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digitalmars.D.bugs - alias bug (dmd .121)

reply zwang <nehzgnaw gmail.com> writes:
I'm not sure if this bug was reported before:

<code>
void main(char[][] args){
	alias const char[] CS;
	CS cs = "string";
	switch(args[0]){
	case cs: break;
	}
}
</code>

The code above is equivalent to

<code>
void main(char[][] args){
	const char[] cs = "string";
	switch(args[0]){
	case cs: break;
	}
}
</code>

and should also compile, but dmd reports:
"test.d(4): case must be a string or an integral constant, not cs"
May 01 2005
next sibling parent Thomas Kuehne <thomas-dloop kuehne.thisisspam.cn> writes:
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zwang schrieb am Sun, 01 May 2005 16:32:06 +0800:

 I'm not sure if this bug was reported before:

<code>
 void main(char[][] args){
 	alias const char[] CS;
 	CS cs = "string";
 	switch(args[0]){
 	case cs: break;
 	}
 }
</code>

 The code above is equivalent to

<code>
 void main(char[][] args){
 	const char[] cs = "string";
 	switch(args[0]){
 	case cs: break;
 	}
 }
</code>

 and should also compile, but dmd reports:
 "test.d(4): case must be a string or an integral constant, not cs"


Added to DStress as
http://dstress.kuehne.cn/run/switch_22.d

Thomas


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May 03 2005
prev sibling parent reply "Walter" <newshound digitalmars.com> writes:
"zwang" <nehzgnaw gmail.com> wrote in message
news:d5247u$28ch$2 digitaldaemon.com...

 I'm not sure if this bug was reported before:

 <code>
 void main(char[][] args){
 alias const char[] CS;
 CS cs = "string";
 switch(args[0]){
 case cs: break;
 }
 }
 </code>


[...]

 and should also compile, but dmd reports:
 "test.d(4): case must be a string or an integral constant, not cs"


What's happening here is const is not part of the type (like it is in C++)
but a storage class. Aliases are for types or symbols, not storage classes.
Hence, the 'const' is not part of the alias. The example works if the
declaration is:

    const CS cs = "string";

Not a compiler bug.
May 07 2005
parent reply =?UTF-8?B?VGhvbWFzIEvDvGhuZQ==?= writes:
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Walter wrote:
| "zwang" <nehzgnaw gmail.com> wrote in message
| news:d5247u$28ch$2 digitaldaemon.com...
|
|>I'm not sure if this bug was reported before:
|>
|><code>
|>void main(char[][] args){
|>alias const char[] CS;
|>CS cs = "string";
|>switch(args[0]){
|>case cs: break;
|>}
|>}
|></code>
|
| [...]
|
|>and should also compile, but dmd reports:
|>"test.d(4): case must be a string or an integral constant, not cs"
|
|
| What's happening here is const is not part of the type (like it is in
| C++) but a storage class. Aliases are for types or symbols, not
| storage classes.
| Hence, the 'const' is not part of the alias. The example works if the
| declaration is:
|
|     const CS cs = "string";
|
| Not a compiler bug.

http://digitalmars.com/d/declaration.html
| Declaration:
|		alias Decl
| Decl:
|		StorageClass Decl

Just to make sure:


is the same as


But

isn't the same as


Is this correct?

Thomas
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May 07 2005
parent reply "Walter" <newshound digitalmars.com> writes:
"Thomas Kühne" <thomas-dloop kuehne.THISISSPAM.cn> wrote in message
news:d5kaml$ng6$1 digitaldaemon.com...

 Just to make sure:


 is the same as



Yes. The 'const' is just ignored because it has no meaning when applied to
alias. One could argue this should result in an error message.


 But

 isn't the same as


 Is this correct?


Yes. Here the 'public' applies to the accessibility of x itself, and has
nothing to do with what x is an alias of.
May 08 2005
parent Thomas Kuehne <thomas-dloop kuehne.thisisspam.cn> writes:
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Walter schrieb am Sun, 8 May 2005 02:17:34 -0700:

 "Thomas Kühne" <thomas-dloop kuehne.THISISSPAM.cn> wrote in message
 news:d5kaml$ng6$1 digitaldaemon.com...

 Just to make sure:


 is the same as



 Yes. The 'const' is just ignored because it has no meaning when applied to
 alias. One could argue this should result in an error message.


 But

 isn't the same as


 Is this correct?


 Yes. Here the 'public' applies to the accessibility of x itself, and has
 nothing to do with what x is an alias of.


How about cleaning up the alias syntax?

illegal:




legal:





As a consequence



would be illegal too.

Thomas



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May 11 2005