Fixes #40197

Fixes #39960

* Refactor tuple implementation

* Tweaks

* Address PR feedback

* Pass tuple data in constructors

* Address more feedback

* Tweak comparison

* Restore constructWithTypeParameters flag to avoid overflow

* Assert that tuple parameter matches TupleUnderlyingType somewhat

* Rename to TupleData. Address some IDE feedback

* Remaining TODO2's

* Fix last IDE test!

* Factor array comparison

* Tweak WithTupleData and EqualsIgnoringTupleUnderlyingType

* Expand a test

* Remove duplicate line

* Remove an EE test for badly formed ValueTuple type

* PR feedback from Neal

* Restore an IDE test without ValueTuple

* Rename constants

* Restore formatting

Fixes #10492

Fixes #38586

Local function control flow analysis should now use the analysis walker from the base
class instead of defining its own.

Fixes #39946

NullableAnnotation on a type symbol returned by TypeInfo should match corresponding FlowState. (#40338)

Fixes #40051.

Pass in the "isGeneratedCode" flag from editorconfig options into syntax tree parse APIs in command line compiler and IDE syntax tree factory service.

Builds on top of #39051
Addresses #3705

Avoid going into an infinite cycle while resolving erroneous event/property implementation within an interface (#40175)

Fixes https://dev.azure.com/devdiv/DevDiv/_workitems/edit/1029574.

Fixes #39888

Fixes #39975

Fixes #39767

* Emit CS8370 instead of CS1674 for ref struct disposable:
- Always try and bind pattern dispose for using
- Check if it's a valid bind per langver if successful
- Don't emit 'near miss' warnings for ref disposable in 7.3

Provides API to fix #3705.

* Implement lambda discard parameters

* Remove duplicate tests

* Factor logic to recognize underscore tokens

* Align symbol display with other discards

* Distinguish discards in QuickInfo

* Add IsDiscard property instead of IDiscardSymbol

* Adjust IDE logic to use IsDiscard

* Avoid large tuple return

* Add test for ref/out discard parameters

* Address PR feedback and test plan ideas

* Allow in expression trees

* Support general discard parameters

* Add IDE tests

* Emit with unspeakable name

* Remove unused error code

* Only support lambdas

* Fix tests

* Address some PR feedback

* Address remaining feedback

* Address more feedback

* Fix conflict

* Update PublicAPI.Unshipped.txt

* Update PublicAPI.Unshipped.txt

* Add ChangeSignature tests

* Add SymbolCompletion tests

* Add InlineRename test

* Typo

In var foreach, use return type of the Current enumerator property instead of attempting to do unnecessary conversions.

This change also separates implementation of ISymbol interfaces from internal symbols in C# compiler.