Hi!
During name lookup, name-lookup.c uses:
if (!(!iter->type && HIDDEN_TYPE_BINDING_P (iter))
&& (bool (want & LOOK_want::HIDDEN_LAMBDA)
|| !is_lambda_ignored_entity (iter->value))
&& qualify_lookup (iter->value, want))
binding = iter->value;
Unfortunately as the following testcase shows, this doesn't work in
generic lambdas, where we on the auto b = ... lambda ICE and on the
auto d = lambda reject it even when it should be valid. The problem
is that the binding doesn't have a FUNCTION_DECL with
LAMBDA_FUNCTION_P for the operator(), but an OVERLOAD with
TEMPLATE_DECL for such FUNCTION_DECL.
The following patch fixes that in is_lambda_ignored_entity, other
possibility would be to do that before calling is_lambda_ignored_entity
in name-lookup.c.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2021-02-25 Jakub Jelinek <ja...@redhat.com>
PR c++/95451
* lambda.c (is_lambda_ignored_entity): Before checking for
FUNCTION_DECL LAMBDA_FUNCTION_P, use OVL_FIRST and STRIP_TEMPLATE.
* g++.dg/cpp1y/lambda-generic-95451.C: New test.
--- gcc/cp/lambda.c.jj 2021-01-04 10:25:48.940119380 +0100
+++ gcc/cp/lambda.c 2021-02-25 17:03:40.099087470 +0100
@@ -1352,6 +1352,8 @@ is_lambda_ignored_entity (tree val)
/* None of the lookups that use qualify_lookup want the op() from the
lambda; they want the one from the enclosing class. */
+ val = OVL_FIRST (val);
+ val = STRIP_TEMPLATE (val);
if (TREE_CODE (val) == FUNCTION_DECL && LAMBDA_FUNCTION_P (val))
return true;
--- gcc/testsuite/g++.dg/cpp1y/lambda-generic-95451.C.jj 2021-02-25
17:11:42.267673666 +0100
+++ gcc/testsuite/g++.dg/cpp1y/lambda-generic-95451.C 2021-02-25
17:10:53.009226742 +0100
@@ -0,0 +1,35 @@
+// PR c++/95451
+// { dg-do run { target c++14 } }
+
+extern "C" void abort ();
+
+struct A {
+ template <typename>
+ void foo ()
+ {
+ auto b = [this] (auto) { return operator () (); } (0);
+ if (b != 3)
+ abort ();
+ auto c = [this] (int) { return operator () (); } (0);
+ if (c != 3)
+ abort ();
+ }
+ void bar ()
+ {
+ auto d = [this] (auto) { return operator () (); } (0);
+ if (d != 3)
+ abort ();
+ auto e = [this] (int) { return operator () (); } (0);
+ if (e != 3)
+ abort ();
+ }
+ int operator () () { return 3; }
+};
+
+int
+main ()
+{
+ A a;
+ a.foo<void> ();
+ a.bar ();
+}
Jakub
