Reduce visibility of retired amendment identifiers:

Identifiers for retired amendments should not generally be used
in the codebase.

This commit reduces their visibility down to one translation
unit and marks them as unused and deprecated to prevent
accidental reuse.

src/ripple/protocol/Feature.h

@@ -368,21 +368,6 @@ extern uint256 const featureRequireFullyCanonicalSig;
 extern uint256 const fix1781;
 extern uint256 const featureHardenedValidations;
 
-// The following amendments have been active for at least two years.
-// Their pre-amendment code has been removed.
-extern uint256 const retiredPayChan;
-extern uint256 const retiredCryptoConditions;
-extern uint256 const retiredTickSize;
-extern uint256 const retiredFix1368;
-extern uint256 const retiredEscrow;
-extern uint256 const retiredFix1373;
-extern uint256 const retiredEnforceInvariants;
-extern uint256 const retiredSortedDirectories;
-extern uint256 const retiredFix1201;
-extern uint256 const retiredFix1512;
-extern uint256 const retiredFix1523;
-extern uint256 const retiredFix1528;
-
 }  // namespace ripple
 
 #endif

src/ripple/protocol/impl/Feature.cpp

@@ -154,58 +154,52 @@ bitsetIndexToFeature(size_t i)
     return featureCollections.bitsetIndexToFeature(i);
 }
 
-uint256 const featureTickets = *getRegisteredFeature("Tickets");
-uint256 const featureOwnerPaysFee = *getRegisteredFeature("OwnerPaysFee");
-uint256 const featureFlow = *getRegisteredFeature("Flow");
-uint256 const featureCompareTakerFlowCross =
-    *getRegisteredFeature("CompareTakerFlowCross");
-uint256 const featureFlowCross = *getRegisteredFeature("FlowCross");
-uint256 const featureCryptoConditionsSuite =
-    *getRegisteredFeature("CryptoConditionsSuite");
-uint256 const fix1513 = *getRegisteredFeature("fix1513");
-uint256 const featureDepositAuth = *getRegisteredFeature("DepositAuth");
-uint256 const featureChecks = *getRegisteredFeature("Checks");
-uint256 const fix1571 = *getRegisteredFeature("fix1571");
-uint256 const fix1543 = *getRegisteredFeature("fix1543");
-uint256 const fix1623 = *getRegisteredFeature("fix1623");
-uint256 const featureDepositPreauth = *getRegisteredFeature("DepositPreauth");
-uint256 const fix1515 = *getRegisteredFeature("fix1515");
-uint256 const fix1578 = *getRegisteredFeature("fix1578");
-uint256 const featureMultiSignReserve =
-    *getRegisteredFeature("MultiSignReserve");
-uint256 const fixTakerDryOfferRemoval =
-    *getRegisteredFeature("fixTakerDryOfferRemoval");
-uint256 const fixMasterKeyAsRegularKey =
-    *getRegisteredFeature("fixMasterKeyAsRegularKey");
-uint256 const fixCheckThreading = *getRegisteredFeature("fixCheckThreading");
-uint256 const fixPayChanRecipientOwnerDir =
-    *getRegisteredFeature("fixPayChanRecipientOwnerDir");
-uint256 const featureDeletableAccounts =
-    *getRegisteredFeature("DeletableAccounts");
-uint256 const fixQualityUpperBound =
-    *getRegisteredFeature("fixQualityUpperBound");
-uint256 const featureRequireFullyCanonicalSig =
-    *getRegisteredFeature("RequireFullyCanonicalSig");
-uint256 const fix1781 = *getRegisteredFeature("fix1781");
-uint256 const featureHardenedValidations =
-    *getRegisteredFeature("HardenedValidations");
+// clang-format off
 
