diff --git a/test/Microsoft.AspNetCore.Razor.Language.Test/Legacy/HtmlErrorTest.cs b/test/Microsoft.AspNetCore.Razor.Language.Test/Legacy/HtmlErrorTest.cs
index 497fceedaa..59a2b99854 100644
--- a/test/Microsoft.AspNetCore.Razor.Language.Test/Legacy/HtmlErrorTest.cs
+++ b/test/Microsoft.AspNetCore.Razor.Language.Test/Legacy/HtmlErrorTest.cs
@@ -7,104 +7,57 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
 {
     public class HtmlErrorTest : CsHtmlMarkupParserTestBase
     {
+        public HtmlErrorTest()
+        {
+            UseBaselineTests = true;
+        }
+
         [Fact]
         public void ParseBlockAllowsInvalidTagNamesAsLongAsParserCanIdentifyEndTag()
         {
-            ParseBlockTest("<1-foo+bar>foo</1-foo+bar>",
-                new MarkupBlock(
-                    new MarkupTagBlock(
-                        Factory.Markup("<1-foo+bar>").Accepts(AcceptedCharactersInternal.None)),
-                    Factory.Markup("foo"),
-                    new MarkupTagBlock(
-                        Factory.Markup("</1-foo+bar>").Accepts(AcceptedCharactersInternal.None))));
+            ParseBlockTest("<1-foo+bar>foo</1-foo+bar>");
         }
 
         [Fact]
         public void ParseBlockThrowsErrorIfStartTextTagContainsTextAfterName()
         {
-            ParseBlockTest("<text foo bar></text>",
-                new MarkupBlock(
-                    new MarkupTagBlock(
-                        Factory.MarkupTransition("<text foo bar>").Accepts(AcceptedCharactersInternal.Any)),
-                    new MarkupTagBlock(
-                        Factory.MarkupTransition("</text>"))),
-                RazorDiagnosticFactory.CreateParsing_TextTagCannotContainAttributes(
-                    new SourceSpan(new SourceLocation(1, 0, 1), contentLength: 4)));
+            ParseBlockTest("<text foo bar></text>");
         }
 
         [Fact]
         public void ParseBlockThrowsErrorIfEndTextTagContainsTextAfterName()
         {
-            ParseBlockTest("<text></text foo bar>",
-                new MarkupBlock(
-                    new MarkupTagBlock(
-                        Factory.MarkupTransition("<text>")),
-                    new MarkupTagBlock(
-                        Factory.MarkupTransition("</text foo bar>").Accepts(AcceptedCharactersInternal.Any))),
-                RazorDiagnosticFactory.CreateParsing_TextTagCannotContainAttributes(
-                    new SourceSpan(new SourceLocation(8, 0, 8), contentLength: 4)));
+            ParseBlockTest("<text></text foo bar>");
         }
 
         [Fact]
         public void ParseBlockThrowsExceptionIfBlockDoesNotStartWithTag()
         {
-            ParseBlockTest("foo bar <baz>",
-                new MarkupBlock(),
-                RazorDiagnosticFactory.CreateParsing_MarkupBlockMustStartWithTag(
-                    new SourceSpan(SourceLocation.Zero, contentLength: 3)));
+            ParseBlockTest("foo bar <baz>");
         }
 
         [Fact]
         public void ParseBlockStartingWithEndTagProducesRazorErrorThenOutputsMarkupSegmentAndEndsBlock()
         {
-            ParseBlockTest("</foo> bar baz",
-                new MarkupBlock(
-                    new MarkupTagBlock(
-                        Factory.Markup("</foo>").Accepts(AcceptedCharactersInternal.None)),
-                    Factory.Markup(" ").Accepts(AcceptedCharactersInternal.None)),
-                RazorDiagnosticFactory.CreateParsing_UnexpectedEndTag(
-                    new SourceSpan(new SourceLocation(2, 0, 2), contentLength: 3), "foo"));
+            ParseBlockTest("</foo> bar baz");
         }
 
         [Fact]
         public void ParseBlockWithUnclosedTopLevelTagThrowsMissingEndTagParserExceptionOnOutermostUnclosedTag()
         {
-            ParseBlockTest("<p><foo></bar>",
-                new MarkupBlock(
-                    new MarkupTagBlock(
-                        Factory.Markup("<p>").Accepts(AcceptedCharactersInternal.None)),
