Comment directive activated when longer string used

[houghtonap]

TypeScript Version: typescript@4.0.0-dev.20200526
NodeJS Version: v12.16.2
Visual Studio Code:

Version: 1.45.1 (system setup)
Commit: 5763d909d5f12fe19f215cbfdd29a91c0fa9208a
Date: 2020-05-14T08:27:35.169Z
Electron: 7.2.4
Chrome: 78.0.3904.130
Node.js: 12.8.1
V8: 7.8.279.23-electron.0
OS: Windows_NT x64 6.1.7601

Search Terms: comment directive, @ts-ignore

Code

let obj = { }
// @ts-ignoreThisShouldNotMatchButItDoes
console.log( `obj.a = ${obj.a}` )

Expected behavior:
Property 'a' does not exist on type 'object'.ts(2339)

Actual behavior:
compile time: no 2339 error or indication in VS Code
run time: obj.a = undefined

Description
Visual Studio code and running tsc will produce error 2339 when the comment directive is removed. When adding in the comment // @ts-ignore both Visual Studio code and tsc will ignore the error. However, misspelling ts-ignore as ts-ignoree or ts-ignoreThisShouldNotMatchButItDoes will invoke the @ts-ignore directive and ignore the error.

I didn't test other directives to see whether they had similar issues... trying to keep things simple, but this issue could be symptomatic of all comment directives, assuming they re-use the same code for parsing.

Playground Link: https://www.typescriptlang.org/play/?target=6&jsx=0&ssl=2&ssc=13&pln=2&pc=41#code/DYUwLgBA9gRgVhAvBA3hAvgKAPTYgATAGcBaASwHMA7KAJxABUALMogZSagFdgATAOShgAsgEMwAYyYAhLmACSYACJQQRTBKhUiUUADpgUCgAoIAA1hw9opBAAkKS9fRmIASkxA

Related Issues: None that I could find. Searched under @ts-ignore, comment directive

[RyanCavanaugh]

I suspect we'll need to allow some delimiters; there's probably code like

// @ts-ignore: Doing something sketchy