PR# 16950 Compiler misses VTGC error when formal constrained by itself and then crashes

Problem Report Summary
Submitter: prestoat2000
Category: Compiler
Priority: Medium
Date: 2010/07/06
Class: Bug
Severity: Serious
Number: 16950
Release: 6.6.83767
Confidential: No
Status: Closed
Environment: Mozilla/5.0 (X11; U; SunOS sun4u; en-US; rv: Gecko/2009042715 Firefox/3.0.10
Synopsis: Compiler misses VTGC error when formal constrained by itself and then crashes

A system has a generic class

  class TEST1 [G -> {G, DOUBLE}]

An entity of type TEST1 [STRING] should be a VTGC error, but the
compiler does not detect it and crashes during degree 2 with a
call on Void target in {CREATE_QUALIFIED}.make_byte_code.

I believe this has the same underlying cause as bug #16948 and
bug #16949.  If the order of the types in the constraint is switched,
then the compiler correctly detects the VTGC error.

Added eweasel test multicon055 for this bug.
To Reproduce
Run eweasel test multicon055.
Problem Report Interactions
From:alexk_es    Date:2010/08/17    Status: Closed    Download   
Added bug#17034 for the attached example.

From:alexk_es    Date:2010/08/17    Download   
Added test#anchor057 for attached test case.

From:alexk_es    Date:2010/08/17    Status: Analyzed    Download   
rev#84192 of EiffelStudio 6.7 fixes test#multicon055.
The attached example still fails for a different reason: it makes sense to create a new bug and a separate eweasel test for it.

From:prestoat2000    Date:2010/07/12    Download   
Here is a more realistic set of classes which demonstrates the
same crash.  Not sure if it needs to be added as a separate eweasel
test (I suspect not).

Attachment: test.e     Size:96
Attachment: test2.e     Size:176
Attachment: parent1.e     Size:19
Attachment: parent2.e     Size:19
Attachment: child.e     Size:43