Issue 12484: Section 8.2.1 Type Conformance on page 37 (ocl2-rtf)
Source:  (, )
Nature: Revision
Severity: Critical
Summary: Section 8.2.1 Type Conformance on page 37 [1] Invalid conforms to all other types. context InvalidType inv: Classifier.allInstances()->forAll (c | self.conformsTo (c)) on page 38 [1] Void conforms to all other types. context VoidType inv: Classifier.allinstances()->forAll(c | self.conformsTo(c)) on page 37 [6] The Conforms operation on Types is anti-symmetric context Classifier inv: Classifier.allInstances()-> forAll(12,t2 | t1.conformsTo(t2) and t2.conformsTo(t1) implies t1 = t2) The first invariant yields Classifier.allInstances()->forAll (c | OclInvalid.conformsTo (c)) and thus OclInvalid.conformsTo (OclVoid) The second invariant yields Classifier.allInstances()->forAll (c | OclVoid.conformsTo (c)) and thus OclVoid.conformsTo (OclInvalid) Now the third invariant implies: OclInvalid = OclVoid

Resolution: 
Revised Text: Update Section 8.2.1 Type Conformance as follows:

InvalidType 

[1]  OclInvalid conforms to all other types except OclVoid. 

context InvalidType 
inv: Classifier.allInstances()->forAll (c |
	not c.oclIsTypeOf(OclVoid) implies self.conformsTo (c)) 

VoidType
 
[1]  OclVoid conforms to all other types except OclInvalid. 

context VoidType 
inv: Classifier.allInstances()->forAll (c | 
	not c.oclIsTypeOf(OclInvalid) implies self.conformsTo (c)) 


Actions taken:
May 15, 2008: received issue
October 16, 2009: closed issue
Discussion: 
As in the proposed resolutions of Issues 10433 and 10434, OclVoid and OclInvalid cannot both be the bottom of a lattice-structured type system.  It is better that OclVoid and OclInvalid be defined as conforming to all other types excepting one another.
End of Annotations:=====

m: webmaster@omg.org
Date: 15 May 2008 05:58:13 -0400
To: <issues@omg.org>
Subject: Issue/Bug Report


Name: Peter H. Schmitt 
Company: Universität Karlsruhe 
mailFrom: pschmitt@ira.uka.de 
Notification: Yes 
Specification: Object Constraint Language 
Section: 8.2.1 
FormalNumber: formal/06-05-01 
Version: 2.0 
RevisionDate: 05/01/06 
Page: 37-38 
Nature: Revision 
Severity: Critical 
HTTP User Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.0.6) Gecko/20060728 SUSE/1.5.0.6-1.3 Firefox/1.5.0.6 


Description



Section 8.2.1 Type Conformance on page 37 [1] Invalid conforms to all other types. context InvalidType inv: Classifier.allInstances()->forAll (c | self.conformsTo (c)) on page 38 [1] Void conforms to all other types. context VoidType inv: Classifier.allinstances()->forAll(c | self.conformsTo(c)) on page 37 [6] The Conforms operation on Types is anti-symmetric context Classifier inv: Classifier.allInstances()-> forAll(12,t2 | t1.conformsTo(t2) and t2.conformsTo(t1) implies t1 = t2) The first invariant yields Classifier.allInstances()->forAll (c | OclInvalid.conformsTo (c)) and thus OclInvalid.conformsTo (OclVoid) The second invariant yields Classifier.allInstances()->forAll (c | OclVoid.conformsTo (c)) and thus OclVoid.conformsTo (OclInvalid) Now the third invariant implies: OclInvalid = OclVoid