Inferred Type for Explicit Cast

[Jonathan Marler via Digitalmars-d]

On Thursday, 18 December 2014 at 23:06:12 UTC, ketmar via 
Digitalmars-d wrote:
> On Thu, 18 Dec 2014 22:46:04 +0000
> Jonathan Marler via Digitalmars-d <digitalmars-d at puremagic.com> 
> wrote:
>
>> What are peoples thoughts on having an inferred type for 
>> "cast"? Good/Bad idea? If good, how helpful would this be? 
>> Would this break existing code somehow? I think this feature 
>> would be a nice added convenience.  Not super helpful but nice 
>> to have.
>> 
>> Here's the details
>> -------------------
>> Typed Cast: cast(T)v
>>    try to cast v to T
>> Type Inferred Cast: cast(auto)v
>>    try to cast v to whatever type is required in the current 
>> context
>> 
>> void foo(string s)
>> {
>>    // ...
>> }
>> void main()
>> {
>>      const(char)[] s = "hello";
>>      foo(cast(string)s); // Current
>>      foo(cast(auto) s);  // The type of the cast is inferred 
>> to be a string
>>      foo(cast() s);      // Another possible syntax
>> }
>> 
>> This would help refactoribility.  If a function argument 
>> changes it's type, and the caller is using a cast, then the 
>> caller's cast type will be updated automatically.  Note that 
>> if it changes to an invalid type, the cast will still fail 
>> like normal.
>
> using casts is a bad practice. and "auto casts" is... i can't 
> even find
> a word. the only thing this will help is to hide bugs, i 
> believe.
>
> please, don't.
>
> nothing personal, i'm just terrified by the idea.

Performing a grep on phobos reveals there are currently almost 
3,000 casts.  I never like to use casts but they are a necessary 
evil.  I think anything D can do to help the programmer get their 
job done is a win.  The initial "pro" I saw for this idea was 
improving refactoribility.  I see this as a huge win.  You claim 
it will hide bugs?  Could you give an example?

When I requested other people to chime in on this idea I was more 
looking for data/examples.  Maybe someone will think of an 
example that shows this idea could encourage bad coding 
practices?  Maybe it will hide bugs?  My point is, I don't want 
to discourage you from providing your opinion, but I  would 
really like to understand where your opinion comes from. I hope 
that wasn't harsh, I've read other posts you've made on the 
forums and although I don't agree with everything you say I would 
value your assessment. Thanks.