[gcc/devel/rust/master] Merge #1587

[Thomas Schwinge <tschwinge@gcc.gnu.org>]

https://gcc.gnu.org/g:c85492954ded963d937de1fa8731be0718d117eb

commit c85492954ded963d937de1fa8731be0718d117eb
Merge: 84ca2f9123a 9bac2dbfe99
Author: bors[bot] <26634292+bors[bot]@users.noreply.github.com>
Date:   Fri Oct 14 09:31:25 2022 +0000

    Merge #1587
    
    1587: Method resolution must support multiple candidates r=philberty a=philberty
    
    This patch fixes bad method resolution in our operator_overload_9 case.
    When we have a &mut reference to something and we deref we must resolve to
    the mutable reference impl block. The interface we are using to resolve
    methods is the can_eq interface which allows for permissive mutability
    which means allowing for mutable reference being unified with an immutable
    one. This meant we actual match against both the immutable and mutable
    version leading to multiple candidate error.
    
    Fixes #1588
    
    Co-authored-by: Philip Herron <philip.herron@embecosm.com>

Diff:

 gcc/rust/typecheck/rust-autoderef.cc               | 12 +++-
 gcc/rust/typecheck/rust-hir-dot-operator.cc        | 80 ++++++++++++++++++----
 gcc/rust/typecheck/rust-hir-dot-operator.h         | 16 +++--
 .../typecheck/rust-hir-inherent-impl-overlap.h     |  5 +-
 gcc/rust/typecheck/rust-hir-type-check-expr.cc     | 35 ++++++++--
 gcc/rust/typecheck/rust-tyty-cmp.h                 | 14 +++-
 gcc/rust/typecheck/rust-tyty.cc                    | 13 ++++
 gcc/rust/typecheck/rust-tyty.h                     |  5 ++
 gcc/testsuite/rust/compile/generics7.rs            |  6 +-
 .../rust/execute/torture/operator_overload_9.rs    |  2 +-
 10 files changed, 157 insertions(+), 31 deletions(-)