C＃编程语言设计的官方仓库-.NET开发

# C# Language Design Notes for 2020 Overview of meetings and agendas for 2020 ## Dec 16, 2020 [C# Language Design Notes for December 16th, 2020](https://github.com/dotnet/csharplang/blob/master/meetings/2020/LDM-2020-12-16.md) - List patterns - Definite assignment changes ## Dec 14, 2020 [C# Language Design Notes for December 14th, 2020](https://github.com/dotnet/csharplang/blob/master/meetings/2020/LDM-2020-12-14.md) - List patterns ## Dec 7, 2020 [C# Language Design Notes for December 7th, 2020](https://github.com/dotnet/csharplang/blob/master/meetings/2020/LDM-2020-12-07.md) - Required Properties ## Dec 2, 2020 [C# Language Design Notes for December 2nd, 2020](https://github.com/dotnet/csharplang/blob/master/meetings/2020/LDM-2020-12-02.md) - Partner scenarios in roles and extensions ## Nov 16, 2020 [C# Language Design Notes for November 16th, 2020](https://github.com/dotnet/csharplang/blob/master/meetings/2020/LDM-2020-11-16.md) - Triage ## Nov 11, 2020 [C# Language Design Notes for November 11th, 2020](https://github.com/dotnet/csharplang/blob/master/meetings/2020/LDM-2020-11-11.md) - IsRecord in metadata - Triage ## Nov 4, 2020 [C# Language Design Notes for November 4th, 2020](https://github.com/dotnet/csharplang/blob/master/meetings/2020/LDM-2020-11-04.md) - Nullable parameter defaults - Argument state after call for AllowNull parameters ## Oct 26, 2020 [C# Language Design Notes for October 26st, 2020](https://github.com/dotnet/csharplang/blob/master/meetings/2020/LDM-2020-10-26.md) - Pointer types in records - Triage ## Oct 21, 2020 [C# Language Design Notes for October 21st, 2020](https://github.com/dotnet/csharplang/blob/master/meetings/2020/LDM-2020-10-21.md) - Primary Constructors - Direct Parameter Constructors ## Oct 14, 2020 [C# Language Design Notes for October 14th, 2020](https://github.com/dotnet/csharplang/blob/master/meetings/2020/LDM-2020-10-14.md) - Triage - Milestone Simplification ## Oct 12, 2020 [C# Language Design Notes for October 12th, 2020](https://github.com/dotnet/csharplang/blob/master/meetings/2020/LDM-2020-10-12.md) - General improvements to the `struct` experience (continued) ## Oct 7, 2020 [C# Language Design Notes for October 7th, 2020](https://github.com/dotnet/csharplang/blob/master/meetings/2020/LDM-2020-10-07.md) - `record struct` syntax - `data` members redux - `ReadOnlySpan<char>` patterns ## Oct 5, 2020 [C# Language Design Notes for October 5th, 2020](https://github.com/dotnet/csharplang/blob/master/meetings/2020/LDM-2020-10-05.md) - `record struct` primary constructor defaults - Changing the member type of a primary constructor parameter - `data` members ## Sep 30, 2020 [C# Language Design Notes for September 30th, 2020](https://github.com/dotnet/csharplang/blob/master/meetings/2020/LDM-2020-09-30.md) - `record structs` - `struct` equality - `with` expressions - Primary constructors and `data` properties ## Sep 28, 2020 [C# Language Design Notes for September 28th, 2020](https://github.com/dotnet/csharplang/blob/master/meetings/2020/LDM-2020-09-28.md) - Warning on `double.NaN` - Triage ## Sep 23, 2020 [C# Language Design Notes for September 23rd, 2020](https://github.com/dotnet/csharplang/blob/master/meetings/2020/LDM-2020-09-23.md) - General improvements to the `struct` experience ## Sep 16, 2020 [C# Language Design Notes for September 16th, 2020](https://github.com/dotnet/csharplang/blob/master/meetings/2020/LDM-2020-09-16.md) - Required Properties - Triage ## Sep 14, 2020 [C# Language Design Notes for September 14th, 2020](https://github.com/dotnet/csharplang/blob/master/meetings/2020/LDM-2020-09-14.md) - Partial method signature matching - Null-conditional handling of the nullable suppression operator - Annotating IEnumerable.Cast - Nullability warnings in user-written record code - Tuple deconstruction mixed assignment and declaration ## Sep 9, 2020 [C# Language Design Notes for September 9th, 