Sema: fill-protocol-stub fixits should include those missing witnesses that are handed by delayed diagnostics.

include/swift/AST/ASTContext.h

@@ -682,6 +682,15 @@ class ASTContext {
   std::vector<DelayedConformanceDiag>
   takeDelayedConformanceDiags(NormalProtocolConformance *conformance);
 
+  /// Add delayed missing witnesses for the given normal protocol conformance.
+  void addDelayedMissingWitnesses(NormalProtocolConformance *conformance,
+                                  ArrayRef<ValueDecl*> witnesses);
+
+  /// Retrieve the delayed missing witnesses for the given normal protocol
+  /// conformance.
+  std::vector<ValueDecl*>
+  takeDelayedMissingWitnesses(NormalProtocolConformance *conformance);
+
   /// \brief Produce a specialized conformance, which takes a generic
   /// conformance and substitutions written in terms of the generic
   /// conformance's signature.

lib/AST/ASTContext.cpp

@@ -206,6 +206,12 @@ struct ASTContext::Implementation {
                  std::vector<ASTContext::DelayedConformanceDiag>>
     DelayedConformanceDiags;
 
+  /// Map from normal protocol conformances to missing witnesses that have
+  /// been delayed until the conformance is fully checked, so that we can
+  /// issue a fixit that fills the entire protocol stub.
+  llvm::DenseMap<NormalProtocolConformance *, std::vector<ValueDecl*>>
+    DelayedMissingWitnesses;
+
   /// Stores information about lazy deserialization of various declarations.
   llvm::DenseMap<const DeclContext *, LazyContextData *> LazyContexts;
 
@@ -1491,6 +1497,24 @@ void ASTContext::addDelayedConformanceDiag(
   Impl.DelayedConformanceDiags[conformance].push_back(std::move(fn));
 }
 
+void ASTContext::
+addDelayedMissingWitnesses(NormalProtocolConformance *conformance,
+                           ArrayRef<ValueDecl*> witnesses) {
+  auto &bucket = Impl.DelayedMissingWitnesses[conformance];
+  bucket.insert(bucket.end(), witnesses.begin(), witnesses.end());
+}
+
+std::vector<ValueDecl*> ASTContext::
+takeDelayedMissingWitnesses(NormalProtocolConformance *conformance) {
+  std::vector<ValueDecl*> result;
+  auto known = Impl.DelayedMissingWitnesses.find(conformance);
+  if (known != Impl.DelayedMissingWitnesses.end()) {
+    result = std::move(known->second);
+    Impl.DelayedMissingWitnesses.erase(known);
+  }
+  return result;
+}
+
 std::vector<ASTContext::DelayedConformanceDiag>
 ASTContext::takeDelayedConformanceDiags(NormalProtocolConformance *conformance){
   std::vector<ASTContext::DelayedConformanceDiag> result;

lib/Sema/TypeCheckProtocol.cpp

@@ -1945,12 +1945,21 @@ namespace {
   ProtocolConformance *MultiConformanceChecker::
   checkIndividualConformance(NormalProtocolConformance *conformance,
                              bool issueFixit) {
+    std::vector<ValueDecl*> revivedMissingWitnesses;
     switch (conformance->getState()) {
       case ProtocolConformanceState::Incomplete:
         if (conformance->isInvalid()) {
-          // Emit any delayed diagnostics and return.
-          ConformanceChecker(TC, conformance, MissingWitnesses, false).
-          emitDelayedDiags();
+          // Revive registered missing witnesses to handle it below.
+          revivedMissingWitnesses = TC.Context.
+            takeDelayedMissingWitnesses(conformance);
+
+          // If we have no missing witnesses for this invalid conformance, the
+          // conformance is invalid for other reasons, so emit diagnosis now.
+          if (revivedMissingWitnesses.empty()) {
+            // Emit any delayed diagnostics.
+            ConformanceChecker(TC, conformance, MissingWitnesses, false).
+              emitDelayedDiags();
+          }
         }
 
         // Check the rest of the conformance below.
@@ -2051,6 +2060,8 @@ namespace {
 
     // The conformance checker we're using.
     AllUsedCheckers.emplace_back(TC, conformance, MissingWitnesses);
+    MissingWitnesses.insert(revivedMissingWitnesses.begin(),
+                            revivedMissingWitnesses.end());
     AllUsedCheckers.back().checkConformance(issueFixit ?
                                       MissingWitnessDiagnosisKind::ErrorFixIt :
                                       MissingWitnessDiagnosisKind::ErrorOnly);
@@ -2618,6 +2629,7 @@ printRequirementStub(ValueDecl *Requirement, DeclContext *Adopter,
     }
 
     PrintOptions Options = PrintOptions::printForDiagnostics();
+    Options.PrintDocumentationComments = false;
     Options.AccessibilityFilter = Accessibility::Private;
     Options.PrintAccessibility = false;
     Options.FunctionBody = [](const ValueDecl *VD) { return "<#code#>"; };
@@ -2721,7 +2733,15 @@ diagnoseMissingWitnesses(MissingWitnessDiagnosisKind Kind) {
 
   switch (Kind) {
   case MissingWitnessDiagnosisKind::ErrorFixIt: {
-    diagnoseOrDefer(LocalMissing[0], true, InsertFixitCallback);
+    if (SuppressDiagnostics) {
+      // If the diagnostics are suppressed, we register these missing witnesses
+      // for later revisiting.
+      Conformance->setInvalid();
+      TC.Context.addDelayedMissingWitnesses(Conformance,
+                                            MissingWitnesses.getArrayRef());
+    } else {
+      diagnoseOrDefer(LocalMissing[0], true, InsertFixitCallback);
+    }
     clearGlobalMissingWitnesses();
     return;
   }
@@ -4875,6 +4895,15 @@ void ConformanceChecker::checkConformance(MissingWitnessDiagnosisKind Kind) {
   // FIXME: Caller checks that this type conforms to all of the
   // inherited protocols.
 
+  // Emit known diags for this conformance.
+  emitDelayedDiags();
+
+  // If delayed diags have already complained, return.
+  if (AlreadyComplained) {
+    Conformance->setInvalid();
+    return;
+  }
+
   // Resolve all of the type witnesses.
   resolveTypeWitnesses();
 

test/decl/protocol/conforms/fixit_stub_editor.swift

@@ -11,3 +11,17 @@ protocol P2 {
 }
 
 class C1 : P1, P2 {} // expected-error{{type 'C1' does not conform to protocol 'P1'}} expected-error{{type 'C1' does not conform to protocol 'P2'}} expected-note{{do you want to add protocol stubs?}}{{20-20=\n    func foo1() {\n        <#code#>\n    \}\n\n    func foo2() {\n        <#code#>\n    \}\n\n    func bar1() {\n        <#code#>\n    \}\n\n    func bar2() {\n        <#code#>\n    \}\n}}
+
+protocol P3 {
+  associatedtype T1
+  associatedtype T2
+  associatedtype T3
+}
+
+protocol P4 : P3 {
+  associatedtype T4 = T1
+  associatedtype T5 = T2
+  associatedtype T6 = T3
+}
+
+class C2 : P4 {} // expected-error{{type 'C2' does not conform to protocol 'P4'}} expected-error{{type 'C2' does not conform to protocol 'P3'}} expected-note{{do you want to add protocol stubs?}}{{16-16=\n    typealias T4 = <#type#>\n\n    typealias T5 = <#type#>\n\n    typealias T6 = <#type#>\n\n    typealias T1 = <#type#>\n\n    typealias T2 = <#type#>\n\n    typealias T3 = <#type#>\n}}