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 --git a/gcc/rust/typecheck/rust-tyty-subst.cc b/gcc/rust/typecheck/rust-tyty-subst.cc
index a5d738744fcbf41f7c2146a8acc933841e1e60b2..0e181efb359e64479ef83238351823e50a3b4c1d 100644 (file)
--- 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;