Is there a reason for default-int?

Ary Borenszweig ary at
Wed Dec 30 18:33:11 PST 2009

Don wrote:
> BCS wrote:
>> Hello Ary,
>>> Don wrote:
>>>> Phil Deets wrote:
>>>>> On Mon, 28 Dec 2009 16:18:46 -0500, Simen kjaeraas
>>>>> <simen.kjaras at> wrote:
>>>>>> Apart from C legacy, is there a reason to assume anything we don't
>>>>>> know what
>>>>>> is, is an int? Shouldn't the compiler instead say 'unknown type' or
>>>>>> something
>>>>>> else that makes sense?
>>>>> C++ abandoned default int. I think it would be best for D to do the
>>>>> same.
>>>> D never had default int. When there's an error, the compiler just has
>>>> to choose *some* type, so that it doesn't crash <g>.
>>> It could be an Error type (that's not an alias for int type) that
>>> don't start to spit errors everywhere and instead just blocks all
>>> further errors on that type.
>> that poses an interesting question: what "type" does this this give?
>> int i;
>> char[] s;
>> int foo(int);
>> char[] foo(int,char[]);
>> int[] foo(char[],int);
>> auto whatType = foo(i ~ s, s);
>> i~s gives the error type but DMD could tell that as long as the other 
>> args are correct, the only foo that works returns a char[] so does the 
>> variable get the error type or char[]?
> Error.

Exactly! You would get an error saying "i ~ s" cannot happen, then it 
resolves to the Error type. Now resolution of "foo" is not done (or yes: 
it defaults to Error) because it has an argument of type Error (one less 
error in the console is shown). Since foo is error, whatType is Error. 
Then if whatType is used it won't trigger errors. Etc.

You would get a single error in the precise position you need to correct 
it, instead of one error hidden with other many unrelated errors.

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