gccrs: fix bad projection normalize

[philberty]

What can happen depending on order of operation is that the non trait position projections can resolve to generics where we can attempt to get the underlying type and base the projection on that.

Fixes #4804

gcc/rust/ChangeLog:

* typecheck/rust-type-util.cc (normalize_projection): add check

gcc/testsuite/ChangeLog:

* rust/execute/torture/issue-4808.rs: New test.

[powerboat9]

@philberty is that issue reference in the commit body right? I don't know if the github ui is screwing with me or not.

[powerboat9]

commit 5303115a1d2065e3a896487abc0ed21c26550b77 (super/phil/dev-2)
Author: Philip Herron <herron.philip@googlemail.com>
Date:   Sun Aug 23 13:57:57 2026 +0100

    gccrs: fix bad projection normalize
    
    What can happen depending on order of operation is that the non trait
    position projections can resolve to generics where we can attempt to get
    the underlying type and base the projection on that.
    
    Fixes Rust-GCC/gccrs#4804
    
    gcc/rust/ChangeLog:
    
            * typecheck/rust-type-util.cc (normalize_projection): add check
    
    gcc/testsuite/ChangeLog:
    
            * rust/execute/torture/issue-4804.rs: New test.
    
    Signed-off-by: Philip Herron <herron.philip@googlemail.com>

Thank you github ui.

[philberty]

yeah it was to fix this #4804 where you fixed the lang item lookups

[powerboat9]

The github ui likes to visually replace Rust-GCC/gccrs#4804 with #4804, where upstream wants the former and not the latter.