* Prefer ReadOnlySpan over Span as better conversion target

* Test identity element conversions

* Exclude span types from the second rule

Addresses LDM feedback.

* Handle Span vs non-span type

* Extend tests

* Add feature flag for emitting string literals into data section as UTF8

* Address feedback

* Simplify some APIs

* Lift well known type member check

* Obtain the string type lazily

* Consolidate static constructor implementations

* Encapsulate IL emit of BytesToStringHelper

* Extract NestedTypeDefinition

* Share ParameterDefinitionBase

* Add more doc comments

* Remove unnecessary `using`s

* Avoid passing text and data together

* Avoid immutable array allocation

* Remove ITokenDeferral and SystemStringType passing

* Simplify parameter definition

* Cache threshold

* Simplify code

* Re-add Opt suffix

* Remove an unnecessary using

* Extend tests

* Improve tests

* Improve code

* Copy feature spec

* Add "literal" to the feature flag

* Add more details

* Convert indentation to spaces

* Rename feature flag

* Improve

* Improve

* Update an implementation detail

* Improve

* Update after feature review

* Make the shared helper private

* Do not detect XXH128 collisions

* Clarify feature flag values

* Improve wording

* Remove note

…6759)

…otnet#76761)

Brings in serialization change from
dotnet/razor#11386

…6866)

Current guess is that this is the cause of the rps/speedometer ngen
failures.
Also the signing variable override doesn't appear to work (variable
already defined in pipeline UI gets overriden to empty. and the msbuild
condition I think should be DotNetSignType)

This reverts commit 2eca5b2, reversing
changes made to fe3a243.

Fixes https://devdiv.visualstudio.com/DevDiv/_workitems/edit/2317372

Presumably something changed in Roslyn where encoding can be null now?
🤷‍♂️

…76876)

Enables format on type when the trigger character is a newline. Removes
text changes that contain the cursor as we do not want to remove the
indentation.



https://github.com/user-attachments/assets/962f8229-f41b-4632-a8e9-b7660575e448



Resolves dotnet/vscode-csharp#6834

…didateSet (dotnet#76835)

* Reduce work in ConversionsBase.AddUserDefinedConversionsToExplicitCandidateSet

The ArrayBuilder usage in this method is showing up slightly in speedometer CPU profiles (0.1%) but more heavily in local profiles I've taken using a much larger version of the file than what the speedometer tests use (2.6%)

This method is called quite often and the (isExplicit && isChecked) check seems to not hit very often (specifically, never in my testing of opening/simple editing of the file). The usage of the pool and populating the array builder aren't necessary unless that case is hit, so I've reshuffled the code around a bit to avoid that.

* Add feature status of Partial Events and Constructors

* Link champion issue

dotnet#76884)

The issue mentioned in the comment has been fixed since almost nine years ago.

Verified this produces a dll with data embedded
```
PS C:\Users\dabarbet\Downloads\net472> .\ibcmerge.exe -dxml -mi C:\Users\dabarbet\Downloads\officual_build_vsix\new_official_build\Microsoft.CodeAnalysis.LanguageServer.Protocol.dll
Reading IBC resource from file: C:\Users\dabarbet\Downloads\officual_build_vsix\new_official_build\Microsoft.CodeAnalysis.LanguageServer.Protocol.dll
Xml output file: C:\Users\dabarbet\Downloads\officual_build_vsix\new_official_build\Microsoft.CodeAnalysis.LanguageServer.Protocol.ibc.xml
```


![image](https://github.com/user-attachments/assets/e67304b5-2f07-4a5d-b7ab-9160b171440b)

…-expressions