Remove -enable-import-objc-generics staging flag.

Author: jckarter

include/swift/Basic/LangOptions.h

@@ -154,10 +154,6 @@ namespace swift {
     /// Whether we are stripping the "NS" prefix from Foundation et al.
     bool StripNSPrefix = false;
 
-    /// Whether classes with Objective-C lightweight generic type parameters
-    /// should be imported into Swift as generic classes.
-    bool ImportObjCGenerics = true;
-
     /// Enable the Swift 3 migration via Fix-Its.
     bool Swift3Migration = false;
 

include/swift/Option/FrontendOptions.td

@@ -232,10 +232,6 @@ def enable_infer_import_as_member :
   Flag<["-"], "enable-infer-import-as-member">,
   HelpText<"Infer when a global could be imported as a member">;
 
-def enable_import_objc_generics :
-  Flag<["-"], "enable-import-objc-generics">,
-  HelpText<"Import Objective-C lightweight generic type params">;
-
 def enable_strip_ns_prefix :
   Flag<["-"], "enable-strip-ns-prefix">,
   HelpText<"Strip 'NS' prefix from Foundation entities">;

lib/ClangImporter/ImportDecl.cpp

@@ -4366,9 +4366,6 @@ namespace {
     Optional<GenericParamList *> importObjCGenericParams(
        const clang::ObjCInterfaceDecl *decl, DeclContext *dc)
     {
-      if (!Impl.SwiftContext.LangOpts.ImportObjCGenerics) {
-        return nullptr;
-      }
       auto typeParamList = decl->getTypeParamList();
       if (!typeParamList) {
         return nullptr;

lib/Frontend/CompilerInvocation.cpp

@@ -783,7 +783,6 @@ static bool ParseLangArgs(LangOptions &Opts, ArgList &Args,
   if (Args.hasArg(OPT_disable_infer_iuos)) {
     Opts.InferIUOs = false;
   }
-  Opts.ImportObjCGenerics |= Args.hasArg(OPT_enable_import_objc_generics);
 
   Opts.EnableThrowWithoutTry |= Args.hasArg(OPT_enable_throw_without_try);