On Fri, Jun 12, 2026 at 10:01:34PM +0800, Wang Jinghao wrote: > Bootstrapped/regtested on x86_64-pc-linux-gnu. > > -- >8 -- > eval_is_explicit_object_parameter() determines whether a parameter is > an explicit object parameter by checking whether the passed-in tree > node is the first parameter in its parameter chain. As described in > the comment for maybe_update_funtion_parm(), if the sequence is
s/funtion/function/ > declaration -> reflection -> definition, the old PARM_DECL will be > compared against the new PARM_DECL, causing the check to produce an > incorrect result. > Calling maybe_update_function_parm() before the comparison updates > the old reflection to the new PARM_DECL in the chain, thereby > avoiding this error. Thanks, this patch looks good to me (though I can't approve it). eval_has_default_argument uses the same maybe_update_function_parm trick, and so it also can't use const_tree. Since there's the Signed-off-by trailer, I assume you want to contribute this patch under DCO <https://gcc.gnu.org/dco.html>. Thanks, > gcc/cp/ChangeLog: > > * reflect.cc (eval_is_explicit_object_parameter): Call > maybe_update_function_parm before checking the parameter > against DECL_ARGUMENTS. > > gcc/testsuite/ChangeLog: > > * g++.dg/reflect/is_explicit_object_parameter2.C: New test. > > Signed-off-by: Wang Jinghao <[email protected]> > --- > gcc/cp/reflect.cc | 10 ++++++---- > .../reflect/is_explicit_object_parameter2.C | 17 +++++++++++++++++ > 2 files changed, 23 insertions(+), 4 deletions(-) > create mode 100644 > gcc/testsuite/g++.dg/reflect/is_explicit_object_parameter2.C > > diff --git a/gcc/cp/reflect.cc b/gcc/cp/reflect.cc > index 673b79d0bde..2c2a5972222 100644 > --- a/gcc/cp/reflect.cc > +++ b/gcc/cp/reflect.cc > @@ -1828,11 +1828,13 @@ eval_is_data_member_spec (const_tree r, reflect_kind > kind) > object parameter. Otherwise, false. */ > > static tree > -eval_is_explicit_object_parameter (const_tree r, reflect_kind kind) > +eval_is_explicit_object_parameter (tree r, reflect_kind kind) > { > - if (eval_is_function_parameter (r, kind) == boolean_true_node > - && r == DECL_ARGUMENTS (DECL_CONTEXT (r)) > - && DECL_XOBJ_MEMBER_FUNCTION_P (DECL_CONTEXT (r))) > + if (eval_is_function_parameter (r, kind) == boolean_false_node) > + return boolean_false_node; > + r = maybe_update_function_parm (r); > + tree fn = DECL_CONTEXT (r); > + if (r == DECL_ARGUMENTS (fn) && DECL_XOBJ_MEMBER_FUNCTION_P (fn)) > return boolean_true_node; > else > return boolean_false_node; > diff --git a/gcc/testsuite/g++.dg/reflect/is_explicit_object_parameter2.C > b/gcc/testsuite/g++.dg/reflect/is_explicit_object_parameter2.C > new file mode 100644 > index 00000000000..cc24e439bc8 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/reflect/is_explicit_object_parameter2.C > @@ -0,0 +1,17 @@ > +// { dg-do compile { target c++26 } } > +// { dg-additional-options "-freflection" } > +// Test std::meta::is_explicit_object_parameter. > + > +#include <meta> > + > +using namespace std::meta; > + > +struct S { > + void f (this S, int); > +}; > + > +constexpr auto p = parameters_of (^^S::f)[0]; > + > +void S::f (this S, int) {} > + > +static_assert (is_explicit_object_parameter (p)); > -- > 2.52.0 > Marek
