Require musttail and preserve_none for interleaved

ConflictSet.cpp

@@ -3183,6 +3183,12 @@ Node *firstGeqPhysical(Node *n, const TrivialSpan key) {
 #define PRESERVE_NONE
 #endif
 
+#if __has_attribute(musttail) && __has_attribute(preserve_none)
+constexpr bool kEnableInterleaved = true;
+#else
+constexpr bool kEnableInterleaved = false;
+#endif
+
 namespace check {
 
 typedef PRESERVE_NONE void (*Continuation)(struct Job *, struct Context *);
@@ -4969,7 +4975,7 @@ struct __attribute__((visibility("hidden"))) ConflictSet::Impl {
     check::Context context;
     context.readContext.impl = this;
 
-#if __has_attribute(musttail)
+    if constexpr (kEnableInterleaved) {
       if (count == 1) {
         useSequential(reads, result, count, context);
       } else {
@@ -4995,8 +5001,8 @@ struct __attribute__((visibility("hidden"))) ConflictSet::Impl {
         inProgress[0].prev = inProgress + started - 1;
         inProgress[started - 1].next = inProgress;
 
-      // Kick off the sequence of tail calls that finally returns once all jobs
-      // are done
+        // Kick off the sequence of tail calls that finally returns once all
+        // jobs are done
         inProgress->continuation(inProgress, &context);
 
 #ifndef NDEBUG
@@ -5009,10 +5015,9 @@ struct __attribute__((visibility("hidden"))) ConflictSet::Impl {
         assert(context.readContext == context2.readContext);
 #endif
       }
-
-#else
+    } else {
       useSequential(reads, result, count, context);
-#endif
+    }
 
     for (int i = 0; i < count; ++i) {
       assert(reads[i].readVersion >= 0);
@@ -5186,11 +5191,6 @@ struct __attribute__((visibility("hidden"))) ConflictSet::Impl {
     assert(allPointWrites || sorted);
 #endif
 
-#if __has_attribute(musttail)
-    constexpr bool kEnableInterleaved = true;
-#else
-    constexpr bool kEnableInterleaved = false;
-#endif
     if (kEnableInterleaved && count > 1) {
       interleavedWrites(writes, count, InternalVersionT(writeVersion));
     } else {