Sema: Remove useObjectiveCBridgeableConformances()

THere is no longer any reason to complete ClangImporter-synthesized _ObjectiveCBridgeable
conformances in Sema. SILGen will determine the ones that it needs and will trigger
conformance checking as needed automatically.

Author: slavapestov

lib/Sema/CSApply.cpp

@@ -4736,11 +4736,6 @@ namespace {
     Expr *walkToExprPost(Expr *expr) {
       Expr *result = visit(expr);
 
-      // Mark any _ObjectiveCBridgeable conformances as 'used'.
-      if (result) {
-        useObjectiveCBridgeableConformances(cs.DC, cs.getType(result));
-      }
-
       assert(expr == ExprStack.back());
       ExprStack.pop_back();
 

lib/Sema/TypeCheckDeclObjC.cpp

@@ -1632,14 +1632,6 @@ void markAsObjC(ValueDecl *D, ObjCReason reason,
     ctx.getLazyResolver()->resolveDeclSignature(D);
   }
 
-  if (!isa<TypeDecl>(D) && !isa<AccessorDecl>(D) && !isa<EnumElementDecl>(D)) {
-    if (ctx.getLazyResolver()) {
-      // Only record conformances when we have a lazy resolver.
-      useObjectiveCBridgeableConformances(D->getInnermostDeclContext(),
-                                          D->getInterfaceType());
-    }
-  }
-
   if (auto method = dyn_cast<AbstractFunctionDecl>(D)) {
     // Determine the foreign error convention.
     if (auto baseMethod = method->getOverriddenDecl()) {

lib/Sema/TypeCheckProtocol.cpp

@@ -4309,92 +4309,6 @@ TypeChecker::LookUpConformance::operator()(
                           ConformanceCheckFlags::SkipConditionalRequirements));
 }
 
-/// Mark any _ObjectiveCBridgeable conformances in the given type as "used".
-///
-/// These conformances might not appear in any substitution lists produced
-/// by Sema, since bridging is done at the SILGen level, so we have to
-/// force them here to ensure SILGen can find them.
-void swift::useObjectiveCBridgeableConformances(DeclContext *dc, Type type) {
-  class Walker : public TypeWalker {
-    ASTContext &Ctx;
-    DeclContext *DC;
-    ProtocolDecl *Proto;
-
-  public:
-    Walker(DeclContext *dc, ProtocolDecl *proto)
-      : Ctx(dc->getASTContext()), DC(dc), Proto(proto) { }
-
-    Action walkToTypePre(Type ty) override {
-      ConformanceCheckOptions options =
-          (ConformanceCheckFlags::InExpression |
-           ConformanceCheckFlags::Used |
-           ConformanceCheckFlags::SuppressDependencyTracking);
-
-      // If we have a nominal type, "use" its conformance to
-      // _ObjectiveCBridgeable if it has one.
-      if (auto *nominalDecl = ty->getAnyNominal()) {
-        if (isa<ClassDecl>(nominalDecl) || isa<ProtocolDecl>(nominalDecl))
-          return Action::Continue;
-
-        auto lazyResolver = Ctx.getLazyResolver();
-        assert(lazyResolver &&
-               "Cannot do conforms-to-protocol check without a type checker");
-        TypeChecker &tc = *static_cast<TypeChecker *>(lazyResolver);
-        (void)tc.conformsToProtocol(ty, Proto, DC, options,
-                                    /*ComplainLoc=*/SourceLoc());
-
-        // Set and Dictionary bridging also requires the conformance
-        // of the key type to Hashable.
-        if (nominalDecl == Ctx.getSetDecl() ||
-            nominalDecl == Ctx.getDictionaryDecl()) {
-          if (auto boundGeneric = ty->getAs<BoundGenericType>()) {
-            auto args = boundGeneric->getGenericArgs();
-            if (!args.empty()) {
-              auto keyType = args[0];
-              auto *hashableProto =
-                Ctx.getProtocol(KnownProtocolKind::Hashable);
-              if (!hashableProto)
-                return Action::Stop;
-
-              (void)tc.conformsToProtocol(
-                  keyType, hashableProto, DC, options,
-                  /*ComplainLoc=*/SourceLoc());
-            }
-          }
-        }
-      }
-
-      return Action::Continue;
-    }
-  };
-
-  auto proto =
-    dc->getASTContext().getProtocol(KnownProtocolKind::ObjectiveCBridgeable);
-  if (!proto) return;
-
-  Walker walker(dc, proto);
-  type.walk(walker);
-}
-
-void swift::useObjectiveCBridgeableConformancesOfArgs(
-       DeclContext *dc, BoundGenericType *bound) {
-  ASTContext &ctx = dc->getASTContext();
-  auto proto = ctx.getProtocol(KnownProtocolKind::ObjectiveCBridgeable);
-  if (!proto) return;
-
-  // Check whether the bound generic type itself is bridged to
-  // Objective-C.
-  ConformanceCheckOptions options =
-    (ConformanceCheckFlags::InExpression |
-     ConformanceCheckFlags::SuppressDependencyTracking);
-  auto lazyResolver = ctx.getLazyResolver();
-  assert(lazyResolver && "Need a type checker to check conforms-to-protocol");
-  auto &tc = *static_cast<TypeChecker *>(lazyResolver);
-  (void)tc.conformsToProtocol(
-      bound->getDecl()->getDeclaredType(), proto, dc,
-      options, /*ComplainLoc=*/SourceLoc());
-}
-
 void TypeChecker::useBridgedNSErrorConformances(DeclContext *dc, Type type) {
   auto errorProto = Context.getProtocol(KnownProtocolKind::Error);
   auto bridgedStoredNSError = Context.getProtocol(