-                    new MarkupTagBlock(
-                        Factory.Markup("<foo>").Accepts(AcceptedCharactersInternal.None)),
-                    new MarkupTagBlock(
-                        Factory.Markup("</bar>").Accepts(AcceptedCharactersInternal.None))),
-                RazorDiagnosticFactory.CreateParsing_MissingEndTag(
-                    new SourceSpan(new SourceLocation(1, 0, 1), contentLength: 1), "p"));
+            ParseBlockTest("<p><foo></bar>");
         }
 
         [Fact]
         public void ParseBlockWithUnclosedTagAtEOFThrowsMissingEndTagException()
         {
-            ParseBlockTest("<foo>blah blah blah blah blah",
-                new MarkupBlock(
-                    new MarkupTagBlock(
-                        Factory.Markup("<foo>").Accepts(AcceptedCharactersInternal.None)),
-                    Factory.Markup("blah blah blah blah blah")),
-                RazorDiagnosticFactory.CreateParsing_MissingEndTag(
-                    new SourceSpan(new SourceLocation(1, 0, 1), contentLength: 3), "foo"));
+            ParseBlockTest("<foo>blah blah blah blah blah");
         }
 
         [Fact]
         public void ParseBlockWithUnfinishedTagAtEOFThrowsIncompleteTagException()
         {
-            ParseBlockTest("<foo bar=baz",
-                new MarkupBlock(
-                    new MarkupTagBlock(
-                    Factory.Markup("<foo"),
-                        new MarkupBlock(new AttributeBlockChunkGenerator("bar", new LocationTagged<string>(" bar=", 4, 0, 4), new LocationTagged<string>(string.Empty, 12, 0, 12)),
-                            Factory.Markup(" bar=").With(SpanChunkGenerator.Null),
-                            Factory.Markup("baz").With(new LiteralAttributeChunkGenerator(new LocationTagged<string>(string.Empty, 9, 0, 9), new LocationTagged<string>("baz", 9, 0, 9)))))),
-                RazorDiagnosticFactory.CreateParsing_UnfinishedTag(
-                    new SourceSpan(new SourceLocation(1, 0, 1), contentLength: 3), "foo"));
+            ParseBlockTest("<foo bar=baz");
         }
     }
 }
diff --git a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockAllowsInvalidTagNamesAsLongAsParserCanIdentifyEndTag.syntaxtree.txt b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockAllowsInvalidTagNamesAsLongAsParserCanIdentifyEndTag.syntaxtree.txt
new file mode 100644
index 0000000000..794202389d
--- /dev/null
+++ b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockAllowsInvalidTagNamesAsLongAsParserCanIdentifyEndTag.syntaxtree.txt
@@ -0,0 +1,14 @@
+Markup block - Gen<None> - 26 - (0:0,0)
+    Tag block - Gen<None> - 11 - (0:0,0)
+        Markup span - Gen<Markup> - [<1-foo+bar>] - SpanEditHandler;Accepts:None - (0:0,0) - Symbols:3
+            HtmlSymbolType.OpenAngle;[<];
+            HtmlSymbolType.Text;[1-foo+bar];
+            HtmlSymbolType.CloseAngle;[>];
+    Markup span - Gen<Markup> - [foo] - SpanEditHandler;Accepts:Any - (11:0,11) - Symbols:1
+        HtmlSymbolType.Text;[foo];
+    Tag block - Gen<None> - 12 - (14:0,14)
+        Markup span - Gen<Markup> - [</1-foo+bar>] - SpanEditHandler;Accepts:None - (14:0,14) - Symbols:4
+            HtmlSymbolType.OpenAngle;[<];
+            HtmlSymbolType.ForwardSlash;[/];
+            HtmlSymbolType.Text;[1-foo+bar];
+            HtmlSymbolType.CloseAngle;[>];
diff --git a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockStartingWithEndTagProducesRazorErrorThenOutputsMarkupSegmentAndEndsBlock.diagnostics.txt b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockStartingWithEndTagProducesRazorErrorThenOutputsMarkupSegmentAndEndsBlock.diagnostics.txt
new file mode 100644
index 0000000000..817c1816ff
--- /dev/null
+++ b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockStartingWithEndTagProducesRazorErrorThenOutputsMarkupSegmentAndEndsBlock.diagnostics.txt
@@ -0,0 +1 @@
+(1,3): Error RZ1026: Encountered end tag "foo" with no matching start tag.  Are your start/end tags properly balanced?
