diff --git a/src/Microsoft.AspNetCore.Razor.Language/DefaultRazorDiagnostic.cs b/src/Microsoft.AspNetCore.Razor.Language/DefaultRazorDiagnostic.cs
index a8bc704e7a..40f558df26 100644
--- a/src/Microsoft.AspNetCore.Razor.Language/DefaultRazorDiagnostic.cs
+++ b/src/Microsoft.AspNetCore.Razor.Language/DefaultRazorDiagnostic.cs
@@ -8,26 +8,29 @@ namespace Microsoft.AspNetCore.Razor.Language
 {
     internal class DefaultRazorDiagnostic : RazorDiagnostic
     {
-        private readonly RazorDiagnosticDescriptor _descriptor;
-        private readonly object[] _args;
-
         internal DefaultRazorDiagnostic(RazorDiagnosticDescriptor descriptor, SourceSpan span, object[] args)
         {
-            _descriptor = descriptor;
+            Descriptor = descriptor;
             Span = span;
-            _args = args;
+            Args = args;
         }
 
-        public override string Id => _descriptor.Id;
+        public override string Id => Descriptor.Id;
 
-        public override RazorDiagnosticSeverity Severity => _descriptor.Severity;
+        public override RazorDiagnosticSeverity Severity => Descriptor.Severity;
 
         public override SourceSpan Span { get; }
 
+        // Internal for testing
+        internal RazorDiagnosticDescriptor Descriptor { get; }
+
+        // Internal for testing
+        internal object[] Args { get; }
+
         public override string GetMessage(IFormatProvider formatProvider)
         {
-            var format = _descriptor.GetMessageFormat();
-            return string.Format(formatProvider, format, _args);
+            var format = Descriptor.GetMessageFormat();
+            return string.Format(formatProvider, format, Args);
         }
 
         public override bool Equals(RazorDiagnostic obj)
@@ -38,7 +41,7 @@ namespace Microsoft.AspNetCore.Razor.Language
                 return false;
             }
 
-            if (!_descriptor.Equals(other._descriptor))
+            if (!Descriptor.Equals(other.Descriptor))
             {
                 return false;
             }
@@ -48,14 +51,14 @@ namespace Microsoft.AspNetCore.Razor.Language
                 return false;
             }
 
-            if (_args.Length != other._args.Length)
+            if (Args.Length != other.Args.Length)
             {
                 return false;
             }
 
-            for (var i = 0; i < _args.Length; i++)
+            for (var i = 0; i < Args.Length; i++)
             {
-                if (!_args[i].Equals(other._args[i]))
+                if (!Args[i].Equals(other.Args[i]))
                 {
                     return false;
                 }
@@ -67,12 +70,12 @@ namespace Microsoft.AspNetCore.Razor.Language
         public override int GetHashCode()
         {
             var hash = new HashCodeCombiner();
-            hash.Add(_descriptor.GetHashCode());
+            hash.Add(Descriptor.GetHashCode());
             hash.Add(Span.GetHashCode());
 
-            for (var i = 0; i < _args.Length; i++)
+            for (var i = 0; i < Args.Length; i++)
             {
-                hash.Add(_args[i]);
+                hash.Add(Args[i]);
             }
 
             return hash;
diff --git a/src/Microsoft.AspNetCore.Razor.Language/Extensions/DefaultTagHelperTargetExtension.cs b/src/Microsoft.AspNetCore.Razor.Language/Extensions/DefaultTagHelperTargetExtension.cs
index 6311a900d9..eacdf6b677 100644
--- a/src/Microsoft.AspNetCore.Razor.Language/Extensions/DefaultTagHelperTargetExtension.cs
+++ b/src/Microsoft.AspNetCore.Razor.Language/Extensions/DefaultTagHelperTargetExtension.cs
@@ -581,7 +581,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Extensions
             else if (node is TemplateIntermediateNode)
             {
                 var expectedTypeName = property.IsIndexerNameMatch ? property.BoundAttribute.IndexerTypeName : property.BoundAttribute.TypeName;
-                var diagnostic = RazorDiagnosticFactory.CreateTagHelper_InlineMarkupBlocksNotSupportedInAttributes(expectedTypeName, span ?? SourceSpan.Undefined);
+                var diagnostic = RazorDiagnosticFactory.CreateTagHelper_InlineMarkupBlocksNotSupportedInAttributes(span ?? SourceSpan.Undefined, expectedTypeName);
                 context.Diagnostics.Add(diagnostic);
             }
         }
diff --git a/src/Microsoft.AspNetCore.Razor.Language/Legacy/TagHelperBlockRewriter.cs b/src/Microsoft.AspNetCore.Razor.Language/Legacy/TagHelperBlockRewriter.cs
index af8b1a9c36..bfb31bce05 100644
--- a/src/Microsoft.AspNetCore.Razor.Language/Legacy/TagHelperBlockRewriter.cs
+++ b/src/Microsoft.AspNetCore.Razor.Language/Legacy/TagHelperBlockRewriter.cs
@@ -61,8 +61,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                 // Only want to track the attribute if we succeeded in parsing its corresponding Block/Span.
                 if (result != null)
                 {
-                    SourceLocation? errorLocation = null;
-
                     // Check if it's a non-boolean bound attribute that is minimized or if it's a bound
                     // non-string attribute that has null or whitespace content.
                     var isMinimized = result.AttributeValueNode == null;
@@ -74,32 +72,19 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                         result.IsBoundNonStringAttribute &&
                          IsNullOrWhitespaceAttributeValue(result.AttributeValueNode)))
                     {
-                        errorLocation = GetAttributeNameStartLocation(child);
-
-                        errorSink.OnError(
-                            errorLocation.Value,
-                            LegacyResources.FormatRewriterError_EmptyTagHelperBoundAttribute(
-                                result.AttributeName,
-                                tagName,
-                                GetPropertyType(result.AttributeName, bindingResult.Descriptors)),
-                            result.AttributeName.Length);
+                        var errorLocation = GetAttributeNameLocation(child, result.AttributeName);
+                        var propertyTypeName = GetPropertyType(result.AttributeName, bindingResult.Descriptors);
+                        var diagnostic = RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(errorLocation, result.AttributeName, tagName, propertyTypeName);
+                        errorSink.OnError(diagnostic);
                     }
 
