Migrate use of analyzer's "element model" to Element2.

[srawlins]

The analyzer package's "element model," (everything declared in package:analyzer/dart/element/element.dart) is migrating to a new API, found at package:analyzer/dart/element/element2.dart. The "element 1" APIs are presently being deprecated.

Consumers of the old element model need to migrate to the new element model. A few notes:

• In order to migrate, drift_dev needs to use at least analyzer version 7.3.0.
• In order to migrate, drift_dev also needs to use a new version of source_gen, not yet released, which also makes its APIs available with Element2 types. Follow Release version with analyzer's Element2 APIs dart-lang/source_gen#743.
• There is a lint rule available to help migrate, analyzer_use_new_elements. Turning it on in drift_dev reveals > 700 references to classes in the "element 1" model.

[simolus3]

This looks like a fun one :D I'll try to prepare a branch using the new element model and a dependency override for source_gen (which should be good enough to roll into your clone).

[simolus3]

@srawlins I gave this a go on the element2 branch, but I think it's too early for client packages to make the migration. I got the >700 usages down to around 50, but the remaining ones are tricky. In addition to source_gen, I also need versions of build that support the element 2 API to complete the migration.

I also need an element2-variant of TypeSystem.instantiateInterfaceToBounds that the analyzer doesn't seem to provide (or I couldn't find it).

Is drift_dev blocking anything internally for you here? Let me know if there's more I can do.

[srawlins]

Sweeet, thanks @simolus3!! If you're interested, you could try the source_gen and build branches that support Element2:

• source_gen: https://github.com/dart-lang/source_gen/tree/analyzer-element2
• build: ... actually I can't find that one.
• TypeSystem.instantiateInterfaceToBounds2 is not yet released. Should be released in analyzer 7.4.0.

CC @scheglov