c++: ICE when building builtin operator->* set [PR103455]

Here when constructing the builtin operator->* candidate set according
to the available conversion functions for the operand types, we end up
considering a candidate with C1=T (through B's dependent conversion
function) and C2=F, during which we crash from DERIVED_FROM_P because
dependent_type_p sees a TEMPLATE_TYPE_PARM outside of a template
context.

Sidestepping the question of whether we should be considering such a
dependent conversion function here in the first place, it seems futile
to test DERIVED_FROM_P for anything other than an actual class type, so
this patch fixes this ICE by simply guarding the DERIVED_FROM_P test
with CLASS_TYPE_P instead of MAYBE_CLASS_TYPE_P.

	PR c++/103455

gcc/cp/ChangeLog:

	* call.cc (add_builtin_candidate) <case MEMBER_REF>: Test
	CLASS_TYPE_P instead of MAYBE_CLASS_TYPE_P.

gcc/testsuite/ChangeLog:

	* g++.dg/overload/builtin6.C: New test.

diff --git a/gcc/cp/call.cc b/gcc/cp/call.cc
index ec6c5d5..dfe370d 100644 (file)
--- a/gcc/cp/call.cc
+++ b/gcc/cp/call.cc
@@ -2821,7 +2821,7 @@ add_builtin_candidate (struct z_candidate **candidates, enum tree_code code,
          tree c1 = TREE_TYPE (type1);
          tree c2 = TYPE_PTRMEM_CLASS_TYPE (type2);
 
-         if (MAYBE_CLASS_TYPE_P (c1) && DERIVED_FROM_P (c2, c1)
+         if (CLASS_TYPE_P (c1) && DERIVED_FROM_P (c2, c1)
              && (TYPE_PTRMEMFUNC_P (type2)
                  || is_complete (TYPE_PTRMEM_POINTED_TO_TYPE (type2))))
            break;

diff --git a/gcc/testsuite/g++.dg/overload/builtin6.C b/gcc/testsuite/g++.dg/overload/builtin6.C
new file mode 100644 (file)
index 0000000..de192be
--- /dev/null
+++ b/gcc/testsuite/g++.dg/overload/builtin6.C
@@ -0,0 +1,14 @@
+// PR c++/103455
+
+struct A { };
+
+struct B {
+  operator A*() const;
+  template<class T> operator T*() const;
+};
+
+typedef void (A::*F)();
+
+void f(B b, F pmf) {
+  (b->*pmf)();
+}