No error when interface declares a function and property with same name and return type

[mattmccutchen]

TypeScript Version: 2.3.4 (same in 2.4.0-dev.20170601)

Code

interface Oops {
  foo(x: string): number;
  foo: number;
}

Expected behavior:
error TS2300: Duplicate identifier 'foo'.

Actual behavior:
No error.

I bisected using the NPM nightly builds (I ran into build problems trying to bisect from source), and this broke between 1.9.0-dev.20160524-1.0 and 1.9.0-dev.20160525-1.0. I suspect #8696.

[mattmccutchen]

Duplicate of #20826.