synthesized symbols should always inherit docs

Author: QuietMisdreavus

lib/SymbolGraphGen/Symbol.cpp

@@ -178,8 +178,10 @@ const ValueDecl *Symbol::getDeclInheritingDocs() const {
       getDocCommentProvidingDecl(VD, /*AllowSerialized=*/true));
 
   // if the decl is the same as the one for this symbol, we're not
-  // inheriting docs, so return null.
-  if (DocCommentProvidingDecl == VD) {
+  // inheriting docs, so return null. however, if this symbol is
+  // a synthesized symbol, `VD` is actually the source symbol, and
+  // we should point to that one regardless.
+  if (DocCommentProvidingDecl == VD && !SynthesizedBaseTypeDecl) {
     return nullptr;
   } else {
     // otherwise, return whatever `getDocCommentProvidingDecl` returned.

test/SymbolGraph/Relationships/Synthesized/InheritedDocs.swift

@@ -4,30 +4,48 @@
 // RUN: %target-swift-symbolgraph-extract -module-name InheritedDocs -I %t -pretty-print -output-dir %t
 // RUN: %FileCheck %s --input-file %t/InheritedDocs.symbols.json --check-prefixes CHECK,DOCS
 // RUN: %FileCheck %s --input-file %t/InheritedDocs.symbols.json --check-prefixes IMPL
+// RUN: %FileCheck %s --input-file %t/InheritedDocs.symbols.json --check-prefixes BONUS
+// RUN: %FileCheck %s --input-file %t/InheritedDocs.symbols.json --check-prefixes BONUS-DOCS
 
 // RUN: %target-swift-symbolgraph-extract -module-name InheritedDocs -I %t -pretty-print -output-dir %t -skip-inherited-docs
 // RUN: %FileCheck %s --input-file %t/InheritedDocs.symbols.json --check-prefixes CHECK,SKIP
 // RUN: %FileCheck %s --input-file %t/InheritedDocs.symbols.json --check-prefixes IMPL
+// RUN: %FileCheck %s --input-file %t/InheritedDocs.symbols.json --check-prefixes BONUS
+// RUN: %FileCheck %s --input-file %t/InheritedDocs.symbols.json --check-prefixes BONUS-SKIP
 
 // RUN: %empty-directory(%t)
 // RUN: %target-build-swift %s -module-name InheritedDocs -emit-module -emit-module-path %t/InheritedDocs.swiftmodule -emit-symbol-graph -emit-symbol-graph-dir %t/ -skip-inherited-docs
 // RUN: %FileCheck %s --input-file %t/InheritedDocs.symbols.json --check-prefixes SKIP
 
 // DOCS-COUNT-3: Some Function
+// BONUS-DOCS-COUNT-2: Bonus docs!
 // SKIP-COUNT-1: Some Function
+// BONUS-SKIP-COUNT-1: Bonus docs!
+
+// synthesized symbols should have a sourceOrigin field that points to where its docs come from
 
 // CHECK:            "source": "s:13InheritedDocs1PPAAE8someFuncyyF::SYNTHESIZED::s:13InheritedDocs1SV"
 // CHECK-NEXT:       "target": "s:13InheritedDocs1SV"
 // CHECK-NEXT:       "sourceOrigin"
 // CHECK-NEXT:         "identifier": "s:13InheritedDocs1PP8someFuncyyF"
 // CHECK-NEXT:         "displayName": "P.someFunc()"
 
+// non-synthesized symbols that nonetheless inherit docs (like this extension) should have the same
+
 // IMPL:             "source": "s:13InheritedDocs1PPAAE8someFuncyyF"
 // IMPL-NEXT:        "target": "s:13InheritedDocs1PP8someFuncyyF"
 // IMPL-NEXT:        "sourceOrigin"
 // IMPL-NEXT:          "identifier": "s:13InheritedDocs1PP8someFuncyyF"
 // IMPL-NEXT:          "displayName": "P.someFunc()"
 
+// synthesized symbols that point directly to their docs should also have a sourceOrigin field
+
+// BONUS:            "source": "s:13InheritedDocs1PPAAE9bonusFuncyyF::SYNTHESIZED::s:13InheritedDocs1SV"
+// BONUS-NEXT:       "target": "s:13InheritedDocs1SV"
+// BONUS-NEXT:       "sourceOrigin"
+// BONUS-NEXT:         "identifier": "s:13InheritedDocs1PPAAE9bonusFuncyyF"
+// BONUS-NEXT:         "displayName": "P.bonusFunc()"
+
 /// Protocol P
 public protocol P {
     /// Some Function
@@ -36,6 +54,9 @@ public protocol P {
 
 public extension P {
     func someFunc() {}
+
+    /// Bonus docs!
+    func bonusFunc() {}
 }
 
 public struct S: P {