[gcc/devel/rust/master] Merge #1220 #1221

[gcc/devel/rust/master] Merge #1220 #1221

[Thomas Schwinge]

https://gcc.gnu.org/g:3b8f3e61394f27100fb788a839e61f8b753f502b

commit 3b8f3e61394f27100fb788a839e61f8b753f502b
Merge: 74e836599ce 224647d24a3 0d8c2984436
Author: bors[bot] <26634292+bors[bot]@users.noreply.github.com>
Date:   Mon May 9 10:11:28 2022 +0000

    Merge #1220 #1221
    
    1220: Ensure the coercion sites are applied correctly on unions r=philberty a=philberty
    
    When we construct a union, we were wrongly compiling the constructor
    without taking into account the associated union index. This meant we
    if you were constructing a union using any other field than the first one
    you had a bad coercion type check resulting in a silent failure of generating
    an error_mark_node.
    
    This was caught using an assertion to ensure there is no error on coercion site but it is valid
    to have errors from coercion sites.
    
    1221: Ensure we don't return error_mark_node for loop expressions r=philberty a=philberty
    
    Loop expressions can return a value even if its a unit-type so we must
    ensure we don't return an error_mark_node for the eventual coercion site
    for the unit-type case.
    
    The offending test-case was: rust/compile/torture/loop7.rs
    
    This was found while fixing #1220
    
    
    Co-authored-by: Philip Herron <philip.herron@embecosm.com>

Diff:

 gcc/rust/backend/rust-compile-expr.h | 80 ++++++++++++++++++++++++------------
 1 file changed, 53 insertions(+), 27 deletions(-)