diff --git a/src/Microsoft.AspNetCore.Razor/Parser/SyntaxTree/Block.cs b/src/Microsoft.AspNetCore.Razor/Parser/SyntaxTree/Block.cs
index 4b282627d4..85baee80e1 100644
--- a/src/Microsoft.AspNetCore.Razor/Parser/SyntaxTree/Block.cs
+++ b/src/Microsoft.AspNetCore.Razor/Parser/SyntaxTree/Block.cs
@@ -154,11 +154,13 @@ namespace Microsoft.AspNetCore.Razor.Parser.SyntaxTree
             }
         }
 
-        public Span LocateOwner(TextChange change)
+        public virtual Span LocateOwner(TextChange change) => LocateOwner(change, Children);
+
+        protected static Span LocateOwner(TextChange change, IEnumerable<SyntaxTreeNode> elements)
         {
             // Ask each child recursively
             Span owner = null;
-            foreach (SyntaxTreeNode element in Children)
+            foreach (var element in elements)
             {
                 var span = element as Span;
                 if (span == null)
diff --git a/src/Microsoft.AspNetCore.Razor/Parser/TagHelpers/Internal/TagHelperBlockRewriter.cs b/src/Microsoft.AspNetCore.Razor/Parser/TagHelpers/Internal/TagHelperBlockRewriter.cs
index 4f2f4129fc..2a786f8460 100644
--- a/src/Microsoft.AspNetCore.Razor/Parser/TagHelpers/Internal/TagHelperBlockRewriter.cs
+++ b/src/Microsoft.AspNetCore.Razor/Parser/TagHelpers/Internal/TagHelperBlockRewriter.cs
@@ -7,6 +7,7 @@ using System.Diagnostics;
 using System.Linq;
 using Microsoft.AspNetCore.Razor.Chunks.Generators;
 using Microsoft.AspNetCore.Razor.Compilation.TagHelpers;
+using Microsoft.AspNetCore.Razor.Editor;
 using Microsoft.AspNetCore.Razor.Parser.Internal;
 using Microsoft.AspNetCore.Razor.Parser.SyntaxTree;
 using Microsoft.AspNetCore.Razor.TagHelpers;
@@ -468,7 +469,8 @@ namespace Microsoft.AspNetCore.Razor.Parser.TagHelpers.Internal
                                 spanBuilder.ChunkGenerator = new MarkupChunkGenerator();
                             }
 
-                            spanBuilder.Kind = SpanKind.Code;
+                            ConfigureNonStringAttribute(spanBuilder);
+
                             span = spanBuilder.Build();
                         }
                     }
@@ -628,7 +630,7 @@ namespace Microsoft.AspNetCore.Razor.Parser.TagHelpers.Internal
             // SyntaxTreeNode reflects that.
             if (isBoundNonStringAttribute)
             {
-                builder.Kind = SpanKind.Code;
+                ConfigureNonStringAttribute(builder);
             }
 
             return builder.Build();
@@ -701,6 +703,18 @@ namespace Microsoft.AspNetCore.Razor.Parser.TagHelpers.Internal
                    htmlSymbol.Type == HtmlSymbolType.SingleQuote;
         }
 
+        private static void ConfigureNonStringAttribute(SpanBuilder builder)
+        {
+            builder.Kind = SpanKind.Code;
+            builder.EditHandler = new ImplicitExpressionEditHandler(
+                    builder.EditHandler.Tokenizer,
+                    CSharpCodeParser.DefaultKeywords,
+                    acceptTrailingDot: true)
+            {
+                AcceptedCharacters = AcceptedCharacters.AnyExceptNewline
+            };
+        }
+
         private class TryParseResult
         {
             public string AttributeName { get; set; }
diff --git a/src/Microsoft.AspNetCore.Razor/Parser/TagHelpers/TagHelperBlock.cs b/src/Microsoft.AspNetCore.Razor/Parser/TagHelpers/TagHelperBlock.cs
index b43a2fd326..f4166faea7 100644
--- a/src/Microsoft.AspNetCore.Razor/Parser/TagHelpers/TagHelperBlock.cs
+++ b/src/Microsoft.AspNetCore.Razor/Parser/TagHelpers/TagHelperBlock.cs
@@ -5,9 +5,10 @@ using System;
 using System.Collections.Generic;
 using System.Globalization;
 using System.Linq;
+using Microsoft.AspNetCore.Razor.Compilation.TagHelpers;
 using Microsoft.AspNetCore.Razor.Parser.SyntaxTree;
 using Microsoft.AspNetCore.Razor.TagHelpers;
-using Microsoft.AspNetCore.Razor.Compilation.TagHelpers;
+using Microsoft.AspNetCore.Razor.Text;
 using Microsoft.Extensions.Internal;
 
 namespace Microsoft.AspNetCore.Razor.Parser.TagHelpers
@@ -123,6 +124,45 @@ namespace Microsoft.AspNetCore.Razor.Parser.TagHelpers
             }
         }
 
+        public override Span LocateOwner(TextChange change)
+        {
+            var oldPosition = change.OldPosition;
+            if (oldPosition < Start.AbsoluteIndex)
+            {
+                // Change occurs prior to the TagHelper.
