Throw when compiling spread in super() but not classes (#12722)

* Throw when compiling spread in `super()` but not classes

* Add comment

packages/babel-plugin-transform-spread/src/index.js

@@ -97,7 +97,13 @@ export default declare((api, options) => {
 
         const calleePath = skipTransparentExprWrappers(path.get("callee"));
 
-        if (calleePath.isSuper()) return;
+        if (calleePath.isSuper()) {
+          // NOTE: spread and classes have almost the same compat data, so this is very unlikely to happen in practice.
+          throw path.buildCodeFrameError(
+            "It's not possible to compile spread arguments in `super()` without compiling classes.\n" +
+              "Please add '@babel/plugin-transform-classes' to your Babel configuration.",
+          );
+        }
 
         let contextLiteral = scope.buildUndefinedNode();
 

packages/babel-plugin-transform-spread/test/fixtures/spread/super-classes-plugin-after/input.js

@@ -0,0 +1,5 @@
+class A extends B {
+  constructor() {
+    super(...foo);
+  }
+}

packages/babel-plugin-transform-spread/test/fixtures/spread/super-classes-plugin-after/options.json

@@ -0,0 +1,7 @@
+{
+  "plugins": [
+    ["external-helpers", { "helperVersion": "7.100.0" }],
+    "transform-spread",
+    "transform-classes"
+  ]
+}

packages/babel-plugin-transform-spread/test/fixtures/spread/super-classes-plugin-after/output.js

@@ -0,0 +1,14 @@
+let A = /*#__PURE__*/function (_B) {
+  "use strict";
+
+  babelHelpers.inherits(A, _B);
+
+  var _super = babelHelpers.createSuper(A);
+
+  function A() {
+    babelHelpers.classCallCheck(this, A);
+    return _super.call.apply(_super, [this].concat(babelHelpers.toConsumableArray(foo)));
+  }
+
+  return A;
+}(B);

packages/babel-plugin-transform-spread/test/fixtures/spread/super-classes-plugin-before/input.js

@@ -0,0 +1,5 @@
+class A extends B {
+  constructor() {
+    super(...foo);
+  }
+}

packages/babel-plugin-transform-spread/test/fixtures/spread/super-classes-plugin-before/options.json

@@ -0,0 +1,7 @@
+{
+  "plugins": [
+    ["external-helpers", { "helperVersion": "7.100.0" }],
+    "transform-classes",
+    "transform-spread"
+  ]
+}

packages/babel-plugin-transform-spread/test/fixtures/spread/super-classes-plugin-before/output.js

@@ -0,0 +1,14 @@
+let A = /*#__PURE__*/function (_B) {
+  "use strict";
+
+  babelHelpers.inherits(A, _B);
+
+  var _super = babelHelpers.createSuper(A);
+
+  function A() {
+    babelHelpers.classCallCheck(this, A);
+    return _super.call.apply(_super, [this].concat(babelHelpers.toConsumableArray(foo)));
+  }
+
+  return A;
+}(B);

packages/babel-plugin-transform-spread/test/fixtures/spread/super-no-classes-plugin/input.js

@@ -0,0 +1,5 @@
+class A extends B {
+  constructor() {
+    super(...foo);
+  }
+}

packages/babel-plugin-transform-spread/test/fixtures/spread/super-no-classes-plugin/options.json

@@ -0,0 +1,7 @@
+{
+  "plugins": [
+    ["external-helpers", { "helperVersion": "7.100.0" }],
+    "transform-spread"
+  ],
+  "throws": "It's not possible to compile spread arguments in `super()` without compiling classes."
+}