diff --git a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockStartingWithEndTagProducesRazorErrorThenOutputsMarkupSegmentAndEndsBlock.syntaxtree.txt b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockStartingWithEndTagProducesRazorErrorThenOutputsMarkupSegmentAndEndsBlock.syntaxtree.txt
new file mode 100644
index 0000000000..837fcf37ea
--- /dev/null
+++ b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockStartingWithEndTagProducesRazorErrorThenOutputsMarkupSegmentAndEndsBlock.syntaxtree.txt
@@ -0,0 +1,9 @@
+Markup block - Gen<None> - 7 - (0:0,0)
+    Tag block - Gen<None> - 6 - (0:0,0)
+        Markup span - Gen<Markup> - [</foo>] - SpanEditHandler;Accepts:None - (0:0,0) - Symbols:4
+            HtmlSymbolType.OpenAngle;[<];
+            HtmlSymbolType.ForwardSlash;[/];
+            HtmlSymbolType.Text;[foo];
+            HtmlSymbolType.CloseAngle;[>];
+    Markup span - Gen<Markup> - [ ] - SpanEditHandler;Accepts:None - (6:0,6) - Symbols:1
+        HtmlSymbolType.WhiteSpace;[ ];
diff --git a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockThrowsErrorIfEndTextTagContainsTextAfterName.diagnostics.txt b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockThrowsErrorIfEndTextTagContainsTextAfterName.diagnostics.txt
new file mode 100644
index 0000000000..3f53c2b067
--- /dev/null
+++ b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockThrowsErrorIfEndTextTagContainsTextAfterName.diagnostics.txt
@@ -0,0 +1 @@
+(1,9): Error RZ1023: "<text>" and "</text>" tags cannot contain attributes.
diff --git a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockThrowsErrorIfEndTextTagContainsTextAfterName.syntaxtree.txt b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockThrowsErrorIfEndTextTagContainsTextAfterName.syntaxtree.txt
new file mode 100644
index 0000000000..2a07155bd9
--- /dev/null
+++ b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockThrowsErrorIfEndTextTagContainsTextAfterName.syntaxtree.txt
@@ -0,0 +1,16 @@
+Markup block - Gen<None> - 21 - (0:0,0)
+    Tag block - Gen<None> - 6 - (0:0,0)
+        Transition span - Gen<None> - [<text>] - SpanEditHandler;Accepts:None - (0:0,0) - Symbols:3
+            HtmlSymbolType.OpenAngle;[<];
+            HtmlSymbolType.Text;[text];
+            HtmlSymbolType.CloseAngle;[>];
+    Tag block - Gen<None> - 15 - (6:0,6)
+        Transition span - Gen<None> - [</text foo bar>] - SpanEditHandler;Accepts:Any - (6:0,6) - Symbols:8
+            HtmlSymbolType.OpenAngle;[<];
+            HtmlSymbolType.ForwardSlash;[/];
+            HtmlSymbolType.Text;[text];
+            HtmlSymbolType.WhiteSpace;[ ];
+            HtmlSymbolType.Text;[foo];
+            HtmlSymbolType.WhiteSpace;[ ];
+            HtmlSymbolType.Text;[bar];
+            HtmlSymbolType.CloseAngle;[>];
diff --git a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockThrowsErrorIfStartTextTagContainsTextAfterName.diagnostics.txt b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockThrowsErrorIfStartTextTagContainsTextAfterName.diagnostics.txt
new file mode 100644
index 0000000000..63bd9873af
--- /dev/null
+++ b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockThrowsErrorIfStartTextTagContainsTextAfterName.diagnostics.txt
@@ -0,0 +1 @@
+(1,2): Error RZ1023: "<text>" and "</text>" tags cannot contain attributes.