lib/Sema/TypeCheckProtocol.h

@@ -937,16 +937,6 @@ llvm::TinyPtrVector<ValueDecl *> findWitnessedObjCRequirements(
                                      const ValueDecl *witness,
                                      bool anySingleRequirement = false);
 
-/// Mark any _ObjectiveCBridgeable conformances in the given type as "used".
-void useObjectiveCBridgeableConformances(
-                      DeclContext *dc, Type type);
-
-/// If this bound-generic type is bridged, mark any
-/// _ObjectiveCBridgeable conformances in the generic arguments of
-/// the given type as "used".
-void useObjectiveCBridgeableConformancesOfArgs(
-                      DeclContext *dc, BoundGenericType *bound);
-
 }
 
 #endif // SWIFT_SEMA_PROTOCOL_H

lib/Sema/TypeCheckType.cpp

@@ -881,11 +881,6 @@ Type TypeChecker::applyUnboundGenericArguments(
                                     subMap, resultType);
   }
 
-  if (isa<NominalTypeDecl>(decl) && resultType) {
-    (void)useObjectiveCBridgeableConformancesOfArgs(
-        dc, resultType->castTo<BoundGenericType>());
-  }
-
   return resultType;
 }
 
@@ -3012,9 +3007,6 @@ Type TypeResolver::resolveArrayType(ArrayTypeRepr *repr,
   if (!sliceTy)
     return ErrorType::get(Context);
 
-  // Check for _ObjectiveCBridgeable conformances in the element type.
-  useObjectiveCBridgeableConformances(DC, baseTy);
-
   return sliceTy;
 }
 
@@ -3045,11 +3037,6 @@ Type TypeResolver::resolveDictionaryType(DictionaryTypeRepr *repr,
       return nullptr;
     }
 
-    // Check for _ObjectiveCBridgeable conformances in the key and value
-    // types.
-    useObjectiveCBridgeableConformances(DC, keyTy);
-    useObjectiveCBridgeableConformances(DC, valueTy);
-
     return dictTy;
   }