Allow taking unmanaged/pinned addresses of readonly lvalues.

Fixes:#22306

Check for null before registering incremental analyzer

* Create tests to cover test plans #19216 and #20127

* clean up

* Improve consistency of handling constant null switch expression
Fixes #20210
* Rationalize reachability for pattern switch.
If a single case could handle all inputs, e.g. has the
same constant value, a wildcard pattern, etc, then
the default label is considered unreachable.
The concept of reachability, which takes the value of the
switch expression into account and can produce warnings,
is separate from the concept of subsumption which takes
the full set of patterns into account and can produce errors.
* Document breaking change in pattern switch.
Alse change formatting as suggested in code review.

Added tests for `out` and `ref` completion in local function

Don't show snippets in VB comments

[SlidingTextWindow] Add another common case for GetText optimization

Fixes #22378

Fixes #21515

* IDE Changes

* tests

* PR comments

Tests in response to issue #22253

Quote variable/array expansions in shell scripts

Fixes issue 21801

Merging on behalf of @alrz. Thanks

Do not emit PDB path in PE file if not generating PDB

Property Reference Underlying Instance Type

Ref ternary should be shielded form optimization in the containing expression that may expose it to mutations

Prevent crash when no capitalization is specified (invalid naming style)

Ref ternary shoudl be shielded form optimization in the containing expression that may expose it to mutations

Just need to add it to the list of other possible writeable lvalues checked by WouldBeAssignableIfUsedAsMethodReceiver helper.

Fixes:#18220