Record the value-witness-of relationship in the ASTContext as we assign witnesses.

Previously, this was being handled when we set conformances. We want
something lazier.


Swift SVN r11339

lib/AST/Decl.cpp

@@ -251,35 +251,8 @@ ImportDecl::findBestImportKind(ArrayRef<ValueDecl *> Decls) {
   return FirstKind;
 }
 
-/// Associates the decls that are conforming, to the protocol decls.
-static void associateConformingValueDecls(ProtocolConformance *Conformance,
-                                          ASTContext &Ctx) {
-  if (!Conformance)
-    return;
-
-  // FIXME: Walking the full value witness table at this point is
-  // really, really unfortunate.
-  Conformance->forEachValueWitness(nullptr,
-                                   [&](ValueDecl *req,
-                                       ConcreteDeclRef witness) {
-    if (witness)
-      Ctx.recordConformingDecl(witness.getDecl(), req);
-  });
-  
-  for (auto InheritedConf: Conformance->getInheritedConformances())
-    associateConformingValueDecls(InheritedConf.second, Ctx);
-}
-
-static void associateConformingValueDecls(
-    ArrayRef<ProtocolConformance *> Conformances, ASTContext &Ctx) {
-  for (auto Conf: Conformances) {
-    associateConformingValueDecls(Conf, Ctx);
-  }
-}
-
 void ExtensionDecl::setConformances(ArrayRef<ProtocolConformance *> c) {
   Conformances = c;
-  associateConformingValueDecls(c, getASTContext());
 }
 
 SourceRange PatternBindingDecl::getSourceRange() const {
@@ -539,10 +512,6 @@ bool TypeDecl::derivesProtocolConformance(ProtocolDecl *protocol) const {
 
 void TypeDecl::setConformances(ArrayRef<ProtocolConformance *> c) {
   Conformances = c;
-  // A typealias should not affect the conformance bit of members of the
-  // original; mark conformances only if this is a nominal type decl.
-  if (isa<NominalTypeDecl>(this))
-    associateConformingValueDecls(c, getASTContext());
 }
 
 GenericSignature::GenericSignature(ArrayRef<GenericTypeParamType *> params,

lib/Sema/TypeCheckProtocol.cpp

@@ -922,6 +922,7 @@ checkConformsToProtocol(TypeChecker &TC, Type T, ProtocolDecl *Proto,
         else
           Mapping[Requirement] = ConcreteDeclRef(TC.Context, best.Witness,
                                                  best.WitnessSubstitutions);
+        TC.Context.recordConformingDecl(best.Witness, Requirement);
 
         // If we deduced any associated types, record them now.
         if (!best.AssociatedTypeDeductions.empty()) {
@@ -968,7 +969,7 @@ checkConformsToProtocol(TypeChecker &TC, Type T, ProtocolDecl *Proto,
         if (matchWitness(TC, Proto, DC, Requirement, T, derived,
                          TypeWitnesses).isViable()) {
           Mapping[Requirement] = derived;
-          numViable = 1;
+          TC.Context.recordConformingDecl(derived, Requirement);
           continue;
         }
         didDerive = true;

lib/Serialization/Deserialization.cpp

@@ -410,6 +410,7 @@ Optional<ConformancePair> ModuleFile::maybeReadConformance(Type conformingType,
       witness = ConcreteDeclRef(ctx, second, substitutions);
 
     witnesses.insert(std::make_pair(first, witness));
+    ctx.recordConformingDecl(second, first);
   }
   assert(rawIDIter <= rawIDs.end() && "read too much");