[nem-bug] [Nemerle 0001021]: ICE: ForceUnify failed to unify

[feedback at nemerle.org]

A NOTE has been added to this issue.
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<http://nemerle.org/bugs/view.php?id=1021> 
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Reported By:                Evin Robertson
Assigned To:                
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Project:                    Nemerle
Issue ID:                   1021
Category:                   Compiler (type engine)
Reproducibility:            always
Severity:                   crash
Priority:                   normal
Status:                     new
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Date Submitted:             05-28-2007 05:11 CEST
Last Modified:              06-02-2007 01:25 CEST
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Summary:                    ICE: ForceUnify failed to unify
Description: 
The following program gives an ICE with Nemerle 0.9.3.99.7691:

public class M['S]
{
	
}

public class P['M, 'S] where 'M : M['S]
{
}

public abstract class A['S]
{
	public abstract I['M](_ : P['M, 'S]) : void 
		where 'M : M['S];
}

public class B['S] : A['S]
{
	public override I['M](_ : P['M, 'S]) : void 
		where 'M : M['S]
	{
	}
}
======================================================================

----------------------------------------------------------------------
 Evin Robertson - 06-02-07 01:25 
----------------------------------------------------------------------
I managed to work around the problem by moving the function type parameter
to being a class type parameter.  Clutters the code, but at least it
compiles.

Here's another program giving a different ICE for a function type
parameter (same work-around applies):

public class M['M, 'S] where 'M : M['M, 'S]
{
}

public class F['S]
{
    public I['M](m : 'M) : void
        where 'M : M['M, 'S]
    {
    }
}


error: internal compiler error: assertion ``constraints != null'' failed
in file typing/StaticTyVar.n, line 73
  at Nemerle.Compiler.StaticTyVar.get_LowerBound () [0x000d1] in
/home/evin/nemerle-0.9.3.99.7691/ncc/typing/StaticTyVar.n:81 
  at Nemerle.Compiler.MType.Require (Nemerle.Compiler.MType t) [0x00c4b]
in /home/evin/nemerle-0.9.3.99.7691/ncc/typing/MType.n:379 
  at Nemerle.Compiler.MType.Require (Nemerle.Compiler.TyVar t) [0x0000c]
in /home/evin/nemerle-0.9.3.99.7691/ncc/typing/MType.n:1032 
  at Nemerle.Compiler.TypeInfo+_N__N_l29583_29630.apply_void
(Nemerle.Compiler.StaticTyVar _N_29628, Nemerle.Compiler.TyVar _N_29629)
[0x00000] 
  at
Nemerle.Builtins.FunctionVoid`2[Nemerle.Compiler.StaticTyVar,Nemerle.Compiler.TyVar].apply_void
(Tuple`2 ) [0x00001] in
/home/evin/nemerle-0.9.3.99.7691/lib/internal-numbered.n:124 
  at Nemerle.Collections.List.Iter2[StaticTyVar,TyVar]
(Nemerle.Core.list`1 a, Nemerle.Core.list`1 b,
Nemerle.Builtins.FunctionVoid`2 f) [0x000cd] in
/home/evin/nemerle-0.9.3.99.7691/lib/list.n:977 
  at Nemerle.Compiler.TypeInfo.ConstructSubst (Nemerle.Compiler.TypeInfo
tc, Nemerle.Core.list`1 typarms, Nemerle.Core.list`1 args, Boolean
check_parms) [0x0007f] in
/home/evin/nemerle-0.9.3.99.7691/ncc/hierarchy/TypeInfo.n:657 
  at Nemerle.Compiler.TypeInfo.MakeSubst (Nemerle.Core.list`1 parms)
[0x00001] in /home/evin/nemerle-0.9.3.99.7691/ncc/hierarchy/TypeInfo.n:685

  at Nemerle.Compiler.TyVarEnv._N_type_class81409
(Nemerle.Compiler._N_closure81374 _N_Bind_cp81408,
Nemerle.Compiler.Parsetree.PExpr tyexpr) [0x003a4] in
/home/evin/nemerle-0.9.3.99.7691/ncc/typing/TyVarEnv.n:372 
  at Nemerle.Compiler.TyVarEnv._N_f281403
(Nemerle.Compiler._N_closure81374 _N_Bind_cp81402,
Nemerle.Compiler.Parsetree.PExpr t, Boolean allow_ref) [0x0074d] in
/home/evin/nemerle-0.9.3.99.7691/ncc/typing/TyVarEnv.n:300 
  at Nemerle.Compiler.TyVarEnv+_N_f_81394.apply
(Nemerle.Compiler.Parsetree.PExpr _N_81393) [0x00000] 
  at Nemerle.Compiler.TyVarEnv.Bind (Nemerle.Compiler.GlobalEnv env,
Nemerle.Compiler.TypeBuilder curtc, Nemerle.Compiler.Parsetree.PExpr t,
Boolean allow_tyvars, Boolean check_parms) [0x0003f] in
/home/evin/nemerle-0.9.3.99.7691/ncc/typing/TyVarEnv.n:379 
  at Nemerle.Compiler.TyVarEnv.MonoBind (Nemerle.Compiler.GlobalEnv env,
Nemerle.Compiler.TypeBuilder curtc, Nemerle.Compiler.Parsetree.PExpr t,
Boolean check_parms) [0x00001] in
/home/evin/nemerle-0.9.3.99.7691/ncc/typing/TyVarEnv.n:74 
  at Nemerle.Compiler.TyVarEnv.AddTyparms (Nemerle.Compiler.GlobalEnv env,
Nemerle.Compiler.Parsetree.Typarms tp, Nemerle.Compiler.TypeBuilder curtc,
Boolean check_parms) [0x002d2] in
/home/evin/nemerle-0.9.3.99.7691/ncc/typing/TyVarEnv.n:428 
  at Nemerle.Compiler.TypeBuilder.BindTyparms (Nemerle.Compiler.TyVarEnv
other_tenv, Nemerle.Compiler.Parsetree.Typarms tp) [0x00001] in
/home/evin/nemerle-0.9.3.99.7691/ncc/hierarchy/TypeBuilder.n:1437 
  at Nemerle.Compiler.TypeBuilder.BindTyparms
(Nemerle.Compiler.Parsetree.Typarms tp) [0x00001] in
/home/evin/nemerle-0.9.3.99.7691/ncc/hierarchy/TypeBuilder.n:1431 
  at Nemerle.Compiler.MethodBuilder..ctor (Nemerle.Compiler.TypeBuilder
par, Nemerle.Compiler.Parsetree.Function functionAst, Boolean is_property)
[0x00162] in
/home/evin/nemerle-0.9.3.99.7691/ncc/hierarchy/ClassMembers.n:977

Issue History
Date Modified  Username       Field                    Change              
======================================================================
05-28-07 05:11 Evin Robertson New Issue                                    
06-02-07 01:25 Evin Robertson Note Added: 0001913                          
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