+                return null;
+            }
+
+            var bodyEndLocation = SourceStartTag?.Start.AbsoluteIndex + SourceStartTag?.Length + base.Length;
+            if (oldPosition > bodyEndLocation)
+            {
+                // Change occurs after the TagHelpers body. End tags for TagHelpers cannot claim ownership of changes
+                // because any change to them impacts whether or not a tag is a TagHelper.
+                return null;
+            }
+
+            var startTagEndLocation = Start.AbsoluteIndex + SourceStartTag?.Length;
+            if (oldPosition < startTagEndLocation)
+            {
+                // Change occurs in the start tag.
+
+                var attributeElements = Attributes
+                    .Select(attribute => attribute.Value)
+                    .Where(value => value != null);
+
+                return LocateOwner(change, attributeElements);
+            }
+
+            if (oldPosition < bodyEndLocation)
+            {
+                // Change occurs in the body
+                return base.LocateOwner(change);
+            }
+
+            // TagHelper does not contain a Span that can claim ownership.
+            return null;
+        }
+
         /// <inheritdoc />
         public override string ToString()
         {
diff --git a/test/Microsoft.AspNetCore.Razor.Test/Framework/TestSpanBuilder.cs b/test/Microsoft.AspNetCore.Razor.Test/Framework/TestSpanBuilder.cs
index d030149d29..be919eff97 100644
--- a/test/Microsoft.AspNetCore.Razor.Test/Framework/TestSpanBuilder.cs
+++ b/test/Microsoft.AspNetCore.Razor.Test/Framework/TestSpanBuilder.cs
@@ -139,7 +139,27 @@ namespace Microsoft.AspNetCore.Razor.Test.Framework
 
         public static SpanConstructor CodeMarkup(this SpanFactory self, params string[] content)
         {
-            return self.Span(SpanKind.Code, content, markup: true).With(new MarkupChunkGenerator());
+            return self
+                .Span(SpanKind.Code, content, markup: true)
+                .AsCodeMarkup();
+        }
+
+        public static SpanConstructor CSharpCodeMarkup(this SpanFactory self, string content)
+        {
+            return self.Code(content)
+                .AsImplicitExpression(CSharpCodeParser.DefaultKeywords, acceptTrailingDot: true)
+                .AsCodeMarkup();
+        }
+
+        public static SpanConstructor AsCodeMarkup(this SpanConstructor self)
+        {
+            return self
+                .With(new ImplicitExpressionEditHandler(
+                    SpanConstructor.TestTokenizer,
+                    CSharpCodeParser.DefaultKeywords,
+                    acceptTrailingDot: true))
+                .With(new MarkupChunkGenerator())
+                .Accepts(AcceptedCharacters.AnyExceptNewline);
         }
 
         public static SourceLocation GetLocationAndAdvance(this SourceLocationTracker self, string content)
diff --git a/test/Microsoft.AspNetCore.Razor.Test/Parser/TagHelpers/Internal/TagHelperBlockRewriterTest.cs b/test/Microsoft.AspNetCore.Razor.Test/Parser/TagHelpers/Internal/TagHelperBlockRewriterTest.cs
index 7cfc585aea..2ceea3d89a 100644
--- a/test/Microsoft.AspNetCore.Razor.Test/Parser/TagHelpers/Internal/TagHelperBlockRewriterTest.cs
+++ b/test/Microsoft.AspNetCore.Razor.Test/Parser/TagHelpers/Internal/TagHelperBlockRewriterTest.cs
@@ -1013,9 +1013,8 @@ namespace Microsoft.AspNetCore.Razor.Parser.TagHelpers.Internal
                                                 new ExpressionBlock(
                                                     factory.CodeTransition(),
                                                     factory
-                                                        .Code("DateTime.Now.Year")
-                                                        .AsImplicitExpression(CSharpCodeParser.DefaultKeywords)
-                                                        .Accepts(AcceptedCharacters.NonWhiteSpace)))))
+                                                        .CSharpCodeMarkup("DateTime.Now.Year")
+                                                        .With(new ExpressionChunkGenerator())))))
                                 }))
                     },
                     {
@@ -1031,14 +1030,10 @@ namespace Microsoft.AspNetCore.Razor.Parser.TagHelpers.Internal
                                             new MarkupBlock(
                                                 factory.CodeMarkup(" "),
                                                 new ExpressionBlock(
+                                                    factory.CSharpCodeMarkup("@"),
                                                     factory
-                                                        .CodeTransition()
-                                                        .As(SpanKind.Code)
-                                                        .With(new MarkupChunkGenerator()),
-                                                    factory
-                                                        .Code("DateTime.Now.Year")
-                                                        .AsImplicitExpression(CSharpCodeParser.DefaultKeywords)
-                                                        .Accepts(AcceptedCharacters.NonWhiteSpace)))))
+                                                        .CSharpCodeMarkup("DateTime.Now.Year")
+                                                        .With(new ExpressionChunkGenerator())))))
                                 }))
                     },
                     {
