Error "'this' implicitly has type 'any'" when used .bind()

› tsc --version
Version 2.7.0-dev.20171020

Code

tsconfig.json:

{
    "compilerOptions": {
        "allowJs": true,
        "checkJs": true,
        "noEmit": true,
        "strict": true
    },
    "files": [
        "index.d.ts",
        "index.js"
    ]
}

index.js:

/** @type {MyObj} */
const o = {
    foo: function() {
        (function() {
            console.log(this); // <- Unexpected error here.
        }.bind(this))();
    }
};

index.d.ts:

interface MyObj {
    foo(this: { a: number }): void;
}

How it looks in the editor:

Context of foo() is defined:

But context passed to the nested function is lost:

Expected behavior:

There should not be error, because this explicitly specified by .bind().

Actual behavior:

› tsc
index.js(5,25): error TS2683: 'this' implicitly has type 'any' because it does not have a type annotation.

[neotan]

I simply tested noImplicitThis: false in TS playground, it seems work

// tsconfig.js

     "noImplicitThis": false,                /* Raise error on 'this' expressions with an implied 'any' type. */

[andy-ms]

It’s possible that we could detect this pattern like we detect IIFEs. A workaround for now might be to use const that = this; instead if your runtime doesn’t yet support arrow functions.