csharplang/meetings/2019/README.md

Upcoming meetings for 2019

Schedule ASAP

Schedule when convenient

• Nullable Reference Types: Open LDM Issues https://github.com/dotnet/csharplang/issues/2201
• Default Implementation Members: Open LDM Issues https://github.com/dotnet/csharplang/issues/406
• Allowing pattern-based foreach and await foreach to bind to an extension GetEnumerator/GetAsyncEnumerator and MoveNext/MoveNextAsync (Julien/Chris)
• Syntax of positional records/primary constructors (Andy)
• Discussion of refreshing language spec (Neal)

Recurring topics

• Triage championed features
• Triage milestones
• Design review

Apr 17, 2019

Apr 15, 2019

Apr 3, 2019

Nullable Reference Types

• Ambiguous implements/overrides with generic methods and NRTs

  See https://github.com/dotnet/csharplang/issues/2378. There is a breaking change in VS2019 to address, as well as a C# 8 language question

• What is the nullability of a dynamic value? Oblivious?

  See also https://github.com/dotnet/roslyn/issues/29893

• When we compute an annotation in the walker (e.g. type inference), do we use the context?

  See also https://github.com/dotnet/roslyn/issues/33639

• Inferred nullable state from a finally block

  See also https://github.com/dotnet/roslyn/issues/34018

Apr 1, 2019

Index/Range Feature

• Pattern-based index/range translation (Jared, Stephen)

Default Interface Methods

• Is object.MemberwiseClone() accessible in an interface?

  Please revisit this question.

Mar 27, 2019

Default Interface Methods

See also https://github.com/dotnet/csharplang/issues/406

We now have a proposed runtime implementation for reabstraction. See https://github.com/dotnet/coreclr/pull/23313

• Reabstraction

• explicit interface abstract overrides in classes

• Is object.MemberwiseClone() accessible in an interface?

• Confirm: static int P { get; set; } is an auto-property with a compiler-generated backing field?

• Confirm: partial on a method declaration implies private, and no access modifier is permitted?

Mar 25, 2019

• Design review

Mar 13, 2019

Default Interface Methods

See also https://github.com/dotnet/csharplang/issues/406

• Reabstraction (open)
• explicit interface abstract overrides in classes (open)

Pattern-Matching

See also https://github.com/dotnet/csharplang/issues/2095

• Propose to change precedence of switch expression to primary (open)

  The switch expression is currently at relational precedence. I propose to change it to primary precedence. See #2331 for details.

• Reserve and and or in patterns (open)

  In anticipation of possibly permitting and and or as pattern combinators in the future, we should forbid (or at least warn) when these identifiers are used as the designator in a declaration or recursive pattern. Otherwise it would be a breaking change.

• To where do null inferences flow from a pattern in a switch? (open)

  1. To the entry of the switch and all previous cases
  2. To that branch of the switch only
  3. To all code that follows the test in logical order

Mar 6, 2019

• Nullable sidecar files (Immo)
• Nullable Reference Types: Open LDM Issues https://github.com/dotnet/csharplang/issues/2201

C# Language Design Notes for 2019

Overview of meetings and agendas for 2019

Mar 4, 2019

C# Language Design Notes for March 4, 2019

1. Nullable user studies
2. Interpolated string and string.Format optimizations

Feb 27, 2019

C# Language Design Notes for Feb 27, 2019

1. Allow ObsoleteAttribute on property accessors
2. More Default Interface Member questions

Feb 25, 2019

C# Language Design Notes for Feb 25, 2019

• Open issues in default interface methods (https://github.com/dotnet/csharplang/issues/406).
  • Base calls
  • We currently have open issues around protected, internal, reabstraction, and static fields among others.

Feb 20, 2019

C# Language Design Notes for Feb 20, 2019

• Nullable Reference Types: Open LDM Issues https://github.com/dotnet/csharplang/issues/2201

Feb 13, 2019

C# Language Design Notes for Feb 13, 2019

• Nullable Reference Types: Open LDM Issues https://github.com/dotnet/csharplang/issues/2201

Jan 23, 2019

C# Language Design Notes for Jan 23, 2019

Function pointers (Updated proposal)

Jan 16, 2019

C# Language Design Notes for Jan 16, 2019

1. Shadowing in lambdas
2. Pattern-based disposal in await foreach

Jan 14, 2019

C# Language Design Notes for Jan 14, 2019

• Generating null-check for parameter! https://github.com/dotnet/csharplang/pull/2144

Jan 9, 2019

C# Language Design Notes for Jan 9, 2019

1. GetAsyncEnumerator signature
2. Ambiguities in nullable array type syntax
3. Recursive Patterns Open Language Issues https://github.com/dotnet/csharplang/issues/2095

Jan 7, 2019

C# Language Design Notes for Jan 7, 2019

Nullable:

1. Variance in overriding/interface implementation
2. Breaking change in parsing array specifiers