CS0103 fixer for missing LHS of assignment incorrectly suggests turning missing variable into a type name.

[ascott18]

Version Used:
VS 2022 17.0.0 Preview 5.0
.NET 6 rc2

Steps to Reproduce:

1. Attempt to assign something to an undefined name (variable/field/property/param), where this name happens to be a match to an un-imported type.
2. Pull up intellisense to run the fixer to generate a field
3. See the first suggestions being to add using statements and turn the LHS of the assignment into a type name.

Expected Behavior:
Suggestions to add usings are not present when the error is an undefined LHS of an assignment.

Actual Behavior:

[ascott18]

I'll add that this used to happen in VS2019 as well, but it was not annoying because the using suggestions appeared below the "Generate variable" suggestions, out of the way of the logical, desired fix.

[CyrusNajmabadi]

This is by design. It may be that the user intends to write something like Formatter.Whatever = ...

They're written the type name, then intend to add the using for it so that they can then acesss members from it.

--

The downside here is the introduction of async lightbulbs. 'add using takes' priority, so it's results come first (even if they are low pri due to fuzzy matching).

We need to break 'add using' up into a high and low pri fixer. Non-fuzzy matches can go first. But fuzzy matches need to be deprioritized.

[CyrusNajmabadi]

tagging @jinujoseph to decide who this should go to. We should fix this. Note: we probably want to disable async-lightbulbs for 17.0 based on this.

[CyrusNajmabadi]

Fixed with #57171. Will be in the 17.0 line.