                     // Check if the attribute was a prefix match for a tag helper dictionary property but the
                     // dictionary key would be the empty string.
                     if (result.IsMissingDictionaryKey)
                     {
-                        if (!errorLocation.HasValue)
-                        {
-                            errorLocation = GetAttributeNameStartLocation(child);
-                        }
-
-                        errorSink.OnError(
-                            errorLocation.Value,
-                            LegacyResources.FormatTagHelperBlockRewriter_IndexerAttributeNameMustIncludeKey(
-                                result.AttributeName,
-                                tagName),
-                            result.AttributeName.Length);
+                        var errorLocation = GetAttributeNameLocation(child, result.AttributeName);
+                        var diagnostic = RazorDiagnosticFactory.CreateParsing_TagHelperIndexerAttributeNameMustIncludeKey(errorLocation, result.AttributeName, tagName);
+                        errorSink.OnError(diagnostic);
                     }
 
                     var attributeNode = new TagHelperAttributeNode(
@@ -299,10 +284,9 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                 // ex: <myTH class="btn"| |
                 if (!string.IsNullOrWhiteSpace(span.Content))
                 {
-                    errorSink.OnError(
-                        span.Start,
-                        LegacyResources.TagHelperBlockRewriter_TagHelperAttributeListMustBeWellFormed,
-                        span.Content.Length);
+                    var location = new SourceSpan(span.Start, span.Content.Length);
+                    var diagnostic = RazorDiagnosticFactory.CreateParsing_TagHelperAttributeListMustBeWellFormed(location);
+                    errorSink.OnError(diagnostic);
                 }
 
                 return null;
@@ -341,10 +325,9 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
 
             if (childSpan == null || childSpan.Kind != SpanKindInternal.Markup)
             {
-                errorSink.OnError(
-                    block.Start,
-                    LegacyResources.FormatTagHelpers_CannotHaveCSharpInTagDeclaration(tagName),
-                    block.Length);
+                var location = new SourceSpan(block.Start, block.Length);
+                var diagnostic = RazorDiagnosticFactory.CreateParsing_TagHelpersCannotHaveCSharpInTagDeclaration(location, tagName);
+                errorSink.OnError(diagnostic);
 
                 return null;
             }
@@ -368,10 +351,9 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
             var name = string.Concat(nameSymbols);
             if (string.IsNullOrEmpty(name))
             {
-                errorSink.OnError(
-                    childSpan.Start,
-                    LegacyResources.FormatTagHelpers_AttributesMustHaveAName(tagName),
-                    childSpan.Length);
+                var location = new SourceSpan(childSpan.Start, childSpan.Length);
+                var diagnostic = RazorDiagnosticFactory.CreateParsing_TagHelperAttributesMustHaveAName(location, tagName);
+                errorSink.OnError(diagnostic);
 
                 return null;
             }
@@ -609,7 +591,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
             return builder.Build();
         }
 
-        private static SourceLocation GetAttributeNameStartLocation(SyntaxTreeNode node)
+        private static SourceSpan GetAttributeNameLocation(SyntaxTreeNode node, string attributeName)
         {
             Span span;
             var nodeStart = SourceLocation.Undefined;
@@ -635,7 +617,8 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                 .OfType<HtmlSymbol>()
                 .First(sym => sym.Type != HtmlSymbolType.WhiteSpace && sym.Type != HtmlSymbolType.NewLine);
 
-            return firstNonWhitespaceSymbol.Start;
+            var location = new SourceSpan(firstNonWhitespaceSymbol.Start, attributeName.Length);
+            return location;
         }
 
         private static Span CreateMarkupAttribute(SpanBuilder builder, TryParseResult result)
diff --git a/src/Microsoft.AspNetCore.Razor.Language/RazorDiagnosticFactory.cs b/src/Microsoft.AspNetCore.Razor.Language/RazorDiagnosticFactory.cs
index c107f22135..eaa924ed7c 100644
--- a/src/Microsoft.AspNetCore.Razor.Language/RazorDiagnosticFactory.cs
+++ b/src/Microsoft.AspNetCore.Razor.Language/RazorDiagnosticFactory.cs
@@ -330,6 +330,46 @@ namespace Microsoft.AspNetCore.Razor.Language
             return RazorDiagnostic.Create(Parsing_RazorCommentNotTerminated, location);
         }
 
+        internal static readonly RazorDiagnosticDescriptor Parsing_TagHelperIndexerAttributeNameMustIncludeKey =
+            new RazorDiagnosticDescriptor(
+                $"{DiagnosticPrefix}1029",
+                () => LegacyResources.TagHelperBlockRewriter_IndexerAttributeNameMustIncludeKey,
+                RazorDiagnosticSeverity.Error);
+        public static RazorDiagnostic CreateParsing_TagHelperIndexerAttributeNameMustIncludeKey(SourceSpan location, string attributeName, string tagName)
+        {
+            return RazorDiagnostic.Create(Parsing_TagHelperIndexerAttributeNameMustIncludeKey, location, attributeName, tagName);
+        }
+
+        internal static readonly RazorDiagnosticDescriptor Parsing_TagHelperAttributeListMustBeWellFormed =
+            new RazorDiagnosticDescriptor(
+                $"{DiagnosticPrefix}1030",
+                () => LegacyResources.TagHelperBlockRewriter_TagHelperAttributeListMustBeWellFormed,
+                RazorDiagnosticSeverity.Error);
+        public static RazorDiagnostic CreateParsing_TagHelperAttributeListMustBeWellFormed(SourceSpan location)
+        {
+            return RazorDiagnostic.Create(Parsing_TagHelperAttributeListMustBeWellFormed, location);
+        }
+
+        internal static readonly RazorDiagnosticDescriptor Parsing_TagHelpersCannotHaveCSharpInTagDeclaration =
+            new RazorDiagnosticDescriptor(
+                $"{DiagnosticPrefix}1031",
+                () => LegacyResources.TagHelpers_CannotHaveCSharpInTagDeclaration,
+                RazorDiagnosticSeverity.Error);
+        public static RazorDiagnostic CreateParsing_TagHelpersCannotHaveCSharpInTagDeclaration(SourceSpan location, string tagName)
+        {
+            return RazorDiagnostic.Create(Parsing_TagHelpersCannotHaveCSharpInTagDeclaration, location, tagName);
+        }
+
+        internal static readonly RazorDiagnosticDescriptor Parsing_TagHelperAttributesMustHaveAName =
+            new RazorDiagnosticDescriptor(
+                $"{DiagnosticPrefix}1032",
+                () => LegacyResources.TagHelpers_AttributesMustHaveAName,
+                RazorDiagnosticSeverity.Error);
+        public static RazorDiagnostic CreateParsing_TagHelperAttributesMustHaveAName(SourceSpan location, string tagName)
+        {
+            return RazorDiagnostic.Create(Parsing_TagHelperAttributesMustHaveAName, location, tagName);
+        }
+
         #endregion
 
