Error: Debug Failure. at Object.assertDefined at Object.getJSDocHost

[minestarks]

TypeScript Version: 3.1.0-dev.20180925

git clone --depth=1 https://github.com/chemzqm/wept
cd wept
tsc --init
tsc --allowJs --checkJs

Compiler crashes with the callstack:

Error: Debug Failure.
    at Object.assertDefined (node_modules\typescript\lib\tsc.js:1268:24)
    at getJSDocHost (node_modules\typescript\lib\tsc.js:7723:25)
    at getHostSignatureFromJSDoc (node_modules\typescript\lib\tsc.js:7709:46)
    at Object.getParameterSymbolFromJSDoc (node_modules\typescript\lib\tsc.js:7700:20)
    at checkJSDocParameterTag (node_modules\typescript\lib\tsc.js:43646:21)
    at checkSourceElement (node_modules\typescript\lib\tsc.js:45970:28)
    at Object.forEach (node_modules\typescript\lib\tsc.js:169:30)
    at node_modules\typescript\lib\tsc.js:45896:31
    at Object.forEach (node_modules\typescript\lib\tsc.js:169:30)
    at checkSourceElement (node_modules\typescript\lib\tsc.js:45894:20)

[RyanCavanaugh]

Also repros on 3.0

[RyanCavanaugh]

Minimal repro

if (false) {
	/**
	 * @param {string} s
	 */
	const x = function (s) {
	};
}

The if expression has to be false 🤷‍♂️

[sandersn]

Parent pointers aren't filled in for the @param tag. Pretty sure this is supposed to happen in the parser.

[sandersn]

Introduced in 2.9

[sandersn]

Specifically, bisecting leads to #23947, which was a fairly large change that added @callback and corrected handling of @template in conjunction with jsdoc type aliases.

[sandersn]

In the binder, unreachable code mistakenly skips the bindJSDoc call in bindChildrenWorker, which sets parent pointers. That's why it has to be if (false) and not if (!!false), for example.

[ghost]

@sandersn Should this be closed?

[sandersn]

Yes, not sure why github didn't catch it.