Merge pull request #2972 from onflow/bastian/incomparable

Make entitlement set access incomparable

runtime/common/incomparable.go

@@ -0,0 +1,25 @@
+/*
+ * Cadence - The resource-oriented smart contract programming language
+ *
+ * Copyright Dapper Labs, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package common
+
+// Incomparable (the zero-sized type [0]func()) makes the surrounding incomparable.
+// It is crucial to ensure its placed at the beginning or middle of the surrounding struct,
+// and NOT at the end of the struct, as otherwise the compiler will add padding bytes.
+// See https://i.hsfzxjy.site/zst-at-the-rear-of-go-struct/ for more details
+type Incomparable [0]func()

runtime/sema/access.go

@@ -53,6 +53,7 @@ const (
 // EntitlementSetAccess
 
 type EntitlementSetAccess struct {
+	_            common.Incomparable
 	Entitlements *EntitlementOrderedSet
 	SetKind      EntitlementSetKind
 }