@@ -1078,14 +1073,9 @@ namespace Microsoft.AspNetCore.Razor.Parser.TagHelpers.Internal
                                             new MarkupBlock(
                                                 factory.CodeMarkup(" "),
                                                 new ExpressionBlock(
-                                                    factory
-                                                        .CodeTransition()
-                                                        .As(SpanKind.Code)
-                                                        .With(new MarkupChunkGenerator()),
-                                                    factory
-                                                        .Code("value")
-                                                        .AsImplicitExpression(CSharpCodeParser.DefaultKeywords)
-                                                        .Accepts(AcceptedCharacters.NonWhiteSpace))),
+                                                    factory.CSharpCodeMarkup("@"),
+                                                    factory.CSharpCodeMarkup("value")
+                                                        .With(new ExpressionChunkGenerator()))),
                                             factory.CodeMarkup(" +"),
                                             factory.CodeMarkup(" 2"))),
                                     new TagHelperAttributeNode(
@@ -1094,33 +1084,26 @@ namespace Microsoft.AspNetCore.Razor.Parser.TagHelpers.Internal
                                             factory.CodeMarkup("(bool)"),
                                             new MarkupBlock(
                                                 new ExpressionBlock(
+                                                    factory.CSharpCodeMarkup("@"),
                                                     factory
-                                                        .CodeTransition()
-                                                        .As(SpanKind.Code)
-                                                        .With(new MarkupChunkGenerator()),
-                                                    factory
-                                                        .Code("Bag[\"val\"]")
-                                                        .AsImplicitExpression(CSharpCodeParser.DefaultKeywords)
-                                                        .Accepts(AcceptedCharacters.NonWhiteSpace))),
+                                                        .CSharpCodeMarkup("Bag[\"val\"]")
+                                                        .With(new ExpressionChunkGenerator()))),
                                             factory.CodeMarkup(" ?"),
                                             new MarkupBlock(
-                                                factory.CodeMarkup(" @").Accepts(AcceptedCharacters.None),
+                                                factory.CodeMarkup(" @")
+                                                    .As(SpanKind.Code),
                                                 factory.CodeMarkup("@")
-                                                    .With(SpanChunkGenerator.Null)
-                                                    .Accepts(AcceptedCharacters.None)),
+                                                    .As(SpanKind.Code)
+                                                    .With(SpanChunkGenerator.Null)),
                                             factory.CodeMarkup("DateTime"),
                                             factory.CodeMarkup(" :"),
                                             new MarkupBlock(
                                                 factory.CodeMarkup(" "),
                                                 new ExpressionBlock(
+                                                    factory.CSharpCodeMarkup("@"),
                                                     factory
-                                                        .CodeTransition()
-                                                        .As(SpanKind.Code)
-                                                        .With(new MarkupChunkGenerator()),
-                                                    factory
-                                                        .Code("DateTime.Now")
-                                                        .AsImplicitExpression(CSharpCodeParser.DefaultKeywords)
-                                                        .Accepts(AcceptedCharacters.NonWhiteSpace)))),
+                                                        .CSharpCodeMarkup("DateTime.Now")
+                                                        .With(new ExpressionChunkGenerator())))),
                                         HtmlAttributeValueStyle.SingleQuotes)
                                 }))
                     },
@@ -1196,27 +1179,19 @@ namespace Microsoft.AspNetCore.Razor.Parser.TagHelpers.Internal
                                         "age",
                                         new MarkupBlock(
                                             new MarkupBlock(
+                                                factory.CodeMarkup("@"),
                                                 factory.CodeMarkup("@")
-                                                    .Accepts(AcceptedCharacters.None)
-                                                    .With(new MarkupChunkGenerator()),
-                                                factory.CodeMarkup("@")
-                                                    .With(SpanChunkGenerator.Null)
