[gcc/devel/rust/master] Merge #818

[gcc/devel/rust/master] Merge #818

[Thomas Schwinge]

https://gcc.gnu.org/g:0024bc2f028369b871a65ceb11b2fddfb0f9c3aa

commit 0024bc2f028369b871a65ceb11b2fddfb0f9c3aa
Merge: 3b8cbff816c c7af812802f
Author: bors[bot] <26634292+bors[bot]@users.noreply.github.com>
Date:   Fri Nov 26 09:19:08 2021 +0000

    Merge #818
    
    818: Deref operator overloading r=philberty a=philberty
    
    This adds initial support for dereferencing operator overloading. We need to be able
    to use this as part of the autoderef cycle next.
    
    It has two default impl's one for '&T' and '&mut T' to apply genericly.
    The reason it is interesting is from the prototype the deref lang item
    always returns &Self::Target in all cases regardless of mutability, the
    lang item here is designed to wrap up any dereference such that when
    applied it guarentees the type system you will get back an immutable
    reference to something. The reason for doing this is more clear when
    thinking about autoderef and method-resolution and how you apply
    dereference operations to custom types and a test case is included for
    that.
    
    
    Fixes #809
    
    Co-authored-by: Philip Herron <philip.herron@embecosm.com>

Diff:

 gcc/rust/backend/rust-compile-expr.cc              | 37 ++++++++++
 gcc/rust/backend/rust-compile-expr.h               | 21 +-----
 gcc/rust/typecheck/rust-hir-type-check-expr.h      | 33 ++++++++-
 gcc/rust/util/rust-hir-map.h                       |  8 +++
 .../rust/execute/torture/operator_overload_10.rs   | 79 ++++++++++++++++++++++
 .../rust/execute/torture/operator_overload_7.rs    | 44 ++++++++++++
 .../rust/execute/torture/operator_overload_8.rs    | 61 +++++++++++++++++
 .../rust/execute/torture/operator_overload_9.rs    | 61 +++++++++++++++++
 8 files changed, 321 insertions(+), 23 deletions(-)