Merge remote-tracking branch 'origin/master' into master-next

lib/Frontend/ParseableInterfaceSupport.cpp

@@ -466,10 +466,15 @@ namespace {
 /// spelling of the protocol type, as well as the locality in the file), but it
 /// does work.
 class InheritedProtocolCollector {
+  static const StringLiteral DummyProtocolName;
+
   /// Protocols that will be included by the ASTPrinter without any extra work.
   SmallVector<ProtocolDecl *, 8> IncludedProtocols;
   /// Protocols that will not be printed by the ASTPrinter.
   SmallVector<ProtocolDecl *, 8> ExtraProtocols;
+  /// Protocols that can be printed, but whose conformances are constrained with
+  /// something that \e can't be printed.
+  SmallVector<const ProtocolType *, 8> ConditionalConformanceProtocols;
 
   /// For each type in \p directlyInherited, classify the protocols it refers to
   /// as included for printing or not, and record them in the appropriate
@@ -492,6 +497,23 @@ class InheritedProtocolCollector {
     }
   }
 
+  /// For each type in \p directlyInherited, record any protocols that we would
+  /// have printed in ConditionalConformanceProtocols.
+  void recordConditionalConformances(ArrayRef<TypeLoc> directlyInherited) {
+    for (TypeLoc inherited : directlyInherited) {
+      Type inheritedTy = inherited.getType();
+      if (!inheritedTy || !inheritedTy->isExistentialType())
+        continue;
+
+      ExistentialLayout layout = inheritedTy->getExistentialLayout();
+      for (ProtocolType *protoTy : layout.getProtocols())
+        if (isPublicOrUsableFromInline(protoTy))
+          ConditionalConformanceProtocols.push_back(protoTy);
+      // FIXME: This ignores layout constraints, but currently we don't support
+      // any of those besides 'AnyObject'.
+    }
+  }
+
 public:
   using PerTypeMap = llvm::MapVector<const NominalTypeDecl *,
                                      InheritedProtocolCollector>;
@@ -530,6 +552,21 @@ public:
       collectProtocols(map, member);
   }
 
+  /// If \p D is an extension providing conditional conformances, record those
+  /// in \p map.
+  ///
+  /// \sa recordConditionalConformances
+  static void collectSkippedConditionalConformances(PerTypeMap &map,
+                                                    const Decl *D) {
+    auto *extension = dyn_cast<ExtensionDecl>(D);
+    if (!extension || !extension->isConstrainedExtension())
+      return;
+
+    const NominalTypeDecl *nominal = extension->getExtendedNominal();
+    map[nominal].recordConditionalConformances(extension->getInherited());
+    // No recursion here because extensions are never nested.
+  }
+
   /// If there were any public protocols that need to be printed (i.e. they
   /// weren't conformed to explicitly or inherited by another printed protocol),
   /// do so now by printing a dummy extension on \p nominal to \p out.
@@ -580,7 +617,40 @@ public:
                       }, [&out] { out << ", "; });
     out << " {}\n";
   }
+
+  /// If there were any conditional conformances that couldn't be printed,
+  /// make a dummy extension that conforms to all of them, constrained by a
+  /// fake protocol.
+  bool printInaccessibleConformanceExtensionIfNeeded(
+      raw_ostream &out, const PrintOptions &printOptions,
+      const NominalTypeDecl *nominal) const {
+    if (ConditionalConformanceProtocols.empty())
+      return false;
+    assert(nominal->isGenericContext());
+
+    out << "extension ";
+    nominal->getDeclaredType().print(out, printOptions);
+    out << " : ";
+    swift::interleave(ConditionalConformanceProtocols,
+                      [&out, &printOptions](const ProtocolType *protoTy) {
+                        protoTy->print(out, printOptions);
+                      }, [&out] { out << ", "; });
+    out << " where "
+        << nominal->getGenericParamsOfContext()->getParams().front()->getName()
+        << " : " << DummyProtocolName << " {}\n";
+    return true;
+  }
+
+  /// Print a fake protocol declaration for use by
+  /// #printInaccessibleConformanceExtensionIfNeeded.
+  static void printDummyProtocolDeclaration(raw_ostream &out) {
+    out << "\n@usableFromInline\ninternal protocol " << DummyProtocolName
+        << " {}\n";
+  }
 };
+
+const StringLiteral InheritedProtocolCollector::DummyProtocolName =
+    "_ConstraintThatIsNotPartOfTheAPIOfThisLibrary";
 } // end anonymous namespace
 