-                                                    .Accepts(AcceptedCharacters.None)),
+                                                    .With(SpanChunkGenerator.Null)),
                                             new MarkupBlock(
-                                                factory.EmptyHtml().As(SpanKind.Code),
+                                                factory.EmptyHtml()
+                                                    .AsCodeMarkup()
+                                                    .As(SpanKind.Code),
                                                 new ExpressionBlock(
-                                                    factory.CodeTransition()
-                                                        .As(SpanKind.Code)
-                                                        .With(new MarkupChunkGenerator()),
-                                                    factory.MetaCode("(")
-                                                        .Accepts(AcceptedCharacters.None)
-                                                        .As(SpanKind.Code)
-                                                        .With(new MarkupChunkGenerator()),
-                                                    factory.Code("11+1").AsExpression(),
-                                                    factory.MetaCode(")")
-                                                        .Accepts(AcceptedCharacters.None)
-                                                        .As(SpanKind.Code)
-                                                        .With(new MarkupChunkGenerator()))))),
+                                                    factory.CSharpCodeMarkup("@"),
+                                                    factory.CSharpCodeMarkup("("),
+                                                    factory.CSharpCodeMarkup("11+1")
+                                                        .With(new ExpressionChunkGenerator()),
+                                                    factory.CSharpCodeMarkup(")"))))),
                                     new TagHelperAttributeNode(
                                         "birthday",
                                         factory.CodeMarkup("DateTime.Now")),
@@ -2237,12 +2212,9 @@ namespace Microsoft.AspNetCore.Razor.Parser.TagHelpers.Internal
                                                 new MarkupBlock(
                                                 factory.CodeMarkup("    "),
                                                 new ExpressionBlock(
-                                                    factory.CodeTransition()
-                                                        .As(SpanKind.Code)
-                                                        .With(new MarkupChunkGenerator()),
-                                                    factory.Code("true")
-                                                        .AsImplicitExpression(CSharpCodeParser.DefaultKeywords)
-                                                        .Accepts(AcceptedCharacters.NonWhiteSpace))),
+                                                    factory.CSharpCodeMarkup("@"),
+                                                    factory.CSharpCodeMarkup("true")
+                                                        .With(new ExpressionChunkGenerator()))),
                                                 factory.CodeMarkup("  ")),
                                             HtmlAttributeValueStyle.SingleQuotes)
                                     }
@@ -2264,18 +2236,11 @@ namespace Microsoft.AspNetCore.Razor.Parser.TagHelpers.Internal
                                                 new MarkupBlock(
                                                 factory.CodeMarkup("    "),
                                                 new ExpressionBlock(
-                                                    factory.CodeTransition()
-                                                        .As(SpanKind.Code)
-                                                        .With(new MarkupChunkGenerator()),
-                                                    factory.MetaCode("(")
-                                                        .Accepts(AcceptedCharacters.None)
-                                                        .As(SpanKind.Code)
-                                                        .With(new MarkupChunkGenerator()),
-                                                    factory.Code("true").AsExpression(),
-                                                    factory.MetaCode(")")
-                                                        .Accepts(AcceptedCharacters.None)
-                                                        .As(SpanKind.Code)
-                                                        .With(new MarkupChunkGenerator()))),
+                                                    factory.CSharpCodeMarkup("@"),
+                                                    factory.CSharpCodeMarkup("("),
+                                                    factory.CSharpCodeMarkup("true")
+                                                        .With(new ExpressionChunkGenerator()),
+                                                    factory.CSharpCodeMarkup(")"))),
                                                 factory.CodeMarkup("  ")),
                                             HtmlAttributeValueStyle.SingleQuotes)
                                     }
