On 6/5/19 10:17 AM, Richard Sandiford wrote:
Thanks for the patch and sorry that there was no response. I've added the C++ maintainers to cc:
Thanks. In the future, mentioning C++ in the subject line will help me see it.
On 2019-04-08 7:20 p.m., Nicholas Krause wrote:This fixes the caller in tsubst_requires_expr to tsubst_constraint_variables to wrap their respective trees in PARM_CONSTR_PARMS. This is to get the correct parmeter constraints from the tree before calling tsubst_constraint_variables like other callers in constraint.cc and to fix the bug id, 88395 on the gcc bugzilla. OK for merge? Signed-off-by: Nicholas Krause <xerofo...@gmail.com> --- gcc/cp/constraint.cc | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc index 9884eb0db50..a78d0a9a49b 100644 --- a/gcc/cp/constraint.cc +++ b/gcc/cp/constraint.cc @@ -1882,7 +1882,7 @@ tsubst_requires_expr (tree t, tree args, tree parms = TREE_OPERAND (t, 0); if (parms) { - parms = tsubst_constraint_variables (parms, args, complain, in_decl); + parms = tsubst_constraint_variables (PARM_CONSTR_PARMS (parms), args, complain, in_decl);
This change makes the testcase crash immediately because "parms" is a PARM_DECL, not a PARM_CONSTR.
As I just wrote on the PR, the problem in this testcase is that there's a recursive dependency of concepts: operator+= requires Concept, but checking Concept involves calling +=. And so the compiler recurses infinitely and runs out of stack. It would be good to catch this and give a more helpful error, but I don't think it's valid C++.
Jason
