Thread overview
[Issue 10378] New: Local imports hide local symbols
Jun 16, 2013
Peter Alexander
Jun 16, 2013
Martin Krejcirik
Jun 16, 2013
Peter Alexander
June 16, 2013
http://d.puremagic.com/issues/show_bug.cgi?id=10378

           Summary: Local imports hide local symbols
           Product: D
           Version: D2
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody@puremagic.com
        ReportedBy: peter.alexander.au@gmail.com


--- Comment #0 from Peter Alexander <peter.alexander.au@gmail.com> 2013-06-16 06:51:39 PDT ---
Imports local to a function are able to hide local symbols, which can lead to subtle breakage when libraries change and unexpected behaviour:

void main()
{
    import std.stdio;
    string message = "Hello, world!";
    writeln(message);
}

Here, if a symbol "message" was added to std.stdio then the function would use that message instead of the local message. This could cause subtle breakage when users update to libraries that have added new symbols.

Local imports should behave the same as module-level imports, except the symbols are only visible in the local scope. This prevents any sort of unexpected behaviour without hindering the power of local imports. Ambiguous names can always be disambiguated using full symbol qualification.

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June 16, 2013
http://d.puremagic.com/issues/show_bug.cgi?id=10378


Martin Krejcirik <mk@krej.cz> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |mk@krej.cz
         Resolution|                            |DUPLICATE


--- Comment #1 from Martin Krejcirik <mk@krej.cz> 2013-06-16 19:45:23 CEST ---
*** This issue has been marked as a duplicate of issue 7329 ***

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June 16, 2013
http://d.puremagic.com/issues/show_bug.cgi?id=10378


Peter Alexander <peter.alexander.au@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |REOPENED
         Resolution|DUPLICATE                   |


--- Comment #2 from Peter Alexander <peter.alexander.au@gmail.com> 2013-06-16 11:44:54 PDT ---
Example was invalid, here's a better one:

string message = "Hello, world!";
void main()
{
    import std.stdio;
    writeln(message);
}

Also, re-opening. This isn't a dupe. The other bug is just that the semantics are undocumented, not that the behaviour is incorrect. If the current behaviour is documented then the other bug may be closed, but this bug will still be present, so they are not the same bug.

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