no-workaround

3 files changed, 1 insertions, 57 deletions

diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc
index 8b20d48dfe3..6387e9a17e2 100644
--- a/gcc/cp/constraint.cc
+++ b/gcc/cp/constraint.cc
@@ -1897,15 +1897,7 @@ satisfy_predicate_constraint (tree t, tree args,
   gcc_assert (TREE_CODE (expr) != EXPR_PACK_EXPANSION);
 
   /* If substitution into the expression fails, the constraint
-     is not satisfied.
-
-     FIXME: There is a (likely) bug related to this substitution.  When a
-     concept check expands to refer to a variable template, this expression
-      may include references to instantiations of those templates.  However,
-      the substitution below fails to preserve those instantiations, and
-      instead creates new uninstantiated specializations, causing the
-      constraint to fail with spurious constexpr errors.  This is explicitly
-      guarded against in tsubst_decl and satisfy_constraint.  */
+     is not satisfied.  */
   expr = tsubst_expr (expr, args, complain, in_decl, false);
   if (expr == error_mark_node)
     return boolean_false_node;
@@ -2169,22 +2161,6 @@ satisfy_constraint_1 (tree t, tree args, tsubst_flags_t complain, tree in_decl)
   return boolean_false_node;
 }
 
-static int eval_constr = 0;
-
-struct evaluating_constraints_sentinel
-{
-  evaluating_constraints_sentinel()
-  {
-    ++eval_constr;
-  }
-
-  ~evaluating_constraints_sentinel()
-  {
-    --eval_constr;
-  }
-};
-
-
 /* Check that the constraint is satisfied, according to the rules
    for that constraint. Note that each satisfy_* function returns
    true or false, depending on whether it is satisfied or not.  */
@@ -2198,9 +2174,6 @@ satisfy_constraint (tree t, tree args)
      to non-dependent terms, so we want to ensure full checking here.  */
   processing_template_decl_sentinel proc (true);
 
-  /* Note that we are evaluating constraints.  */
-  evaluating_constraints_sentinel eval;
-
   /* Avoid early exit in tsubst and tsubst_copy from null args; since earlier
      substitution was done with processing_template_decl forced on, there will
      be expressions that still need semantic processing, possibly buried in
@@ -2346,17 +2319,6 @@ constraint_expression_satisfied_p (tree expr, tree args)
 
 } /* namespace */
 
-/* Returns true when constraints are being evaluated for satisfaction.
-
-   TODO: This is only used in tsubst_decl to guard against a possible
-   bug in specialization registration/lookup for variable templates
-   instantiated during concept expansion.  */
-bool
-evaluating_constraints_p ()
-{
-  return eval_constr;
-}
-
 /*---------------------------------------------------------------------------
                 Semantic analysis of requires-expressions
 ---------------------------------------------------------------------------*/
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 61356bd86b7..2fa894d9433 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -6900,7 +6900,6 @@ extern tree evaluate_variable_concept           (tree, tree);
 extern tree evaluate_constraint_expression      (tree, tree);
 extern bool constraints_satisfied_p             (tree);
 extern bool constraints_satisfied_p             (tree, tree);
-extern bool evaluating_constraints_p            ();
 extern tree lookup_constraint_satisfaction      (tree, tree);
 extern tree memoize_constraint_satisfaction     (tree, tree, tree);
 extern tree lookup_concept_satisfaction         (tree, tree);
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index c8bb57ad984..0e6d36fcaad 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -12314,23 +12314,6 @@ tsubst_decl (tree t, tree args, tsubst_flags_t complain)
 
 	    if (!spec)
 	      {
-                if (evaluating_constraints_p()
-                    && VAR_P (t)
-                    && DECL_TEMPLATE_INSTANTIATED (t))
-                  {
-                    /* If the variable is already an instantiation, there are
-                       no viable substitutions.  We get here during constraint
-                       satisfaction where an expanded concept refers to a
-                       variable template, and later we later re-substitute
-                       in order to evaluate the constraint.
-
-                       FIXME: This seems to be masking a bug where the
-                       specialization lookup below fails for a previously
-                       instantiated variable template.  */
-                    r = t;
-                    break;
-                  }
-
 		tmpl = DECL_TI_TEMPLATE (t);
 		gen_tmpl = most_general_template (tmpl);
 		argvec = tsubst (DECL_TI_ARGS (t), args, complain, in_decl);