diff --git a/test/Microsoft.AspNetCore.Razor.Test/Parser/TagHelpers/Internal/TagHelperParseTreeRewriterTest.cs b/test/Microsoft.AspNetCore.Razor.Test/Parser/TagHelpers/Internal/TagHelperParseTreeRewriterTest.cs
index 6b0bf074fb..d329f1ec79 100644
--- a/test/Microsoft.AspNetCore.Razor.Test/Parser/TagHelpers/Internal/TagHelperParseTreeRewriterTest.cs
+++ b/test/Microsoft.AspNetCore.Razor.Test/Parser/TagHelpers/Internal/TagHelperParseTreeRewriterTest.cs
@@ -7,6 +7,7 @@ using System.Globalization;
 using System.Linq;
 using Microsoft.AspNetCore.Razor.Chunks.Generators;
 using Microsoft.AspNetCore.Razor.Compilation.TagHelpers;
+using Microsoft.AspNetCore.Razor.Editor;
 using Microsoft.AspNetCore.Razor.Parser.Internal;
 using Microsoft.AspNetCore.Razor.Parser.SyntaxTree;
 using Microsoft.AspNetCore.Razor.TagHelpers;
@@ -2452,8 +2453,8 @@ namespace Microsoft.AspNetCore.Razor.Parser.TagHelpers.Internal
                                                     new ExpressionBlock(
                                                         factory.CodeTransition(),
                                                         factory.Code("DateTime.Now")
-                                                            .AsImplicitExpression(CSharpCodeParser.DefaultKeywords)
-                                                            .Accepts(AcceptedCharacters.NonWhiteSpace)))))
+                                                            .AsImplicitExpression(CSharpCodeParser.DefaultKeywords, acceptTrailingDot: true)
+                                                            .Accepts(AcceptedCharacters.AnyExceptNewline)))))
                                     }
                                 })),
                         availableDescriptorsColon
@@ -2474,8 +2475,8 @@ namespace Microsoft.AspNetCore.Razor.Parser.TagHelpers.Internal
                                                     new ExpressionBlock(
                                                         factory.CodeTransition(),
                                                         factory.Code("DateTime.Now")
-                                                            .AsImplicitExpression(CSharpCodeParser.DefaultKeywords)
-                                                            .Accepts(AcceptedCharacters.NonWhiteSpace)))))
+                                                            .AsImplicitExpression(CSharpCodeParser.DefaultKeywords, acceptTrailingDot: true)
+                                                            .Accepts(AcceptedCharacters.AnyExceptNewline)))))
                                     }
                                 })),
                         availableDescriptorsText
@@ -2493,24 +2494,19 @@ namespace Microsoft.AspNetCore.Razor.Parser.TagHelpers.Internal
                                             "bound",
                                             new MarkupBlock(
                                                 new MarkupBlock(
+                                                    factory.CodeMarkup("@"),
                                                     factory
                                                         .CodeMarkup("@")
-                                                        .With(new MarkupChunkGenerator())
-                                                        .Accepts(AcceptedCharacters.None),
-                                                    factory
-                                                        .CodeMarkup("@")
-                                                        .With(SpanChunkGenerator.Null)
-                                                        .Accepts(AcceptedCharacters.None)),
+                                                        .With(SpanChunkGenerator.Null)),
                                                 new MarkupBlock(
-                                                    factory.EmptyHtml().As(SpanKind.Code),
+                                                    factory
+                                                        .EmptyHtml()
+                                                        .As(SpanKind.Code)
+                                                        .AsCodeMarkup(),
                                                     new ExpressionBlock(
-                                                        factory
-                                                            .CodeTransition()
-                                                            .As(SpanKind.Code)
-                                                            .With(new MarkupChunkGenerator()),
-                                                        factory.Code("DateTime.Now")
-                                                            .AsImplicitExpression(CSharpCodeParser.DefaultKeywords)
-                                                            .Accepts(AcceptedCharacters.NonWhiteSpace)))))
+                                                        factory.CSharpCodeMarkup("@"),
+                                                        factory.CSharpCodeMarkup("DateTime.Now")
+                                                            .With(new ExpressionChunkGenerator())))))
                                     }
                                 })),
                         availableDescriptorsText
diff --git a/test/Microsoft.AspNetCore.Razor.Test/PartialParsingTestBase.cs b/test/Microsoft.AspNetCore.Razor.Test/PartialParsingTestBase.cs
index 79655dd3d6..f1b06fd8ae 100644
--- a/test/Microsoft.AspNetCore.Razor.Test/PartialParsingTestBase.cs
+++ b/test/Microsoft.AspNetCore.Razor.Test/PartialParsingTestBase.cs
@@ -5,6 +5,7 @@ using System;
