[Type checker] Add "all members" request.

Introduce an "all members" request to compute all of the members of a
given iterable declaration context in stable order. This builds on ABI
members so that it will also include, e.g., type aliases synthesized
for associated types.

(cherry picked from commit c4e265e)

Author: DougGregor

include/swift/AST/DeclContext.h

@@ -784,6 +784,12 @@ class IterableDeclContext {
   /// The resulting list of members will be stable across translation units.
   ArrayRef<Decl *> getABIMembers() const;
 
+  /// Get all of the members within this context, including any
+  /// implicitly-synthesized members.
+  ///
+  /// The resulting list of members will be stable across translation units.
+  ArrayRef<Decl *> getAllMembers() const;
+
   /// Retrieve the set of members in this context without loading any from the
   /// associated lazy loader; this should only be used as part of implementing
   /// abstractions on top of member loading, such as a name lookup table.

include/swift/AST/TypeCheckRequests.h

@@ -1239,6 +1239,24 @@ class ABIMembersRequest :
   bool isCached() const { return true; }
 };
 
+class AllMembersRequest :
+    public SimpleRequest<AllMembersRequest,
+                         ArrayRef<Decl *>(IterableDeclContext *),
+                         RequestFlags::Cached> {
+public:
+  using SimpleRequest::SimpleRequest;
+
+private:
+  friend SimpleRequest;
+
+  // Evaluation.
+  ArrayRef<Decl *>
+  evaluate(Evaluator &evaluator, IterableDeclContext *idc) const;
+
+public:
+  bool isCached() const { return true; }
+};
+
 class IsImplicitlyUnwrappedOptionalRequest :
     public SimpleRequest<IsImplicitlyUnwrappedOptionalRequest,
                          bool(ValueDecl *),

include/swift/AST/TypeCheckerTypeIDZone.def

@@ -67,6 +67,8 @@ SWIFT_REQUEST(TypeChecker, DynamicallyReplacedDeclRequest,
               Cached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, ABIMembersRequest,
               ArrayRef<Decl *>(IterableDeclContext *), Cached, NoLocationInfo)
+SWIFT_REQUEST(TypeChecker, AllMembersRequest,
+              ArrayRef<Decl *>(IterableDeclContext *), Cached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, SpecializeAttrTargetDeclRequest,
               ValueDecl *(const ValueDecl *, SpecializeAttr *),
               Cached, NoLocationInfo)

lib/AST/DeclContext.cpp

@@ -766,6 +766,14 @@ ArrayRef<Decl *> IterableDeclContext::getABIMembers() const {
       ArrayRef<Decl *>());
 }
 
+ArrayRef<Decl *> IterableDeclContext::getAllMembers() const {
+  ASTContext &ctx = getASTContext();
+  return evaluateOrDefault(
+      ctx.evaluator,
+      AllMembersRequest{const_cast<IterableDeclContext *>(this)},
+      ArrayRef<Decl *>());
+}
+
 void IterableDeclContext::addMemberPreservingSourceOrder(Decl *member) {
   auto &SM = getASTContext().SourceMgr;
 

lib/Sema/TypeCheckDecl.cpp

@@ -2550,14 +2550,23 @@ struct SortedDeclList {
 
 } // end namespace
 
-ArrayRef<Decl *>
-ABIMembersRequest::evaluate(
-    Evaluator &evaluator, IterableDeclContext *idc) const {
+namespace {
+  enum class MembersRequestKind {
+    ABI,
+    All,
+  };
+
+}
+
+/// Evaluate a request for a particular set of members of an iterable
+/// declaration context.
+static ArrayRef<Decl *> evaluateMembersRequest(
+  IterableDeclContext *idc, MembersRequestKind kind) {
   auto dc = cast<DeclContext>(idc->getDecl());
-  auto &Context = dc->getASTContext();
+  auto &ctx = dc->getASTContext();
   SmallVector<Decl *, 8> result;
 
-  // Esnure that we add any synthesized members.
+  // Ensure that we add any synthesized members.
   if (dc->getParentSourceFile()) {
     auto nominal = dyn_cast<NominalTypeDecl>(idc);
 
@@ -2567,20 +2576,43 @@ ABIMembersRequest::evaluate(
       TypeChecker::addImplicitConstructors(nominal);
     }
 
-    // Force any derivable conformances in this context. This ensures that any
-    // synthesized members will approach in the member list.
+    // Force any conformances that may introduce more members.
     for (auto conformance : idc->getLocalConformances()) {
-      if (conformance->getState() == ProtocolConformanceState::Incomplete &&
-          conformance->getProtocol()->getKnownDerivableProtocolKind())
-        TypeChecker::checkConformance(conformance->getRootNormalConformance());
+      auto proto = conformance->getProtocol();
+      bool isDerivable =
+        conformance->getState() == ProtocolConformanceState::Incomplete &&
+        proto->getKnownDerivableProtocolKind();
+
+      switch (kind) {
+      case MembersRequestKind::ABI:
+        // Force any derivable conformances in this context.
+        if (isDerivable)
+          break;
+
+        continue;
+
+      case MembersRequestKind::All:
+        // Force any derivable conformances.
+        if (isDerivable)
+          break;
+
+        // If there are any associated types in the protocol, they might add
+        // type aliases here.
+        if (!proto->getAssociatedTypeMembers().empty())
+          break;
+
+        continue;
+      }
+
+      TypeChecker::checkConformance(conformance->getRootNormalConformance());
     }
 
     // If the type conforms to Encodable or Decodable, even via an extension,
     // the CodingKeys enum is synthesized as a member of the type itself.
     // Force it into existence.
     if (nominal) {
       (void) evaluateOrDefault(
-        Context.evaluator,
+        ctx.evaluator,
         ResolveImplicitMemberRequest{nominal,
                    ImplicitMemberAction::ResolveCodingKeys},
         {});
@@ -2589,7 +2621,7 @@ ABIMembersRequest::evaluate(
     // If the decl has a @main attribute, we need to force synthesis of the
     // $main function.
     (void) evaluateOrDefault(
-        Context.evaluator,
+        ctx.evaluator,
         SynthesizeMainFunctionRequest{const_cast<Decl *>(idc->getDecl())},
         nullptr);
 
@@ -2633,7 +2665,19 @@ ABIMembersRequest::evaluate(
       result.push_back(pair.second);
   }
 
-  return Context.AllocateCopy(result);
+  return ctx.AllocateCopy(result);
+}
+
+ArrayRef<Decl *>
+ABIMembersRequest::evaluate(
+    Evaluator &evaluator, IterableDeclContext *idc) const {
+  return evaluateMembersRequest(idc, MembersRequestKind::ABI);
+}
+
+ArrayRef<Decl *>
+AllMembersRequest::evaluate(
+    Evaluator &evaluator, IterableDeclContext *idc) const {
+  return evaluateMembersRequest(idc, MembersRequestKind::All);
 }
 
 bool TypeChecker::isPassThroughTypealias(TypeAliasDecl *typealias,

lib/Sema/TypeCheckDeclPrimary.cpp

@@ -2129,7 +2129,7 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
 
     TypeChecker::checkDeclAttributes(CD);
 
-    for (Decl *Member : CD->getABIMembers())
+    for (Decl *Member : CD->getAllMembers())
       visit(Member);
 
     TypeChecker::checkPatternBindingCaptures(CD);