deno bundle doesn't resolve conflicting names (ex. Map)

[bxantus]

deno bundle (also Deno.emit with bundle) seems to have broken.

For example when I export a class named Map, it conflicts with the builtin javascript Map type. By conflict I mean, that on each place where I like to use the map data structure, my own Map class will be instantiated (bundle should have renamed it to Map1 or something similar).

Steps to reproduce

I made a minimal example consisting of two files, with which the problem can be easily reproduced:
myMap.ts

export class Map {
    hello() {
        console.log("Hi")
    }
}

test.ts

import { Map as MyMap } from "./myMap.ts"

const map = new MyMap()
map.hello()
const tests = new Map<string, string>()
tests.set("test1", "my test")

When running test via deno run test.ts, I get the correct results:

Hi

But when running, after bundling, the error shows up:

>deno bundle test.ts test.js
Check file:///C:/work/test/test.ts
Bundle file:///C:/work/test/test.ts
Emit "test.js" (153B)

>deno run test.js 
Hi
error: Uncaught TypeError: tests.set is not a function
tests.set("test1", "my test");
      ^
    at file:///C:/work/test/test.js:9:7

test.js

class Map {
    hello() {
        console.log("Hi");
    }
}
const map = new Map();
map.hello();
const tests = new Map();
tests.set("test1", "my test");

Which is obviously incorrect.

Additional details

Deno version: deno 1.14.0

[bxantus]

Update: deno 1.13 isn't affected by this bug (my project and the small test behaves correctly with it too)
test.js with deno 1.13.0

class Map1 {
    hello() {
        console.log("Hi");
    }
}
const map = new Map1();
map.hello();
const tests = new Map();
tests.set("test1", "my test");

[MarkTiedemann]

Seems like this is the same issue: #12086

[kitsonk]

Yes, duplicate of #10286. Previously symbols that shadowed the global scope symbols were being unnecessarily renamed, now they aren't being renamed at all.