inconsistent and misleading error message for type mismatch

[psnider]

The following code:

interface HasDate {date: Date;}
var o : HasDate = {"date": "2014-05-01T14:00:00.000Z"}
var a : HasDate[] = [{"date": "2014-05-01T14:00:00.000Z"}]

when entered into the TypeScript Playground, produces the following errors:

/private/tmp/t.ts(2,5): error TS2012: Cannot convert '{ "date": string; }' to 'HasDate':
    Types of property 'date' of types '{ "date": string; }' and 'HasDate' are incompatible:
        Type 'String' is missing property 'toDateString' from type 'Date'.
/private/tmp/t.ts(3,5): error TS2012: Cannot convert '{}[]' to 'HasDate[]':
    Types of property 'pop' of types '{}[]' and 'HasDate[]' are incompatible:
        Call signatures of types '() => {}' and '() => HasDate' are incompatible:
            Type '{}' is missing property 'date' from type 'HasDate'.

Notice that the error for the plain object is correct, but the error for the array is incorrect and misleading, indicating that the field is missing, not that it is of the wrong type.

Details:

• In line 3 of the second error, "Call signatures of types '() => {}' and '() => HasDate' are incompatible:", the reference "()" is unclear.
• In line 4, "Type '{}' is missing property 'date' from type 'HasDate'.", is incorrect, as the date property is there.
• I would like this second error to be very similar to the first error.

[RyanCavanaugh]

The new compiler generates the error message you asked for.

[psnider]

Which version should I be using?
I have tsc version 1.0.1.0 installed, which appears to be the latest version available via: npm update typescript.

However, when I checked https://github.com/Microsoft/TypeScript/blob/master/package.json,
it shows the version as 1.1.0.

Which version should I use, and how should I install it?
I've assumed that I can get the latest version via npm update.

Thanks for your help.

[DanielRosenwasser]

1.1 is intended to be a faster, better, drop-in replaceable batch compiler, however, we're not officially at 1.1 yet.

On our repository, we have a release-1.1 branch from which you can build the compiler locally. The built compiler will be have path [TypeScript repo path]/built/local/tsc.js.

If you want to use the newly built compiler as your system default (though, as a warning, recall it's not officially released), you'll be able to run the commands jake LKG and npm install -g which will overwrite the older compiler.

If you do choose to use the 1.1 branch for now, we'd love to get your feedback!

[psnider]

Thanks for the information and suggestions.
I installed the 1.1.0.0 compiler, and am using it.

The new compiler found some legitimate errors in my ~10k lines of TypeScript code, which is great!

However, I also encountered an incorrect error message, which I documented here:
version 1.1.0.0: misleading error for incorrectly referenced interface #722

[psnider]

It seems like I've now rebuilt my entire project with the 1.1.0.0 compiler.

FWIW, my project has:

• 36 external modules
• 2700 lines of application code in TypeScript (comments and blank lines stripped)
• 4700 lines of tests in Typescript

The new compiler found two types of errors in my code that has been compiling cleanly using tsc version 1.0.1.0:

• A class and module with the same name
  Reported incorrectly as an error here: version 1.1.0.0: are module and class names colliding? #725
  I had about 10 instances of this problem.
• An interface was defined in one module, but incorrectly referenced on a class in another module.
  The module and class had dissimilar and unrelated names.
  I had 1 instance of this problem.

All of my 180 functional tests pass.
Please thank pass along my thanks to your team for all of their help today.

[DanielRosenwasser]

Glad to hear that we're catching some more issues, and it seems like you've got a good chunk of TypeScript code on your hands, so we hope the new changes give you a much better experience! Always good to hear positive feedback. 😃