AST: add a BuiltinUnprotectedAddressOf language feature

Author: eeckstein

include/swift/Basic/Features.def

@@ -82,6 +82,7 @@ LANGUAGE_FEATURE(BuiltinCreateAsyncTaskInGroup, 0, "MainActor executor building
 LANGUAGE_FEATURE(BuiltinCopy, 0, "Builtin.copy()", true)
 LANGUAGE_FEATURE(BuiltinStackAlloc, 0, "Builtin.stackAlloc", true)
 LANGUAGE_FEATURE(BuiltinTaskRunInline, 0, "Builtin.taskRunInline", true)
+LANGUAGE_FEATURE(BuiltinUnprotectedAddressOf, 0, "Builtin.unprotectedAddressOf", true)
 SUPPRESSIBLE_LANGUAGE_FEATURE(SpecializeAttributeWithAvailability, 0, "@_specialize attribute with availability", true)
 LANGUAGE_FEATURE(BuiltinAssumeAlignment, 0, "Builtin.assumeAlignment", true)
 SUPPRESSIBLE_LANGUAGE_FEATURE(UnsafeInheritExecutor, 0, "@_unsafeInheritExecutor", true)

lib/AST/ASTPrinter.cpp

@@ -2921,6 +2921,8 @@ static bool usesFeatureBuiltinCopy(Decl *decl) { return false; }
 
 static bool usesFeatureBuiltinTaskRunInline(Decl *) { return false; }
 
+static bool usesFeatureBuiltinUnprotectedAddressOf(Decl *) { return false; }
+
 static bool usesFeatureSpecializeAttributeWithAvailability(Decl *decl) {
   if (auto func = dyn_cast<AbstractFunctionDecl>(decl)) {
     for (auto specialize : func->getAttrs().getAttributes<SpecializeAttr>()) {