Added LDM notes for May 15th, 2023

meetings/2023/LDM-2023-05-15.md

@@ -0,0 +1,57 @@
+# C# Language Design Meeting for May 15th, 2023
+
+## Agenda
+
+- [Breaking Change Warnings](#breaking-change-warnings)
+- [Primary Constructors](#primary-constructors)
+
+## Quote of the Day
+
+- "The main point of closing the door is so that people who are slightly late feel that bit of embarrassment opening the door"
+
+## Discussion
+
+### Breaking Change Warnings
+
+https://github.com/dotnet/csharplang/discussions/7033  
+https://github.com/dotnet/csharplang/blob/ab5afc419eed3d67bf064ec417f69a65aecbef5c/proposals/breaking-change-warnings.md
+
+Our previous issue on this feature had a large number of moving parts and generated a lot of interesting discussion. This discussion was good, but
+it left us wondering what a pared back and small-scale version of this proposal would look like: one where we simply did the break and very little
+infrastructure around it, to avoid snowballing the proposal and adding many moving parts; in response, a small group sat down and made a minimal
+version of this feature to see what that would actually look like. The minimal version of this is very simple; when using a newer .NET SDK with a
+newer C# compiler targeting an older version of the language, warnings will be reported for any potential breaks detected. That's it, no flow
+around upgrading. LDM members had a few immediate concerns with this:
+
+* Is there any guarantee that users will actually enter this state? Particularly on systems where a new warning would fail the build, as opposed
+  to on a machine where a new warning in the list might be missed?
+* We have plenty of examples via MSBuild and NuGet where new warnings on toolset upgrade breaks our users. Is that something we're prepared to deal
+  with?
+    * All our new warnings on existing code (Warning Waves) are activated by an explicit user action; upgrading to a new version of .NET. This
+      would be the opposite.
+* If warnings are easily missed, should these be errors instead?
+    * There's some concern that this is too harsh: is it really necessary to break the build with no recourse other than downgrading the toolset?
+      There could be an opportunity to create a level between warning and error; diagnostics that appear as errors but are user-suppressible.
+* In general, catching the moment of upgrade in this system is hard.
+
+One additional consideration that was raised is that we might be trying to force this in too quickly, for the purposes of getting `field` out in C#
+12 in its idealized form. If we instead made it so that C# 12 reported warnings, and the version after breaking the scenario. Unfortunately, this
+has some of the same issues; there's no guarantee that C# 12 will actually be the migration target. It could be that user goes straight from 11, or
+from .NET Framework, or any other non-12 version. Even if we do LTS->LTS, there could still be missed warnings, and we'd also significantly delay
+new features.
+
+#### Conclusions
+
+No conclusions today. We've identified some significant problems with the minimal approach and need to keep thinking. We'll revisit again soon.
+
+### Primary Constructors
+
+https://github.com/dotnet/csharplang/issues/2691  
+https://github.com/dotnet/csharplang/blob/7bd6a9ff7f19df1e5fdbe18f593e5b18264b50da/proposals/primary-constructors.md#double-storage-warning-for-initialization-plus-capture
+
+Finally today, we looked at a small proposed potential double storage warning for primary constructors. We think this is completely inline with
+our previous decisions and approved it unanimously. Several members were surprised we hadn't already made this a warning.
+
+#### Conclusion
+
+Approved as proposed.

meetings/2023/README.md

@@ -17,11 +17,6 @@ All schedule items must have a public issue or checked-in proposal that can be l
 
 - https://github.com/dotnet/csharplang/blob/main/proposals/inline-arrays.md#the-foreach-statement (Aleksey)
 
-## Mon May 15, 2023
-
-- Breaking change warnings (Mads): https://github.com/dotnet/csharplang/blob/main/proposals/breaking-change-warnings.md
-- Dual storage warnings for initialization and capture with primary constructors (Mads/Aleksey): https://github.com/dotnet/csharplang/blob/main/proposals/primary-constructors.md#double-storage-warning-for-initialization-plus-capture
-
 ## Wed Mar 15, 2023
 
 - Discriminated Unions (Fred and Matt) - https://github.com/dotnet/csharplang/discussions/7010
@@ -29,6 +24,13 @@ All schedule items must have a public issue or checked-in proposal that can be l
 
 # C# Language Design Notes for 2023
 
+## Mon May 15, 2023
+
+[C# Language Design Meeting for May 15th, 2023](https://github.com/dotnet/csharplang/blob/main/meetings/2023/LDM-2023-05-15.md)
+
+- Breaking Change Warnings
+- Primary Constructors
+
 ## Mon May 8, 2023
 
 [C# Language Design Meeting for May 8th, 2023](https://github.com/dotnet/csharplang/blob/main/meetings/2023/LDM-2023-05-08.md)