Remove staging flag for unimplemented key path components.

All the originally-planned component kinds are now implemented.

Author: jckarter

include/swift/Basic/LangOptions.h

@@ -238,9 +238,6 @@ namespace swift {
     /// Diagnose uses of NSCoding with classes that have unstable mangled names.
     bool EnableNSKeyedArchiverDiagnostics = true;
 
-    /// Enable keypath components that aren't fully implemented.
-    bool EnableExperimentalKeyPathComponents = false;
-
     /// When a conversion from String to Substring fails, emit a fix-it to append
     /// the void subscript '[]'.
     /// FIXME: Remove this flag when void subscripts are implemented.

include/swift/Option/FrontendOptions.td

@@ -279,10 +279,6 @@ def enable_experimental_property_behaviors :
   Flag<["-"], "enable-experimental-property-behaviors">,
   HelpText<"Enable experimental property behaviors">;
 
-def enable_experimental_keypath_components :
-  Flag<["-"], "enable-experimental-keypath-components">,
-  HelpText<"Enable unimplemented keypath component kinds">;
-
 def enable_deserialization_recovery :
   Flag<["-"], "enable-deserialization-recovery">,
   HelpText<"Attempt to recover from missing xrefs (etc) in swiftmodules">;

lib/Frontend/CompilerInvocation.cpp

@@ -945,9 +945,6 @@ static bool ParseLangArgs(LangOptions &Opts, ArgList &Args,
   Opts.EnableExperimentalPropertyBehaviors |=
     Args.hasArg(OPT_enable_experimental_property_behaviors);
 
-  Opts.EnableExperimentalKeyPathComponents |=
-    Args.hasArg(OPT_enable_experimental_keypath_components);
-
   Opts.EnableClassResilience |=
     Args.hasArg(OPT_enable_class_resilience);
 

lib/Sema/TypeCheckConstraints.cpp

@@ -1453,12 +1453,6 @@ void PreCheckExpression::resolveKeyPathExpr(KeyPathExpr *KPE) {
 
         expr = UDE->getBase();
       } else if (auto SE = dyn_cast<SubscriptExpr>(expr)) {
-        if (!TC.Context.LangOpts.EnableExperimentalKeyPathComponents) {
-          TC.diagnose(SE->getLoc(),
-                      diag::expr_swift_keypath_unimplemented_component,
-                      "subscript");
-        }
-      
         // .[0] or just plain [0]
         components.push_back(
             KeyPathExpr::Component::forUnresolvedSubscriptWithPrebuiltIndexExpr(

test/SILGen/keypath_application.swift

@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -enable-experimental-keypath-components -emit-silgen %s | %FileCheck %s
+// RUN: %target-swift-frontend -emit-silgen %s | %FileCheck %s
 
 class A {}
 class B {}

test/SILGen/keypaths.swift

@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -enable-experimental-keypath-components -emit-silgen %s | %FileCheck %s
+// RUN: %target-swift-frontend -emit-silgen %s | %FileCheck %s
 
 struct S<T> {
   var x: T

test/SILGen/keypaths_objc.swift

@@ -1,5 +1,5 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-experimental-keypath-components -emit-silgen -import-objc-header %S/Inputs/keypaths_objc.h %s | %FileCheck %s
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -enable-experimental-keypath-components -emit-ir -import-objc-header %S/Inputs/keypaths_objc.h %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-silgen -import-objc-header %S/Inputs/keypaths_objc.h %s | %FileCheck %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-ir -import-objc-header %S/Inputs/keypaths_objc.h %s
 // REQUIRES: objc_interop
 
 import Foundation

test/expr/unary/keypath/keypath-unimplemented.swift

@@ -9,10 +9,6 @@ class C {
   var i = 0
 }
 
-func unsupportedComponents() {
-  _ = \A.[0] // expected-error{{key path support for subscript components is not implemented}}
-}
-
 // rdar://problem/32209039 - Improve diagnostic when unsupported tuple element references are used in key path literals
 let _ = \(Int, String).0 // expected-error {{key path cannot reference tuple elements}}
 let _ = \(a: Int, b: String).b // expected-error {{key path cannot reference tuple elements}}

test/expr/unary/keypath/keypath.swift

@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -typecheck -parse-as-library -enable-experimental-keypath-components %s -verify
+// RUN: %target-swift-frontend -typecheck -parse-as-library %s -verify
 
 struct Sub: Hashable {
   static func ==(_: Sub, _: Sub) -> Bool { return true }

test/stdlib/KeyPath.swift

@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-build-swift %s -Xfrontend -enable-experimental-keypath-components -o %t/a.out
+// RUN: %target-build-swift %s -o %t/a.out
 // RUN: %target-run %t/a.out
 // REQUIRES: executable_test
 

test/stdlib/KeyPathImplementation.swift

@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-build-swift %s -g -Xfrontend -enable-experimental-keypath-components -o %t/a.out
+// RUN: %target-build-swift %s -g -o %t/a.out
 // RUN: %target-run %t/a.out
 // REQUIRES: executable_test
 

test/stdlib/KeyPathObjC.swift

@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-build-swift %s -Xfrontend -enable-experimental-keypath-components -o %t/a.out
+// RUN: %target-build-swift %s -o %t/a.out
 // RUN: %target-run %t/a.out
 // REQUIRES: executable_test
 // REQUIRES: objc_interop