Dictionary expressions

• Specification: https://github.com/dotnet/csharplang/blob/main/proposals/dictionary-expressions.md
• Discussion: [Proposal]: Dictionary expressions #8658

Summary

Dictionary Expressions are a continuation of the C# 12 Collection Expressions feature. They extend that system with a new terse syntax, ["mads": 21, "dustin": 22], for creating common dictionary values. Like with collection expressions, merging other dictionaries into these values is possible using the existing spread operator .. like so: [.. currentStudents, "mads": 21, "dustin": 22]

Design meetings

• https://github.com/dotnet/csharplang/blob/main/meetings/2024/LDM-2024-03-11.md#dictionary-expressions
• https://github.com/dotnet/csharplang/blob/main/meetings/2024/LDM-2024-05-15.md#dictionary-expressions
• https://github.com/dotnet/csharplang/blob/main/meetings/2024/LDM-2024-09-04.md#dictionary-expressions
• https://github.com/dotnet/csharplang/blob/main/meetings/2024/LDM-2024-11-20.md#dictionary-expressions
• https://github.com/dotnet/csharplang/blob/main/meetings/2025/LDM-2025-03-05.md#dictionary-expressions
• https://github.com/dotnet/csharplang/blob/main/meetings/2025/LDM-2025-03-17.md#dictionary-expressions
• https://github.com/dotnet/csharplang/blob/main/meetings/2025/LDM-2025-03-24.md#dictionary-expressions
• https://github.com/dotnet/csharplang/blob/main/meetings/2025/LDM-2025-04-09.md#dictionary-expressions
• https://github.com/dotnet/csharplang/blob/main/meetings/2025/LDM-2025-04-14.md#dictionary-expressions
• https://github.com/dotnet/csharplang/blob/main/meetings/2025/LDM-2025-04-23.md#dictionary-expressions
• https://github.com/dotnet/csharplang/blob/main/meetings/2025/LDM-2025-05-12.md#dictionary-expressions
• https://github.com/dotnet/csharplang/blob/main/meetings/2025/LDM-2025-08-18.md#dictionary-expressions