• Rollup Version: 1.20.3
• Operating System (or Browser): Windows
• Node Version: v8.11.1

How Do We Reproduce?

Unpack attached example code, run npm install, run
.\node_modules\.bin\rollup -c .\rollup.config.js

See also: ezolenko/rollup-plugin-typescript2#169

Expected Behavior

my-lib.js bundle should look like this:

import { myFn } from './my-tools.js';

console.log(myFn());

Actual Behavior

Contents of my-tools.js gets bundled in.

Reason

Rollup seems to be using resolved import paths as keys without normalizing them, rollup-plugin-typescript2 uses typescript's resolver and returns POXIS path, whatever rollup uses returns Windows paths, so strings are different.

There is an option for rollup-plugin-typescript2 (rollupCommonJSResolveHack: true) to run resolved import through resolve() to get native OS path before returning it to rollup, using that produces correct bundles.

Ideally rollup should just normalize import paths somewhere.