lexidor
commented
1 year ago Hi, leaving a drive-by comment here.
I do agree that the sentence structure is strange. It reads: No non-x can be implicitly converted to x. which is equivalent to: No value can be implicitly converted to a value of type x.
The sentence All other conversions to type x must be explicit. could then be written as: Converting a value to a value of type x must be done explicitly.
The comment about needing an explicit conversion is correct though. function takes_bool(bool $b): void; can not be called with an int without an explicit conversion. takes_bool((bool) 0) or takes_bool(boolval(0)).
Implicit conversion from classname to string is an example where no explicit conversion is required.
In the section on boolean conversions: https://docs.hhvm.com/hack/types/type-conversion#conversion-to-bool
The first sentence says "No non-bool type can be converted implicitly to bool. All other conversions must be explicit.".
But then the proceeds proceeds to give a long list of implicit conversions.