         #region Semantic Errors
@@ -412,7 +452,7 @@ namespace Microsoft.AspNetCore.Razor.Language
                 $"{DiagnosticPrefix}2007",
                 () => LegacyResources.TagHelpers_InlineMarkupBlocks_NotSupported_InAttributes,
                 RazorDiagnosticSeverity.Error);
-        public static RazorDiagnostic CreateTagHelper_InlineMarkupBlocksNotSupportedInAttributes(string expectedTypeName, SourceSpan location)
+        public static RazorDiagnostic CreateTagHelper_InlineMarkupBlocksNotSupportedInAttributes(SourceSpan location, string expectedTypeName)
         {
             var diagnostic = RazorDiagnostic.Create(
                 TagHelper_InlineMarkupBlocksNotSupportedInAttributes,
@@ -422,6 +462,16 @@ namespace Microsoft.AspNetCore.Razor.Language
             return diagnostic;
         }
 
+        internal static readonly RazorDiagnosticDescriptor TagHelper_EmptyBoundAttribute =
+            new RazorDiagnosticDescriptor(
+                $"{DiagnosticPrefix}2008",
+                () => LegacyResources.RewriterError_EmptyTagHelperBoundAttribute,
+                RazorDiagnosticSeverity.Error);
+        public static RazorDiagnostic CreateTagHelper_EmptyBoundAttribute(SourceSpan location, string attributeName, string tagName, string propertyTypeName)
+        {
+            return RazorDiagnostic.Create(TagHelper_EmptyBoundAttribute, location, attributeName, tagName, propertyTypeName);
+        }
+
         #endregion
 
         #region TagHelper Errors
@@ -625,7 +675,7 @@ namespace Microsoft.AspNetCore.Razor.Language
 
         internal static readonly RazorDiagnosticDescriptor TagHelper_InvalidTargetedAttributeNameNullOrWhitespace =
             new RazorDiagnosticDescriptor(
-                $"{DiagnosticPrefix}3009",
+                $"{DiagnosticPrefix}3011",
                 () => Resources.TagHelper_InvalidTargetedAttributeNameNullOrWhitespace,
                 RazorDiagnosticSeverity.Error);
         public static RazorDiagnostic CreateTagHelper_InvalidTargetedAttributeNameNullOrWhitespace()
@@ -639,7 +689,7 @@ namespace Microsoft.AspNetCore.Razor.Language
 
         internal static readonly RazorDiagnosticDescriptor TagHelper_InvalidTargetedAttributeName =
             new RazorDiagnosticDescriptor(
-                $"{DiagnosticPrefix}3010",
+                $"{DiagnosticPrefix}3012",
                 () => Resources.TagHelper_InvalidTargetedAttributeName,
                 RazorDiagnosticSeverity.Error);
         public static RazorDiagnostic CreateTagHelper_InvalidTargetedAttributeName(string invalidAttributeName, char invalidCharacter)
diff --git a/src/Microsoft.AspNetCore.Razor.Language/SourceSpan.cs b/src/Microsoft.AspNetCore.Razor.Language/SourceSpan.cs
index 970aab07b4..5da785c911 100644
--- a/src/Microsoft.AspNetCore.Razor.Language/SourceSpan.cs
+++ b/src/Microsoft.AspNetCore.Razor.Language/SourceSpan.cs
@@ -30,6 +30,11 @@ namespace Microsoft.AspNetCore.Razor.Language
             FilePath = filePath;
         }
 
+        public SourceSpan(int absoluteIndex, int lineIndex, int characterIndex, int length) 
+            : this(filePath: null, absoluteIndex: absoluteIndex, lineIndex: lineIndex, characterIndex: characterIndex, length: length)
+        {
+        }
+
         public int Length { get; }
 
         public int AbsoluteIndex { get; }
diff --git a/test/Microsoft.AspNetCore.Razor.Language.Test/Extensions/DefaultTagHelperTargetExtensionTest.cs b/test/Microsoft.AspNetCore.Razor.Language.Test/Extensions/DefaultTagHelperTargetExtensionTest.cs
index cbcedb8316..67084a4052 100644
--- a/test/Microsoft.AspNetCore.Razor.Language.Test/Extensions/DefaultTagHelperTargetExtensionTest.cs
+++ b/test/Microsoft.AspNetCore.Razor.Language.Test/Extensions/DefaultTagHelperTargetExtensionTest.cs
@@ -393,7 +393,7 @@ EndAddHtmlAttributeValues(__tagHelperExecutionContext);
                 IsIndexerNameMatch = true,
             };
             var expectedLocation = new SourceSpan(100, 10);
-            var expectedDiagnostic = RazorDiagnosticFactory.CreateTagHelper_InlineMarkupBlocksNotSupportedInAttributes("System.Int32", expectedLocation);
+            var expectedDiagnostic = RazorDiagnosticFactory.CreateTagHelper_InlineMarkupBlocksNotSupportedInAttributes(expectedLocation, "System.Int32");
 
             // Act
             extension.RenderTagHelperAttributeInline(context, node, new TemplateIntermediateNode(), expectedLocation);
@@ -416,8 +416,8 @@ EndAddHtmlAttributeValues(__tagHelperExecutionContext);
             };
             var expectedLocation = new SourceSpan(100, 10);
             var expectedDiagnostic = RazorDiagnosticFactory.CreateTagHelper_InlineMarkupBlocksNotSupportedInAttributes(
-                "System.Collections.Generic.Dictionary<System.String, System.Int32>",
-                expectedLocation);
+                expectedLocation,
+                "System.Collections.Generic.Dictionary<System.String, System.Int32>");
 
