This documentation page only mentions the 'class' and 'struct' constraint. But the current (VS 17.3) error message contains more:
The 'class', 'struct', 'unmanaged', 'notnull', and 'default' constraints cannot be combined or duplicated, and must be specified first in the constraints list.
This page should be updated to contain all of them.

In my case, I was looking for a reason why I can't combine class and notnull constraints. I had to find the generic type constraint documentation page to find the reason (class already implies notnull in a nullable context). Maybe that special case could be mentioned here. But at least the documentation page should be linked.

Document Details

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• ID: db2c4fd8-bf61-f438-df47-9659bde6232f
• Version Independent ID: c0fc18fb-3cfb-2d54-640e-7872695b9f2d
• Content: Compiler Error CS0449
• Content Source: docs/csharp/misc/cs0449.md
• Product: dotnet-csharp
• Technology: csharp-diagnostics
• GitHub Login: @BillWagner
• Microsoft Alias: wiwagn

Associated WorkItem - 476841