Exception when typing ampersand inside attribute in VS2026

[dodexahedron]

If the cursor is inside an attribute's quotes and you type an ampersand and any other character following it (to put in an XML-escaped entity), the below exception occurs.

Ignoring it and continuing to type keeps throwing it on every keystroke until the value is complete and terminated with a semicolon.

This is occurring in VS2026, and I have not tested it in 2022.

Happens in any attribute I've tried it in.

Exception message box text:

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Assertion Failed: Abort=Quit, Retry=Debug, Ignore=Continue
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   at MonoDevelop.MSBuild.Language.Expressions.ExpressionParser.ConsumeXmlName(String buffer, Int32& offset, Int32 endOffset) in D:\a\MonoDevelop.MSBuildEditor\MonoDevelop.MSBuildEditor\MonoDevelop.MSBuild\Language\Expressions\ExpressionParser.cs:line 407

   at MonoDevelop.MSBuild.Language.Expressions.ExpressionParser.ConsumeEntity(String buffer, Int32& offset, Int32 endOffset) in D:\a\MonoDevelop.MSBuildEditor\MonoDevelop.MSBuildEditor\MonoDevelop.MSBuild\Language\Expressions\ExpressionParser.cs:line 391

   at MonoDevelop.MSBuild.Language.Expressions.ExpressionParser.Parse(String buffer, Int32& offset, Int32 endOffset, ExpressionOptions options, Int32 baseOffset, Boolean& hasError, Char topLevelTerminator) in D:\a\MonoDevelop.MSBuildEditor\MonoDevelop.MSBuildEditor\MonoDevelop.MSBuild\Language\Expressions\ExpressionParser.cs:line 67

   at MonoDevelop.MSBuild.Language.Expressions.ExpressionParser.Parse(String buffer, Int32 startOffset, Int32 endOffset, ExpressionOptions options, Int32 baseOffset, Bo......

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Doesn't matter which element or which attribute. Seems to happen on all of them.

It does not happen when typing inside the text value of the element - only inside attributes.

Currently using version 2.9.524.37316 in Visual Studio 2026 Professional build 11206.111