[nem-bug] [Nemerle 0000789]: Incorrect type is inferred in lambda expression when iterated list consists of members that support multiple interfaces

[feedback at nemerle.org]

The following issue has been RESOLVED.
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<http://nemerle.org/bugs/view.php?id=789> 
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Reported By:                akhropov
Assigned To:                malekith
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Project:                    Nemerle
Issue ID:                   789
Category:                   Compiler (type engine)
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     resolved
Resolution:                 fixed
Fixed in Version:           
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Date Submitted:             11-16-2006 14:58 CET
Last Modified:              11-20-2006 15:05 CET
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Summary:                    Incorrect type is inferred in lambda expression when
iterated list consists of members that support multiple interfaces
Description: 
The following code:
--------------------------------------------------
interface I1{ f1(x:int):int; }
interface I2{ f2(x:int):int; }

class M1 : I1, I2
{
  public f1(x:int):int {x+1}
  public f2(x:int):int {x+2}
}

class M2 : I1, I2
{
  public f1(x:int):int {x-1}
  public f2(x:int):int {x-2}
}

def x1 = 5;
def Processors = [M1() : I2,M2() : I2];

def y = Processors.Map( m => 
  match(m) {
    | m is M1 => m.f1(x1)
    | m is M2 => m.f2(x1)
    | _ => x1
  } );

System.Console.WriteLine($"y = $y"); 
--------------------------------------------------

results in the following compiler complaints:
--------------------------------------------------
D:\MyProjects\Nemerle>ncc Interfaces.n
Interfaces.n:31:7:31:14:
&http://nemerle.org/bugs/view.php?id=8592;[01;31merror&http://nemerle.org/bugs/view.php?id=8592;[0m:
matched value has
type M1 while the
pattern enforces M2
Interfaces.n:32:7:32:8:
&http://nemerle.org/bugs/view.php?id=8592;[01;33mwarning&http://nemerle.org/bugs/view.php?id=8592;[0m:
this match clause
is unused
Interfaces.n:28:9:28:26:
&http://nemerle.org/bugs/view.php?id=8592;[01;31merror&http://nemerle.org/bugs/view.php?id=8592;[0m:
in argument http://nemerle.org/bugs/view.php?id=1 (f)
of Processors.Map
.[?], needed a I2- -> ?, got M1 -> int-: I2 is not a subtype of M1 [simple
requi
re]
--------------------------------------------------

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----------------------------------------------------------------------
 malekith - 11-20-06 15:05 
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Resolved on trunk r6968.

Issue History
Date Modified  Username       Field                    Change              
======================================================================
11-16-06 14:58 akhropov       New Issue                                    
11-20-06 15:05 malekith       Status                   new => resolved     
11-20-06 15:05 malekith       Resolution               open => fixed       
11-20-06 15:05 malekith       Assigned To               => malekith        
11-20-06 15:05 malekith       Note Added: 0001514                          
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