[Proposal] Extension constants
Author: jcouvCreated Jun 20, 2026Updated Aug 27, 2026
LabelsProposal champion
Specification: https://github.com/dotnet/csharplang/blob/main/proposals/extension-constants.md Discussion: https://github.com/dotnet/csharplang/discussions/10243
Summary
Allow extension constants in extension blocks:
M(int.Dozen);
public static partial class E
{
extension(int)
{
public const int Dozen = 12;
}
}Design Meetings
Source: dotnet/csharplang