             // Act
             extension.RenderTagHelperAttributeInline(context, node, new TemplateIntermediateNode(), expectedLocation);
diff --git a/test/Microsoft.AspNetCore.Razor.Language.Test/Legacy/TagHelperBlockRewriterTest.cs b/test/Microsoft.AspNetCore.Razor.Language.Test/Legacy/TagHelperBlockRewriterTest.cs
index 63c6ac1677..a5a631d231 100644
--- a/test/Microsoft.AspNetCore.Razor.Language.Test/Legacy/TagHelperBlockRewriterTest.cs
+++ b/test/Microsoft.AspNetCore.Razor.Language.Test/Legacy/TagHelperBlockRewriterTest.cs
@@ -346,8 +346,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                 var errorFormatUnclosed = "Found a malformed '{0}' tag helper. Tag helpers must have a start and " +
                                           "end tag or be self closing.";
                 var errorFormatNoCloseAngle = "Missing close angle for tag helper '{0}'.";
-                var errorFormatNoCSharp = "The tag helper '{0}' must not have C# in the element's attribute " +
-                                           "declaration area.";
                 Func<string, Block> createInvalidDoBlock = extraCode =>
                 {
                     return new MarkupBlock(
@@ -472,10 +470,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 string.Format(CultureInfo.InvariantCulture, errorFormatUnclosed, "p"),
                                 new SourceLocation(1, 0, 1),
                                 length: 1)),
-                            RazorDiagnostic.Create(new RazorError(
-                                "TagHelper attributes must be well-formed.",
-                                new SourceLocation(12, 0, 12),
-                                length: 1))
+                            RazorDiagnosticFactory.CreateParsing_TagHelperAttributeListMustBeWellFormed(new SourceSpan(12, 0, 12, 1))
                         }
                     },
                     {
@@ -629,9 +624,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                             new MarkupTagHelperBlock("p")),
                         new []
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(CultureInfo.InvariantCulture, errorFormatNoCSharp, "p"),
-                                absoluteIndex: 3, lineIndex: 0 , columnIndex: 3, length: 13))
+                            RazorDiagnosticFactory.CreateParsing_TagHelpersCannotHaveCSharpInTagDeclaration(new SourceSpan(3, 0, 3, 13), "p")
                         }
                     },
                     {
@@ -640,9 +633,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                             new MarkupTagHelperBlock("p")),
                         new []
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(CultureInfo.InvariantCulture, errorFormatNoCSharp, "p"),
-                                absoluteIndex: 3, lineIndex: 0 , columnIndex: 3, length: 13))
+                            RazorDiagnosticFactory.CreateParsing_TagHelpersCannotHaveCSharpInTagDeclaration(new SourceSpan(3, 0, 3, 13), "p")
                         }
                     },
                     {
@@ -737,9 +728,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 string.Format(CultureInfo.InvariantCulture, errorFormatUnclosed, "p"),
                                 new SourceLocation(1, 0, 1),
                                 length: 1)),
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(CultureInfo.InvariantCulture, errorFormatNoCSharp, "p"),
-                                absoluteIndex: 3, lineIndex: 0 , columnIndex: 3, length: 30)),
+                            RazorDiagnosticFactory.CreateParsing_TagHelpersCannotHaveCSharpInTagDeclaration(new SourceSpan(3, 0, 3, 30), "p"),
                             RazorDiagnosticFactory.CreateParsing_ExpectedEndOfBlockBeforeEOF(
                                 new SourceSpan(new SourceLocation(4, 0, 4), contentLength: 1), "do", "}", "{"),
                             RazorDiagnosticFactory.CreateParsing_UnexpectedEndTag(
@@ -756,10 +745,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new []
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                "TagHelper attributes must be well-formed.",
-                                new SourceLocation(13, 0, 13),
-                                length: 13))
+                            RazorDiagnosticFactory.CreateParsing_TagHelperAttributeListMustBeWellFormed(new SourceSpan(13, 0, 13, 13))
                         }
                     },
                 };
@@ -1920,9 +1906,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
             get
             {
                 var factory = new SpanFactory();
-                var emptyAttributeError =
-                    "Attribute '{0}' on tag helper element '{1}' requires a value. Tag helper bound attributes of " +
-                    "type '{2}' cannot be empty or contain only whitespace.";
                 var boolTypeName = typeof(bool).FullName;
 
