- Remove BoundDagEvaluation.Symbol from the public API
- BoundDagTemp is not permitted a null type
- Adjust test for new lowering of pattern-is
- Adjust tests per changes in `is pattern` code generation
- Lower RecursivePattern.VariableAccess
- Retire or comment out (for now) some retiring code.
- Move MatchConstantValue into the class with its only client.
- Use the more efficient equality for double, decimal, etc switches.
- Implement and test support for tuples.
- Implement building the decision tree and its subsumption errors.

- Add support for recursive patterns in `is`.
- Add the discard pattern `_`.
- Add skeletal IOperation support.
- Adjust tests per changes in `is pattern` code gen.

Using statement

Add IOperation API for deconstruction assignment expression and declaration expression.

Fixed issue with converting auto properties in partial classes

Remove duplicate member symbol from EventReferenceExpression

Add IOperation API for local symbol initializers

fix perf runs

Add tests to make sure virtual slot is set correctly for parent types of types that have modreq members or implementations (#22646)

* Add tests to make sure virtual slot is set correctly for parent types of types that have modreq members or implementations

* PR comments

Revert "Remove duplicate member symbol from EventReferenceExpression"

Remove duplicate member symbol from EventReferenceExpression

* Compiler API not to return [Obsolete] for IsByRefLikeTypes

* Clean up

* typo

Fixes #20103

Change branch we're publishing from to dev15.5.x

* dotnet/master:
  fixed using block (#22570)
  Fix default literal in default value of nullable parameter (#22527)
  Include PDB in determinism testing
  Disable test discover in VS
  Ensure that we throw the CLR's InsufficientExecutionStackException instead of CancelledByStackGuardException

* fixed using block

* updated tests after synching master

* PR feedbacks

Merged on behalf of @svick. Thanks for the contribution!

Include PDB in determinism testing