Builds failing due tslint crash using nightly build

[DanielRosenwasser]

Looks like it was introduced by 9df1ed4

Repro

1. From an initialized TypeScript repo (i.e. you've already run npm install within it), run npm install typescript@1.8.0-dev.20160114
2. Run jake lint.

Expected: No lint errors.
Actual:

$ jake lint
jake aborted.
TypeError: Cannot read property 'name' of undefined
    at getPropertySymbolsFromBaseTypes (C:\Users\drosen\TypeScript2\node_modules\typescript\lib\typescript.js:49945:73)
    at getPropertySymbolFromTypeReference (C:\Users\drosen\TypeScript2\node_modules\typescript\lib\typescript.js:49970:29)

@yuit can you look into this?

Any fix should also include a revert of 62c3bfb from #6484.

[DanielRosenwasser]

The fix is pretty trivial. Just remove the symbol && in getPropertySymbolsFromBaseTypes and add a guard to the top like

if (!symbol) {
    return;
}

I just don't know what the solid repro would be.

[DickvdBrink]

CC: @adidahiya @jkillian - you might be interested as well

[DanielRosenwasser]

If it helps, it seems to occur when linting src/compiler/utilities.ts and calling getPropertySymbolsFromBaseTypes with "getCanonicalFileName" as a property name.

[jkillian]

Thanks for the heads-up @DickvdBrink. If anything needs changing/investigating in TSLint I'll do it ASAP.

[jkillian]

Made the change suggested by @DanielRosenwasser and added a test case over in #6507.

I reverted 62c3bfb as requested as well, but of course that will make the CI fail for the PR, as the CI is now using the previous nightly which still contains the bug.

[DanielRosenwasser]

Thanks a ton @jkillian we really appreciate it. I'll perform the revert tonight/tomorrow morning.