                 // documentContent, expectedOutput, expectedErrors
@@ -1940,9 +1923,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(emptyAttributeError, "bound", "myth", boolTypeName),
-                                absoluteIndex: 6, lineIndex: 0, columnIndex: 6, length: 5))
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(6, 0, 6, 5),
+                                "bound",
+                                "myth",
+                                boolTypeName)
                         }
                     },
                     {
@@ -1975,9 +1960,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(emptyAttributeError, "bound", "myth", boolTypeName),
-                                absoluteIndex: 6, lineIndex: 0, columnIndex: 6, length: 5))
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(6, 0, 6, 5),
+                                "bound",
+                                "myth",
+                                boolTypeName),
                         }
                     },
                     {
@@ -1993,12 +1980,16 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(emptyAttributeError, "bound", "myth", boolTypeName),
-                                absoluteIndex: 6, lineIndex: 0, columnIndex: 6, length: 5)),
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(emptyAttributeError, "bound", "myth", boolTypeName),
-                                absoluteIndex: 16, lineIndex: 0, columnIndex: 16, length: 5))
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(6, 0, 6, 5),
+                                "bound",
+                                "myth",
+                                boolTypeName),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(16, 0, 16, 5),
+                                "bound",
+                                "myth",
+                                boolTypeName),
                         }
                     },
                     {
@@ -2019,12 +2010,16 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(emptyAttributeError, "bound", "myth", boolTypeName),
-                                absoluteIndex: 6, lineIndex: 0, columnIndex: 6, length: 5)),
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(emptyAttributeError, "bound", "myth", boolTypeName),
-                                absoluteIndex: 17, lineIndex: 0, columnIndex: 17, length: 5))
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(6, 0, 6, 5),
+                                "bound",
+                                "myth",
+                                boolTypeName),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(17, 0, 17, 5),
+                                "bound",
+                                "myth",
+                                boolTypeName),
                         }
                     },
                     {
@@ -2046,9 +2041,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(emptyAttributeError, "bound", "myth", boolTypeName),
-                                absoluteIndex: 19, lineIndex: 0, columnIndex: 19, length: 5))
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(19, 0, 19, 5),
+                                "bound",
+                                "myth",
+                                boolTypeName),
                         }
                     },
                     {
@@ -2067,9 +2064,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(emptyAttributeError, "bound", "myth", boolTypeName),
-                                absoluteIndex: 6, lineIndex: 0, columnIndex: 6, length: 5)),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(6, 0, 6, 5),
+                                "bound",
+                                "myth",
+                                boolTypeName),
                         }
                     },
                     {
@@ -2088,9 +2087,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(emptyAttributeError, "bound", "myth", boolTypeName),
-                                absoluteIndex: 6, lineIndex: 0, columnIndex: 6, length: 5)),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(6, 0, 6, 5),
+                                "bound",
+                                "myth",
+                                boolTypeName),
                         }
                     },
                     {
@@ -2117,9 +2118,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(emptyAttributeError, "bound", "myth", boolTypeName),
-                                absoluteIndex: 31, lineIndex: 0, columnIndex: 31, length: 5)),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(31, 0, 31, 5),
+                                "bound",
+                                "myth",
+                                boolTypeName),
                         }
                     },
                     {
@@ -2134,9 +2137,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(emptyAttributeError, "BouND", "myth", boolTypeName),
-                                absoluteIndex: 6, lineIndex: 0, columnIndex: 6, length: 5)),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(6, 0, 6, 5),
+                                "BouND",
+                                "myth",
+                                boolTypeName),
                         }
                     },
                     {
@@ -2152,12 +2157,16 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(emptyAttributeError, "BOUND", "myth", boolTypeName),
-                                absoluteIndex: 6, lineIndex: 0, columnIndex: 6, length: 5)),
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(emptyAttributeError, "bOUnd", "myth", boolTypeName),
-                                absoluteIndex: 18, lineIndex: 0, columnIndex: 18, length: 5))
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(6, 0, 6, 5),
+                                "BOUND",
+                                "myth",
+                                boolTypeName),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(18, 0, 18, 5),
+                                "bOUnd",
+                                "myth",
+                                boolTypeName),
                         }
                     },
                     {
@@ -2175,9 +2184,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(emptyAttributeError, "BOUND", "myth", boolTypeName),
-                                absoluteIndex: 6, lineIndex: 0, columnIndex: 6, length: 5))
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(6, 0, 6, 5),
+                                "BOUND",
+                                "myth",
+                                boolTypeName),
                         }
                     },
                     {
@@ -2865,10 +2876,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
             {
                 var factory = new SpanFactory();
                 var noErrors = new RazorDiagnostic[0];
-                var errorFormat = "Attribute '{0}' on tag helper element '{1}' requires a value. Tag helper bound " +
-                    "attributes of type '{2}' cannot be empty or contain only whitespace.";
-                var emptyKeyFormat = "The tag helper attribute '{0}' in element '{1}' is missing a key. The " +
-                    "syntax is '<{1} {0}{{ key }}=\"value\">'.";
                 var stringType = typeof(string).FullName;
                 var intType = typeof(int).FullName;
                 var expressionString = "@DateTime.Now + 1";
@@ -2921,8 +2928,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(errorFormat, "bound-string", "p", stringType), 3, 0, 3, 12))
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(3, 0, 3, 12),
+                                "bound-string",
+                                "p",
+                                stringType),
                         }
                     },
                     {
@@ -2937,8 +2947,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(errorFormat, "bound-required-string", "input", stringType), 7, 0, 7, 21))
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(7, 0, 7, 21),
+                                "bound-required-string",
+                                "input",
+                                stringType),
                         }
                     },
                     {
@@ -2953,8 +2966,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(errorFormat, "bound-required-int", "input", intType), 7, 0, 7, 18))
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(7, 0, 7, 18),
+                                "bound-required-int",
+                                "input",
+                                intType),
                         }
                     },
                     {
@@ -2967,7 +2983,14 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 {
                                     new TagHelperAttributeNode("bound-int", null, AttributeStructure.Minimized),
                                 })),
-                        new[] { RazorDiagnostic.Create(new RazorError(string.Format(errorFormat, "bound-int", "p", intType), 3, 0, 3, 9)) }
+                        new[]
+                        {
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(3, 0, 3, 9),
+                                "bound-int",
+                                "p",
+                                intType),
+                        }
                     },
                     {
                         "<input int-dictionary/>",
@@ -2981,12 +3004,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(errorFormat, "int-dictionary", "input", typeof(IDictionary<string, int>).Namespace + ".IDictionary<System.String, System.Int32>"),
-                                absoluteIndex: 7,
-                                lineIndex: 0,
-                                columnIndex: 7,
-                                length: 14)),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(7, 0, 7, 14),
+                                "int-dictionary",
+                                "input",
+                                typeof(IDictionary<string, int>).Namespace + ".IDictionary<System.String, System.Int32>"),
                         }
                     },
                     {
@@ -3001,12 +3023,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(errorFormat, "string-dictionary", "input", typeof(IDictionary<string, string>).Namespace + ".IDictionary<System.String, System.String>"),
-                                absoluteIndex: 7,
-                                lineIndex: 0,
-                                columnIndex: 7,
-                                length: 17)),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(7, 0, 7, 17),
+                                "string-dictionary",
+                                "input",
+                                typeof(IDictionary<string, string>).Namespace + ".IDictionary<System.String, System.String>"),
                         }
                     },
                     {
@@ -3021,18 +3042,15 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(errorFormat, "int-prefix-", "input", typeof(int).FullName),
-                                absoluteIndex: 7,
-                                lineIndex: 0,
-                                columnIndex: 7,
-                                length: 11)),
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(emptyKeyFormat, "int-prefix-", "input"),
-                                absoluteIndex: 7,
-                                lineIndex: 0,
-                                columnIndex: 7,
-                                length: 11)),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(7, 0, 7, 11),
+                                "int-prefix-",
+                                "input",
+                                intType),
+                            RazorDiagnosticFactory.CreateParsing_TagHelperIndexerAttributeNameMustIncludeKey(
+                                new SourceSpan(7, 0, 7, 11),
+                                "int-prefix-", 
+                                "input"),
                         }
                     },
                     {
@@ -3047,18 +3065,15 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(errorFormat, "string-prefix-", "input", typeof(string).FullName),
-                                absoluteIndex: 7,
-                                lineIndex: 0,
-                                columnIndex: 7,
-                                length: 14)),
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(emptyKeyFormat, "string-prefix-", "input"),
-                                absoluteIndex: 7,
-                                lineIndex: 0,
-                                columnIndex: 7,
-                                length: 14)),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(7, 0, 7, 14),
+                                "string-prefix-",
