[Fixes #698] Removed unnecessary Debug.Assert in TagHelperBlockRewriter

src/Microsoft.AspNetCore.Razor/Parser/TagHelpers/TagHelperBlockRewriter.cs

@@ -105,6 +105,11 @@ namespace Microsoft.AspNetCore.Razor.Parser.TagHelpers.Internal
                     attributes.Add(
                         new KeyValuePair<string, SyntaxTreeNode>(result.AttributeName, result.AttributeValueNode));
                 }
+                else
+                {
+                    // Error occured while parsing the attribute. Don't try parsing the rest to avoid misleading errors.
+                    break;
+                }
             }
 
             return attributes;
@@ -205,10 +210,6 @@ namespace Microsoft.AspNetCore.Razor.Parser.TagHelpers.Internal
                 }
                 else if (symbol.Type == HtmlSymbolType.Equals)
                 {
-                    Debug.Assert(
-                        name != null,
-                        "Name should never be null here. The parser should guarantee an attribute has a name.");
-
                     // We've captured all leading whitespace and the attribute name.
                     // We're now at: " asp-for|='...'" or " asp-for|=..."
                     // The goal here is to consume the equal sign and the optional single/double-quote.

test/Microsoft.AspNetCore.Razor.Test/TagHelpers/TagHelperBlockRewriterTest.cs

@@ -757,7 +757,23 @@ namespace Microsoft.AspNetCore.Razor.Compilation.TagHelpers
                                 RazorResources.FormatParseError_UnexpectedEndTag("p"),
                                 absoluteIndex: 31, lineIndex: 0, columnIndex: 31, length: 1)
                         }
-                    }
+                    },
+                    {
+                        "<p class=some=thing attr=\"@value\"></p>",
+                        new MarkupBlock(
+                            new MarkupTagHelperBlock("p",
+                                new List<KeyValuePair<string, SyntaxTreeNode>>
+                                {
+                                    new KeyValuePair<string, SyntaxTreeNode>("class", factory.Markup("some"))
+                                })),
+                        new []
+                        {
+                            new RazorError(
+                                "TagHelper attributes must be well-formed.",
+                                new SourceLocation(13, 0, 13),
+                                length: 13)
+                        }
+                    },
                 };
             }
         }