Proposal: "void f() { return 7; }" should be illegal

[Denis Koroskin]

On Tue, 29 Sep 2009 15:43:55 +0400, Jason House  
<jason.james.house at gmail.com> wrote:

> bearophile Wrote:
>
>> Don:
>>
>> > In the docs for "return statement" in statement.html it says:
>> > ---
>> > ReturnStatement:
>> >      return;
>> >      return Expression ;
>> >
>> > Expression is allowed even if the function specifies a void return  
>> type.
>> > The Expression will be evaluated, but nothing will be returned.
>>
>> I agree that making the language a little more strict in such regards  
>> is better.
>>
>>
>> > This makes sense for things we definitely want to allow, such as:
>> > void foo() { return bar(); }
>> > where bar() is another void function.
>>
>> If bar() is a void function then "return bar();" looks like a bug. Why  
>> do you want to allow such semantically wrong situation?
>>
>> Bye,
>> bearophile
>
> I believe the argument is to allow templated code to gracefully handle a  
> void return type without special cases. It doesn't quite work since void  
> is not a valid type for intermediate variables (leads to increased code  
> duplication)

Unfortunately, you still have to special-case void type in a lot of cases.  
Here are just 2 examples:

RetType doSomething(Args, RetType)(Args args, RetType retType)
{
     RetType result = callSomeDelegate(args);	// doesn't work for 'void'
     addLogEntry("bla-bla-bla");
     return result;
}

class Test(T)
{
     T foo(T t) { ... }
     T bar() { ... }

     T test()
     {
         return bar(foo()); // works for all types but 'void'
     }
}