Extension type augmentations do not have representation declarations, so
an `ExtensionTypeDeclaration` can no longer always expose its name
through a primary constructor. Add `ExtensionTypeDeclaration.namePart`
as the canonical API for the declared name and type parameters, and keep
`primaryConstructor` as a deprecated compatibility API for introductory
declarations.
Report `extensionTypeAugmentationHasRepresentation` when an augmentation
writes representation syntax. This keeps the parser recovery explicit:
the augmentation still gets a plain `namePart`, while the invalid
representation is diagnosed instead of being modeled as the
declaration's primary constructor.
Synthesize recovery representation and primary constructor fragments
only for the element model when an extension type has no introductory
declaration.
Migrate analyzer, analysis server, analyzer plugin, and linter clients
to read extension type names and type parameters from `namePart`.
Change-Id: I59dd957ac38f087c861b993caf246986dcdac713
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/505067
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>
Konstantin Shcheglov
8c6366e66e