diff --git a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockThrowsErrorIfStartTextTagContainsTextAfterName.syntaxtree.txt b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockThrowsErrorIfStartTextTagContainsTextAfterName.syntaxtree.txt
new file mode 100644
index 0000000000..558bd85db1
--- /dev/null
+++ b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockThrowsErrorIfStartTextTagContainsTextAfterName.syntaxtree.txt
@@ -0,0 +1,16 @@
+Markup block - Gen<None> - 21 - (0:0,0)
+    Tag block - Gen<None> - 14 - (0:0,0)
+        Transition span - Gen<None> - [<text foo bar>] - SpanEditHandler;Accepts:Any - (0:0,0) - Symbols:7
+            HtmlSymbolType.OpenAngle;[<];
+            HtmlSymbolType.Text;[text];
+            HtmlSymbolType.WhiteSpace;[ ];
+            HtmlSymbolType.Text;[foo];
+            HtmlSymbolType.WhiteSpace;[ ];
+            HtmlSymbolType.Text;[bar];
+            HtmlSymbolType.CloseAngle;[>];
+    Tag block - Gen<None> - 7 - (14:0,14)
+        Transition span - Gen<None> - [</text>] - SpanEditHandler;Accepts:None - (14:0,14) - Symbols:4
+            HtmlSymbolType.OpenAngle;[<];
+            HtmlSymbolType.ForwardSlash;[/];
+            HtmlSymbolType.Text;[text];
+            HtmlSymbolType.CloseAngle;[>];
diff --git a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockThrowsExceptionIfBlockDoesNotStartWithTag.diagnostics.txt b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockThrowsExceptionIfBlockDoesNotStartWithTag.diagnostics.txt
new file mode 100644
index 0000000000..7895bdeeab
--- /dev/null
+++ b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockThrowsExceptionIfBlockDoesNotStartWithTag.diagnostics.txt
@@ -0,0 +1 @@
+(1,1): Error RZ1021: Markup in a code block must start with a tag and all start tags must be matched with end tags.  Do not use unclosed tags like "<br>".  Instead use self-closing tags like "<br/>".
diff --git a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockThrowsExceptionIfBlockDoesNotStartWithTag.syntaxtree.txt b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockThrowsExceptionIfBlockDoesNotStartWithTag.syntaxtree.txt
new file mode 100644
index 0000000000..2817f30307
--- /dev/null
+++ b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockThrowsExceptionIfBlockDoesNotStartWithTag.syntaxtree.txt
@@ -0,0 +1 @@
+Markup block - Gen<None> - 0 - (0:0,0)
diff --git a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockWithUnclosedTagAtEOFThrowsMissingEndTagException.diagnostics.txt b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockWithUnclosedTagAtEOFThrowsMissingEndTagException.diagnostics.txt
new file mode 100644
index 0000000000..1de63b58d1
--- /dev/null
+++ b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockWithUnclosedTagAtEOFThrowsMissingEndTagException.diagnostics.txt
@@ -0,0 +1 @@
+(1,2): Error RZ1025: The "foo" element was not closed.  All elements must be either self-closing or have a matching end tag.
diff --git a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockWithUnclosedTagAtEOFThrowsMissingEndTagException.syntaxtree.txt b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockWithUnclosedTagAtEOFThrowsMissingEndTagException.syntaxtree.txt
new file mode 100644
index 0000000000..7ef17370f7
--- /dev/null
+++ b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockWithUnclosedTagAtEOFThrowsMissingEndTagException.syntaxtree.txt
@@ -0,0 +1,16 @@
+Markup block - Gen<None> - 29 - (0:0,0)
+    Tag block - Gen<None> - 5 - (0:0,0)
+        Markup span - Gen<Markup> - [<foo>] - SpanEditHandler;Accepts:None - (0:0,0) - Symbols:3
+            HtmlSymbolType.OpenAngle;[<];
+            HtmlSymbolType.Text;[foo];
+            HtmlSymbolType.CloseAngle;[>];
+    Markup span - Gen<Markup> - [blah blah blah blah blah] - SpanEditHandler;Accepts:Any - (5:0,5) - Symbols:9
+        HtmlSymbolType.Text;[blah];
+        HtmlSymbolType.WhiteSpace;[ ];
+        HtmlSymbolType.Text;[blah];
+        HtmlSymbolType.WhiteSpace;[ ];
+        HtmlSymbolType.Text;[blah];
+        HtmlSymbolType.WhiteSpace;[ ];
+        HtmlSymbolType.Text;[blah];
+        HtmlSymbolType.WhiteSpace;[ ];
+        HtmlSymbolType.Text;[blah];
diff --git a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockWithUnclosedTopLevelTagThrowsMissingEndTagParserExceptionOnOutermostUnclosedTag.diagnostics.txt b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockWithUnclosedTopLevelTagThrowsMissingEndTagParserExceptionOnOutermostUnclosedTag.diagnostics.txt
new file mode 100644
index 0000000000..62f7a40547
--- /dev/null
+++ b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockWithUnclosedTopLevelTagThrowsMissingEndTagParserExceptionOnOutermostUnclosedTag.diagnostics.txt
@@ -0,0 +1 @@
+(1,2): Error RZ1025: The "p" element was not closed.  All elements must be either self-closing or have a matching end tag.
