isError undefined

Topics: General
Jun 19, 2013 at 10:39 AM
Should I be getting this error from 0.9 (final) in VS on a build?

EXEC : tsc.js(38161, 13) Microsoft JScript runtime error : Unable to get value of the property 'isError': object is null or undefined

Jun 19, 2013 at 2:54 PM
That looks like an internal compiler error. Do you have the code that causes that?
Jun 19, 2013 at 3:16 PM
Edited Jun 19, 2013 at 4:08 PM
I'm upgrading a project from 0.8 to 0.9 and I'm getting the same error in tsc.js:
PullTypeResolver.prototype.isAnyOrEquivalent = function (type) {
              return (type === this.semanticInfoChain.anyTypeSymbol) || type.isError();
It appears that type may be null, so I've "fixed" tsc.js by changing the above to this:
  PullTypeResolver.prototype.isAnyOrEquivalent = function (type) {
              return type !== null && ( (type === this.semanticInfoChain.anyTypeSymbol) || type.isError() );
and then it compiled just fine, and it revealed another minor error in my code (I still had KnockoutObservableAny instead of KnockoutObservable<any> at one place). After fixing this, I was able to undo the change in tsc.js and my project is still compiling.
Jun 20, 2013 at 3:35 AM
Could you create a work item with the code you have that was causing the initial error? Even if your code had a bug we shouldn't be giving errors of this sort.
Jun 20, 2013 at 8:34 AM
Sure, I've managed to narrow it down to only a few lines. See
Jun 20, 2013 at 8:44 AM
For me, this happened when I was moving my codebase into modules. I also noticed the VS interactive errors were out of sync with what a full build reported in the VS Output panel.

I've been using 0.9 since the betas came out, so this wasn't a 0.8=>0.9 thing.

The error went away when I closed and re-opened Visual Studio - so I don't have any code I can give you. It's great @DankoD does.
Jun 21, 2013 at 7:06 AM
I have the same problem. Everything worked with 090 beta and now this error. Because it is a bigger project i am still seeking for the problematic code...