src/jdk.compiler/share/classes/com/sun/tools/javac/comp/MemberEnter.java

*** 285,297 ****
                  ? env.info.scope.owner.kind == MTH ? Type.noType : syms.errType
                  : tree.vartype.type;
          VarSymbol v = new VarSymbol(0, tree.name, vartype, enclScope.owner);
          v.flags_field = chk.checkFlags(tree.pos(), tree.mods.flags, v, tree);
          tree.sym = v;
          if (tree.init != null) {
              v.flags_field |= HASINIT;
!             if ((v.flags_field & FINAL) != 0 &&
                  needsLazyConstValue(tree.init)) {
                  Env<AttrContext> initEnv = getInitEnv(tree, env);
                  initEnv.info.enclVar = v;
                  v.setLazyConstValue(initEnv(tree, initEnv), attr, tree);
              }
--- 285,300 ----
                  ? env.info.scope.owner.kind == MTH ? Type.noType : syms.errType
                  : tree.vartype.type;
          VarSymbol v = new VarSymbol(0, tree.name, vartype, enclScope.owner);
          v.flags_field = chk.checkFlags(tree.pos(), tree.mods.flags, v, tree);
          tree.sym = v;
+         /* Don't want constant propagation/folding for instance fields of value classes,
+            as these can undergo updates via copy on write.
+         */
          if (tree.init != null) {
              v.flags_field |= HASINIT;
!             if ((v.flags_field & FINAL) != 0 && ((v.flags_field & STATIC) != 0 || !types.isValue(v.owner.type)) &&
                  needsLazyConstValue(tree.init)) {
                  Env<AttrContext> initEnv = getInitEnv(tree, env);
                  initEnv.info.enclVar = v;
                  v.setLazyConstValue(initEnv(tree, initEnv), attr, tree);
              }