 bool swift::emitParseableInterface(raw_ostream &out,
@@ -597,8 +667,12 @@ bool swift::emitParseableInterface(raw_ostream &out,
   SmallVector<Decl *, 16> topLevelDecls;
   M->getTopLevelDecls(topLevelDecls);
   for (const Decl *D : topLevelDecls) {
-    if (!D->shouldPrintInContext(printOptions))
+    if (!D->shouldPrintInContext(printOptions) ||
+        !printOptions.CurrentPrintabilityChecker->shouldPrint(D, printOptions)){
+      InheritedProtocolCollector::collectSkippedConditionalConformances(
+          inheritedProtocolMap, D);
       continue;
+    }
 
     D->print(out, printOptions);
     out << "\n";
@@ -607,11 +681,18 @@ bool swift::emitParseableInterface(raw_ostream &out,
   }
 
   // Print dummy extensions for any protocols that were indirectly conformed to.
+  bool needDummyProtocolDeclaration = false;
   for (const auto &nominalAndCollector : inheritedProtocolMap) {
+    const NominalTypeDecl *nominal = nominalAndCollector.first;
     const InheritedProtocolCollector &collector = nominalAndCollector.second;
-    collector.printSynthesizedExtensionIfNeeded(out, printOptions,
-                                                nominalAndCollector.first);
+    collector.printSynthesizedExtensionIfNeeded(out, printOptions, nominal);
+    needDummyProtocolDeclaration |=
+        collector.printInaccessibleConformanceExtensionIfNeeded(out,
+                                                                printOptions,
+                                                                nominal);
   }
+  if (needDummyProtocolDeclaration)
+    InheritedProtocolCollector::printDummyProtocolDeclaration(out);
 
   return false;
 }

lib/SILGen/SILGenType.cpp

@@ -823,11 +823,13 @@ public:
       genVTable.emitVTable();
     }
 
-    // Build a default witness table if this is a protocol.
+    // Build a default witness table if this is a protocol that needs one.
     if (auto protocol = dyn_cast<ProtocolDecl>(theType)) {
-      if (!protocol->isObjC() &&
-          protocol->isResilient())
+      if (!protocol->isObjC() && protocol->isResilient()) {
+        auto *SF = protocol->getParentSourceFile();
+        if (!SF || SF->Kind != SourceFileKind::Interface)
           SGM.emitDefaultWitnessTable(protocol);
+      }
       return;
     }
 

lib/Sema/TypeCheckDecl.cpp

@@ -3155,6 +3155,7 @@ public:
     if (!PD->hasValidSignature())
       return;
 
+    auto *SF = PD->getParentSourceFile();
     {
       // Check for circular inheritance within the protocol.
       SmallVector<ProtocolDecl *, 8> path;
@@ -3162,7 +3163,7 @@ public:
       checkCircularity(TC, PD, diag::circular_protocol_def,
                        DescriptiveDeclKind::Protocol, path);
 
-      if (auto *SF = PD->getParentSourceFile()) {
+      if (SF) {
         if (auto *tracker = SF->getReferencedNameTracker()) {
           bool isNonPrivate =
               (PD->getFormalAccess() > AccessLevel::FilePrivate);
@@ -3184,6 +3185,7 @@ public:
 
     TC.checkDeclCircularity(PD);
     if (PD->isResilient())
+      if (!SF || SF->Kind != SourceFileKind::Interface)
         TC.inferDefaultWitnesses(PD);
 
     if (TC.Context.LangOpts.DebugGenericSignatures) {

test/ParseableInterface/Conformances.swiftinterface

@@ -2,7 +2,9 @@
 // swift-module-flags: 
 
