    factory.Markup(@"/^[a-z0-9!#$%&'*+\/=?^_`{|}~.-]+").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 11, 0, 11), new LocationTagged<string>(@"/^[a-z0-9!#$%&'*+\/=?^_`{|}~.-]+", 11, 0, 11))),
+                                    new MarkupBlock(
+                                        factory.Markup("@").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 43, 0, 43), new LocationTagged<string>("@", 43, 0, 43))).Accepts(AcceptedCharacters.None),
+                                        factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                    factory.Markup(@"[a-z0-9]([a-z0-9-]*[a-z0-9])?\.([a-z0-9]([a-z0-9-]*[a-z0-9])?)*$/i").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 45, 0, 45), new LocationTagged<string>(@"[a-z0-9]([a-z0-9-]*[a-z0-9])?\.([a-z0-9]([a-z0-9-]*[a-z0-9])?)*$/i", 45, 0, 45))),
+                                    factory.Markup("\"").With(SpanCodeGenerator.Null)),
+                                factory.Markup(" />")))
+                    },
+                };
+            }
+        }
+
+        [Theory]
+        [MemberData(nameof(BlockWithEscapedTransitionData))]
+        public void ParseBlock_WithDoubleTransition_DoesNotThrow(string input, Block expected)
+        {
+            // Act & Assert
+            ParseDocumentTest(input, expected);
+        }
+
+        [Fact]
+        public void ParseDocument_WithUnexpectedTransitionsInAttributeValue_Throws()
+        {
+            // Arrange
+            var expected = new MarkupBlock(
+                new MarkupTagBlock(
+                    Factory.Markup("<span"),
+                    new MarkupBlock(
+                        new AttributeBlockCodeGenerator("foo", new LocationTagged<string>(" foo='", 5, 0, 5), new LocationTagged<string>("'", 14, 0, 14)),
+                        Factory.Markup(" foo='").With(SpanCodeGenerator.Null),
+                        new MarkupBlock(
+                            new DynamicAttributeBlockCodeGenerator(new LocationTagged<string>(string.Empty, 11, 0, 11), 11, 0, 11),
+                            new ExpressionBlock(
+                                Factory.CodeTransition(),
+                                Factory.EmptyCSharp().AsImplicitExpression(CSharpCodeParser.DefaultKeywords).Accepts(AcceptedCharacters.NonWhiteSpace))),
+                        new MarkupBlock(
+                            new DynamicAttributeBlockCodeGenerator(new LocationTagged<string>(" ", 12, 0, 12), 12, 0, 12),
+                            Factory.Markup(" ").With(SpanCodeGenerator.Null),
+                            new ExpressionBlock(
+                                Factory.CodeTransition().Accepts(AcceptedCharacters.None).With(SpanCodeGenerator.Null),
+                                Factory.EmptyCSharp().AsImplicitExpression(CSharpCodeParser.DefaultKeywords).Accepts(AcceptedCharacters.NonWhiteSpace))),
+                        Factory.Markup("'").With(SpanCodeGenerator.Null)),
+                    Factory.Markup(" />")));
+            var expectedErrors = new RazorError[]
+            {
+                new RazorError(@"A space or line break was encountered after the ""@"" character.  Only valid identifiers, keywords, comments, ""("" and ""{"" are valid at the start of a code block and they must occur immediately following ""@"" with no space in between.", new SourceLocation(12, 0, 12)),
+                new RazorError(@"""' />"" is not valid at the start of a code block.  Only identifiers, keywords, comments, ""("" and ""{"" are valid.", new SourceLocation(14, 0, 14)),
+            };
+
+            // Act & Assert
+            ParseDocumentTest("<span foo='@ @' />", expected, expectedErrors);
+        }
+
+        private static SpanFactory CreateDefaultSpanFactory()
+        {
+            return new SpanFactory
+            {
+                MarkupTokenizerFactory = doc => new HtmlTokenizer(doc),
+                CodeTokenizerFactory = doc => new CSharpTokenizer(doc)
+            };
+        }
     }
 }
diff --git a/test/Microsoft.AspNet.Razor.Test/TagHelpers/TagHelperParseTreeRewriterTest.cs b/test/Microsoft.AspNet.Razor.Test/TagHelpers/TagHelperParseTreeRewriterTest.cs
index f7eb817209..de2254478f 100644
--- a/test/Microsoft.AspNet.Razor.Test/TagHelpers/TagHelperParseTreeRewriterTest.cs
+++ b/test/Microsoft.AspNet.Razor.Test/TagHelpers/TagHelperParseTreeRewriterTest.cs
@@ -352,6 +352,24 @@ namespace Microsoft.AspNet.Razor.Test.TagHelpers
                                 },
                                 children: factory.Markup("words and spaces")))
                     },
+                    {
+                        "<div style=\"\" class=\"btn\" catchAll=\"@@hi\" >words and spaces</div>",
+                        new MarkupBlock(
+                            new MarkupTagHelperBlock(
+                                "div",
+                                attributes: new List<KeyValuePair<string, SyntaxTreeNode>>
+                                {
+                                    new KeyValuePair<string, SyntaxTreeNode>("style", new MarkupBlock()),
+                                    new KeyValuePair<string, SyntaxTreeNode>("class", factory.Markup("btn")),
+                                    new KeyValuePair<string, SyntaxTreeNode>("catchAll",
+                                        new MarkupBlock(
+                                            new MarkupBlock(
+                                                factory.Markup("@").Accepts(AcceptedCharacters.None),
+                                                factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                            factory.Markup("hi"))),
+                                },
+                                children: factory.Markup("words and spaces")))
+                    },
                     {
                         "<div style=\"@DateTime.Now\" class=\"@DateTime.Now\" catchAll=\"@DateTime.Now\" >words and " +
                         "spaces</div>",
@@ -1143,6 +1161,32 @@ namespace Microsoft.AspNet.Razor.Test.TagHelpers
                                 })),
                         availableDescriptorsText
                     },
+                    {
+                        "<PREFIXmyth2 bound=\"@@@DateTime.Now\" />",