 using System.Threading;
 using System.Web.WebPages.TestUtils;
 using Microsoft.AspNetCore.Razor.CodeGenerators;
+using Microsoft.AspNetCore.Razor.Compilation.TagHelpers;
 using Microsoft.AspNetCore.Razor.Parser.SyntaxTree;
 using Microsoft.AspNetCore.Razor.Test.Framework;
 using Microsoft.AspNetCore.Razor.Test.Utils;
@@ -58,7 +59,7 @@ namespace Microsoft.AspNetCore.Razor
             return new TestParserManager(parser);
         }
 
-        protected static RazorEngineHost CreateHost()
+        protected static RazorEngineHost CreateHost(ITagHelperDescriptorResolver descriptorResolver = null)
         {
             return new RazorEngineHost(new TLanguage())
             {
@@ -71,7 +72,8 @@ namespace Microsoft.AspNetCore.Razor
                     "Template",
                     "DefineSection",
                     new GeneratedTagHelperContext()),
-                DesignTimeMode = true
+                DesignTimeMode = true,
+                TagHelperDescriptorResolver = descriptorResolver
             };
         }
 
diff --git a/test/Microsoft.AspNetCore.Razor.Test/RazorEditorParserTest.cs b/test/Microsoft.AspNetCore.Razor.Test/RazorEditorParserTest.cs
index 34e1e31a6e..c5ad449c94 100644
--- a/test/Microsoft.AspNetCore.Razor.Test/RazorEditorParserTest.cs
+++ b/test/Microsoft.AspNetCore.Razor.Test/RazorEditorParserTest.cs
@@ -2,17 +2,21 @@
 // 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 System.Threading;
 using System.Web.WebPages.TestUtils;
+using Microsoft.AspNetCore.Razor.Compilation.TagHelpers;
 using Microsoft.AspNetCore.Razor.Editor;
 using Microsoft.AspNetCore.Razor.Parser;
 using Microsoft.AspNetCore.Razor.Parser.SyntaxTree;
+using Microsoft.AspNetCore.Razor.Parser.TagHelpers;
 using Microsoft.AspNetCore.Razor.TagHelpers;
 using Microsoft.AspNetCore.Razor.Test.CodeGenerators;
 using Microsoft.AspNetCore.Razor.Test.Framework;
 using Microsoft.AspNetCore.Razor.Test.Utils;
 using Microsoft.AspNetCore.Razor.Text;
 using Microsoft.AspNetCore.Testing;
+using Moq;
 using Xunit;
 
 namespace Microsoft.AspNetCore.Razor
@@ -23,6 +27,273 @@ namespace Microsoft.AspNetCore.Razor
         private static readonly TestFile SimpleCSHTMLDocumentGenerated = TestFile.Create("TestFiles/DesignTime/Simple.txt");
         private const string TestLinePragmaFileName = "C:\\This\\Path\\Is\\Just\\For\\Line\\Pragmas.cshtml";
 
+        public static TheoryData TagHelperPartialParseRejectData
+        {
+            get
+            {
+                var factory = SpanFactory.CreateCsHtml();
+
+                // change, expectedDocument
+                return new TheoryData<TextChange, MarkupBlock>
+                {
+                    {
+                        CreateInsertionChange("<p></p>", 2, " "),
+                        new MarkupBlock(
+                            new MarkupTagHelperBlock("p"))
+                    },
+                    {
+                        CreateInsertionChange("<p></p>", 6, " "),
+                        new MarkupBlock(
+                            new MarkupTagHelperBlock("p"))
+                    },
+                    {
+                        CreateInsertionChange("<p some-attr></p>", 12, " "),
+                        new MarkupBlock(
+                            new MarkupTagHelperBlock(
+                                "p",
+                                attributes: new List<TagHelperAttributeNode>
+                                {
+                                    new TagHelperAttributeNode(
+                                        "some-attr",
+                                        value: null,
+                                        valueStyle: HtmlAttributeValueStyle.Minimized)
+                                }))
+                    },
+                    {
+                        CreateInsertionChange("<p some-attr></p>", 12, "ibute"),
+                        new MarkupBlock(
+                            new MarkupTagHelperBlock(
+                                "p",
+                                attributes: new List<TagHelperAttributeNode>
+                                {
+                                    new TagHelperAttributeNode(
+                                        "some-attribute",
+                                        value: null,
+                                        valueStyle: HtmlAttributeValueStyle.Minimized)
+                                }))
+                    },
+                    {
+                        CreateInsertionChange("<p some-attr></p>", 2, " before"),
+                        new MarkupBlock(
+                            new MarkupTagHelperBlock(
+                                "p",
+                                attributes: new List<TagHelperAttributeNode>
+                                {
+                                    new TagHelperAttributeNode(
+                                        "before",
+                                        value: null,
+                                        valueStyle: HtmlAttributeValueStyle.Minimized),
+                                    new TagHelperAttributeNode(
+                                        "some-attr",
+                                        value: null,
+                                        valueStyle: HtmlAttributeValueStyle.Minimized)
+                                }))
+                    },
+                };
+            }
+        }
+
+        [Theory]
+        [MemberData(nameof(TagHelperPartialParseRejectData))]
+        public void TagHelperTagBodiesRejectPartialChanges(TextChange change, MarkupBlock expectedDocument)