+                                "input",
+                                stringType),
+                            RazorDiagnosticFactory.CreateParsing_TagHelperIndexerAttributeNameMustIncludeKey(
+                                new SourceSpan(7, 0, 7, 14),
+                                "string-prefix-", 
+                                "input"),
                         }
                     },
                     {
@@ -3073,12 +3088,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(errorFormat, "int-prefix-value", "input", typeof(int).FullName),
-                                absoluteIndex: 7,
-                                lineIndex: 0,
-                                columnIndex: 7,
-                                length: 16)),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(7, 0, 7, 16),
+                                "int-prefix-value",
+                                "input",
+                                intType),
                         }
                     },
                     {
@@ -3093,12 +3107,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(errorFormat, "string-prefix-value", "input", typeof(string).FullName),
-                                absoluteIndex: 7,
-                                lineIndex: 0,
-                                columnIndex: 7,
-                                length: 19)),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(7, 0, 7, 19),
+                                "string-prefix-value",
+                                "input",
+                                stringType),
                         }
                     },
                     {
@@ -3113,12 +3126,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(errorFormat, "int-prefix-value", "input", typeof(int).FullName),
-                                absoluteIndex: 7,
-                                lineIndex: 0,
-                                columnIndex: 7,
-                                length: 16)),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(7, 0, 7, 16),
+                                "int-prefix-value",
+                                "input",
+                                intType),
                         }
                     },
                     {
@@ -3178,12 +3190,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(errorFormat, "bound-required-string", "input", stringType),
-                                absoluteIndex: 24,
-                                lineIndex: 0,
-                                columnIndex: 24,
-                                length: 21))
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(24, 0, 24, 21),
+                                "bound-required-string",
+                                "input",
+                                stringType),
                         }
                     },
                     {
@@ -3199,8 +3210,16 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(string.Format(errorFormat, "bound-int", "p", intType), 3, 0, 3, 9)),
-                            RazorDiagnostic.Create(new RazorError(string.Format(errorFormat, "bound-string", "p", stringType), 13, 0, 13, 12)),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(3, 0, 3, 9),
+                                "bound-int",
+                                "p",
+                                intType),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(13, 0, 13, 12),
+                                "bound-string",
+                                "p",
+                                stringType),
                         }
                     },
                     {
@@ -3217,14 +3236,16 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(errorFormat, "bound-required-int", "input", intType), 7, 0, 7, 18)),
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(errorFormat, "bound-required-string", "input", stringType),
-                                absoluteIndex: 43,
-                                lineIndex: 0,
-                                columnIndex: 43,
-                                length: 21))
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(7, 0, 7, 18),
+                                "bound-required-int",
+                                "input",
+                                intType),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(43, 0, 43, 21),
+                                "bound-required-string",
+                                "input",
+                                stringType),
                         }
                     },
                     {
@@ -3241,9 +3262,21 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(string.Format(errorFormat, "bound-int", "p", intType), 3, 0, 3, 9)),
-                            RazorDiagnostic.Create(new RazorError(string.Format(errorFormat, "bound-string", "p", stringType), 13, 0, 13, 12)),
-                            RazorDiagnostic.Create(new RazorError(string.Format(errorFormat, "bound-string", "p", stringType), 26, 0, 26, 12)),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(3, 0, 3, 9),
+                                "bound-int",
+                                "p",
+                                intType),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(13, 0, 13, 12),
+                                "bound-string",
+                                "p",
+                                stringType),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(26, 0, 26, 12),
+                                "bound-string",
+                                "p",
+                                stringType),
                         }
                     },
                     {
@@ -3272,12 +3305,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(errorFormat, "bound-string", "p", stringType),
-                                absoluteIndex: 3,
-                                lineIndex: 0,
-                                columnIndex: 3,
-                                length: 12))
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(3, 0, 3, 12),
+                                "bound-string",
+                                "p",
+                                stringType),
                         }
                     },
                     {
@@ -3306,12 +3338,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(errorFormat, "bound-string", "p", stringType),
-                                absoluteIndex: 15,
-                                lineIndex: 0,
-                                columnIndex: 15,
-                                length: 12))
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(15, 0, 15, 12),
+                                "bound-string",
+                                "p",
+                                stringType),
                         }
                     },
                     {
@@ -3327,12 +3358,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(errorFormat, "bound-required-string", "input", stringType),
-                                absoluteIndex: 7,
-                                lineIndex: 0,
-                                columnIndex: 7,
-                                length: 21))
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(7, 0, 7, 21),
+                                "bound-required-string",
+                                "input",
+                                stringType),
                         }
                     },
                     {
@@ -3348,12 +3378,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(errorFormat, "bound-required-string", "input", stringType),
-                                absoluteIndex: 19,
-                                lineIndex: 0,
-                                columnIndex: 19,
-                                length: 21))
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(19, 0, 19, 21),
+                                "bound-required-string",
+                                "input",
+                                stringType),
                         }
                     },
                     {
@@ -3369,8 +3398,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(errorFormat, "bound-required-int", "input", intType), 7, 0, 7, 18))
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(7, 0, 7, 18),
+                                "bound-required-int",
+                                "input",
+                                intType),
                         }
                     },
                     {
@@ -3386,7 +3418,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(string.Format(errorFormat, "bound-int", "p", intType), 3, 0, 3, 9))
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(3, 0, 3, 9),
+                                "bound-int",
+                                "p",
+                                intType),
                         }
                     },
                     {
@@ -3402,7 +3438,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(string.Format(errorFormat, "bound-required-int", "input", intType), 19, 0, 19, 18))
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(19, 0, 19, 18),
+                                "bound-required-int",
+                                "input",
+                                intType),
                         }
                     },
                     {
@@ -3418,7 +3458,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(string.Format(errorFormat, "bound-int", "p", intType), 15, 0, 15, 9))
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(15, 0, 15, 9),
+                                "bound-int",
+                                "p",
+                                intType),
                         }
                     },
                     {
@@ -3434,8 +3478,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(errorFormat, "bound-required-int", "input", intType), 33, 0, 33, 18))
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(33, 0, 33, 18),
+                                "bound-required-int",
+                                "input",
+                                intType),
                         }
                     },
                     {
@@ -3451,7 +3498,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(string.Format(errorFormat, "bound-int", "p", intType), 29, 0, 29, 9))
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(29, 0, 29, 9),
+                                "bound-int",
+                                "p",
+                                intType),
                         }
                     },
                     {
@@ -3471,14 +3522,16 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(errorFormat, "bound-required-int", "input", intType), 10, 0, 10, 18)),
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(errorFormat, "bound-required-string", "input", stringType),
-                                absoluteIndex: 57,
-                                lineIndex: 0,
-                                columnIndex: 57,
-                                length: 21)),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(10, 0, 10, 18),
+                                "bound-required-int",
+                                "input",
+                                intType),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(57, 0, 57, 21),
+                                "bound-required-string",
+                                "input",
+                                stringType),
                         }
                     },
                     {
@@ -3498,9 +3551,21 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 })),
                         new[]
                         {
-                            RazorDiagnostic.Create(new RazorError(string.Format(errorFormat, "bound-int", "p", intType), 6, 0, 6, 9)),
-                            RazorDiagnostic.Create(new RazorError(string.Format(errorFormat, "bound-string", "p", stringType), 44, 0, 44, 12)),
-                            RazorDiagnostic.Create(new RazorError(string.Format(errorFormat, "bound-string", "p", stringType), 84, 0, 84, 12)),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(6, 0, 6, 9),
+                                "bound-int",
+                                "p",
+                                intType),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(44, 0, 44, 12),
+                                "bound-string",
+                                "p",
+                                stringType),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(84, 0, 84, 12),
+                                "bound-string",
+                                "p",
+                                stringType),
                         }
                     },
                 };
@@ -3611,11 +3676,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
 
