[gcc/devel/rust/master] Merge #1419

[gcc/devel/rust/master] Merge #1419

[Thomas Schwinge]

https://gcc.gnu.org/g:add0846629c918618a0a9196ba62ccb466d05beb

commit add0846629c918618a0a9196ba62ccb466d05beb
Merge: 205096066a5 69430668781
Author: bors[bot] <26634292+bors[bot]@users.noreply.github.com>
Date:   Thu Jul 28 13:15:44 2022 +0000

    Merge #1419
    
    1419: Const checker r=CohenArthur a=CohenArthur
    
    This commit serves as a base to ensure that only the allowed subset of
    the language is called from const contexts. For example, this limits
    function calls to calls to const functions only when in a const context
    
    You can skip reviewing b4864c7e5a59a19fea6203c4b581889d4d6c20a1 as it's the exact same commit cherry-picked from #1415
    
    Co-authored-by: Arthur Cohen <arthur.cohen@embecosm.com>

Diff:

 gcc/rust/Make-lang.in                        |   1 +
 gcc/rust/checks/errors/rust-const-checker.cc | 803 +++++++++++++++++++++++++++
 gcc/rust/checks/errors/rust-const-checker.h  | 183 ++++++
 gcc/rust/checks/errors/rust-unsafe-checker.h |   4 +-
 gcc/rust/hir/rust-ast-lower-expr.h           |  18 +-
 gcc/rust/hir/tree/rust-hir-expr.h            |  20 +-
 gcc/rust/rust-session-manager.cc             |   5 +-
 gcc/rust/util/rust-stacked-contexts.h        |  86 +++
 gcc/testsuite/rust/compile/const1.rs         |   6 +
 gcc/testsuite/rust/compile/const2.rs         |   7 +
 gcc/testsuite/rust/compile/const3.rs         |   7 +
 11 files changed, 1129 insertions(+), 11 deletions(-)