Collection expressions are suggested for types where it doesn't make sense, and their error messages show inconsistent types

[cremor]

Collection expressions are suggested for types where it doesn't make sense, and their error messages show inconsistent types

[dotnet-issue-labeler]

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

[RikkiGibson]

Thanks for filing this issue.

• Could you please confirm whether the issue still occurs in the latest VS/dotnet SDK preview?
• Could you please include the SharpLab code directly in the issue description in a ```cs block?

[cremor]

Yes, I can still reproduce this with the latest preview versions of VS and the .NET SDK. I've updated the issue description to include this information. And I've also directly included the sample code as requested.

[RikkiGibson]

I'm not sure right now whether to classify as a compiler or IDE (suggest using collection-exprs) issue. I'll have to spend a little more time paging in what's going on to do so.

[CyrusNajmabadi]

@RikkiGibson this is likely on hte IDE side. However, the core issue is that there are no APis the compiler exposes to know anything here. So we basically have had to reimplement all the logic aronud the rules in the language to know if somethign is a legal collectoin-expr type. that wasn't tenable originally, and it gets even harder as we add more complex and involved rules for collection types. As mentioned originally, the IDE needs apis to know if something is a legal collection expr type. Since that logic already exists in the compiler, we wouldn't have to duplicate it and we could defer directly to that to know if we can even bother offering collection exprs at all.

[cremor]

this is likely on hte IDE side

Aren't the error messages coming from the compiler?