[gcc/devel/rust/master] gccrs: Clear the substitution callbacks when copying ArgumentMappings

[gcc/devel/rust/master] gccrs: Clear the substitution callbacks when copying ArgumentMappings

[Thomas Schwinge]

https://gcc.gnu.org/g:fc6c5f7dc2062d222a99157fb514d71ad87b1b45

commit fc6c5f7dc2062d222a99157fb514d71ad87b1b45
Author: Philip Herron <herron.philip@googlemail.com>
Date:   Fri Jan 27 18:31:11 2023 +0000

    gccrs: Clear the substitution callbacks when copying ArgumentMappings
    
    When we set the callback on substitutions this is not safe to be copied
    around since we store the used argument mappings and can reuse them in
    different contexts. This clears the callback on copy's to make it safer.
    
    Signed-off-by: Philip Herron <herron.philip@googlemail.com>
    
    gcc/rust/ChangeLog:
    
            * typecheck/rust-tyty-subst.cc: update copy constructors

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 a5d738744fc..0e181efb359 100644
--- a/gcc/rust/typecheck/rust-tyty-subst.cc
+++ b/gcc/rust/typecheck/rust-tyty-subst.cc
@@ -241,7 +241,7 @@ SubstitutionArgumentMappings::SubstitutionArgumentMappings (
 SubstitutionArgumentMappings::SubstitutionArgumentMappings (
   const SubstitutionArgumentMappings &other)
   : mappings (other.mappings), binding_args (other.binding_args),
-    locus (other.locus), param_subst_cb (other.param_subst_cb),
+    locus (other.locus), param_subst_cb (nullptr),
     trait_item_flag (other.trait_item_flag)
 {}
 
@@ -252,7 +252,7 @@ SubstitutionArgumentMappings::operator= (
   mappings = other.mappings;
   binding_args = other.binding_args;
   locus = other.locus;
-  param_subst_cb = other.param_subst_cb;
+  param_subst_cb = nullptr;
   trait_item_flag = other.trait_item_flag;
 
   return *this;