Unexpected Remove::rmnsm error when trying to Remove Temporary Symbol - wolfram-mathematica

Question

Good day,
Consider the following:
In[1]:= HoldComplete[With[{line=a},Null]]
Names["`*"]
Attributes/#Names["`*"]
Remove/#Names["`*"]
Out[1]= HoldComplete[With[{line=a},Null]]
Out[2]= {a,line,line$}
Out[3]= {{},{},{Temporary}}
During evaluation of In[1]:= Remove::rmnsm: There are no symbols matching
"line$". >>
Out[4]= {Null,Null,Null}
One can see that Remove::rmnsm message appear although the temporary
Symbol line$ still exists up the that moment. Why this happens?
P.S. I am using Mathematica 7.01. In v.5.2 this message does not appear.

Answer 1

I think what is happening is when you remove the Symbol line then there are no further references to the temporary variable line$ and so it is automagically removed.
In[1]:= HoldComplete[With[{line=a},Null]]
Names["`*"]
Attributes/#Names["`*"]
Out[1]= HoldComplete[With[{line=a},Null]]
Out[2]= {a,line,line$}
Out[3]= {{},{},{Temporary}}
In[4]:= Remove["line"]
In[5]:= Names["`*"]
Out[5]= {a}
This was tested in Mma v8. So maybe the reference counting (or the implementation of localization) has changed slightly since v5?
Note that if you try to remove the temporary symbol first, you get quite an informative warning:
In[6]:= HoldComplete[With[{line=a},Null]]
Names["`*"]
Attributes/#Names["`*"]
Remove/#Reverse#Names["`*"]
Out[6]= HoldComplete[With[{line=a},Null]]
Out[7]= {a,line,line$}
Out[8]= {{},{},{Temporary}}
During evaluation of In[6]:= Remove::relex: Cannot remove lexical symbol
line$ except automatically (when line is removed). >>
Out[9]= {Null,Null,Null}