Implement Annex B.3.9 ("Runtime Errors for Function Call Assignment Targets")

acorn-loose/src/expression.js

@@ -9,6 +9,7 @@ lp.checkLVal = function(expr) {
   switch (expr.type) {
   case "Identifier":
   case "MemberExpression":
+  case "CallExpression":
     return expr
 
   case "ParenthesizedExpression":
@@ -551,7 +552,8 @@ lp.initFunction = function(node) {
 // if possible.
 
 lp.toAssignable = function(node, binding) {
-  if (!node || node.type === "Identifier" || (node.type === "MemberExpression" && !binding)) {
+  if (!node || node.type === "Identifier" ||
+    !binding && (node.type === "MemberExpression" || node.type === "CallExpression")) {
     // Okay
   } else if (node.type === "ParenthesizedExpression") {
     this.toAssignable(node.expression, binding)

acorn/src/expression.js

@@ -136,7 +136,7 @@ pp.parseMaybeAssign = function(forInit, refDestructuringErrors, afterLeftParse)
   if (afterLeftParse) left = afterLeftParse.call(this, left, startPos, startLoc)
   if (this.type.isAssign) {
     let node = this.startNodeAt(startPos, startLoc)
-    node.operator = this.value
+    const op = node.operator = this.value
     if (this.type === tt.eq)
       left = this.toAssignable(left, false, refDestructuringErrors)
     if (!ownDestructuringErrors) {
@@ -147,7 +147,7 @@ pp.parseMaybeAssign = function(forInit, refDestructuringErrors, afterLeftParse)
     if (this.type === tt.eq)
       this.checkLValPattern(left)
     else
-      this.checkLValSimple(left)
+      this.checkLValSimple(left, undefined, undefined, op === "??=" || op === "||=" || op === "&&=")
     node.left = left
     this.next()
     node.right = this.parseMaybeAssign(forInit)

acorn/src/lval.js

@@ -75,10 +75,10 @@ pp.toAssignable = function(node, isBinding, refDestructuringErrors) {
       this.raiseRecoverable(node.start, "Optional chaining cannot appear in left-hand side")
       break
 
-    case "MemberExpression":
-      if (!isBinding) break
-
     default:
+      if (!isBinding && (node.type === "MemberExpression" || !this.strict && node.type === "CallExpression")) {
+        break
+      }
       this.raise(node.start, "Assigning to rvalue")
     }
   } else if (refDestructuringErrors) this.checkPatternErrors(refDestructuringErrors, true)
@@ -249,7 +249,7 @@ pp.parseMaybeDefault = function(startPos, startLoc, left) {
 // duplicate argument names. checkClashes is ignored if the provided construct
 // is an assignment (i.e., bindingType is BIND_NONE).
 
-pp.checkLValSimple = function(expr, bindingType = BIND_NONE, checkClashes) {
+pp.checkLValSimple = function(expr, bindingType = BIND_NONE, checkClashes, isLogicalAssignment) {
   const isBind = bindingType !== BIND_NONE
 
   switch (expr.type) {
@@ -278,9 +278,12 @@ pp.checkLValSimple = function(expr, bindingType = BIND_NONE, checkClashes) {
 
   case "ParenthesizedExpression":
     if (isBind) this.raiseRecoverable(expr.start, "Binding parenthesized expression")
-    return this.checkLValSimple(expr.expression, bindingType, checkClashes)
+    return this.checkLValSimple(expr.expression, bindingType, checkClashes, isLogicalAssignment)
 
   default:
+    if (!isBind && !this.strict && !isLogicalAssignment && expr.type === "CallExpression") {
+      break
+    }
     this.raise(expr.start, (isBind ? "Binding" : "Assigning to") + " rvalue")
   }
 }

bin/test262.whitelist

@@ -2,10 +2,3 @@ staging/explicit-resource-management/await-using-in-switch-case-block.js (defaul
 staging/explicit-resource-management/await-using-in-switch-case-block.js (strict mode)
 staging/explicit-resource-management/call-dispose-methods.js (default)
 staging/explicit-resource-management/call-dispose-methods.js (strict mode)
-annexB/language/expressions/assignmenttargettype/callexpression-as-for-in-lhs.js (default)
-annexB/language/expressions/assignmenttargettype/callexpression-as-for-of-lhs.js (default)
-annexB/language/expressions/assignmenttargettype/callexpression-in-compound-assignment.js (default)
-annexB/language/expressions/assignmenttargettype/callexpression-in-prefix-update.js (default)
-annexB/language/expressions/assignmenttargettype/callexpression.js (default)
-annexB/language/expressions/assignmenttargettype/callexpression-in-postfix-update.js (default)
-annexB/language/expressions/assignmenttargettype/cover-callexpression-and-asyncarrowhead.js (default)

test/tests.js

@@ -27170,8 +27170,50 @@ testFail("var x = /[a-z]/\\ux",
 testFail("3 = 4",
          "Assigning to rvalue (1:0)");
 
+test("func() = 4", {
+  "type": "Program",
+  "start": 0,
+  "end": 10,
+  "body": [
+    {
+      "type": "ExpressionStatement",
+      "start": 0,
+      "end": 10,
+      "expression": {
+        "type": "AssignmentExpression",
+        "start": 0,
+        "end": 10,
+        "operator": "=",
+        "left": {
+          "type": "CallExpression",
+          "start": 0,
+          "end": 6,
+          "callee": {
+            "type": "Identifier",
+            "start": 0,
+            "end": 4,
+            "name": "func"
+          },
+          "arguments": []
+        },
+        "right": {
+          "type": "Literal",
+          "start": 9,
+          "end": 10,
+          "value": 4,
+          "raw": "4"
+        }
+      }
+    }
+  ],
+  "sourceType": "script"
+});
+
+testFail("'use strict'; func() = 4",
+         "Assigning to rvalue (1:14)");
+
 testFail("func() = 4",
-         "Assigning to rvalue (1:0)");
+         "Assigning to rvalue (1:0)", {sourceType: "module"});
 
 testFail("(1 + 1) = 10",
          "Assigning to rvalue (1:0)");