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -emit-module -enable-resilience -o %t/Conformances.swiftmodule %s
+// RUN: %target-swift-frontend -emit-module-path %t/Conformances.swiftmodule -enable-resilience -emit-sil -o %t/Conformances.sil %s
+// RUN: %FileCheck -check-prefix CHECK-MODULE %s < %t/Conformances.sil
+// RUN: %FileCheck -check-prefix NEGATIVE-MODULE %s < %t/Conformances.sil
 // RUN: %target-swift-frontend -emit-sil -I %t %S/Inputs/ConformancesUser.swift -O | %FileCheck %s
 
 public protocol MyProto {
@@ -11,6 +13,15 @@ public protocol MyProto {
   var prop: Int { get set }
   subscript(index: Int) -> Int { get set }
 }
+extension MyProto {
+  public func method() {}
+}
+
+// Make sure there's no default witness table. (But also make sure we printed at
+// least some regular witness tables, or we'll have to change the test.)
+// CHECK-MODULE: sil_witness_table{{.+}}: MyProto module Conformances
+// NEGATIVE-MODULE-NOT: sil_default_witness_table{{.+}}MyProto
+
 
 @_fixed_layout // allow conformance devirtualization
 public struct FullStructImpl: MyProto {
@@ -31,7 +42,8 @@ public struct OpaqueStructImpl: MyProto {}
 
 // CHECK-LABEL: sil @$s16ConformancesUser10testOpaqueSiyF
 // CHECK: function_ref @$s12Conformances7MyProtoPxycfC
-// CHECK: function_ref @$s12Conformances7MyProtoP6methodyyF
+// Note the default implementation is filled in here.
+// CHECK: function_ref @$s12Conformances7MyProtoPAAE6methodyyF
 // CHECK: function_ref @$s12Conformances7MyProtoP4propSivs
 // CHECK: function_ref @$s12Conformances7MyProtoPyS2icig
 // CHECK: end sil function '$s16ConformancesUser10testOpaqueSiyF'

test/ParseableInterface/conformances.swift

@@ -81,7 +81,18 @@ public struct OuterGeneric<T> {
   // CHECK-NEXT: {{^  }$}}
 }
 // CHECK-NEXT: {{^}$}}
+
+public protocol ConditionallyConformed {}
+public protocol ConditionallyConformedAgain {}
+
+// CHECK-END: extension conformances.OuterGeneric : ConditionallyConformed, ConditionallyConformedAgain where T : _ConstraintThatIsNotPartOfTheAPIOfThisLibrary {}
+extension OuterGeneric: ConditionallyConformed where T: PrivateProto {}
+extension OuterGeneric: ConditionallyConformedAgain where T == PrivateProto {}
+
 // CHECK-END: extension conformances.OuterGeneric.Inner : PublicBaseProto {}
+// CHECK-END: extension conformances.OuterGeneric.Inner : ConditionallyConformed, ConditionallyConformedAgain where T : _ConstraintThatIsNotPartOfTheAPIOfThisLibrary {}
+extension OuterGeneric.Inner: ConditionallyConformed where T: PrivateProto {}
+extension OuterGeneric.Inner: ConditionallyConformedAgain where T == PrivateProto {}
 
 private protocol AnotherPrivateSubProto: PublicBaseProto {}
 
@@ -147,3 +158,13 @@ private protocol BaseConstrainedProto: Base, PublicProto {}
 public class H1: Base, ClassConstrainedProto {}
 // CHECK: public class H1 : Base {
 // CHECK-END: extension conformances.H1 : PublicProto {}
+
+public struct MultiGeneric<T, U, V> {}
+extension MultiGeneric: PublicProto where U: PrivateProto {}
+
+// CHECK: public struct MultiGeneric<T, U, V> {
+// CHECK-END: extension conformances.MultiGeneric : PublicProto where T : _ConstraintThatIsNotPartOfTheAPIOfThisLibrary {}
+
+
+// CHECK-END: @usableFromInline
+// CHECK-END-NEXT: internal protocol _ConstraintThatIsNotPartOfTheAPIOfThisLibrary {}