Tracking lib/SymbolGraphGen bugs

[taylorswift]

just using this thread as a place to centrally organize lib/SymbolGraphGen problems, as the descriptions for these bugs are currently all scattered across the forums, slack threads, and apple/swift GitHub issue reports.

1. PATs always dropped from function declarations (GitHub issue)

2. protocol extensions are missing associatedtype constraints (forums thread)

3. types contain multiple generated conformances to Equatable (forums thread)

4. symbolgraphs are missing names of @_spi attributes (originally reported on Slack, GitHub issue)

5. AnyObject constraints are always dropped (GitHub issue, might be the same bug as #2)

6. subclasses are missing synthesized symbols for typealiases inherited from base classes (GitHub issue)

7. @Sendable is missing from function declarations (Slack thread)

8. symbol graphs contain invalid default implementation relationships (GitHub issue)

if you’ve also got SymbolGraphGen bugs that have been lost in the churn, feel free to add them here!

[taylorswift]

updating list with new items from 2024:

• incorrect parsing of concrete Self type tokens in function signatures

• types should not inherit extension members from @available(*, unavailable) conformances

• conformance conditions do not match generic constraints of associated extension block

• crash when emitting conditional conformances to protocol that inherits from underscored protocol, needs verifying on Swift 6.0

• clip the ACL of nested declarations to the ACL of their lexical parents

• types nested in @_exported types appear in the wrong subgraph

• encoding of same-type generic constraints loses information for shadowed types

• DeclarationFragmentPrinter.h: Assertion `NumFragments' failed

there are also a number of crashes others have reported which i have not tried to reproduce myself yet, but should be looked at as well.