                     for (var i = 0; i < errors.Length; i++)
                     {
-                        var error = errors[i];
+                        var error = errors[i] as DefaultRazorDiagnostic;
                         var currentErrorLocation = new SourceLocation(error.Span.AbsoluteIndex, error.Span.LineIndex, error.Span.CharacterIndex);
                         var newErrorLocation = SourceLocationTracker.Advance(currentErrorLocation, "@{");
-                        var newError = new RazorError(error.GetMessage(), newErrorLocation, error.Span.Length);
-                        errors[i] = RazorDiagnostic.Create(newError);
+                        var copiedDiagnostic = new DefaultRazorDiagnostic(error.Descriptor, new SourceSpan(newErrorLocation, error.Span.Length), error.Args);
+                        errors[i] = copiedDiagnostic;
                     }
                 }
 
@@ -3632,8 +3697,6 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                 var errorFormatUnclosed = "Found a malformed '{0}' tag helper. Tag helpers must have a start and " +
                     "end tag or be self closing.";
                 var errorFormatNoCloseAngle = "Missing close angle for tag helper '{0}'.";
-                var errorFormatNoValue = "Attribute '{0}' on tag helper element '{1}' requires a value. Tag helper bound " +
-                    "attributes of type '{2}' cannot be empty or contain only whitespace.";
                 var stringType = typeof(string).FullName;
                 var intType = typeof(int).FullName;
 
@@ -3682,12 +3745,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 string.Format(errorFormatUnclosed, "input"),
                                 new SourceLocation(1, 0, 1),
                                 length: 5)),
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(errorFormatNoValue, "bound-required-string", "input", stringType),
-                                absoluteIndex: 7,
-                                lineIndex: 0,
-                                columnIndex: 7,
-                                length: 21)),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(7, 0, 7, 21),
+                                "bound-required-string",
+                                "input", 
+                                stringType),
                         }
                     },
                     {
@@ -3710,12 +3772,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 string.Format(errorFormatUnclosed, "input"),
                                 new SourceLocation(1, 0, 1),
                                 length: 5)),
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(errorFormatNoValue, "bound-required-int", "input", intType),
-                                absoluteIndex: 7,
-                                lineIndex: 0,
-                                columnIndex: 7,
-                                length: 18)),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(7, 0, 7, 18),
+                                "bound-required-int",
+                                "input",
+                                intType),
                         }
                     },
                     {
@@ -3740,18 +3801,16 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 string.Format(errorFormatUnclosed, "input"),
                                 new SourceLocation(1, 0, 1),
                                 length: 5)),
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(errorFormatNoValue, "bound-required-int", "input", intType),
-                                absoluteIndex: 7,
-                                lineIndex: 0,
-                                columnIndex: 7,
-                                length: 18)),
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(errorFormatNoValue, "bound-required-string", "input", stringType),
-                                absoluteIndex: 43,
-                                lineIndex: 0,
-                                columnIndex: 43,
-                                length: 21)),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(7, 0, 7, 18),
+                                "bound-required-int",
+                                "input",
+                                intType),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(43, 0, 43, 21),
+                                "bound-required-string",
+                                "input",
+                                stringType),
                         }
                     },
                     {
@@ -3774,8 +3833,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 string.Format(errorFormatUnclosed, "p"),
                                 new SourceLocation(1, 0, 1),
                                 length: 1)),
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(errorFormatNoValue, "bound-string", "p", stringType), 3, 0, 3, 12)),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(3, 0, 3, 12),
+                                "bound-string",
+                                "p",
+                                stringType),
                         }
                     },
                     {
@@ -3798,7 +3860,11 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 string.Format(errorFormatUnclosed, "p"),
                                 new SourceLocation(1, 0, 1),
                                 length: 1)),
-                            RazorDiagnostic.Create(new RazorError(string.Format(errorFormatNoValue, "bound-int", "p", intType), 3, 0, 3, 9)),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(3, 0, 3, 9),
+                                "bound-int",
+                                "p",
+                                intType),
                         }
                     },
                     {
@@ -3822,9 +3888,16 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 string.Format(errorFormatUnclosed, "p"),
                                 new SourceLocation(1, 0, 1),
                                 length: 1)),
-                            RazorDiagnostic.Create(new RazorError(string.Format(errorFormatNoValue, "bound-int", "p", intType), 3, 0, 3, 9)),
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(errorFormatNoValue, "bound-string", "p", stringType), 13, 0, 13, 12)),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(3, 0, 3, 9),
+                                "bound-int",
+                                "p",
+                                intType),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(13, 0, 13, 12),
+                                "bound-string",
+                                "p",
+                                stringType),
                         }
                     },
                     {
@@ -3857,14 +3930,16 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 string.Format(errorFormatUnclosed, "input"),
                                 new SourceLocation(1, 0, 1),
                                 length: 5)),
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(errorFormatNoValue, "bound-required-int", "input", intType), 7, 0, 7, 18)),
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(errorFormatNoValue, "bound-required-string", "input", stringType),
-                                absoluteIndex: 43,
-                                lineIndex: 0,
-                                columnIndex: 43,
-                                length: 21)),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(7, 0, 7, 18),
+                                "bound-required-int",
+                                "input",
+                                intType),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(43, 0, 43, 21),
+                                "bound-required-string",
+                                "input",
+                                stringType),
                             RazorDiagnostic.Create(new RazorError(
                                 string.Format(errorFormatNoCloseAngle, "p"),
                                 new SourceLocation(65, 0, 65),
@@ -3873,13 +3948,16 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
                                 string.Format(errorFormatUnclosed, "p"),
                                 new SourceLocation(65, 0, 65),
                                 length: 1)),
-                            RazorDiagnostic.Create(new RazorError(string.Format(errorFormatNoValue, "bound-int", "p", intType), 67, 0, 67, 9)),
-                            RazorDiagnostic.Create(new RazorError(
-                                string.Format(errorFormatNoValue, "bound-string", "p", stringType),
-                                absoluteIndex: 77,
-                                lineIndex: 0,
-                                columnIndex: 77,
-                                length: 12)),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(67, 0, 67, 9),
+                                "bound-int",
+                                "p",
+                                intType),
+                            RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                                new SourceSpan(77, 0, 77, 12),
+                                "bound-string",
+                                "p",
+                                stringType),
                         }
                     },
                 };
@@ -4036,14 +4114,16 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy
 
