Deprecate implicit `int` to `bool` conversion for integer literals

[H. S. Teoh]

On Tue, Nov 14, 2017 at 11:05:51PM +0000, Michael V. Franklin via Digitalmars-d wrote:
> On Tuesday, 14 November 2017 at 13:54:03 UTC, Steven Schveighoffer wrote:
> 
> > IMO, no character types should implicitly convert from integer
> > types. In fact, character types shouldn't convert from ANYTHING
> > (even other character types). We have so many problems with this.
> 
> Is everyone in general agreement on this?  Can anyone think of a
> compelling use case?
[...]

I am 100% for this change.  I've been bitten before by things like this:

	void myfunc(char ch) { ... }
	void myfunc(int i) { ... }

	char c;
	int i;

	myfunc(c);	// calls first overload
	myfunc('a');	// calls second overload (WAT)
	myfunc(i);	// calls second overload
	myfunc(1);	// calls second overload

There is no compelling use case for implicitly converting char types to
int.  If you want to directly manipulate ASCII values / Unicode code
point values, a direct cast is warranted (clearer code intent).

Converting char to wchar (or dchar, or vice versa, etc.) implicitly is
also fraught with peril: if the char happens to be an upper byte of a
multibyte sequence, you *implicitly* get a garbage value.  Not useful at
all.  Needing to write an explicit cast will remind you to think twice,
which is a good thing.


T

-- 
Famous last words: I wonder what will happen if I do *this*...