temporarily forbid AssignmentExpression destructuring outside of ExpressionStatement

CHANGELOG.md

@@ -1,3 +1,7 @@
+# 1.12.8
+
+ * Temporarily forbid `AssignmentExpression` destructuring outside of `ExpressionStatement`.
+
 # 1.12.7
 
  * Update to latest `acorn-6to5`.

lib/6to5/transformation/transformers/destructuring.js

@@ -146,6 +146,12 @@ exports.ExpressionStatement = function (node, parent, file, scope) {
   return nodes;
 };
 
+exports.AssignmentExpression = function (node, parent, file) {
+  if (parent.type === "ExpressionStatement") return;
+  if (!t.isPattern(node.left)) return;
+  throw file.errorWithNode(node, "AssignmentExpression destructuring outside of a ExpressionStatement is forbidden due to current limitations");
+};
+
 exports.VariableDeclaration = function (node, parent, file, scope) {
   if (t.isForInStatement(parent) || t.isForOfStatement(parent)) return;
 

test/fixtures/transformation/destructuring/assignment-expression/actual.js

@@ -0,0 +1 @@
+console.log([x] = [123]);

test/fixtures/transformation/destructuring/assignment-expression/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "AssignmentExpression destructuring outside of a ExpressionStatement is forbidden due to current limitations"
+}