Throw if rest element is not in last position for object expressions

scripts/test262_whitelist.txt

@@ -750,8 +750,6 @@ language/block-scope/syntax/redeclaration/let-declaration-attempt-to-redeclare-w
 language/block-scope/syntax/redeclaration/let-declaration-attempt-to-redeclare-with-async-generator-declaration.js(strict mode)
 language/block-scope/syntax/redeclaration/var-declaration-attempt-to-redeclare-with-async-generator-declaration.js(default)
 language/block-scope/syntax/redeclaration/var-declaration-attempt-to-redeclare-with-async-generator-declaration.js(strict mode)
-language/expressions/assignment/dstr-obj-rest-not-last-element-invalid.js(default)
-language/expressions/assignment/dstr-obj-rest-not-last-element-invalid.js(strict mode)
 language/expressions/async-generator/dflt-params-duplicates.js(default)
 language/expressions/async-generator/early-errors-expression-await-as-function-binding-identifier.js(default)
 language/expressions/async-generator/early-errors-expression-await-as-function-binding-identifier.js(strict mode)
@@ -784,12 +782,8 @@ language/statements/for-await-of/escaped-of.js(default)
 language/statements/for-await-of/escaped-of.js(strict mode)
 language/statements/for-in/decl-async-gen.js(default)
 language/statements/for-in/decl-async-gen.js(strict mode)
-language/statements/for-in/dstr-obj-rest-not-last-element-invalid.js(default)
-language/statements/for-in/dstr-obj-rest-not-last-element-invalid.js(strict mode)
 language/statements/for-of/decl-async-gen.js(default)
 language/statements/for-of/decl-async-gen.js(strict mode)
-language/statements/for-of/dstr-obj-rest-not-last-element-invalid.js(default)
-language/statements/for-of/dstr-obj-rest-not-last-element-invalid.js(strict mode)
 language/statements/if/if-async-gen-else-async-gen.js(default)
 language/statements/if/if-async-gen-else-async-gen.js(strict mode)
 language/statements/if/if-async-gen-else-stmt.js(default)

src/parser/lval.js

@@ -56,26 +56,12 @@ export default class LValParser extends NodeUtils {
 
         case "ObjectExpression":
           node.type = "ObjectPattern";
-          for (const prop of node.properties) {
-            if (prop.type === "ObjectMethod") {
-              if (prop.kind === "get" || prop.kind === "set") {
-                this.raise(
-                  prop.key.start,
-                  "Object pattern can't contain getter or setter",
-                );
-              } else {
-                this.raise(
-                  prop.key.start,
-                  "Object pattern can't contain methods",
-                );
-              }
-            } else {
-              this.toAssignable(
-                prop,
-                isBinding,
-                "object destructuring pattern",
-              );
-            }
+          for (const [index, prop] of node.properties.entries()) {
+            this.toAssignableObjectExpressionProp(
+              prop,
+              isBinding,
+              index === node.properties.length - 1,
+            );
           }
           break;
 
@@ -124,6 +110,28 @@ export default class LValParser extends NodeUtils {
     return node;
   }
 
+  toAssignableObjectExpressionProp(
+    prop: Node,
+    isBinding: ?boolean,
+    isLast: boolean,
+  ) {
+    if (prop.type === "ObjectMethod") {
+      const error =
+        prop.kind === "get" || prop.kind === "set"
+          ? "Object pattern can't contain getter or setter"
+          : "Object pattern can't contain methods";
+
+      this.raise(prop.key.start, error);
+    } else if (prop.type === "SpreadElement" && !isLast) {
+      this.raise(
+        prop.start,
+        "The rest element has to be the last element when destructuring",
+      );
+    } else {
+      this.toAssignable(prop, isBinding, "object destructuring pattern");
+    }
+  }
+
   // Convert list of expression atoms to binding list.
 
   toAssignableList(

src/plugins/estree.js

@@ -317,25 +317,26 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       if (isSimpleProperty(node)) {
         this.toAssignable(node.value, isBinding, contextDescription);
 
-        return node;
-      } else if (node.type === "ObjectExpression") {
-        node.type = "ObjectPattern";
-        for (const prop of node.properties) {
-          if (prop.kind === "get" || prop.kind === "set") {
-            this.raise(
-              prop.key.start,
-              "Object pattern can't contain getter or setter",
-            );
-          } else if (prop.method) {
-            this.raise(prop.key.start, "Object pattern can't contain methods");
-          } else {
-            this.toAssignable(prop, isBinding, "object destructuring pattern");
-          }
-        }
-
         return node;
       }
 
       return super.toAssignable(node, isBinding, contextDescription);
     }
+
+    toAssignableObjectExpressionProp(
+      prop: N.Node,
+      isBinding: ?boolean,
+      isLast: boolean,
+    ) {
+      if (prop.kind === "get" || prop.kind === "set") {
+        this.raise(
+          prop.key.start,
+          "Object pattern can't contain getter or setter",
+        );
+      } else if (prop.method) {
+        this.raise(prop.key.start, "Object pattern can't contain methods");
+      } else {
+        super.toAssignableObjectExpressionProp(prop, isBinding, isLast);
+      }
+    }
   };

test/fixtures/experimental/object-rest-spread/expression-rest-not-last-invalid/actual.js

@@ -0,0 +1 @@
+({...rest, b} = {})

test/fixtures/experimental/object-rest-spread/expression-rest-not-last-invalid/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "The rest element has to be the last element when destructuring (1:2)"
+}