Remove redundant getMembers

Also make LazyMemberLoader abstract
Add "final" to (Class|Protocol|Enum|Struct)Decl classes

Author: David Ungar

include/swift/AST/Decl.h

@@ -1722,8 +1722,6 @@ class ExtensionDecl final : public Decl, public GenericContext,
 
   void setConformanceLoader(LazyMemberLoader *resolver, uint64_t contextData);
 
-  DeclRange getMembers() const;
-
   /// Determine whether this is a constrained extension, which adds additional
   /// requirements beyond those of the nominal type.
   bool isConstrainedExtension() const;
@@ -2775,7 +2773,6 @@ class NominalTypeDecl : public GenericTypeDecl, public IterableDeclContext {
 public:
   using GenericTypeDecl::getASTContext;
 
-  DeclRange getMembers() const;
   SourceRange getBraces() const { return Braces; }
 
   void setBraces(SourceRange braces) { Braces = braces; }
@@ -2967,7 +2964,7 @@ class NominalTypeDecl : public GenericTypeDecl, public IterableDeclContext {
 ///
 /// The type of the decl itself is a MetatypeType; use getDeclaredType()
 /// to get the declared type ("Bool" or "Optional" in the above example).
-class EnumDecl : public NominalTypeDecl {
+class EnumDecl final : public NominalTypeDecl {
   SourceLoc EnumLoc;
 
   struct {
@@ -3123,7 +3120,7 @@ class EnumDecl : public NominalTypeDecl {
 ///
 /// The type of the decl itself is a MetatypeType; use getDeclaredType()
 /// to get the declared type ("Complex" in the above example).
-class StructDecl : public NominalTypeDecl {
+class StructDecl final : public NominalTypeDecl {
   SourceLoc StructLoc;
 
 public:
@@ -3193,7 +3190,7 @@ enum class ObjCClassKind : uint8_t {
 ///
 /// The type of the decl itself is a MetatypeType; use getDeclaredType()
 /// to get the declared type ("Complex" in the above example).
-class ClassDecl : public NominalTypeDecl {
+class ClassDecl final : public NominalTypeDecl {
   class ObjCMethodLookupTable;
 
   SourceLoc ClassLoc;
@@ -3488,7 +3485,7 @@ struct SelfReferenceKind {
 ///   protocol Drawable {
 ///     func draw()
 ///   }
-class ProtocolDecl : public NominalTypeDecl {
+class ProtocolDecl final : public NominalTypeDecl {
   SourceLoc ProtocolLoc;
 
   /// The location of the 'class' keyword for class-bound protocols.

include/swift/AST/LazyResolver.h

@@ -211,37 +211,27 @@ class alignas(void*) LazyMemberLoader {
   ///
   /// The implementation should add the members to D.
   virtual void
-  loadAllMembers(Decl *D, uint64_t contextData) {
-    llvm_unreachable("unimplemented");
-  }
+  loadAllMembers(Decl *D, uint64_t contextData) = 0;
 
   /// Populates the given vector with all conformances for \p D.
   ///
   /// The implementation should \em not call setConformances on \p D.
   virtual void
   loadAllConformances(const Decl *D, uint64_t contextData,
-                      SmallVectorImpl<ProtocolConformance *> &Conformances) {
-    llvm_unreachable("unimplemented");
-  }
+                      SmallVectorImpl<ProtocolConformance *> &Conformances) = 0;
 
   /// Populates the given vector with all conformances for \p D.
   virtual void
   finishNormalConformance(NormalProtocolConformance *conformance,
-                          uint64_t contextData) {
-    llvm_unreachable("unimplemented");
-  }
+                          uint64_t contextData) = 0;
 
   /// Returns the default definition type for \p ATD.
   virtual TypeLoc loadAssociatedTypeDefault(const AssociatedTypeDecl *ATD,
-                                            uint64_t contextData) {
-    llvm_unreachable("unimplemented");
-  }
+                                            uint64_t contextData) = 0;
 
   /// Returns the generic environment.
   virtual GenericEnvironment *loadGenericEnvironment(const DeclContext *decl,
-                                                     uint64_t contextData) {
-    llvm_unreachable("unimplemented");
-  }
+                                                     uint64_t contextData) = 0;
 };
 
 }

lib/AST/Decl.cpp

@@ -807,11 +807,6 @@ ImportDecl::findBestImportKind(ArrayRef<ValueDecl *> Decls) {
   return FirstKind;
 }
 
-DeclRange NominalTypeDecl::getMembers() const {
-  loadAllMembers();
-  return IterableDeclContext::getMembers();
-}
-
 void NominalTypeDecl::setConformanceLoader(LazyMemberLoader *lazyLoader,
                                            uint64_t contextData) {
   assert(!NominalTypeDeclBits.HasLazyConformances &&
@@ -871,11 +866,6 @@ ExtensionDecl *ExtensionDecl::create(ASTContext &ctx, SourceLoc extensionLoc,
   return result;
 }
 
-DeclRange ExtensionDecl::getMembers() const {
-  loadAllMembers();
-  return IterableDeclContext::getMembers();
-}
-
 void ExtensionDecl::setConformanceLoader(LazyMemberLoader *lazyLoader,
                                          uint64_t contextData) {
   assert(!ExtensionDeclBits.HasLazyConformances && 

lib/ClangImporter/ImporterImpl.h

@@ -1126,6 +1126,18 @@ class LLVM_LIBRARY_VISIBILITY ClangImporter::Implementation
 
   void finishNormalConformance(NormalProtocolConformance *conformance,
                                uint64_t unused) override;
+  
+  /// Returns the default definition type for \p ATD.
+  TypeLoc loadAssociatedTypeDefault(const AssociatedTypeDecl *ATD,
+                                            uint64_t contextData) override {
+    llvm_unreachable("unimplemented for ClangImporter");
+  }
+  
+  /// Returns the generic environment.
+  virtual GenericEnvironment *loadGenericEnvironment(const DeclContext *decl,
+                                                     uint64_t contextData) override {
+    llvm_unreachable("unimplemented for ClangImporter");
+  }
 
   template <typename DeclTy, typename ...Targs>
   DeclTy *createDeclWithClangNode(ClangNode ClangN, Accessibility access,