Merge pull request #38240 from apple/QuietMisdreavus/no-subclass-synth

[SymbolGraph] do not synthesize subclass methods

Author: QuietMisdreavus

lib/SymbolGraphGen/SymbolGraph.cpp

@@ -196,7 +196,6 @@ void SymbolGraph::recordNode(Symbol S) {
   // with this declaration.
   recordMemberRelationship(S);
   recordConformanceSynthesizedMemberRelationships(S);
-  recordSuperclassSynthesizedMemberRelationships(S);
   recordConformanceRelationships(S);
   recordInheritanceRelationships(S);
   recordDefaultImplementationRelationships(S);
@@ -259,45 +258,6 @@ void SymbolGraph::recordMemberRelationship(Symbol S) {
   }
 }
 
-void SymbolGraph::recordSuperclassSynthesizedMemberRelationships(Symbol S) {
-  if (!Walker.Options.EmitSynthesizedMembers) {
-    return;
-  }
-  // Via class inheritance...
-  if (const auto *C = dyn_cast<ClassDecl>(S.getSymbolDecl())) {
-    // Collect all superclass members up the inheritance chain.
-    SmallPtrSet<const ValueDecl *, 32> SuperClassMembers;
-    const auto *Super = C->getSuperclassDecl();
-    while (Super) {
-      for (const auto *SuperMember : Super->getMembers()) {
-        if (const auto *SuperMemberVD = dyn_cast<ValueDecl>(SuperMember)) {
-          SuperClassMembers.insert(SuperMemberVD);
-        }
-      }
-      Super = Super->getSuperclassDecl();
-    }
-    // Remove any that are overridden by this class.
-    for (const auto *DerivedMember : C->getMembers()) {
-      if (const auto *DerivedMemberVD = dyn_cast<ValueDecl>(DerivedMember)) {
-        if (const auto *Overridden = DerivedMemberVD->getOverriddenDecl()) {
-          SuperClassMembers.erase(Overridden);
-        }
-      }
-    }
-    // What remains in SuperClassMembers are inherited members that
-    // haven't been overridden by the class.
-    // Add a synthesized relationship.
-    for (const auto *InheritedMember : SuperClassMembers) {
-      if (canIncludeDeclAsNode(InheritedMember)) {
-        Symbol Source(this, InheritedMember, C);
-        Symbol Target(this, C, nullptr);
-        Nodes.insert(Source);
-        recordEdge(Source, Target, RelationshipKind::MemberOf());
-      }
-    }
-  }
-}
-
 bool SymbolGraph::synthesizedMemberIsBestCandidate(const ValueDecl *VD,
     const NominalTypeDecl *Owner) const {
   const auto *FD = dyn_cast<FuncDecl>(VD);

lib/SymbolGraphGen/SymbolGraph.h

@@ -145,15 +145,6 @@ struct SymbolGraph {
    */
   void recordConformanceSynthesizedMemberRelationships(Symbol S);
 
-  /**
-   If a declaration has members by subclassing, record a symbol with a
-   "synthesized" USR to disambiguate from the superclass's real implementation.
-
-   This makes it more convenient
-   to curate symbols on a subclass's documentation.
-   */
-  void recordSuperclassSynthesizedMemberRelationships(Symbol S);
-
   /**
    Record InheritsFrom relationships for every class from which the
    declaration inherits.

test/SymbolGraph/Relationships/Synthesized/SuperclassImplementation.swift

@@ -3,15 +3,24 @@
 // RUN: %target-swift-symbolgraph-extract -module-name SuperclassImplementation -I %t -pretty-print -output-dir %t
 // RUN: %FileCheck %s --input-file %t/SuperclassImplementation.symbols.json
 
+// This test references code that has been removed. The implementation that synthesized superclass
+// methods was inconsistent; it failed to generate symbols for superclasses from another module.
+// From a symbol-relation perspective, the `inheritsFrom` relation from a subclass to its superclass
+// still exists, which already implies that all of the superclass's methods are available on the
+// subclass. The synthesized methods for subclasses were removed to provide consistency between
+// superclasses from the same module and those from a different one. If the implementation is
+// brought back, ensure that it consistently adds synthesized methods for superclasses from
+// different modules.
+
 public class Base {
   public init() {}
   public func foo() {}
 }
 
 public class Derived: Base {
-  // CHECK-DAG: "precise": "s:24SuperclassImplementation4BaseC3fooyyF::SYNTHESIZED::s:24SuperclassImplementation7DerivedC"
+  // CHECK-NOT: "precise": "s:24SuperclassImplementation4BaseC3fooyyF::SYNTHESIZED::s:24SuperclassImplementation7DerivedC"
 }
 
 public class DerivedDerived: Derived {
-  // CHECK-DAG: "precise": "s:24SuperclassImplementation4BaseC3fooyyF::SYNTHESIZED::s:24SuperclassImplementation07DerivedC0C"
+  // CHECK-NOT: "precise": "s:24SuperclassImplementation4BaseC3fooyyF::SYNTHESIZED::s:24SuperclassImplementation07DerivedC0C"
 }