Move DefaultTagHelperTargetExtension errors to use RazorDiagnosticFactory.

- Added tests validating these errors because we didn't have any before.

#1827

src/Microsoft.AspNetCore.Razor.Language/Extensions/DefaultTagHelperTargetExtension.cs

@@ -550,7 +550,8 @@ namespace Microsoft.AspNetCore.Razor.Language.Extensions
             }
         }
 
-        private void RenderTagHelperAttributeInline(
+        // Internal for testing
+        internal void RenderTagHelperAttributeInline(
             CodeRenderingContext context,
             DefaultTagHelperPropertyIntermediateNode property,
             IntermediateNode node,
@@ -574,20 +575,14 @@ namespace Microsoft.AspNetCore.Razor.Language.Extensions
             }
             else if (node is CSharpCodeIntermediateNode)
             {
-                var error = new RazorError(
+                var diagnostic = RazorDiagnosticFactory.CreateTagHelper_CodeBlocksNotSupportedInAttributes(span ?? SourceSpan.Undefined);
-                    LegacyResources.TagHelpers_CodeBlocks_NotSupported_InAttributes,
+                context.Diagnostics.Add(diagnostic);
-                    SourceLocation.FromSpan(span),
-                    span == null ? -1 : span.Value.Length);
-                context.Diagnostics.Add(RazorDiagnostic.Create(error));
             }
             else if (node is TemplateIntermediateNode)
             {
                 var expectedTypeName = property.IsIndexerNameMatch ? property.BoundAttribute.IndexerTypeName : property.BoundAttribute.TypeName;
-                var error = new RazorError(
+                var diagnostic = RazorDiagnosticFactory.CreateTagHelper_InlineMarkupBlocksNotSupportedInAttributes(expectedTypeName, span ?? SourceSpan.Undefined);
-                    LegacyResources.FormatTagHelpers_InlineMarkupBlocks_NotSupported_InAttributes(expectedTypeName),
+                context.Diagnostics.Add(diagnostic);
-                    SourceLocation.FromSpan(span),
-                    span == null ? -1 : span.Value.Length);
-                context.Diagnostics.Add(RazorDiagnostic.Create(error));
             }
         }
 

src/Microsoft.AspNetCore.Razor.Language/RazorDiagnosticFactory.cs

@@ -85,6 +85,32 @@ namespace Microsoft.AspNetCore.Razor.Language
             return RazorDiagnostic.Create(Parsing_SectionsCannotBeNested, location, LegacyResources.SectionExample_CS);
         }
 
+        internal static readonly RazorDiagnosticDescriptor TagHelper_CodeBlocksNotSupportedInAttributes =
+            new RazorDiagnosticDescriptor(
+                $"{DiagnosticPrefix}2003",
+                () => LegacyResources.TagHelpers_CodeBlocks_NotSupported_InAttributes,
+                RazorDiagnosticSeverity.Error);
+        public static RazorDiagnostic CreateTagHelper_CodeBlocksNotSupportedInAttributes(SourceSpan location)
+        {
+            var diagnostic = RazorDiagnostic.Create(TagHelper_CodeBlocksNotSupportedInAttributes, location);
+            return diagnostic;
+        }
+
+        internal static readonly RazorDiagnosticDescriptor TagHelper_InlineMarkupBlocksNotSupportedInAttributes =
+            new RazorDiagnosticDescriptor(
+                $"{DiagnosticPrefix}2004",
+                () => LegacyResources.TagHelpers_InlineMarkupBlocks_NotSupported_InAttributes,
+                RazorDiagnosticSeverity.Error);
+        public static RazorDiagnostic CreateTagHelper_InlineMarkupBlocksNotSupportedInAttributes(string expectedTypeName, SourceSpan location)
+        {
+            var diagnostic = RazorDiagnostic.Create(
+                TagHelper_InlineMarkupBlocksNotSupportedInAttributes,
+                location,
+                expectedTypeName);
+
+            return diagnostic;
+        }
+
         #endregion
 
         #region TagHelper Errors

test/Microsoft.AspNetCore.Razor.Language.Test/Extensions/DefaultTagHelperTargetExtensionTest.cs

@@ -359,6 +359,74 @@ EndAddHtmlAttributeValues(__tagHelperExecutionContext);
                 ignoreLineEndingDifferences: true);
         }
 
+        [Fact]
+        public void RenderTagHelperAttributeInline_NonString_StatementInAttribute_Errors()
+        {
+            // Arrange
+            var extension = new DefaultTagHelperTargetExtension();
+            var context = TestCodeRenderingContext.CreateRuntime();
+            var node = new DefaultTagHelperPropertyIntermediateNode()
+            {
+                BoundAttribute = IntPropertyTagHelper.BoundAttributes.Single(),
+                IsIndexerNameMatch = false,
+            };
+            var expectedLocation = new SourceSpan(100, 10);
+            var expectedDiagnostic = RazorDiagnosticFactory.CreateTagHelper_CodeBlocksNotSupportedInAttributes(expectedLocation);
+
+            // Act
+            extension.RenderTagHelperAttributeInline(context, node, new CSharpCodeIntermediateNode(), expectedLocation);
+
+            // Assert
+            var diagnostic = Assert.Single(context.Diagnostics);
+            Assert.Equal(expectedDiagnostic, diagnostic);
+        }
+
+        [Fact]
+        public void RenderTagHelperAttributeInline_NonStringIndexerMatch_TemplateInAttribute_Errors()
+        {
+            // Arrange
+            var extension = new DefaultTagHelperTargetExtension();
+            var context = TestCodeRenderingContext.CreateRuntime();
+            var node = new DefaultTagHelperPropertyIntermediateNode()
+            {
+                BoundAttribute = IntIndexerTagHelper.BoundAttributes.Single(),
+                IsIndexerNameMatch = true,
+            };
+            var expectedLocation = new SourceSpan(100, 10);
+            var expectedDiagnostic = RazorDiagnosticFactory.CreateTagHelper_InlineMarkupBlocksNotSupportedInAttributes("System.Int32", expectedLocation);
+
+            // Act
+            extension.RenderTagHelperAttributeInline(context, node, new TemplateIntermediateNode(), expectedLocation);
+
+            // Assert
+            var diagnostic = Assert.Single(context.Diagnostics);
+            Assert.Equal(expectedDiagnostic, diagnostic);
+        }
+
+        [Fact]
+        public void RenderTagHelperAttributeInline_NonString_TemplateInAttribute_Errors()
+        {
+            // Arrange
+            var extension = new DefaultTagHelperTargetExtension();
+            var context = TestCodeRenderingContext.CreateRuntime();
+            var node = new DefaultTagHelperPropertyIntermediateNode()
+            {
+                BoundAttribute = IntIndexerTagHelper.BoundAttributes.Single(),
+                IsIndexerNameMatch = false,
+            };
+            var expectedLocation = new SourceSpan(100, 10);
+            var expectedDiagnostic = RazorDiagnosticFactory.CreateTagHelper_InlineMarkupBlocksNotSupportedInAttributes(
+                "System.Collections.Generic.Dictionary<System.String, System.Int32>",
+                expectedLocation);
+
+            // Act
+            extension.RenderTagHelperAttributeInline(context, node, new TemplateIntermediateNode(), expectedLocation);
+
+            // Assert
+            var diagnostic = Assert.Single(context.Diagnostics);
+            Assert.Equal(expectedDiagnostic, diagnostic);
+        }
+
         [Fact]
         public void WriteTagHelperProperty_DesignTime_StringProperty_HtmlContent_RendersCorrectly()
         {