varname alias not allowed?

[Dave Airey]

If I import a dataset with variable "alias" it will not be recognized and gives an error. Furthermore I cannot create a variable named "alias". Is this a bug or intentionally related to fralias? I'm using Stata 18.

[Daniel Feenberg]

Are you sure? Could it be someething else? In Stata 18 I get:

[CODE]
. gen alias=1
. list
+-------+
| alias |
|-------|
1. | 1 |
+-------+
[ /CODE]

Perhaps you could post some details.
I am aware that data types (int, float, etc) are reserved, but I am not aware of any "official" list of reserved words.

[Leonardo Guizzetti]

It seems that -alias- has become a protected name in Stata 18 very likely due to the new frame alias feature? I think this may qualify as a bug because -alias- is not listed in the reserved word list for variable names (-help naming conventions-).

If you try to create the variable directly then you get the following error. I wonder if Stata treats alias a type behind the scenes.

. gen alias = .
type alias not allowed

Edit: crossed with #2. It seems that Daniel and I arrived at conflicting results. I'm using Stata 18 (15may2023) for Windows.

[Dave Airey]

Weird. Thanks both. I'd say this is a bug. I'll send a note to tech support.

[daniel klein]

alias indeed is a (possible) variable type in Stata 18

help dta_120##variabletypes

[Leonardo Guizzetti]

Thank you for highlighting this Daniel. I would still think this is a bug (and perhaps a need to update documentation for the reserved words list).

If -alias- were not intended to be a reserved word, then explicitly setting the variable type should resolve the problem, but it does not. Indeed, all variable types are included as part of the reserved words list.

[daniel klein]

I would still think this is a bug

I am not sure whether I would call it a bug; anyway, the rules for alias seem to be different than those for the other data types. This is most apparent in Mata:

. clear

. mata : (void) st_addvar("byte", "alias")

. describe

Contains data
 Observations:             0                  
    Variables:             1                  
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Variable      Storage   Display    Value
    name         type    format    label      Variable label
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
alias           byte    %8.0g                 
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Sorted by: 
     Note: Dataset has changed since last saved.

. mata : (void) st_addvar("byte", "int")
int invalid varname
r(198);

[Dave Airey]

According to the response from tech support, alias is now a reserved word in Stata version 18 and the documentation will be updated.

[Leonardo Guizzetti]

Thanks for reporting back on the issue. I was uncomfortable with that inconsistency.