1. Don't warn about anything not used in the prelude which is autmoatically
injected, accomplished with a test that the span is equal to a dummy span.
2. Don't warn about unused imports from the injected intrinsic module,
accomplished by testing against the name of the imported module
3. If anything is used from a glob import, don't warn about the glob import.
4. If an import imports more than one thing, and none of them are used, only
issue a warning once
Also updated the unused-imports-warn test to have stricter requirements on
error messages.
It looks to me like the string_reader and tt_reader structs are
GC pointers only because they predate the modern borrow system.
This commit leaves the type names string_reader and tt_reader alone
(they still refer to GC-ed pointers), but internally the functions
now use borrowed pointers to refer to these structures. My guess
would be that it's possible to move this change outward and not
use the GCed pointers at all, but that change looks like it could be
a larger one. Actually, I'm delighted at how quick this change was.
Calling it on a special value now causes a failure, however `to_str_radix_special()` is provided which can be
used if those values are expected, and which returns a tupel to allow differentating them.
Also fixed all conflicting calls of the old functions in the rest of the codebase.
The set of string conversion functions for each float type now consists of those items:
- to_str(), converts to number in base 10
- to_str_hex(), converts to number in base 16
- to_str_radix(), converts to number in given radix
- to_str_exact(), converts to number in base 10 with a exact number of trailing digits
- to_str_digits(), converts to number in base 10 with a maximum number of trailing digits
- implementations for to_str::ToStr and num::ToStrRadix
- from_str(), parses a string as number in base 10 including decimal exponent and special values
- from_str_hex(), parses a string as a number in base 16 including binary exponent and special values
- from_str_radix(), parses a string as a number in a given base excluding any exponent and special values
- implementations for from_str::FromStr and num::FromStrRadix