+                        new MarkupBlock(
+                            new MarkupTagHelperBlock(
+                                "PREFIXmyth2",
+                                selfClosing: true,
+                                attributes: new List<KeyValuePair<string, SyntaxTreeNode>>
+                                {
+                                    {
+                                        new KeyValuePair<string, SyntaxTreeNode>(
+                                            "bound",
+                                            new MarkupBlock(
+                                                new MarkupBlock(
+                                                    factory.Markup("@").Accepts(AcceptedCharacters.None),
+                                                    factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                                new MarkupBlock(
+                                                    factory.EmptyHtml(),
+                                                    new ExpressionBlock(
+                                                        factory.CodeTransition(),
+                                                        factory.Code("DateTime.Now")
+                                                            .AsImplicitExpression(CSharpCodeParser.DefaultKeywords)
+                                                            .Accepts(AcceptedCharacters.NonWhiteSpace)))))
+                                    }
+                                })),
+                        availableDescriptorsText
+                    },
                 };
             }
         }
@@ -2175,6 +2219,41 @@ namespace Microsoft.AspNet.Razor.Test.TagHelpers
                                     absoluteIndex: 2, lineIndex: 0, columnIndex: 2)
                             }
                     },
+                    {
+                        "@{<!p class=\"btn@@}",
+                        buildPartialStatementBlock(
+                            () => new MarkupBlock(
+                                new MarkupTagBlock(
+                                    factory.Markup("<"),
+                                    factory.BangEscape(),
+                                    factory.Markup("p"),
+                                    new MarkupBlock(
+                                        new AttributeBlockCodeGenerator(
+                                            name: "class",
+                                            prefix: new LocationTagged<string>(" class=\"", 5, 0, 5),
+                                            suffix: new LocationTagged<string>(string.Empty, 19, 0, 19)),
+                                        factory.Markup(" class=\"").With(SpanCodeGenerator.Null),
+                                        factory.Markup("btn").With(
+                                            new LiteralAttributeCodeGenerator(
+                                                prefix: new LocationTagged<string>(string.Empty, 13, 0, 13),
+                                                value: new LocationTagged<string>("btn", 13, 0, 13))),
+                                        new MarkupBlock(
+                                            factory.Markup("@").With(new LiteralAttributeCodeGenerator(new LocationTagged<string>(string.Empty, 16, 0, 16), new LocationTagged<string>("@", 16, 0, 16))).Accepts(AcceptedCharacters.None),
+                                            factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                        factory.Markup("}").With(
+                                            new LiteralAttributeCodeGenerator(
+                                                prefix: new LocationTagged<string>(string.Empty, 18, 0, 18),
+                                                value: new LocationTagged<string>("}", 18, 0, 18))))))),
+                            new []
+                            {
+                                new RazorError(
+                                    errorMatchingBrace,
+                                    absoluteIndex: 1, lineIndex: 0, columnIndex: 1),
+                                new RazorError(
+                                    string.Format(errorEOFMatchingBrace, "!p"),
+                                    absoluteIndex: 2, lineIndex: 0, columnIndex: 2)
+                            }
+                    },
                     {
                         "@{<!p class=\"btn\"}",
                         buildPartialStatementBlock(
@@ -3697,6 +3776,75 @@ namespace Microsoft.AspNet.Razor.Test.TagHelpers
                                         new MarkupBlock(factory.Markup("Time:"), dateTimeNow))
                                 }))
                     },
+                    {
+                        "<person age=\"12\" birthday=\"DateTime.Now\" name=\"Time: @@ @DateTime.Now\" />",
+                        new MarkupBlock(
+                            new MarkupTagHelperBlock("person",
+                                selfClosing: true,
+                                attributes: new List<KeyValuePair<string, SyntaxTreeNode>>
+                                {
+                                    new KeyValuePair<string, SyntaxTreeNode>("age", factory.CodeMarkup("12")),
+                                    new KeyValuePair<string, SyntaxTreeNode>(
+                                        "birthday",
+                                        factory.CodeMarkup("DateTime.Now")),
+                                    new KeyValuePair<string, SyntaxTreeNode>(
+                                        "name",
+                                        new MarkupBlock(
+                                            factory.Markup("Time:"),
+                                             new MarkupBlock(
+                                                factory.Markup(" @").Accepts(AcceptedCharacters.None),
+                                                factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                            dateTimeNow))
+                                }))
+                    },
+                    {
+                        "<person age=\"12\" birthday=\"DateTime.Now\" name=\"@@BoundStringAttribute\" />",