diff --git a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockWithUnclosedTopLevelTagThrowsMissingEndTagParserExceptionOnOutermostUnclosedTag.syntaxtree.txt b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockWithUnclosedTopLevelTagThrowsMissingEndTagParserExceptionOnOutermostUnclosedTag.syntaxtree.txt
new file mode 100644
index 0000000000..88641f430d
--- /dev/null
+++ b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockWithUnclosedTopLevelTagThrowsMissingEndTagParserExceptionOnOutermostUnclosedTag.syntaxtree.txt
@@ -0,0 +1,17 @@
+Markup block - Gen<None> - 14 - (0:0,0)
+    Tag block - Gen<None> - 3 - (0:0,0)
+        Markup span - Gen<Markup> - [<p>] - SpanEditHandler;Accepts:None - (0:0,0) - Symbols:3
+            HtmlSymbolType.OpenAngle;[<];
+            HtmlSymbolType.Text;[p];
+            HtmlSymbolType.CloseAngle;[>];
+    Tag block - Gen<None> - 5 - (3:0,3)
+        Markup span - Gen<Markup> - [<foo>] - SpanEditHandler;Accepts:None - (3:0,3) - Symbols:3
+            HtmlSymbolType.OpenAngle;[<];
+            HtmlSymbolType.Text;[foo];
+            HtmlSymbolType.CloseAngle;[>];
+    Tag block - Gen<None> - 6 - (8:0,8)
+        Markup span - Gen<Markup> - [</bar>] - SpanEditHandler;Accepts:None - (8:0,8) - Symbols:4
+            HtmlSymbolType.OpenAngle;[<];
+            HtmlSymbolType.ForwardSlash;[/];
+            HtmlSymbolType.Text;[bar];
+            HtmlSymbolType.CloseAngle;[>];
diff --git a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockWithUnfinishedTagAtEOFThrowsIncompleteTagException.diagnostics.txt b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockWithUnfinishedTagAtEOFThrowsIncompleteTagException.diagnostics.txt
new file mode 100644
index 0000000000..3ad9732fe6
--- /dev/null
+++ b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockWithUnfinishedTagAtEOFThrowsIncompleteTagException.diagnostics.txt
@@ -0,0 +1 @@
+(1,2): Error RZ1024: End of file or an unexpected character was reached before the "foo" 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.
diff --git a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockWithUnfinishedTagAtEOFThrowsIncompleteTagException.syntaxtree.txt b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockWithUnfinishedTagAtEOFThrowsIncompleteTagException.syntaxtree.txt
new file mode 100644
index 0000000000..14f833f254
--- /dev/null
+++ b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/ParserTests/HtmlErrorTest/ParseBlockWithUnfinishedTagAtEOFThrowsIncompleteTagException.syntaxtree.txt
@@ -0,0 +1,12 @@
+Markup block - Gen<None> - 12 - (0:0,0)
+    Tag block - Gen<None> - 12 - (0:0,0)
+        Markup span - Gen<Markup> - [<foo] - SpanEditHandler;Accepts:Any - (0:0,0) - Symbols:2
+            HtmlSymbolType.OpenAngle;[<];
+            HtmlSymbolType.Text;[foo];
+        Markup block - Gen<Attr:bar, bar=@(4:0,4),@(12:0,12)> - 8 - (4:0,4)
+            Markup span - Gen<None> - [ bar=] - SpanEditHandler;Accepts:Any - (4:0,4) - Symbols:3
+                HtmlSymbolType.WhiteSpace;[ ];
+                HtmlSymbolType.Text;[bar];
+                HtmlSymbolType.Equals;[=];
+            Markup span - Gen<LitAttr:@(9:0,9)> - [baz] - SpanEditHandler;Accepts:Any - (9:0,9) - Symbols:1
+                HtmlSymbolType.Text;[baz];