[Concurrency] Make Swift 6 available in noasserts compilers.

Author: hborla

include/swift/Basic/Version.h

@@ -134,8 +134,8 @@ class Version {
 
   // List of backward-compatibility versions that we permit passing as
   // -swift-version <vers>
-  static std::array<StringRef, 3> getValidEffectiveVersions() {
-    return {{"4", "4.2", "5"}};
+  static std::array<StringRef, 4> getValidEffectiveVersions() {
+    return {{"4", "4.2", "5", "6"}};
   };
 };
 

lib/Basic/Version.cpp

@@ -180,16 +180,7 @@ llvm::Optional<Version> Version::getEffectiveLanguageVersion() const {
                   "getCurrentLanguageVersion is no longer correct here");
     return Version::getCurrentLanguageVersion();
   case 6:
-    // Allow version '6' in asserts compilers *only* so that we can start
-    // testing changes slated for Swift 6. Note that it's still not listed in
-    // `Version::getValidEffectiveVersions()`.
-    // FIXME: When Swift 6 becomes real, remove 'REQUIRES: asserts' from tests
-    //        using '-swift-version 6'.
-#ifdef NDEBUG
-    LLVM_FALLTHROUGH;
-#else
     return Version{6};
-#endif
   default:
     return llvm::None;
   }

test/Driver/swift-version-6-asserts.swift

@@ -1,7 +1,3 @@
-// Tests temporary -swift-version 6 behavior in compilers with asserts enabled,
-// where we allow -swift-version 6 for testing but don't list it as a permitted
-// version.
-
 // REQUIRES: asserts
 
 // RUN: not %target-swiftc_driver -swift-version 6 -typecheck %s 2>&1 | %FileCheck --check-prefix ERROR_6 %s
@@ -51,4 +47,4 @@ jkl
 
 // ERROR_7: <unknown>:0: error: invalid value '7' in '-swift-version 7'
 // ERROR_7: <unknown>:0: note: valid arguments to '-swift-version'
-// ERROR_7-NOT: '6'
+// ERROR_7: valid arguments to '-swift-version' are '4', '4.2', '5', '6'