Fix references to enum values with merging (#16137)

* Add test

* Fix `path.resolve()` usage in enum transform

* Fix references to enum values with merging

* One more test

packages/babel-plugin-transform-typescript/src/enum.ts

@@ -155,7 +155,9 @@ const enumSelfReferenceVisitor = {
 };
 
 export function translateEnumValues(path: NodePath<t.TSEnumDeclaration>, t: t) {
-  const seen: PreviousEnumMembers = new Map();
+  const bindingIdentifier = path.scope.getBindingIdentifier(path.node.id.name);
+  const seen: PreviousEnumMembers = ENUMS.get(bindingIdentifier) ?? new Map();
+
   // Start at -1 so the first enum member is its increment, 0.
   let constValue: number | string | undefined = -1;
   let lastName: string;
@@ -320,15 +322,11 @@ function computeConstantValue(
       }
 
       if (seen.has(path.node)) return;
+      seen.add(path.node);
 
-      const bindingInitPath = path.resolve(); // It only resolves constant bindings
-      if (bindingInitPath) {
-        seen.add(path.node);
-
-        value = computeConstantValue(bindingInitPath, undefined, seen);
-        prevMembers?.set(name, value);
-        return value;
-      }
+      value = computeConstantValue(path.resolve(), prevMembers, seen);
+      prevMembers?.set(name, value);
+      return value;
     }
   }
 

packages/babel-plugin-transform-typescript/test/fixtures/enum/enum-merging-inner-references-shadow/input.ts

@@ -0,0 +1,14 @@
+const Cat = 10;
+const Dog = 20;
+
+enum Animals {
+	Cat = 1
+}
+
+enum Animals {
+	Dog = 2
+}
+
+enum Animals {
+	CatDog =  Cat | Dog
+}

packages/babel-plugin-transform-typescript/test/fixtures/enum/enum-merging-inner-references-shadow/output.js

@@ -0,0 +1,14 @@
+const Cat = 10;
+const Dog = 20;
+var Animals = /*#__PURE__*/function (Animals) {
+  Animals[Animals["Cat"] = 1] = "Cat";
+  return Animals;
+}(Animals || {});
+Animals = /*#__PURE__*/function (Animals) {
+  Animals[Animals["Dog"] = 2] = "Dog";
+  return Animals;
+}(Animals || {});
+Animals = /*#__PURE__*/function (Animals) {
+  Animals[Animals["CatDog"] = 3] = "CatDog";
+  return Animals;
+}(Animals || {});

packages/babel-plugin-transform-typescript/test/fixtures/enum/enum-merging-inner-references/input.ts

@@ -0,0 +1,7 @@
+enum Animals {
+	Cat = 1,
+	Dog = 2
+}
+enum Animals {
+	CatDog =  Cat - Dog
+}

packages/babel-plugin-transform-typescript/test/fixtures/enum/enum-merging-inner-references/output.js

@@ -0,0 +1,9 @@
+var Animals = /*#__PURE__*/function (Animals) {
+  Animals[Animals["Cat"] = 1] = "Cat";
+  Animals[Animals["Dog"] = 2] = "Dog";
+  return Animals;
+}(Animals || {});
+Animals = /*#__PURE__*/function (Animals) {
+  Animals[Animals["CatDog"] = -1] = "CatDog";
+  return Animals;
+}(Animals || {});