IDETypeChecking: Add a function to collect protocol members who have default implementations in protocol extensions. Need for rdar://25032869

Author: nkcsgexi

include/swift/Sema/IDETypeChecking.h

@@ -28,6 +28,7 @@ namespace swift {
   class Expr;
   class LazyResolver;
   class ExtensionDecl;
+  class ProtocolDecl;
 
   /// \brief Typecheck a declaration parsed during code completion.
   ///
@@ -47,6 +48,9 @@ namespace swift {
 
   Type lookUpTypeInContext(DeclContext *DC, StringRef Name);
 
+  void collectDefaultImplementationForProtocolMembers(ProtocolDecl *PD,
+                        llvm::SmallDenseMap<ValueDecl*, ValueDecl*> &DefaultMap);
+
   /// \brief Given an unresolved member E and its parent P, this function tries
   /// to infer the type of E.
   /// \returns true on success, false on error.

lib/Sema/CSGen.cpp

@@ -3282,7 +3282,7 @@ swift::resolveValueMember(DeclContext &DC, Type BaseTy, DeclName Name) {
   Optional<Solution> OpSolution = CS.solveSingle();
   if (!OpSolution.hasValue())
     return Result;
-  SelectedOverload Selected =  OpSolution.getValue().overloadChoices[Locator];
+  SelectedOverload Selected = OpSolution.getValue().overloadChoices[Locator];
   Result.Favored = Selected.choice.getDecl();
   for (OverloadChoice& Choice : LookupResult.ViableCandidates) {
     ValueDecl *VD = Choice.getDecl();
@@ -3291,3 +3291,26 @@ swift::resolveValueMember(DeclContext &DC, Type BaseTy, DeclName Name) {
   }
   return Result;
 }
+
+void swift::collectDefaultImplementationForProtocolMembers(ProtocolDecl *PD,
+                    llvm::SmallDenseMap<ValueDecl*, ValueDecl*> &DefaultMap) {
+  Type BaseTy = PD->getDeclaredTypeInContext();
+  DeclContext *DC = PD->getDeclContext();
+  auto *TC = static_cast<TypeChecker*>(DC->getASTContext().getLazyResolver());
+  if (!TC) {
+    TC = new TypeChecker(DC->getASTContext());
+  }
+  for (Decl *D : PD->getMembers()) {
+    ValueDecl *VD = dyn_cast<ValueDecl>(D);
+    if (!VD)
+      continue;
+    ResolveMemberResult Result = resolveValueMember(*DC, BaseTy,
+                                                    VD->getFullName());
+    if (Result.OtherViables.empty())
+      continue;
+    for(ValueDecl *Other : Result.OtherViables) {
+      if (Other->getDeclContext()->isExtensionContext())
+        DefaultMap.insert({VD, Other});
+    }
+  }
+}

lib/Sema/TypeCheckProtocol.cpp

@@ -27,6 +27,7 @@
 #include "swift/AST/TypeMatcher.h"
 #include "swift/AST/TypeWalker.h"
 #include "swift/Basic/Defer.h"
+#include "swift/Sema/IDETypeChecking.h"
 #include "llvm/ADT/ScopedHashTable.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/Support/SaveAndRestore.h"
@@ -4311,3 +4312,4 @@ bool TypeChecker::isProtocolExtensionUsable(DeclContext *dc, Type type,
   // If we can solve the solution, the protocol extension is usable.
   return cs.solveSingle().hasValue();
 }
+

test/IDE/print_synthesized_extensions.swift

@@ -12,6 +12,7 @@
 // RUN: FileCheck %s -check-prefix=CHECK9 < %t.syn.txt
 // RUN: FileCheck %s -check-prefix=CHECK10 < %t.syn.txt
 // RUN: FileCheck %s -check-prefix=CHECK11 < %t.syn.txt
+// RUN: FileCheck %s -check-prefix=CHECK12 < %t.syn.txt
 
 public protocol P1{
   associatedtype T1
@@ -197,12 +198,20 @@ public extension P5 {
   public func foo4() {}
 }
 
-
 public struct S12 : P5{
   public typealias T1 = Int
   public func foo1() {}
 }
 
+public protocol P6 {
+  func foo1()
+  func foo2()
+}
+
+public extension P6 {
+  public func foo1() {}
+}
+
 // CHECK1: <synthesized>extension <ref:Struct>S1</ref> where T : P2 {
 // CHECK1-NEXT:     <decl:Func>public func <loc>p2member()</loc></decl>
 // CHECK1-NEXT:     <decl:Func>public func <loc>ef1(<decl:Param>t: T</decl>)</loc></decl>
@@ -276,3 +285,8 @@ public struct S12 : P5{
 // CHECK11-NEXT:  <decl:Func>/// This is picked
 // CHECK11-NEXT:    public func <loc>foo4()</loc></decl>
 // CHECK11-NEXT: }</synthesized>
+
+// CHECK12:       <decl:Protocol>public protocol <loc>P6</loc> {
+// CHECK12-NEXT:    <decl:Func(HasDefault)>public func <loc>foo1()</loc></decl>
+// CHECK12-NEXT:    <decl:Func>public func <loc>foo2()</loc></decl>
+// CHECK12-NEXT:  }</decl>

tools/swift-ide-test/swift-ide-test.cpp

@@ -38,6 +38,7 @@
 #include "swift/IDE/SourceEntityWalker.h"
 #include "swift/IDE/SyntaxModel.h"
 #include "swift/IDE/Utils.h"
+#include "swift/Sema/IDETypeChecking.h"
 #include "swift/Markup/Markup.h"
 #include "swift/Config.h"
 #include "clang/APINotes/APINotesReader.h"
@@ -1574,11 +1575,28 @@ static int doPrintLocalTypes(const CompilerInvocation &InitInvok,
 
 namespace {
 class AnnotatingPrinter : public StreamPrinter {
+  llvm::SmallDenseMap<ValueDecl*, ValueDecl*> DefaultImplementationMap;
+  bool InProtocol = false;
 public:
   using StreamPrinter::StreamPrinter;
 
   void printDeclPre(const Decl *D, Optional<BracketOptions> Bracket) override {
-    OS << "<decl:" << Decl::getKindName(D->getKind()) << '>';
+    StringRef HasDefault = "";
+    if (D->getKind() == DeclKind::Protocol) {
+      InProtocol = true;
+      DefaultImplementationMap.clear();
+      ProtocolDecl *PD = const_cast<ProtocolDecl*>(dyn_cast<ProtocolDecl>(D));
+      collectDefaultImplementationForProtocolMembers(PD,
+                                                     DefaultImplementationMap);
+    }
+    if (InProtocol) {
+      if (auto *VD = const_cast<ValueDecl*>(dyn_cast<ValueDecl>(D))) {
+        if (DefaultImplementationMap.count(VD) != 0) {
+          HasDefault = "(HasDefault)";
+        }
+      }
+    }
+    OS << "<decl:" << Decl::getKindName(D->getKind()) << HasDefault << '>';
   }
   void printDeclLoc(const Decl *D) override {
     OS << "<loc>";
@@ -1587,6 +1605,9 @@ class AnnotatingPrinter : public StreamPrinter {
     OS << "</loc>";
   }
   void printDeclPost(const Decl *D, Optional<BracketOptions> Bracket) override {
+    if (D->getKind() == DeclKind::Protocol) {
+      InProtocol = false;
+    }
     OS << "</decl>";
   }
   void printStructurePre(PrintStructureKind Kind, const Decl *D) override {