Summary

Added the new rule noImplicitCoercion, which disallows shorthand type conversions in favor of explicit type conversion functions.

Example (Invalid): Boolean conversion using double negation:

!!foo;
!!(foo + bar);

Example (Invalid): Number conversion using unary operators:

+foo;
-(-foo);
foo - 0;
foo * 1;
foo / 1;

Example (Invalid): String conversion using concatenation:

"" + foo;
foo + "";
`` + foo;
foo += "";

Example (Invalid): Index checking using bitwise NOT:

~foo.indexOf(1);
~foo.bar.indexOf(2);

Example (Valid): Using explicit type conversion functions:

Boolean(foo);
Number(foo);
String(foo);
foo.indexOf(1) !== -1;

Test Plan

Tests are included.

Closes #3935.