fix(placeholders): improve argument hoist logic

Previous hoist logic would hoist too far and could drop the lifted paths before the declarations they use, causing `ReferenceError`s.

dist/util.js

@@ -60,14 +60,26 @@ function findWrapper(path, noCallee) {
 }
 
 function hoistArguments(t, caller) {
-  const args = caller.get('body.body.0.argument.arguments');
+  var _args;
+
+  let args, upper;
+
+  if (caller.isArrowFunctionExpression()) {
+    args = caller.get('body.body.0.argument.arguments');
+    upper = caller.getStatementParent();
+  } else if (caller.isCallExpression()) {
+    args = caller.get('arguments');
+    upper = caller.findParent(_it2 => {
+      return _it2.isArrowFunctionExpression();
+    }).getStatementParent();
+  }
+
+  if (!((_args = args) === null || _args === void 0 ? void 0 : _args.length)) return;
   args.forEach(arg => {
     if (!shouldHoist(arg)) return;
-    const id = arg.scope.generateUidIdentifier('ref');
-    caller.scope.parent.push({
-      id,
-      init: arg.node
-    });
+    const id = upper.scope.generateUidIdentifier('ref');
+    const ref = t.variableDeclaration('const', [t.variableDeclarator(id, arg.node)]);
+    upper.insertBefore(ref);
     arg.replaceWith(id);
   });
 }

src/util.js

@@ -51,13 +51,27 @@ export function findWrapper (path, noCallee) {
 }
 
 export function hoistArguments (t, caller) {
-  const args = caller.get('body.body.0.argument.arguments')
+  let args, upper
+  if (caller.isArrowFunctionExpression()) {
+    args = caller.get('body.body.0.argument.arguments')
+    upper = caller.getStatementParent()
+  } else if (caller.isCallExpression()) {
+    args = caller.get('arguments')
+    upper = caller
+      .findParent(it.isArrowFunctionExpression())
+      .getStatementParent()
+  }
+
+  if (!args?.length) return
 
   args.forEach(arg => {
     if (!shouldHoist(arg)) return
 
-    const id = arg.scope.generateUidIdentifier('ref')
-    caller.scope.parent.push({ id, init: arg.node })
+    const id = upper.scope.generateUidIdentifier('ref')
+    const ref = t.variableDeclaration('const', [
+      t.variableDeclarator(id, arg.node)
+    ])
+    upper.insertBefore(ref)
     arg.replaceWith(id)
   })
 }

test.js

@@ -199,8 +199,9 @@ test(
     const log = console.log(_, {}, foo(), new Person(), 2, _.bar())
   `,
   $`
-    var _ref = foo(),
-        _ref2 = new Person();
+    const _ref = foo();
+
+    const _ref2 = new Person();
 
     const log = (_arg, _arg2) => {
       return console.log(_arg, {}, _ref, _ref2, 2, _arg2.bar());