+                        new MarkupBlock(
+                            new MarkupTagHelperBlock("person",
+                                selfClosing: true,
+                                attributes: new List<KeyValuePair<string, SyntaxTreeNode>>
+                                {
+                                    new KeyValuePair<string, SyntaxTreeNode>("age", factory.CodeMarkup("12")),
+                                    new KeyValuePair<string, SyntaxTreeNode>(
+                                        "birthday",
+                                        factory.CodeMarkup("DateTime.Now")),
+                                    new KeyValuePair<string, SyntaxTreeNode>(
+                                        "name",
+                                        new MarkupBlock(
+                                             new MarkupBlock(
+                                                factory.Markup("@").Accepts(AcceptedCharacters.None),
+                                                factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                            factory.Markup("BoundStringAttribute")))
+                                }))
+                    },
+                    {
+                        "<person age=\"@@@(11+1)\" birthday=\"DateTime.Now\" name=\"Time: @DateTime.Now\" />",
+                        new MarkupBlock(
+                            new MarkupTagHelperBlock("person",
+                                selfClosing: true,
+                                attributes: new List<KeyValuePair<string, SyntaxTreeNode>>
+                                {
+                                    new KeyValuePair<string, SyntaxTreeNode>(
+                                        "age",
+                                        new MarkupBlock(
+                                            new MarkupBlock(
+                                                factory.Markup("@").Accepts(AcceptedCharacters.None),
+                                                factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                            new MarkupBlock(
+                                                factory.EmptyHtml(),
+                                                new ExpressionBlock(
+                                                    factory.CodeTransition(),
+                                                    factory.MetaCode("(").Accepts(AcceptedCharacters.None),
+                                                    factory.Code("11+1").AsExpression(),
+                                                    factory.MetaCode(")").Accepts(AcceptedCharacters.None))))),
+                                    new KeyValuePair<string, SyntaxTreeNode>(
+                                        "birthday",
+                                        factory.CodeMarkup("DateTime.Now")),
+                                    new KeyValuePair<string, SyntaxTreeNode>(
+                                        "name",
+                                        new MarkupBlock(factory.Markup("Time:"), dateTimeNow))
+                                }))
+                    },
                 };
             }
         }
@@ -4535,6 +4683,25 @@ namespace Microsoft.AspNet.Razor.Test.TagHelpers
                                 }),
                             factory.Markup(" World")))
                 };
+                yield return new object[] {
+                    "<p>Hello <script class=\"@@foo@bar.com\" style=\"color:red;\"></script> World</p>",
+                    new MarkupBlock(
+                        new MarkupTagHelperBlock("p",
+                            factory.Markup("Hello "),
+                            new MarkupTagHelperBlock("script",
+                                new List<KeyValuePair<string, SyntaxTreeNode>>
+                                {
+                                    new KeyValuePair<string, SyntaxTreeNode>(
+                                        "class",
+                                        new MarkupBlock(
+                                            new MarkupBlock(
+                                                factory.Markup("@").Accepts(AcceptedCharacters.None),
+                                                factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                            factory.Markup("foo@bar.com"))),
+                                    new KeyValuePair<string, SyntaxTreeNode>("style", factory.Markup("color:red;"))
+                                }),
+                            factory.Markup(" World")))
+                };
             }
         }
 
@@ -4651,6 +4818,25 @@ namespace Microsoft.AspNet.Razor.Test.TagHelpers
                             },
                             factory.Markup("Hello World")))
                 };
+                yield return new object[] {
+                    "<p class=foo dynamic=@DateTime.Now style=color@@:red;>Hello World</p>",
+                    new MarkupBlock(
+                        new MarkupTagHelperBlock("p",
+                            new List<KeyValuePair<string, SyntaxTreeNode>>
+                            {
+                                new KeyValuePair<string, SyntaxTreeNode>("class", factory.Markup("foo")),
+                                new KeyValuePair<string, SyntaxTreeNode>("dynamic", new MarkupBlock(dateTimeNow)),
+                                new KeyValuePair<string, SyntaxTreeNode>(
+                                    "style",
+                                    new MarkupBlock(
+                                        factory.Markup("color"),
+                                         new MarkupBlock(
+                                            factory.Markup("@").Accepts(AcceptedCharacters.None),
+                                            factory.Markup("@").With(SpanCodeGenerator.Null).Accepts(AcceptedCharacters.None)),
+                                        factory.Markup(":red;")))
+                            },
+                            factory.Markup("Hello World")))
+                };
                 yield return new object[] {
                     "<p class=foo dynamic=@DateTime.Now>Hello</p> <p style=color:red; dynamic=@DateTime.Now>World</p>",
                     new MarkupBlock(