[gcc/devel/rust/master] gccrs: Fix nullptr dereference

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

https://gcc.gnu.org/g:e612713029296dac8429e4b00ec7659bcad5cffe

commit e612713029296dac8429e4b00ec7659bcad5cffe
Author: Philip Herron <herron.philip@googlemail.com>
Date:   Tue Jan 31 14:27:49 2023 +0000

    gccrs: Fix nullptr dereference
    
    When we check if this is concrete the guard checks to ensure the argument
    is non null but the check here is wrongly returning early when the check
    is non null meaning when it is null and therefore not concrete it will
    end up doing a null dereference.
    
    Signed-off-by: Philip Herron <herron.philip@googlemail.com>
    
    gcc/rust/ChangeLog:
    
            * typecheck/rust-tyty-subst.cc (SubstitutionArg::is_conrete): fix check

Diff:
---
 gcc/rust/typecheck/rust-tyty-subst.cc | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/gcc/rust/typecheck/rust-tyty-subst.cc b/gcc/rust/typecheck/rust-tyty-subst.cc
index 7f5bb22687d..996bbf2d885 100644
--- a/gcc/rust/typecheck/rust-tyty-subst.cc
+++ b/gcc/rust/typecheck/rust-tyty-subst.cc
@@ -213,8 +213,8 @@ SubstitutionArg::is_error () const
 bool
 SubstitutionArg::is_conrete () const
 {
-  if (argument != nullptr)
-    return true;
+  if (argument == nullptr)
+    return false;
 
   if (argument->get_kind () == TyTy::TypeKind::PARAM)
     return false;