Bug 143066 – Poor runtime error message dealing with undefined in strict mode compared to non-strict mode

• Status: ASSIGNED
• Component: JavaScriptCore

[Joseph Pecoraro]

* SUMMARY
Very poor runtime error message dealing with undefined in strict mode compared to non-strict mode.

* TEST
<script>
"use strict";
function Foo() {
    this._key = undefined;
    this._key.name = "test";
}
new Foo;
</script>

* NON-STRICT (expected)
[Error] TypeError: undefined is not an object (evaluating 'this._key.name = "test"')

* STRICT (actual)
[Error] TypeError: Attempted to assign to readonly property.

* NOTES
- Because Classes imply strict mode and we've started making heavy use of classes, this will greatly impact us when working on WebInspector.

[Timothy Hatcher]

This stumped me for a while today.

[Saam Barati]

I'll take this