Error: Debug Failure. False expression:

[pelotom]

Hey, your library looks really cool and useful! However when I try to run it on any source file of my library it fails with the following error:

Error: Debug Failure. False expression:
    at Object.assert (/Users/tom/code/runtypes/node_modules/typescript/lib/typescript.js:3259:23)
    at checkElementTypeOfArrayOrString (/Users/tom/code/runtypes/node_modules/typescript/lib/typescript.js:41263:22)
    at checkIteratedTypeOrElementType (/Users/tom/code/runtypes/node_modules/typescript/lib/typescript.js:41107:24)
    at checkRightHandSideOfForOf (/Users/tom/code/runtypes/node_modules/typescript/lib/typescript.js:41097:20)
    at getTypeForVariableLikeDeclaration (/Users/tom/code/runtypes/node_modules/typescript/lib/typescript.js:27680:24)
    at getWidenedTypeForVariableLikeDeclaration (/Users/tom/code/runtypes/node_modules/typescript/lib/typescript.js:27851:24)
    at getTypeOfVariableOrParameterOrProperty (/Users/tom/code/runtypes/node_modules/typescript/lib/typescript.js:27913:28)
    at checkVariableLikeDeclaration (/Users/tom/code/runtypes/node_modules/typescript/lib/typescript.js:40875:41)
    at checkVariableDeclaration (/Users/tom/code/runtypes/node_modules/typescript/lib/typescript.js:40931:20)
    at checkForInOrForOfVariableDeclaration (/Users/tom/code/runtypes/node_modules/typescript/lib/typescript.js:41092:17)
    at checkForOfStatement (/Users/tom/code/runtypes/node_modules/typescript/lib/typescript.js:41014:17)
    at checkSourceElement (/Users/tom/code/runtypes/node_modules/typescript/lib/typescript.js:42693:28)
    at Object.forEach (/Users/tom/code/runtypes/node_modules/typescript/lib/typescript.js:1398:30)
    at checkBlock (/Users/tom/code/runtypes/node_modules/typescript/lib/typescript.js:40557:16)
    at checkSourceElement (/Users/tom/code/runtypes/node_modules/typescript/lib/typescript.js:42677:28)
    at checkFunctionExpressionOrObjectLiteralMethodDeferred (/Users/tom/code/runtypes/node_modules/typescript/lib/typescript.js:38107:21)
    at checkDeferredNodes (/Users/tom/code/runtypes/node_modules/typescript/lib/typescript.js:42763:25)
    at checkSourceFileWorker (/Users/tom/code/runtypes/node_modules/typescript/lib/typescript.js:42798:17)
    at checkSourceFile (/Users/tom/code/runtypes/node_modules/typescript/lib/typescript.js:42777:13)
    at getDiagnosticsWorker (/Users/tom/code/runtypes/node_modules/typescript/lib/typescript.js:42841:17)
    at Object.getDiagnostics (/Users/tom/code/runtypes/node_modules/typescript/lib/typescript.js:42827:24)
    at /Users/tom/code/runtypes/node_modules/typescript/lib/typescript.js:64374:97
    at runWithCancellationToken (/Users/tom/code/runtypes/node_modules/typescript/lib/typescript.js:64347:24)
    at getSemanticDiagnosticsForFile (/Users/tom/code/runtypes/node_modules/typescript/lib/typescript.js:64367:20)
    at /Users/tom/code/runtypes/node_modules/typescript/lib/typescript.js:64314:45
    at Object.forEach (/Users/tom/code/runtypes/node_modules/typescript/lib/typescript.js:1398:30)
    at getDiagnosticsHelper (/Users/tom/code/runtypes/node_modules/typescript/lib/typescript.js:64310:16)
    at Object.getSemanticDiagnostics (/Users/tom/code/runtypes/node_modules/typescript/lib/typescript.js:64322:20)
    at Object.getPreEmitDiagnostics (/Users/tom/code/runtypes/node_modules/typescript/lib/typescript.js:63792:204)
    at Object.<anonymous> (/Users/tom/code/runtypes/node_modules/typings-checker/dist/index.js:33:22)
    at Module._compile (module.js:571:32)
    at Object.Module._extensions..js (module.js:580:10)
    at Module.load (module.js:488:32)
    at tryModuleLoad (module.js:447:12)
    at Function.Module._load (module.js:439:3)
    at Module.runMain (module.js:605:10)
    at run (bootstrap_node.js:418:7)
    at startup (bootstrap_node.js:139:9)
    at bootstrap_node.js:533:3

Any ideas?

[danvk]

Is that the full stack trace? It's all in typescript library code. Would be helpful if we could see where in typings-checker the error is happening.

[pelotom]

Yeah, unfortunately that's all that gets printed out :/

[danvk]

Try this: http://stackoverflow.com/questions/7697038/more-than-10-lines-in-a-node-js-stack-error

[pelotom]

Ah, good trick to know about. I've updated the stack trace.

[danvk]

Are you able to run tsc on your program?

I believe this is the assertion that's failing (would be helpful if you could double-check)

            ts.Debug.assert(languageVersion < 2 /* ES2015 */);

The line in typings-checker is:

var diagnostics = ts.getPreEmitDiagnostics(program);

which I think just type checks your program.

[pelotom]

Yes, tsc works fine.

[danvk]

I'm able to reproduce your problem, but I'm at a loss as to what it means. You might check out https://github.com/Microsoft/dtslint. Its type linter is based on typings-checker, but it's being more actively developed.

[amir-arad]

His all.
This looks like a typescript bug. sometimes typescript language server crashes on stuff it doesnt expect. in the current typescript version (2.4.2) you can get it when you use this expession for example:

function foo<G extends []>(){}

the extends [] crashes the language server. it used to be a lot worse, they're getting much better at this.