[nem-bug] [Nemerle 0001040]: Invalid IL generated by block return

[feedback at nemerle.org]

The following issue has been RESOLVED.
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<http://nemerle.org/bugs/view.php?id=1040> 
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Reported By:                Evin Robertson
Assigned To:                divan
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Project:                    Nemerle
Issue ID:                   1040
Category:                   Compiler
Reproducibility:            always
Severity:                   major
Priority:                   normal
Status:                     resolved
Resolution:                 fixed
Fixed in Version:           
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Date Submitted:             08-18-2007 03:41 CEST
Last Modified:              10-20-2007 19:10 CEST
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Summary:                    Invalid IL generated by block return
Description: 
The following program generates invalid IL.  I think the problem is the
unneeded initial ldarg.1

public class InvalidBlockReturn
{
    private static F(x : int, z : ref int) : int
    {
        result:
        {
            z = match(x)
            {
                | 0 =>
                    result(5)
                | _ =>
                    x
            }
            F(x-1, ref z)
        }
    }

    public static Main(_ : array[string]) : void
    {
        mutable z;
        System.Console.WriteLine(F(2, ref z).ToString())
    }
}


I can work around it by declaring a temporary variable to hold the result
of the match and then assigning it to z.

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----------------------------------------------------------------------
 divan - 10-20-07 19:10 
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Fixed on r7819.
It's compile error now, use temporary variable ;)
A bit more about changes:
- now it's wrong to write return/block return as a last statement in
block, it actually doesn't make much sense 
- you can't return in the middle of assignment or another expression
(earlier assignment was an exception, as we can see it's not too cool)
- Wrong return can result in type errors, not "don't use return here",
it's sad
- documentation needs to be fixed, i'll update it soon

Issue History
Date Modified  Username       Field                    Change              
======================================================================
08-18-07 03:41 Evin Robertson New Issue                                    
10-18-07 19:57 divan          Issue Monitored: divan                       
10-19-07 18:42 divan          Status                   new => assigned     
10-19-07 18:42 divan          Assigned To               => divan           
10-20-07 19:10 divan          Note Added: 0001971                          
10-20-07 19:10 divan          Status                   assigned => resolved
10-20-07 19:10 divan          Resolution               open => fixed       
10-20-07 19:10 divan          Description Updated                          
10-20-07 19:10 divan          Additional Information Updated                    
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