non-definable-global-var.js (1199B)
1 // Copyright (C) 2015 André Bargull. All rights reserved. 2 // This code is governed by the BSD license found in the LICENSE file. 3 4 /*--- 5 es6id: 18.2.1.2 6 description: Throws a TypeError if a global variable cannot be defined. 7 info: | 8 Runtime Semantics: EvalDeclarationInstantiation( body, varEnv, lexEnv, strict) 9 10 ... 11 10. For each d in varDeclarations, do 12 a. If d is a VariableDeclaration or a ForBinding, then 13 i. For each String vn in the BoundNames of d, do 14 1. If vn is not an element of declaredFunctionNames, then 15 a. If varEnvRec is a global Environment Record, then 16 i. Let vnDefinable be varEnvRec.CanDeclareGlobalVar(vn). 17 ii. ReturnIfAbrupt(vnDefinable). 18 iii. If vnDefinable is false, throw TypeError exception. 19 ... 20 flags: [noStrict] 21 ---*/ 22 23 var nonExtensible; 24 try { 25 Object.preventExtensions(this); 26 nonExtensible = !Object.isExtensible(this); 27 } catch (e) { 28 nonExtensible = false; 29 } 30 31 // Run test if global object is non-extensible. 32 if (nonExtensible) { 33 var error; 34 try { 35 eval("var unlikelyVariableName"); 36 } catch (e) { 37 error = e; 38 } 39 40 assert(error instanceof TypeError); 41 } 42 43 reportCompare(0, 0);