-// The following amendments have been active for at least two years.
-// Their pre-amendment code has been removed.
-uint256 const retiredPayChan = *getRegisteredFeature("PayChan");
-uint256 const retiredCryptoConditions =
-    *getRegisteredFeature("CryptoConditions");
-uint256 const retiredTickSize = *getRegisteredFeature("TickSize");
-uint256 const retiredFix1368 = *getRegisteredFeature("fix1368");
-uint256 const retiredEscrow = *getRegisteredFeature("Escrow");
-uint256 const retiredFix1373 = *getRegisteredFeature("fix1373");
-uint256 const retiredEnforceInvariants =
-    *getRegisteredFeature("EnforceInvariants");
-uint256 const retiredSortedDirectories =
-    *getRegisteredFeature("SortedDirectories");
-uint256 const retiredFix1201 = *getRegisteredFeature("fix1201");
-uint256 const retiredFix1512 = *getRegisteredFeature("fix1512");
-uint256 const retiredFix1523 = *getRegisteredFeature("fix1523");
-uint256 const retiredFix1528 = *getRegisteredFeature("fix1528");
+uint256 const
+    featureTickets                  = *getRegisteredFeature("Tickets"),
+    featureOwnerPaysFee             = *getRegisteredFeature("OwnerPaysFee"),
+    featureFlow                     = *getRegisteredFeature("Flow"),
+    featureCompareTakerFlowCross    = *getRegisteredFeature("CompareTakerFlowCross"),
+    featureFlowCross                = *getRegisteredFeature("FlowCross"),
+    featureCryptoConditionsSuite    = *getRegisteredFeature("CryptoConditionsSuite"),
+    fix1513                         = *getRegisteredFeature("fix1513"),
+    featureDepositAuth              = *getRegisteredFeature("DepositAuth"),
+    featureChecks                   = *getRegisteredFeature("Checks"),
+    fix1571                         = *getRegisteredFeature("fix1571"),
+    fix1543                         = *getRegisteredFeature("fix1543"),
+    fix1623                         = *getRegisteredFeature("fix1623"),
+    featureDepositPreauth           = *getRegisteredFeature("DepositPreauth"),
+    fix1515                         = *getRegisteredFeature("fix1515"),
+    fix1578                         = *getRegisteredFeature("fix1578"),
+    featureMultiSignReserve         = *getRegisteredFeature("MultiSignReserve"),
+    fixTakerDryOfferRemoval         = *getRegisteredFeature("fixTakerDryOfferRemoval"),
+    fixMasterKeyAsRegularKey        = *getRegisteredFeature("fixMasterKeyAsRegularKey"),
+    fixCheckThreading               = *getRegisteredFeature("fixCheckThreading"),
+    fixPayChanRecipientOwnerDir     = *getRegisteredFeature("fixPayChanRecipientOwnerDir"),
+    featureDeletableAccounts        = *getRegisteredFeature("DeletableAccounts"),
+    fixQualityUpperBound            = *getRegisteredFeature("fixQualityUpperBound"),
+    featureRequireFullyCanonicalSig = *getRegisteredFeature("RequireFullyCanonicalSig"),
+    fix1781                         = *getRegisteredFeature("fix1781"),
+    featureHardenedValidations      = *getRegisteredFeature("HardenedValidations");
+
+// The following amendments have been active for at least two years. Their
+// pre-amendment code has been removed and the identifiers are deprecated.
+[[deprecated("The referenced amendment has been retired"), maybe_unused]]
+uint256 const
+    retiredPayChan           = *getRegisteredFeature("PayChan"),
+    retiredCryptoConditions  = *getRegisteredFeature("CryptoConditions"),
+    retiredTickSize          = *getRegisteredFeature("TickSize"),
+    retiredFix1368           = *getRegisteredFeature("fix1368"),
+    retiredEscrow            = *getRegisteredFeature("Escrow"),
+    retiredFix1373           = *getRegisteredFeature("fix1373"),
+    retiredEnforceInvariants = *getRegisteredFeature("EnforceInvariants"),
+    retiredSortedDirectories = *getRegisteredFeature("SortedDirectories"),
+    retiredFix1201           = *getRegisteredFeature("fix1201"),
+    retiredFix1512           = *getRegisteredFeature("fix1512"),
+    retiredFix1523           = *getRegisteredFeature("fix1523"),
+    retiredFix1528           = *getRegisteredFeature("fix1528");
+
+// clang-format on
 
 }  // namespace ripple