restrict-plus-operands should apply to template strings

[buu700]

Bug Report

• TSLint version: 5.9.1
• TypeScript version: 2.6.2
• Running TSLint via: CLI

TypeScript code being linted

const foo = {balls: 'balls'};

// Accidentally referenced foo instead of foo.balls
const bar = `bar-${foo}`;

with tslint.json configuration:

{
	"rules": {
		"restrict-plus-operands": true
	}
}

Actual behavior

No error is detected, so bar gets set to "bar-[object Object]" instead of the intended "bar-balls".

Expected behavior

Given that the equivalent const bar = 'bar-' + foo; would have been flagged by this rule, it seems logical that the example should be too.

If not by default, it would be nice to have this use case covered either by an optional parameter or by a separate rule.

[OliverJAsh]

I also just ran into this. Would love to see this rule extended to template strings!

[buu700]

Thanks @ColCh (#4807)! This problem was pretty painful.