* [Sema]: Add Codable synthesis for enums with associated values
* Incorporate review feedback for enum Codable synthesis
* Implement enum specific versions of existing Codable tests
* Encode parameterless enum cases as
* Add test for overloaded case identifiers
* Align code generation with latest proposal revision
* Put enum codable derivation behind flag
* clang-format sources
* Address review feedback and fix tests
* Add diagnostic for conflicting parameter identifiers
* Restructure code after rebase
Make both Error and CodingKey conform to ConcurrentValue, so that
thrown errors always conform to ConcurrentValue. Downgrade (to
warnings) and ConcurrentValue-related diagnostics that are triggered
by this change in existing Error and CodingKey-conforming types to
reduce the impact on source compatibility.
Codable's magic previously relied on the subject of every qualified lookup in an
unqualified lookup stack to force the synthesis of this member. This
allowed users to reference CodingKeys transitively through a non-primary input
without qualification. As part of the requestification of name lookup,
this synthesis was moved out of the normal qualified lookup path and into the
Type Checker's semantic lookup entrypoints in order to prevent wild
cycles caused by protocol conformance resolution. In the process, we
forget to restore the synthesis check at this entrypoint.
To patch up the source break this caused, we need to walk the context
stack again and force synthesis. Unfortunately, we're stuck with a hack like
this until we bring Codable's implementation back out of the realm of magic
once more. A future implementation of synthesizeSemanticMembersIfNeeded
should aim to just craft the AST for CodingKeys, but not actually run
any of the semantic checks until we check the conformance to CodingKey.
rdar://65088901, SR-13137
* Allow CodingKey conformance to be automatically derived for enums
which have no raw type (with no associated values) and which have
a raw type of String or Int.
* Allow Encodable and Decodable conformance to be automatically derived
for classes and structs with Encodable/Decodable properties
* Add initial unit tests for verifying derived conformance
