BEFORE:
The following would throw in the dev mode because `f` would return a new array when called by checkNoChanges.
@Component({
template: `
{{f()}}
`
})
class A {
f() { return [1]; }
}
AFTER:
The checkNoChanges function compares only primitives types for equality, and deeply compares iterables. Other objects cannot cause checkNoChanges to throw. This means that the dev mode would never fail given a legal program, but may allow some illegal programs.