Fix binding rest element semantics in ES6/ES7+

Fixes acornjs#550 Ref: acornjs#335 (comment)
PrincessEve · May 19, 2017 · d8769e8 · d8769e8
1 parent 79acac0
commit d8769e8
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Showing 4 changed files with 14 additions and 12 deletions.
diff --git a/src/expression.js b/src/expression.js
@@ -405,7 +405,7 @@ pp.parseParenAndDistinguishExpression = function(canBeArrow) {
         break
       } else if (this.type === tt.ellipsis) {
         spreadStart = this.start
-        exprList.push(this.parseParenItem(this.parseRest()))
+        exprList.push(this.parseParenItem(this.parseRest(true)))
         if (this.type === tt.comma) this.raise(this.start, "Comma is not permitted after the rest element")
         break
       } else {

diff --git a/src/lval.js b/src/lval.js
@@ -76,7 +76,7 @@ pp.toAssignableList = function(exprList, isBinding) {
       --end
     }
 
-    if (isBinding && last && last.type === "RestElement" && last.argument.type !== "Identifier")
+    if (this.options.ecmaVersion === 6 && isBinding && last && last.type === "RestElement" && last.argument.type !== "Identifier")
       this.unexpected(last.argument.start)
   }
   for (let i = 0; i < end; i++) {
@@ -95,13 +95,15 @@ pp.parseSpread = function(refDestructuringErrors) {
   return this.finishNode(node, "SpreadElement")
 }
 
-pp.parseRest = function(allowNonIdent) {
+pp.parseRest = function(isBinding) {
   let node = this.startNode()
   this.next()
 
   // RestElement inside of a function parameter must be an identifier
-  if (allowNonIdent) node.argument = this.type === tt.name ? this.parseIdent() : this.unexpected()
-  else node.argument = this.type === tt.name || this.type === tt.bracketL ? this.parseBindingAtom() : this.unexpected()
+  if (this.options.ecmaVersion === 6 && isBinding && this.type !== tt.name)
+    this.unexpected()
+
+  node.argument = this.parseBindingAtom()
 
   return this.finishNode(node, "RestElement")
 }
@@ -128,7 +130,7 @@ pp.parseBindingAtom = function() {
   }
 }
 
-pp.parseBindingList = function(close, allowEmpty, allowTrailingComma, allowNonIdent) {
+pp.parseBindingList = function(close, allowEmpty, allowTrailingComma) {
   let elts = [], first = true
   while (!this.eat(close)) {
     if (first) first = false
@@ -138,7 +140,7 @@ pp.parseBindingList = function(close, allowEmpty, allowTrailingComma, allowNonId
     } else if (allowTrailingComma && this.afterTrailingComma(close)) {
       break
     } else if (this.type === tt.ellipsis) {
-      let rest = this.parseRest(allowNonIdent)
+      let rest = this.parseRest(true)
       this.parseBindingListItem(rest)
       elts.push(rest)
       if (this.type === tt.comma) this.raise(this.start, "Comma is not permitted after the rest element")

diff --git a/src/statement.js b/src/statement.js
@@ -500,7 +500,7 @@ pp.parseFunction = function(node, isStatement, allowExpressionBody, isAsync) {
 
 pp.parseFunctionParams = function(node) {
   this.expect(tt.parenL)
-  node.params = this.parseBindingList(tt.parenR, false, this.options.ecmaVersion >= 8, true)
+  node.params = this.parseBindingList(tt.parenR, false, this.options.ecmaVersion >= 8)
   this.checkYieldAwaitInDefaultParams()
 }
 

diff --git a/test/tests-harmony.js b/test/tests-harmony.js
@@ -10951,7 +10951,7 @@ test("({ x(...[ a, b ]){} })", {
     end: {line: 1, column: 22}
   }
 }, {
-  ecmaVersion: 6,
+  ecmaVersion: 7,
   ranges: true,
   locations: true
 });
@@ -11187,7 +11187,7 @@ test("({ x({ a: { w, x }, b: [y, z] }, ...[a, b, c]){} })", {
     end: {line: 1, column: 51}
   }
 }, {
-  ecmaVersion: 6,
+  ecmaVersion: 7,
   ranges: true,
   locations: true
 });
@@ -12353,7 +12353,7 @@ test("var [a, ...[b, c]] = d", {
     end: {line: 1, column: 22}
   }
 }, {
-  ecmaVersion: 6,
+  ecmaVersion: 7,
   ranges: true,
   locations: true
 });
@@ -13051,7 +13051,7 @@ testFail("([ 5 ]) => {}", "Assigning to rvalue (1:3)", {ecmaVersion: 6});
 
 testFail("({ 5 }) => {}", "Unexpected token (1:5)", {ecmaVersion: 6});
 
-testFail("(...[ 5 ]) => {}", "Unexpected token (1:6)", {ecmaVersion: 6});
+testFail("(...[ 5 ]) => {}", "Unexpected token (1:6)", {ecmaVersion: 7});
 
 test("[...{ a }] = b", {}, {ecmaVersion: 6});