Isolated deinit is 6.1 available but experimental

Author: ktoso

include/swift/AST/DiagnosticsSema.def

@@ -5960,6 +5960,9 @@ ERROR(isolated_deinit_no_isolation,none,
 ERROR(isolated_deinit_on_value_type,none,
       "only classes and actors can have isolated deinit",
       ())
+ERROR(isolated_deinit_unavailable,none,
+      "isolated deinit is only available in %0 %1 or newer",
+      (StringRef, llvm::VersionTuple))
 ERROR(isolated_deinit_experimental,none,
       "'isolated' deinit requires frontend flag -enable-experimental-feature IsolatedDeinit "
       "to enable the usage of this language feature", ())

include/swift/AST/FeatureAvailability.def

@@ -76,6 +76,7 @@ FEATURE(InitRawStructMetadata,                          (6, 0))
 
 FEATURE(LayoutStringValueWitnesses,                     (6, 1))
 FEATURE(CreateTaskWithConsumedFunction,                 (6, 1))
+FEATURE(IsolatedDeinit,                                 (6, 1))
 
 FEATURE(TaskExecutor,                                   FUTURE)
 FEATURE(Differentiation,                                FUTURE)

include/swift/Basic/Features.def

@@ -410,7 +410,7 @@ EXPERIMENTAL_FEATURE(SafeInterop, true)
 EXPERIMENTAL_FEATURE(AssumeResilientCxxTypes, true)
 
 // Isolated deinit
-EXPERIMENTAL_FEATURE(IsolatedDeinit, true)
+SUPPRESSIBLE_EXPERIMENTAL_FEATURE(IsolatedDeinit, false)
 
 // Enable values in generic signatures, e.g. <let N: Int>
 EXPERIMENTAL_FEATURE(ValueGenerics, true)

lib/Sema/TypeCheckAttr.cpp

@@ -127,6 +127,14 @@ class AttributeChecker : public AttributeVisitor<AttributeChecker> {
           return;
         }
       }
+
+      TypeChecker::checkAvailability(
+          attr->getRange(), C.getIsolatedDeinitAvailability(),
+          D->getDeclContext(),
+          [&](StringRef platformName, llvm::VersionTuple version) {
+            return diagnoseAndRemoveAttr(
+                attr, diag::isolated_deinit_unavailable, platformName, version);
+          });
     }
   }