Add docs

Author: keith

lib/Index/Index.cpp

@@ -966,8 +966,18 @@ class IndexSwiftASTWalker : public SourceEntityWalker {
   bool startEntityDecl(ValueDecl *D);
 
   bool reportRelatedRef(ValueDecl *D, SourceLoc Loc, bool isImplicit, SymbolRoleSet Relations, Decl *Related);
+
+  /// Report references for dependent types
+  ///
+  /// NOTE: If the dependent type is a typealias, report the underlying types as well.
+  ///
+  /// \param Ty The type being referenced.
+  /// \param Relations The relationship between the referenced type and the passed Decl.
+  /// \param Related The Decl that is referencing the type.
+  /// \param isImplicit Whether the reference is implicit, such as for a typealias' underlying type.
+  /// \param Loc The location of the reference, otherwise the location of the TypeLoc is used.
   bool reportRelatedTypeRef(const TypeLoc &Ty, SymbolRoleSet Relations, Decl *Related,
-                            bool isImplicit=false, const Optional<SourceLoc> Loc=Optional<SourceLoc>());
+                            bool isImplicit=false, Optional<SourceLoc> Loc=Optional<SourceLoc>());
   bool reportInheritedTypeRefs(
       ArrayRef<InheritedEntry> Inherited, Decl *Inheritee);
   NominalTypeDecl *getTypeLocAsNominalTypeDecl(const TypeLoc &Ty);
@@ -1384,7 +1394,7 @@ bool IndexSwiftASTWalker::reportInheritedTypeRefs(ArrayRef<InheritedEntry> Inher
 }
 
 bool IndexSwiftASTWalker::reportRelatedTypeRef(const TypeLoc &Ty, SymbolRoleSet Relations,
-                                               Decl *Related, bool Implicit, const Optional<SourceLoc> Loc) {
+                                               Decl *Related, bool Implicit, Optional<SourceLoc> Loc) {
   if (auto *composite = llvm::dyn_cast_or_null<CompositionTypeRepr>(Ty.getTypeRepr())) {
     SourceLoc IdLoc = Loc.value_or(composite->getSourceLoc());
     for (auto *Type : composite->getTypes())