v8/test/mjsunit/harmony/block-eval-var-over-let.js
adamk ed18aa65ea Remove support for legacy const, part 1
Now that ES2015 const has shipped, in Chrome 49, legacy const declarations
are no more. This lets us remove a bunch of code from many parts of the
codebase.

In this patch, I remove parser support for generating legacy const variables
from const declarations. This also removes the special "illegal declaration"
bit from Scope, which has ripples into all compiler backends.

Also gone are any tests which relied on legacy const declarations.

Note that we do still generate a Variable in mode CONST_LEGACY in one case:
function name bindings in sloppy mode. The likely fix there is to add a new
Variable::Kind for this case and handle it appropriately for stores in each
backend, but I leave that for a later patch to make this one completely
subtractive.

Review URL: https://codereview.chromium.org/1819123002

Cr-Commit-Position: refs/heads/master@{#35002}
2016-03-22 17:52:13 +00:00

144 lines
2.5 KiB
JavaScript

// Copyright 2015 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Flags: --harmony-sloppy --harmony-sloppy-let --harmony-sloppy-function
// Var-let conflict in a function throws, even if the var is in an eval
// Throws at the top level of a function
assertThrows(function() {
let x = 1;
eval('var x');
}, TypeError);
// If the eval is in its own block scope, throws
assertThrows(function() {
let y = 1;
{ eval('var y'); }
}, TypeError);
// If the let is in its own block scope, with the eval, throws
assertThrows(function() {
{
let x = 1;
eval('var x');
}
}, TypeError);
// Legal if the let is no longer visible
assertDoesNotThrow(function() {
{
let x = 1;
}
eval('var x');
});
// All the same works for const:
// Throws at the top level of a function
assertThrows(function() {
const x = 1;
eval('var x');
}, TypeError);
// If the eval is in its own block scope, throws
assertThrows(function() {
const y = 1;
{ eval('var y'); }
}, TypeError);
// If the const is in its own block scope, with the eval, throws
assertThrows(function() {
{
const x = 1;
eval('var x');
}
}, TypeError);
// Legal if the const is no longer visible
assertDoesNotThrow(function() {
{
const x = 1;
}
eval('var x');
});
// In global scope
let caught = false;
try {
let z = 1;
eval('var z');
} catch (e) {
caught = true;
}
assertTrue(caught);
// Let declarations beyond a function boundary don't conflict
caught = false;
try {
let a = 1;
(function() {
eval('var a');
})();
} catch (e) {
caught = true;
}
assertFalse(caught);
// var across with doesn't conflict
caught = false;
try {
(function() {
with ({x: 1}) {
eval("var x");
}
})();
} catch (e) {
caught = true;
}
assertFalse(caught);
// var can still conflict with let across a with
caught = false;
try {
(function() {
let x;
with ({x: 1}) {
eval("var x");
}
})();
} catch (e) {
caught = true;
}
assertTrue(caught);
// Functions declared in eval also conflict
caught = false
try {
(function() {
{
let x = 1;
eval('function x() {}');
}
})();
} catch (e) {
caught = true;
}
assertTrue(caught);
// TODO(littledan): Hoisting x out of the block should be
// prevented in this case BUG(v8:4479)
caught = false
try {
(function() {
{
let x = 1;
eval('{ function x() {} }');
}
})();
} catch (e) {
caught = true;
}
// TODO(littledan): switch to assertTrue when bug is fixed
assertTrue(caught);