PR# 17297 Incorrect VGCC(6) error in descendant for generic creation with explicit type

Problem Report Summary
Submitter: prestoat2000
Category: Compiler
Priority: Medium
Date: 2011/01/26
Class: Bug
Severity: Serious
Number: 17297
Release: 6.7.85123
Confidential: No
Status: Closed
Environment: Mozilla/5.0 (X11; U; SunOS sun4u; en-US; rv: Gecko/2009042715 Firefox/3.0.10 Solaris 10 on SPARC
Synopsis: Incorrect VGCC(6) error in descendant for generic creation with explicit type

A generic class TEST3 with formal generic G and a function with instructions

   Result := create {G}.default_create
   create {G} Result.default_create

causes the compiler to incorrectly report a VGCC(6) error (and a VGCC(3) error)
in a descendant class if TEST3 inherits from a generic class TEST2 and its
descendant TEST inherits both FOO and TEST2 with a different generic derivation.
If the order of the inheritance clauses in TEST is switched, the compiler does
not report any errors and system execution produces correct output.

I'm not certain that direct and indirect inheritance of a generic class with
different actual generics is valid, but the compiler's behavior definitely
should not depend on the order of inheritance clauses.  Feel free to correct
the test if needed.

Added eweasel test svalid030 for this bug.

To Reproduce
Run eweasel test svalid030.
Problem Report Interactions
From:alexk_es    Date:2018/03/30    Status: Closed    Download   
Starting from rev#101613 of EiffelStudio 18.05, the compiler reports a violation of VHPR(5): different generic derivations are ancestors of the same class.