+        {
+            // Arrange
+            var descriptors = new[]
+            {
+                new TagHelperDescriptor
+                {
+                    TagName = "p",
+                    TypeName = "PTagHelper"
+                },
+            };
+            var descriptorResolver = new Mock<ITagHelperDescriptorResolver>();
+            descriptorResolver
+                .Setup(resolver => resolver.Resolve(It.IsAny<TagHelperDescriptorResolutionContext>()))
+                .Returns(descriptors);
+            var host = CreateHost(descriptorResolver.Object);
+            var parser = new RazorEditorParser(host, @"C:\This\Is\A\Test\Path");
+
+            using (var manager = new TestParserManager(parser))
+            {
+                manager.InitializeWithDocument(change.OldBuffer);
+
+                // Act
+                var result = manager.CheckForStructureChangesAndWait(change);
+
+                // Assert
+                Assert.Equal(PartialParseResult.Rejected, result);
+                Assert.Equal(2, manager.ParseCount);
+                ParserTestBase.EvaluateParseTree(manager.Parser.CurrentParseTree, expectedDocument);
+            }
+        }
+
+        public static TheoryData TagHelperAttributeAcceptData
+        {
+            get
+            {
+                var factory = SpanFactory.CreateCsHtml();
+
+                // change, expectedDocument, partialParseResult
+                return new TheoryData<TextChange, MarkupBlock, PartialParseResult>
+                {
+                    {
+                        CreateInsertionChange("<p str-attr='@DateTime'></p>", 22, "."),
+                        new MarkupBlock(
+                            new MarkupTagHelperBlock(
+                                "p",
+                                attributes: new List<TagHelperAttributeNode>
+                                {
+                                    new TagHelperAttributeNode(
+                                        "str-attr",
+                                        new MarkupBlock(
+                                            new MarkupBlock(
+                                                new ExpressionBlock(
+                                                    factory.CodeTransition(),
+                                                    factory
+                                                        .Code("DateTime.")
+                                                        .AsImplicitExpression(CSharpCodeParser.DefaultKeywords)
+                                                        .Accepts(AcceptedCharacters.NonWhiteSpace)))),
+                                        HtmlAttributeValueStyle.SingleQuotes)
+                                })),
+                        PartialParseResult.Accepted | PartialParseResult.Provisional
+                    },
+                    {
+                        CreateInsertionChange("<p obj-attr='DateTime'></p>", 21, "."),
+                        new MarkupBlock(
+                            new MarkupTagHelperBlock(
+                                "p",
+                                attributes: new List<TagHelperAttributeNode>
+                                {
+                                    new TagHelperAttributeNode(
+                                        "obj-attr",
+                                        factory.CodeMarkup("DateTime."),
+                                        HtmlAttributeValueStyle.SingleQuotes)
+                                })),
+                        PartialParseResult.Accepted
+                    },
+                    {
+                        CreateInsertionChange("<p obj-attr='1 + DateTime'></p>", 25, "."),
+                        new MarkupBlock(
+                            new MarkupTagHelperBlock(
+                                "p",
+                                attributes: new List<TagHelperAttributeNode>
+                                {
+                                    new TagHelperAttributeNode(
+                                        "obj-attr",
+                                        factory.CodeMarkup("1 + DateTime."),
+                                        HtmlAttributeValueStyle.SingleQuotes)
+                                })),
+                        PartialParseResult.Accepted
+                    },
+                    {
+                        CreateInsertionChange("<p before-attr str-attr='@DateTime' after-attr></p>", 34, "."),
+                        new MarkupBlock(
+                            new MarkupTagHelperBlock(
+                                "p",
+                                attributes: new List<TagHelperAttributeNode>
+                                {
+                                    new TagHelperAttributeNode(
+                                        "before-attr",
+                                        value: null,
+                                        valueStyle: HtmlAttributeValueStyle.Minimized),
+                                    new TagHelperAttributeNode(
+                                        "str-attr",
+                                        new MarkupBlock(
+                                            new MarkupBlock(
+                                                new ExpressionBlock(
+                                                    factory.CodeTransition(),
+                                                    factory
+                                                        .Code("DateTime.")
