[clang][ExtractAPI] Fix handling of anonymous TagDecls (#87772)

This changes the handling of anonymous TagDecls to the following rules:
- If the TagDecl is embedded in the declaration for some VarDecl (this
is the only possibility for RecordDecls), then pretend the child decls
belong to the VarDecl
- If it's an EnumDecl proceed as we did previously, i.e., embed it in
the enclosing DeclContext.

Additionally this fixes a few issues with declaration fragments not
consistently including "{ ... }" for anonymous TagDecls. To make testing
these additions easier this patch fixes some text declaration fragments
merging issues and updates tests accordingly.

rdar://121436298

1 files changed, 8 insertions, 0 deletions

diff --git a/clang/lib/ExtractAPI/Serialization/SymbolGraphSerializer.cpp b/clang/lib/ExtractAPI/Serialization/SymbolGraphSerializer.cpp
index 8b1dcb4..34278b5 100644
--- a/clang/lib/ExtractAPI/Serialization/SymbolGraphSerializer.cpp
+++ b/clang/lib/ExtractAPI/Serialization/SymbolGraphSerializer.cpp
@@ -667,6 +667,14 @@ bool SymbolGraphSerializer::shouldSkip(const APIRecord *Record) const {
   if (Record->Availability.isUnconditionallyUnavailable())
     return true;
 
+  // Filter out symbols without a name as we can generate correct symbol graphs
+  // for them. In practice these are anonymous record types that aren't attached
+  // to a declaration.
+  if (auto *Tag = dyn_cast<TagRecord>(Record)) {
+    if (Tag->IsEmbeddedInVarDeclarator)
+      return true;
+  }
+
   // Filter out symbols prefixed with an underscored as they are understood to
   // be symbols clients should not use.
   if (Record->Name.starts_with("_"))