csharplang/meetings/2019/README.md

# Upcoming meetings for 2019

## Schedule ASAP


## Schedule when convenient

- Syntax of positional records/primary constructors (Andy)
- Discussion of refreshing language spec (Neal)
- Conceptual model for tuples (Mads, Neal)

## Recurring topics

- *Triage championed features*
- *Triage milestones*
- *Design review*

## May 20, 2019

- async LINQ (Julien)
- compile-time `is` vs runtime `instanceof` (Neal)

## May 15, 2019

- Close on nullable attributes (Mads and Steve)
- Close on flag for warning waves (existing `/warn` or new `/warnVersion`?)


## May 1, 2019

* Nullable attributes - continue discussion
* Nullable opt-in - do we need to adjust the story?

# C# Language Design Notes for 2019

Overview of meetings and agendas for 2019

## May 13, 2019
[C# Language Design Notes for May 13, 2019](LDM-2019-05-13.md)

- Close on desired rules for warning suppressions and `#nullable` interacting

## Apr 29, 2019

[C# Language Design Notes for Apr 29, 2019](LDM-2019-04-29.md)

1. Default interface implementations and `base()` calls
2. Async iterator cancellation
3. Attributes on local functions

## Apr 24, 2019

[C# Language Design Notes for Apr 24, 2019](LDM-2019-04-24.md)

MaybeNull and related nullable reference type attributes

## Apr 22, 2019

[C# Language Design Notes for Apr 22, 2019](LDM-2019-04-22.md)

1. Inferred nullable state from a finally block
2. Implied constraint for a type parameter of a partial?
3. Target-typed switch expression
4. DefaultCancellationAttribute and overriding/hiding/interface implementation

## Apr 15, 2019

[C# Language Design Notes for Apr 15, 2019](LDM-2019-04-15.md)

1. CancellationToken in iterators
2. Implied nullable constraints in nullable disabled code
3. Inheriting constraints in nullable disabled code
4. Declarations with constraints declared in #nullable disabled code
5. Result type of `??=` expression
6. Use annotation context to compute the annotations?
7. Follow-up decisions for pattern-based Index/Range

## Apr 3, 2019

[C# Language Design Notes for Apr 3, 2019](LDM-2019-04-03.md)

1. Ambiguous implementations/overrides with generic methods and NRTs
2. NRT and `dynamic`

## Apr 1, 2019

[C# Language Design Notes for Apr 1, 2019](LDM-2019-04-01.md)

1. Pattern-based Index/Range translation

2. Default interface implementations: Is object.MemberwiseClone() accessible in
an interface?


## Mar 27, 2019

[C# Language Design Notes for Mar 27, 2019](LDM-2019-03-27.md)

1. Switch expression syntax

1. Default interface implementations

    1. Reabstraction

    2. Explicit interface abstract overrides in classes

    3. `object.MemberwiseClone()`

    4. `static int P {get; set}` semantics

    5. `partial` on interface methods

2. `?` on unconstrained generic param `T`

## Mar 25, 2019

[C# Design Review Notes for Mar 25, 2019](LDM-2019-03-25.md)

We brought in the design review team to look at some of our recent and open decisions in C# LDM.

1. Nullable reference types: shipping annotations
2. Pattern-based indexing with `Index` and `Range`
3. Cancellation tokens in async streams

## Mar 19, 2019

[C# Language Design Notes for March 19, 2019](LDM-2019-03-19.md)

We held a live LDM during the MVP summit with some Q&A about C# 8 and the future

Topics:

1. Records
2. "Extension interfaces"/roles
3. Macros
4. IAsyncEnumerable
5. "Partially automatic" properties
6. More integration with reactive extensions

## Mar 13, 2019

[C# Language Design Notes for March 13, 2019](LDM-2019-03-13.md)

1. Interface "reabstraction" with default interface implementations
2. Precedence of the switch expression
3. `or` keyword in patterns
4. "Pure" null tests and the switch statement/expression

## Mar 6, 2019

[C# Language Design Notes for March 6th, 2019](LDM-2019-03-06.md)

1. Pure checks in the switch expression
2. Nullable analysis of unreachable code
3. Warnings about nullability on expressions with errors
4. Handling of type parameters that cannot be annotated
5. Should anonymous type fields have top-level nullability?
6. Element-wise analysis of tuple conversions

## Mar 4, 2019

[C# Language Design Notes for March 4, 2019](LDM-2019-03-04.md)

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

## Feb 27, 2019

[C# Language Design Notes for Feb 27, 2019](LDM-2019-02-27.md)

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

## Feb 25, 2019

[C# Language Design Notes for Feb 25, 2019](LDM-2019-02-25.md)

- 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](LDM-2019-02-20.md)

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

## Feb 13, 2019

[C# Language Design Notes for Feb 13, 2019](LDM-2019-02-13.md)

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

## Jan 23, 2019

[C# Language Design Notes for Jan 23, 2019](LDM-2019-01-23.md)

Function pointers ([Updated proposal](https://github.com/dotnet/csharplang/blob/master/proposals/function-pointers.md))

## Jan 16, 2019

[C# Language Design Notes for Jan 16, 2019](LDM-2019-01-16.md)

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

## Jan 14, 2019

[C# Language Design Notes for Jan 14, 2019](LDM-2019-01-14.md)

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

## Jan 9, 2019

[C# Language Design Notes for Jan 9, 2019](LDM-2019-01-09.md)

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

## Jan 7, 2019

[C# Language Design Notes for Jan 7, 2019](LDM-2019-01-07.md)

Nullable:

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