[AST] Enable inheritance node for protocol conformance

rdar://problem/49043711

Author: rintaro

lib/AST/DocComment.cpp

@@ -479,12 +479,10 @@ swift::getCascadingDocComment(swift::markup::MarkupContext &MC, const Decl *D) {
   auto *doc = getSingleDocComment(MC, docD);
   assert(doc && "getDocCommentProvidingDecl() returned decl with no comment");
 
-  // Iff the doc is inherited from overridden decl, add a note about that.
-  // FIXME: This is inconsistent <rdar://problem/49043711>, but let's keep the
-  // behavior for now.
+  // If the doc-comment is inherited from other decl, add a note about it.
   if (docD != D)
-    if (auto baseClassD = docD->getDeclContext()->getSelfClassDecl())
-      doc->addInheritanceNote(MC, baseClassD);
+    if (auto baseD = docD->getDeclContext()->getSelfNominalTypeDecl())
+      doc->addInheritanceNote(MC, baseD);
 
   return doc;
 }

test/IDE/comment_inherited_protocol.swift

@@ -63,23 +63,23 @@ protocol ChildProtocol : ParentProtocol1, ParentProtocol2 {
 extension ChildProtocol {
   // Should come from ParentProtocol1.
   func onlyParent1() {}
-  // CHECK: Func/onlyParent1 {{.*}} DocCommentAsXML=[<Function file="{{.*}}" line="{{.*}}" column="{{.*}}"><Name>onlyParent1()</Name><USR>s:14swift_ide_test13ChildProtocolPAAE11onlyParent1yyF</USR><Declaration>func onlyParent1()</Declaration><CommentParts><Abstract><Para>ParentProtocol1.onlyParent1()</Para></Abstract></CommentParts></Function>]
+  // CHECK: Func/onlyParent1 {{.*}} DocCommentAsXML=[<Function file="{{.*}}" line="{{.*}}" column="{{.*}}"><Name>onlyParent1()</Name><USR>s:14swift_ide_test13ChildProtocolPAAE11onlyParent1yyF</USR><Declaration>func onlyParent1()</Declaration><CommentParts><Abstract><Para>ParentProtocol1.onlyParent1()</Para></Abstract><Discussion><Note><Para>This documentation comment was inherited from <codeVoice>ParentProtocol1</codeVoice>.</Para></Note></Discussion></CommentParts></Function>]
 
   // Should come from ParentProtocol1.
   var onlyParent1Var: Int { return 0 }
-  // CHECK: Var/onlyParent1Var {{.*}} DocCommentAsXML=[<Other file="{{.*}}" line="{{.*}}" column="{{.*}}"><Name>onlyParent1Var</Name><USR>s:14swift_ide_test13ChildProtocolPAAE14onlyParent1VarSivp</USR><Declaration>var onlyParent1Var: Int { get }</Declaration><CommentParts><Abstract><Para>ParentProtocol.onlyParent1Var</Para></Abstract></CommentParts></Other>]
+  // CHECK: Var/onlyParent1Var {{.*}} DocCommentAsXML=[<Other file="{{.*}}" line="{{.*}}" column="{{.*}}"><Name>onlyParent1Var</Name><USR>s:14swift_ide_test13ChildProtocolPAAE14onlyParent1VarSivp</USR><Declaration>var onlyParent1Var: Int { get }</Declaration><CommentParts><Abstract><Para>ParentProtocol.onlyParent1Var</Para></Abstract><Discussion><Note><Para>This documentation comment was inherited from <codeVoice>ParentProtocol1</codeVoice>.</Para></Note></Discussion></CommentParts></Other>]
 
   // Should come from ParentProtocol1.
   subscript(index: Int) -> Int { return 0 }
-  // CHECK: Subscript/subscript {{.*}} DocCommentAsXML=[<Other file="{{.*}}" line="{{.*}}" column="{{.*}}"><Name>subscript(_:)</Name><USR>{{.*}}</USR><Declaration>subscript(index: Int) -&gt; Int { get }</Declaration><CommentParts><Abstract><Para>ParentProtocol.subscript(index:)</Para></Abstract></CommentParts></Other>]
+  // CHECK: Subscript/subscript {{.*}} DocCommentAsXML=[<Other file="{{.*}}" line="{{.*}}" column="{{.*}}"><Name>subscript(_:)</Name><USR>{{.*}}</USR><Declaration>subscript(index: Int) -&gt; Int { get }</Declaration><CommentParts><Abstract><Para>ParentProtocol.subscript(index:)</Para></Abstract><Discussion><Note><Para>This documentation comment was inherited from <codeVoice>ParentProtocol1</codeVoice>.</Para></Note></Discussion></CommentParts></Other>]
 
   // Should come from ParentProtocol1.
   typealias AssocType = Int
-  // CHECK: TypeAlias/AssocType {{.*}} DocCommentAsXML=[<Other file="{{.*}}" line="{{.*}}" column="{{.*}}"><Name>AssocType</Name><USR>s:14swift_ide_test13ChildProtocolPAAE9AssocTypea</USR><Declaration>typealias AssocType = Int</Declaration><CommentParts><Abstract><Para>ParentProtocol.AssocType</Para></Abstract></CommentParts></Other>]
+  // CHECK: TypeAlias/AssocType {{.*}} DocCommentAsXML=[<Other file="{{.*}}" line="{{.*}}" column="{{.*}}"><Name>AssocType</Name><USR>s:14swift_ide_test13ChildProtocolPAAE9AssocTypea</USR><Declaration>typealias AssocType = Int</Declaration><CommentParts><Abstract><Para>ParentProtocol.AssocType</Para></Abstract><Discussion><Note><Para>This documentation comment was inherited from <codeVoice>ParentProtocol1</codeVoice>.</Para></Note></Discussion></CommentParts></Other>]
 
   // Should come from ParentProtocol2.
   func onlyParent2() {}
-  // CHECK: Func/onlyParent2 {{.*}} DocCommentAsXML=[<Function file="{{.*}}" line="{{.*}}" column="{{.*}}"><Name>onlyParent2()</Name><USR>s:14swift_ide_test13ChildProtocolPAAE11onlyParent2yyF</USR><Declaration>func onlyParent2()</Declaration><CommentParts><Abstract><Para>ParentProtocol2.onlyParent2()</Para></Abstract></CommentParts></Function>]
+  // CHECK: Func/onlyParent2 {{.*}} DocCommentAsXML=[<Function file="{{.*}}" line="{{.*}}" column="{{.*}}"><Name>onlyParent2()</Name><USR>s:14swift_ide_test13ChildProtocolPAAE11onlyParent2yyF</USR><Declaration>func onlyParent2()</Declaration><CommentParts><Abstract><Para>ParentProtocol2.onlyParent2()</Para></Abstract><Discussion><Note><Para>This documentation comment was inherited from <codeVoice>ParentProtocol2</codeVoice>.</Para></Note></Discussion></CommentParts></Function>]
 
   // Should show nothing because the requirement is in both parents.
   func commonParentRequirement() {}