[nem-bug] [Nemerle 0000655]: Implicit cast not works for generic structs if converted operand has generic parameter type

[feedback at nemerle.org]

The following issue has been SUBMITTED.
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<http://nemerle.org/bugs/view.php?id=655> 
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Reported By:                OysterDva
Assigned To:                
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Project:                    Nemerle
Issue ID:                   655
Category:                   Compiler
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     new
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Date Submitted:             04-11-2006 11:20 CEST
Last Modified:              04-11-2006 11:20 CEST
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Summary:                    Implicit cast not works for generic structs if
converted operand has generic parameter type
Description: 
The following code will not compile:

interface IFoo {}

struct Bar1['a] where 'a : IFoo
{
  static public @:(_ : 'a) : Bar1['a]
  {
    Bar1()
  }
}

struct Bar2 : IFoo {}

def bar : Bar1.[IFoo] = Bar2()

The error message will be: "expected Bar1[IFoo], got Bar2 in type-enforced
expression: Bar2 is not a subtype of Bar1 [simple require]".

However, I'm expecting that implicit cast operator can be used here. For
example, the same C# code compiles without any problems:

interface IFoo {}

struct Bar1<T> where T : IFoo
{
  static public implicit operator Bar1<T>(T obj)
  {
    return new Bar1<T>();
  }
}

struct Bar2 : IFoo {}

class Program
{
  static void Main(string[] args)
  {
    Bar1<IFoo> bar = new Bar2();
  }
}

PS: Actually I want to use the following code:

interface IFoo {}

struct Bar1['a] where 'a : IFoo
{
	static public @:['b](_ : 'b) : Bar1['a] where 'b : IFoo
	{
		Bar1()
	}
}

struct Bar2 : IFoo {}

def bar : Bar1.[IFoo] = Bar2()

Which is seem to be valid but not compiles for the same reason.
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Issue History
Date Modified  Username       Field                    Change              
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04-11-06 11:20 OysterDva      New Issue                                    
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