Bug 1296814 - Simplify checking of targets within destructuring patterns. r=anba

--HG--
extra : rebase_source : 884c343c765819d09ea7725d0b3c4b6ff2d8cf01

js/src/frontend/Parser.cpp

@@ -4056,22 +4056,23 @@ Parser<FullParseHandler>::checkDestructuringName(ParseNode* expr, Maybe<Declarat
     }
 
     // Otherwise this is an expression in destructuring outside a declaration.
-    if (!reportIfNotValidSimpleAssignmentTarget(expr, KeyedDestructuringAssignment))
-        return false;
-
-    MOZ_ASSERT(!handler.isFunctionCall(expr),
-               "function calls shouldn't be considered valid targets in "
-               "destructuring patterns");
-
     if (handler.isNameAnyParentheses(expr)) {
-        // The arguments/eval identifiers are simple in non-strict mode code.
-        // Warn to discourage their use nonetheless.
-        return reportIfArgumentsEvalTarget(expr);
+        if (const char* chars = handler.nameIsArgumentsEvalAnyParentheses(expr, context)) {
+            if (!reportWithNode(ParseStrictError, pc->sc()->strict(), expr,
+                                JSMSG_BAD_STRICT_ASSIGN, chars))
+            {
+                return false;
+            }
+        }
+
+        return true;
     }
 
-    // Nothing further to do for property accesses.
-    MOZ_ASSERT(handler.isPropertyAccess(expr));
-    return true;
+    if (handler.isPropertyAccess(expr))
+        return true;
+
+    reportWithNode(ParseError, pc->sc()->strict(), expr, JSMSG_BAD_DESTRUCT_TARGET);
+    return false;
 }
 
 template <>
@@ -7778,65 +7779,6 @@ Parser<ParseHandler>::isValidSimpleAssignmentTarget(Node node,
     return false;
 }
 
-template <typename ParseHandler>
-bool
-Parser<ParseHandler>::reportIfArgumentsEvalTarget(Node nameNode)
-{
-    const char* chars = handler.nameIsArgumentsEvalAnyParentheses(nameNode, context);
-    if (!chars)
-        return true;
-
-    bool strict = pc->sc()->strict();
-    if (!reportWithNode(ParseStrictError, strict, nameNode, JSMSG_BAD_STRICT_ASSIGN, chars))
-        return false;
-
-    MOZ_ASSERT(!strict,
-               "an error should have been reported if this was strict mode "
-               "code");
-    return true;
-}
-
-template <typename ParseHandler>
-bool
-Parser<ParseHandler>::reportIfNotValidSimpleAssignmentTarget(Node target, AssignmentFlavor flavor)
-{
-    FunctionCallBehavior behavior = flavor == KeyedDestructuringAssignment
-                                    ? ForbidAssignmentToFunctionCalls
-                                    : PermitAssignmentToFunctionCalls;
-    if (isValidSimpleAssignmentTarget(target, behavior))
-        return true;
-
-    if (handler.isNameAnyParentheses(target)) {
-        // Use a special error if the target is arguments/eval.  This ensures
-        // targeting these names is consistently a SyntaxError (which error numbers
-        // below don't guarantee) while giving us a nicer error message.
-        if (!reportIfArgumentsEvalTarget(target))
-            return false;
-    }
-
-    unsigned errnum = 0;
-    const char* extra = nullptr;
-
-    switch (flavor) {
-      case IncrementAssignment:
-        errnum = JSMSG_BAD_OPERAND;
-        extra = "increment";
-        break;
-
-      case DecrementAssignment:
-        errnum = JSMSG_BAD_OPERAND;
-        extra = "decrement";
-        break;
-
-      case KeyedDestructuringAssignment:
-        errnum = JSMSG_BAD_DESTRUCT_TARGET;
-        break;
-    }
-
-    reportWithNode(ParseError, pc->sc()->strict(), target, errnum, extra);
-    return false;
-}
-
 template <typename ParseHandler>
 bool
 Parser<ParseHandler>::checkAndMarkAsIncOperand(Node target)

js/src/frontend/Parser.h

@@ -1325,12 +1325,6 @@ class Parser final : private JS::AutoGCRooter, public StrictModeGetter
 #endif
     }
 
-    enum AssignmentFlavor {
-        KeyedDestructuringAssignment,
-        IncrementAssignment,
-        DecrementAssignment,
-    };
-
     bool matchInOrOf(bool* isForInp, bool* isForOfp);
 
     bool hasUsedFunctionSpecialName(HandlePropertyName name);
@@ -1370,9 +1364,6 @@ class Parser final : private JS::AutoGCRooter, public StrictModeGetter
                                        FunctionCallBehavior behavior = ForbidAssignmentToFunctionCalls);
 
   private:
-    bool reportIfArgumentsEvalTarget(Node nameNode);
-    bool reportIfNotValidSimpleAssignmentTarget(Node target, AssignmentFlavor flavor);
-
     bool checkAndMarkAsIncOperand(Node kid);
     bool checkStrictAssignment(Node lhs);
     bool checkStrictBinding(PropertyName* name, TokenPos pos);

js/src/js.msg

@@ -206,7 +206,6 @@ MSG_DEF(JSMSG_BAD_GENEXP_BODY,         1, JSEXN_SYNTAXERR, "illegal use of {0} i
 MSG_DEF(JSMSG_BAD_INCOP_OPERAND,       0, JSEXN_SYNTAXERR, "invalid increment/decrement operand")
 MSG_DEF(JSMSG_BAD_METHOD_DEF,          0, JSEXN_SYNTAXERR, "bad method definition")
 MSG_DEF(JSMSG_BAD_OCTAL,               1, JSEXN_SYNTAXERR, "{0} is not a legal ECMA-262 octal constant")
-MSG_DEF(JSMSG_BAD_OPERAND,             1, JSEXN_SYNTAXERR, "invalid {0} operand")
 MSG_DEF(JSMSG_BAD_POW_LEFTSIDE,        0, JSEXN_SYNTAXERR, "unparenthesized unary expression can't appear on the left-hand side of '**'")
 MSG_DEF(JSMSG_BAD_PROP_ID,             0, JSEXN_SYNTAXERR, "invalid property id")
 MSG_DEF(JSMSG_BAD_RETURN_OR_YIELD,     1, JSEXN_SYNTAXERR, "{0} not in function")