minify-type-constructors shouldn’t rewrite `String(symbol)`

Input

var symbol = Symbol();
String(symbol);
// → 'Symbol()'

Current output:

var symbol = Symbol();
symbol+"";
// → throws TypeError: Cannot convert a Symbol value to a string

[mathiasbynens]

Note that String(x) and x + "" (or "" + x) are not equivalent in general. Here’s another snippet that doesn’t use symbols but still produces different output after minification:

var object = {
  toString() { return '33'; },
  valueOf() { return 99; }
};

String(object);
// → '33'

// After minification, this becomes:
object+"";
// → '99'

Another example:

var object = {
  toString() { console.log('toString'); return '33'; },
  valueOf() { console.log('valueOf'); return 99; }
};

String(object);
// 1. logs `toString`
// 2. returns '33'

// After minification, this becomes:
object+"";
// 1. logs `valueOf`
// 2. returns '99'

Here’s a more elaborate example:

var object = {
  toString: _ => { console.log('toString'); return {}; },
  valueOf: _ => { console.log('valueOf'); return {}; }
};

try { String(object); } catch (exception) { console.log(exception); }
// 1. toString
// 2. valueOf
// 3. TypeError: Cannot convert object to primitive value

// After minification, this becomes something like:
try { object+""; } catch (exception) { console.log(exception); }
// 1. valueOf
// 2. toString
// 3. TypeError: Cannot convert object to primitive value

[boopathi]

This is merged and now there is an option to disable only String() type constructors.