diff --git a/src/Razor/Microsoft.AspNetCore.Razor.Language/src/Components/ComponentDiagnosticFactory.cs b/src/Razor/Microsoft.AspNetCore.Razor.Language/src/Components/ComponentDiagnosticFactory.cs
index 7d83745575..06902eb7e2 100644
--- a/src/Razor/Microsoft.AspNetCore.Razor.Language/src/Components/ComponentDiagnosticFactory.cs
+++ b/src/Razor/Microsoft.AspNetCore.Razor.Language/src/Components/ComponentDiagnosticFactory.cs
@@ -50,16 +50,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Components
             return RazorDiagnostic.Create(UnexpectedClosingTag, span ?? SourceSpan.Undefined, tagName);
         }
 
-        public static readonly RazorDiagnosticDescriptor MismatchedClosingTag = new RazorDiagnosticDescriptor(
-            "BL9982",
-            () => "Mismatching closing tag. Found '{0}' but expected '{1}'.",
-            RazorDiagnosticSeverity.Error);
-
-        public static RazorDiagnostic Create_MismatchedClosingTag(SourceSpan? span, string expectedTagName, string tagName)
-        {
-            return RazorDiagnostic.Create(MismatchedClosingTag, span ?? SourceSpan.Undefined, expectedTagName, tagName);
-        }
-
         public static readonly RazorDiagnosticDescriptor UnexpectedClosingTagForVoidElement = new RazorDiagnosticDescriptor(
             "BL9983",
             () => "Unexpected closing tag '{0}'. The element '{0}' is a void element, and should be used without a closing tag.",
diff --git a/src/Razor/Microsoft.AspNetCore.Razor.Language/src/DefaultRazorIntermediateNodeLoweringPhase.cs b/src/Razor/Microsoft.AspNetCore.Razor.Language/src/DefaultRazorIntermediateNodeLoweringPhase.cs
index dd0d281f34..38f05d593b 100644
--- a/src/Razor/Microsoft.AspNetCore.Razor.Language/src/DefaultRazorIntermediateNodeLoweringPhase.cs
+++ b/src/Razor/Microsoft.AspNetCore.Razor.Language/src/DefaultRazorIntermediateNodeLoweringPhase.cs
@@ -5,6 +5,7 @@ using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
+using Microsoft.AspNetCore.Razor.Language.Components;
 using Microsoft.AspNetCore.Razor.Language.Extensions;
 using Microsoft.AspNetCore.Razor.Language.Intermediate;
 using Microsoft.AspNetCore.Razor.Language.Legacy;
@@ -1137,13 +1138,34 @@ namespace Microsoft.AspNetCore.Razor.Language
 
             public override void VisitMarkupElement(MarkupElementSyntax node)
             {
-                _builder.Push(new MarkupElementIntermediateNode()
+                var element = new MarkupElementIntermediateNode()
                 {
                     Source = BuildSourceSpanFromNode(node),
 
                     // Could be empty while the tag is being typed in.
-                    TagName = node.StartTag?.GetTagNameWithOptionalBang() ?? node.EndTag?.GetTagName() ?? string.Empty,
-                });
+                    TagName = node.StartTag?.GetTagNameWithOptionalBang() ?? node.EndTag?.GetTagNameWithOptionalBang() ?? string.Empty,
+                };
+
+                if (node.StartTag != null && node.EndTag != null && node.StartTag.IsVoidElement())
+                {
+                    element.Diagnostics.Add(
+                            ComponentDiagnosticFactory.Create_UnexpectedClosingTagForVoidElement(
+                                BuildSourceSpanFromNode(node.EndTag), node.EndTag.GetTagNameWithOptionalBang()));
+                }
+                else if (node.StartTag != null && node.EndTag == null && !node.StartTag.IsVoidElement() && !node.StartTag.IsSelfClosing())
+                {
+                    element.Diagnostics.Add(
+                        ComponentDiagnosticFactory.Create_UnclosedTag(
+                            BuildSourceSpanFromNode(node.StartTag), node.StartTag.GetTagNameWithOptionalBang()));
+                }
+                else if (node.StartTag == null && node.EndTag != null)
+                {
+                    element.Diagnostics.Add(
+                        ComponentDiagnosticFactory.Create_UnexpectedClosingTag(
+                            BuildSourceSpanFromNode(node.EndTag), node.EndTag.GetTagNameWithOptionalBang()));
+                }
+
+                _builder.Push(element);
 
                 base.VisitMarkupElement(node);
 
diff --git a/src/Razor/Microsoft.AspNetCore.Razor.Language/src/Legacy/TagHelperParseTreeRewriter.cs b/src/Razor/Microsoft.AspNetCore.Razor.Language/src/Legacy/TagHelperParseTreeRewriter.cs
index 4b1d8355f5..0af7a34363 100644
--- a/src/Razor/Microsoft.AspNetCore.Razor.Language/src/Legacy/TagHelperParseTreeRewriter.cs
+++ b/src/Razor/Microsoft.AspNetCore.Razor.Language/src/Legacy/TagHelperParseTreeRewriter.cs
@@ -162,7 +162,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                 var endTag = (MarkupEndTagSyntax)Visit(node.EndTag);
                 if (endTag != null)
                 {
-                    var tagName = endTag.GetTagName();
+                    var tagName = endTag.GetTagNameWithOptionalBang();
                     if (TryRewriteTagHelperEnd(endTag, out tagHelperEnd))
                     {
                         // This is a tag helper
@@ -288,7 +288,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
             private bool TryRewriteTagHelperEnd(MarkupEndTagSyntax tagBlock, out MarkupTagHelperEndTagSyntax rewritten)
             {
                 rewritten = null;
-                var tagName = tagBlock.GetTagName();
+                var tagName = tagBlock.GetTagNameWithOptionalBang();
                 // Could not determine tag name, it can't be a TagHelper, continue on and track the element.
                 if (string.IsNullOrEmpty(tagName) || tagName.StartsWith("!"))
                 {
@@ -599,7 +599,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
 
             private void ValidateParentAllowsPlainEndTag(MarkupEndTagSyntax tagBlock)
             {
-                var tagName = tagBlock.GetTagName();
+                var tagName = tagBlock.GetTagNameWithOptionalBang();
 
                 // Treat partial tags such as '</' which have no tag names as content.
                 if (string.IsNullOrEmpty(tagName))
diff --git a/src/Razor/Microsoft.AspNetCore.Razor.Language/src/Syntax/MarkupEndTagSyntax.cs b/src/Razor/Microsoft.AspNetCore.Razor.Language/src/Syntax/MarkupEndTagSyntax.cs
index 2f2a529f55..b4fc904f25 100644
--- a/src/Razor/Microsoft.AspNetCore.Razor.Language/src/Syntax/MarkupEndTagSyntax.cs
+++ b/src/Razor/Microsoft.AspNetCore.Razor.Language/src/Syntax/MarkupEndTagSyntax.cs
@@ -17,7 +17,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Syntax
 
         public SyntaxList<RazorSyntaxNode> Children => GetLegacyChildren();
 
-        public string GetTagName()
+        public string GetTagNameWithOptionalBang()
         {
             return Name.IsMissing ? string.Empty : Bang?.Content + Name.Content;
         }