+                                                        .AsImplicitExpression(CSharpCodeParser.DefaultKeywords)
+                                                        .Accepts(AcceptedCharacters.NonWhiteSpace)))),
+                                        HtmlAttributeValueStyle.SingleQuotes),
+                                    new TagHelperAttributeNode(
+                                        "after-attr",
+                                        value: null,
+                                        valueStyle: HtmlAttributeValueStyle.Minimized),
+                                })),
+                        PartialParseResult.Accepted | PartialParseResult.Provisional
+                    },
+                    {
+                        CreateInsertionChange("<p str-attr='before @DateTime after'></p>", 29, "."),
+                        new MarkupBlock(
+                            new MarkupTagHelperBlock(
+                                "p",
+                                attributes: new List<TagHelperAttributeNode>
+                                {
+                                    new TagHelperAttributeNode(
+                                        "str-attr",
+                                        new MarkupBlock(
+                                            factory.Markup("before"),
+                                            new MarkupBlock(
+                                                factory.Markup(" "),
+                                                new ExpressionBlock(
+                                                    factory.CodeTransition(),
+                                                    factory
+                                                        .Code("DateTime.")
+                                                        .AsImplicitExpression(CSharpCodeParser.DefaultKeywords)
+                                                        .Accepts(AcceptedCharacters.NonWhiteSpace))),
+                                            factory.Markup(" after")),
+                                        HtmlAttributeValueStyle.SingleQuotes)
+                                })),
+                        PartialParseResult.Accepted | PartialParseResult.Provisional
+                    },
+                };
+            }
+        }
+
+        [Theory]
+        [MemberData(nameof(TagHelperAttributeAcceptData))]
+        public void TagHelperAttributesAreLocatedAndAcceptChangesCorrectly(
+            TextChange change,
+            MarkupBlock expectedDocument,
+            PartialParseResult partialParseResult)
+        {
+            // Arrange
+            var descriptors = new[]
+            {
+                new TagHelperDescriptor
+                {
+                    TagName = "p",
+                    TypeName = "PTagHelper",
+                    Attributes = new[]
+                    {
+                        new TagHelperAttributeDescriptor
+                        {
+                            Name = "obj-attr",
+                            TypeName = typeof(object).FullName,
+                            PropertyName = "ObjectAttribute",
+                        },
+                        new TagHelperAttributeDescriptor
+                        {
+                            Name = "str-attr",
+                            TypeName = typeof(string).FullName,
+                            PropertyName = "StringAttribute",
+                        },
+                    }
+                },
+            };
+            var descriptorResolver = new Mock<ITagHelperDescriptorResolver>();
+            descriptorResolver
+                .Setup(resolver => resolver.Resolve(It.IsAny<TagHelperDescriptorResolutionContext>()))
+                .Returns(descriptors);
+            var host = CreateHost(descriptorResolver.Object);
+            var parser = new RazorEditorParser(host, @"C:\This\Is\A\Test\Path");
+
+            using (var manager = new TestParserManager(parser))
+            {
+                manager.InitializeWithDocument(change.OldBuffer);
+
+                // Act
+                var result = manager.CheckForStructureChangesAndWait(change);
+
+                // Assert
+                Assert.Equal(partialParseResult, result);
+                Assert.Equal(1, manager.ParseCount);
+                ParserTestBase.EvaluateParseTree(manager.Parser.CurrentParseTree, expectedDocument);
+            }
+        }
+
         [Fact]
         public void ConstructorRequiresNonNullPhysicalPath()
         {
@@ -898,5 +1169,14 @@ namespace Microsoft.AspNetCore.Razor
         {
             return new CodeGenTestHost(new CSharpRazorCodeLanguage()) { DesignTimeMode = true };
         }
+
+        private static TextChange CreateInsertionChange(string initialText, int insertionLocation, string insertionText)
+        {
+            var changedText = initialText.Insert(insertionLocation, insertionText);
+
+            var original = new StringTextBuffer(initialText);
+            var changed = new StringTextBuffer(changedText);
+            return new TextChange(insertionLocation, 0, original, insertionText.Length, changed);
+        }
     }
 }