The C# 9 IntPtr / UIntPtr guard in IsBinaryCompatibleWithType read
type.Kind is not TypeKind.NInt or TypeKind.NUInt
which parses as `(is not NInt) or (is NUInt)` — true unless
Kind == NInt. The intent (per the surrounding comment "but not nint
or C# 11 IntPtr") is "Kind is neither NInt nor NUInt", which needs
parentheses around the alternation:
type.Kind is not (TypeKind.NInt or TypeKind.NUInt)
Effect: when Kind == NUInt the branch no longer mistakenly applies
the C# 9 IntPtr-only restrictions (suppressing compound assignment
without nint, disallowing shifts).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Siegfried Pammer