             var expectedErrors = new[]
             {
-                RazorDiagnostic.Create(new RazorError(
-                    "Attribute 'boundbool' on tag helper element 'input' requires a value. Tag helper bound attributes of type 'System.Boolean' cannot be empty or contain only whitespace.",
-                    new SourceLocation(7, 0, 7),
-                    length: 9)),
-                RazorDiagnostic.Create(new RazorError(
-                    "Attribute 'boundbooldict-key' on tag helper element 'input' requires a value. Tag helper bound attributes of type 'System.Boolean' cannot be empty or contain only whitespace.",
-                    new SourceLocation(17, 0, 17),
-                    length: 17)),
+                RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                    new SourceSpan(7, 0, 7, 9),
+                    "boundbool",
+                    "input",
+                    "System.Boolean"),
+                RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(
+                    new SourceSpan(17, 0, 17, 17),
+                    "boundbooldict-key",
+                    "input",
+                    "System.Boolean"),
             };
 
             // Act & Assert
diff --git a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/EmptyAttributeTagHelpers_DesignTime.diagnostics.txt b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/EmptyAttributeTagHelpers_DesignTime.diagnostics.txt
index f4d4633005..0b20997aff 100644
--- a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/EmptyAttributeTagHelpers_DesignTime.diagnostics.txt
+++ b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/EmptyAttributeTagHelpers_DesignTime.diagnostics.txt
@@ -1,3 +1,3 @@
-TestFiles/IntegrationTests/CodeGenerationIntegrationTest/EmptyAttributeTagHelpers.cshtml(4,18): Error RZ9999: Attribute 'checked' on tag helper element 'input' requires a value. Tag helper bound attributes of type 'System.Boolean' cannot be empty or contain only whitespace.
-TestFiles/IntegrationTests/CodeGenerationIntegrationTest/EmptyAttributeTagHelpers.cshtml(5,8): Error RZ9999: Attribute 'age' on tag helper element 'p' requires a value. Tag helper bound attributes of type 'System.Int32' cannot be empty or contain only whitespace.
-TestFiles/IntegrationTests/CodeGenerationIntegrationTest/EmptyAttributeTagHelpers.cshtml(6,23): Error RZ9999: Attribute 'checked' on tag helper element 'input' requires a value. Tag helper bound attributes of type 'System.Boolean' cannot be empty or contain only whitespace.
+TestFiles/IntegrationTests/CodeGenerationIntegrationTest/EmptyAttributeTagHelpers.cshtml(4,18): Error RZ2008: Attribute 'checked' on tag helper element 'input' requires a value. Tag helper bound attributes of type 'System.Boolean' cannot be empty or contain only whitespace.
+TestFiles/IntegrationTests/CodeGenerationIntegrationTest/EmptyAttributeTagHelpers.cshtml(5,8): Error RZ2008: Attribute 'age' on tag helper element 'p' requires a value. Tag helper bound attributes of type 'System.Int32' cannot be empty or contain only whitespace.
+TestFiles/IntegrationTests/CodeGenerationIntegrationTest/EmptyAttributeTagHelpers.cshtml(6,23): Error RZ2008: Attribute 'checked' on tag helper element 'input' requires a value. Tag helper bound attributes of type 'System.Boolean' cannot be empty or contain only whitespace.
diff --git a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/EmptyAttributeTagHelpers_Runtime.diagnostics.txt b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/EmptyAttributeTagHelpers_Runtime.diagnostics.txt
index f4d4633005..0b20997aff 100644
--- a/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/EmptyAttributeTagHelpers_Runtime.diagnostics.txt
+++ b/test/Microsoft.AspNetCore.Razor.Language.Test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/EmptyAttributeTagHelpers_Runtime.diagnostics.txt
@@ -1,3 +1,3 @@
-TestFiles/IntegrationTests/CodeGenerationIntegrationTest/EmptyAttributeTagHelpers.cshtml(4,18): Error RZ9999: Attribute 'checked' on tag helper element 'input' requires a value. Tag helper bound attributes of type 'System.Boolean' cannot be empty or contain only whitespace.
-TestFiles/IntegrationTests/CodeGenerationIntegrationTest/EmptyAttributeTagHelpers.cshtml(5,8): Error RZ9999: Attribute 'age' on tag helper element 'p' requires a value. Tag helper bound attributes of type 'System.Int32' cannot be empty or contain only whitespace.
-TestFiles/IntegrationTests/CodeGenerationIntegrationTest/EmptyAttributeTagHelpers.cshtml(6,23): Error RZ9999: Attribute 'checked' on tag helper element 'input' requires a value. Tag helper bound attributes of type 'System.Boolean' cannot be empty or contain only whitespace.
+TestFiles/IntegrationTests/CodeGenerationIntegrationTest/EmptyAttributeTagHelpers.cshtml(4,18): Error RZ2008: Attribute 'checked' on tag helper element 'input' requires a value. Tag helper bound attributes of type 'System.Boolean' cannot be empty or contain only whitespace.
+TestFiles/IntegrationTests/CodeGenerationIntegrationTest/EmptyAttributeTagHelpers.cshtml(5,8): Error RZ2008: Attribute 'age' on tag helper element 'p' requires a value. Tag helper bound attributes of type 'System.Int32' cannot be empty or contain only whitespace.
+TestFiles/IntegrationTests/CodeGenerationIntegrationTest/EmptyAttributeTagHelpers.cshtml(6,23): Error RZ2008: Attribute 'checked' on tag helper element 'input' requires a value. Tag helper bound attributes of type 'System.Boolean' cannot be empty or contain only whitespace.