[sending] Enable sending whenever region isolation is enabled and make SE-0430 an upcoming feature.

I also added support for expressing suppressable upcoming features.

rdar://128216574

Author: gottesmm

include/swift/Basic/Features.def

@@ -69,6 +69,21 @@
 #  endif
 #endif
 
+// A feature that's both suppressible and upcoming.
+// Delegates to whichever the includer defines.
+#ifndef SUPPRESSIBLE_UPCOMING_FEATURE
+#  if defined(SUPPRESSIBLE_UPCOMING_FEATURE) && \
+      defined(UPCOMING_FEATURE)
+#    error ambiguous defines when including Features.def
+#  elif defined(SUPPRESSIBLE_LANGUAGE_FEATURE)
+#    define SUPPRESSIBLE_UPCOMING_FEATURE(FeatureName, SENumber, Version) \
+       SUPPRESSIBLE_LANGUAGE_FEATURE(FeatureName, SENumber, #FeatureName)
+#  else
+#    define SUPPRESSIBLE_UPCOMING_FEATURE(FeatureName, SENumber, Version) \
+       UPCOMING_FEATURE(FeatureName, SENumber, Version)
+#  endif
+#endif
+
 #ifndef SUPPRESSIBLE_LANGUAGE_FEATURE
 #  define SUPPRESSIBLE_LANGUAGE_FEATURE(FeatureName, SENumber, Description) \
   LANGUAGE_FEATURE(FeatureName, SENumber, Description)
@@ -198,6 +213,8 @@ UPCOMING_FEATURE(DynamicActorIsolation, 423, 6)
 UPCOMING_FEATURE(NonfrozenEnumExhaustivity, 192, 6)
 UPCOMING_FEATURE(GlobalActorIsolatedTypesUsability, 0434, 6)
 UPCOMING_FEATURE(BorrowingSwitch, 432, 6)
+UPCOMING_FEATURE(TransferringArgsAndResults, 430, 6)
+SUPPRESSIBLE_UPCOMING_FEATURE(SendingArgsAndResults, 430, 6)
 
 // Swift 7
 UPCOMING_FEATURE(ExistentialAny, 335, 7)
@@ -352,16 +369,6 @@ EXPERIMENTAL_FEATURE(FixedArrays, true)
 // Group Main Actor Isolation Errors by Scope
 EXPERIMENTAL_FEATURE(GroupActorErrors, true)
 
-// Allow for the 'transferring' keyword to be applied to arguments and results.
-//
-// Enables SendingArgsAndResults as well. After parsing, we just represent this
-// as 'sendable' implying that since both are always enabled together, this
-// doesn't need to be suppressed.
-EXPERIMENTAL_FEATURE(TransferringArgsAndResults, true)
-
-// Allow for the 'sending' keyword to be applied to arguments and results.
-SUPPRESSIBLE_EXPERIMENTAL_FEATURE(SendingArgsAndResults, true)
-
 // Enable explicit isolation of closures.
 EXPERIMENTAL_FEATURE(ClosureIsolation, true)
 

lib/DriverTool/sil_opt_main.cpp

@@ -794,6 +794,12 @@ int sil_opt_main(ArrayRef<const char *> argv, void *MainAddr) {
     Invocation.getLangOptions().enableFeature(Feature::RegionBasedIsolation);
   }
 
+  if (Invocation.getLangOptions().hasFeature(Feature::RegionBasedIsolation)) {
+    Invocation.getLangOptions().enableFeature(
+        Feature::TransferringArgsAndResults);
+    Invocation.getLangOptions().enableFeature(Feature::SendingArgsAndResults);
+  }
+
   if (Invocation.getLangOptions().hasFeature(
           Feature::TransferringArgsAndResults)) {
     Invocation.getLangOptions().enableFeature(Feature::SendingArgsAndResults);

lib/Frontend/CompilerInvocation.cpp

@@ -1064,6 +1064,13 @@ static bool ParseLangArgs(LangOptions &Opts, ArgList &Args,
       Opts.enableFeature(Feature::RegionBasedIsolation);
   }
 
+  // Enable TransferringArgsAndResults/SendingArgsAndResults whenever
+  // RegionIsolation is enabled.
+  if (Opts.hasFeature(Feature::RegionBasedIsolation)) {
+    Opts.enableFeature(Feature::TransferringArgsAndResults);
+    Opts.enableFeature(Feature::SendingArgsAndResults);
+  }
+
   // Enable SendingArgsAndResults whenever TransferringArgsAndResults is
   // enabled.
   //