2020](https://github.com/dotnet/csharplang/blob/master/meetings/2020/LDM-2020-09-09.md) - Triage issues still in C# 9.0 candidate - Triage issues in C# 10.0 candidate ## Aug 24, 2020 [C# Language Design Notes for August 24th, 2020](https://github.com/dotnet/csharplang/blob/master/meetings/2020/LDM-2020-08-24.md) - Warnings on types named `record` - `base` calls on parameterless `record`s - Omitting unnecessary synthesized `record` members - [`record` `ToString` behavior review](https://github.com/dotnet/csharplang/blob/master/proposals/csharp-9.0/records.md#printing-members-printmembers-and-tostring-methods) - Behavior of trailing commas - Handling stack overflows - Should we omit the implementation of `ToString` on `abstract` records - Should we call `ToString` prior to `StringBuilder.Append` on value types - Should we try and avoid the double-space in an empty record - Should we try and make the typename header print more economic - Reference equality short circuiting ## Jul 27, 2020 [C# Language Design Notes for July 27th, 2020](https://github.com/dotnet/csharplang/blob/master/meetings/2020/LDM-2020-07-27.md) - [Improved nullable analysis in constructors](https://github.com/RikkiGibson/csharplang/blob/nullable-ctor/proposals/nullable-constructor-analysis.md) (Rikki) - [Equality operators (`==` and `!=`) in records](https://github.com/dotnet/csharplang/issues/3707#issuecomment-661800278) (Fred) - `.ToString()` or `GetDebuggerDisplay()` on records? (Julien) - Restore W-warning to `T t = default;` for generic `T`, now you can write `T?`? (Julien) ## Jul 20, 2020 [C# Language Design Notes for July 20th, 2020](https://github.com/dotnet/csharplang/blob/master/meetings/2020/LDM-2020-07-20.md) - [struct private fields in definite assignment](https://github.com/dotnet/csharplang/issues/3431) (Neal/Julien) - [Proposal 1](https://github.com/dotnet/roslyn/issues/30194#issuecomment-657858716) - [Proposal 2](https://github.com/dotnet/roslyn/issues/30194#issuecomment-657900257) - Finish [Triage](https://github.com/dotnet/csharplang/issues?q=is%3Aopen+is%3Aissue+label%3A%22Proposal+champion%22+no%3Amilestone) - Records-related features to pick up in the next version of C# (Mads) ## Jul 13, 2020 [C# Language Design Notes for July 13th, 2020](https://github.com/dotnet/csharplang/blob/master/meetings/2020/LDM-2020-07-13.md) - Triage open issues ## Jul 6, 2020 [C# Language Design Notes for July 6, 2020](https://github.com/dotnet/csharplang/blob/master/meetings/2020/LDM-2020-07-06.md) - [Repeat Attributes in Partial Members](https://github.com/RikkiGibson/csharplang/blob/repeated-attributes/proposals/repeat-attributes.md) (Rikki) - `sealed` on `data` members - [Required properties](https://github.com/dotnet/csharplang/issues/3630) (Fred) ## Jul 1, 2020 [C# Language Design Notes for July 1, 2020](https://github.com/dotnet/csharplang/blob/master/meetings/2020/LDM-2020-07-01.md) - [Non-defaultable struct types](https://github.com/dotnet/csharplang/issues/99#issuecomment-601792573) (Sam, Chuck) - Confirm unspeakable `Clone` method and long-term implications (Jared/Julien) ## Jun 29, 2020 [C# Language Design Notes for June 29, 2020](https://github.com/dotnet/csharplang/blob/master/meetings/2020/LDM-2020-06-29.md) - [Static interface members](https://github.com/Partydonk/partydonk/issues/1) (Miguel, Aaron, Mads, Carol) ## Jun 24, 2020 [C# Language Design Notes for June 24, 2020](https://github.com/dotnet/csharplang/blob/master/meetings/2020/LDM-2020-06-24.md) - Parameter null checking: finalize syntax - https://github.com/dotnet/csharplang/issues/3275 Variance on static interface members (Aleksey) - [Function pointer question](https://github.com/dotnet/roslyn/issues/39865#issuecomment-647692516) (Fred) ## Jun 22, 2020 [C# Language Design Notes for June 22, 2020](https://github.com/dotnet/csharplang/blob/master/meetings/2020/LDM-2020-06-22.md) 1. Data properties 1. Clarifying what's supported in reco