https://gcc.gnu.org/g:16664bccc9d7b8f40f32f154493723fe285bdc92
commit r16-9626-g16664bccc9d7b8f40f32f154493723fe285bdc92 Author: Odysseas Georgoudis <[email protected]> Date: Sun Jul 26 23:48:20 2026 +0100 c++: Avoid access check for dependent lookup result [PR124983] strip_using_decl turns a dependent typename USING_DECL into a dependent TYPE_DECL. If member lookup finds that declaration while looking for a typo correction, lookup_member can therefore try to perform an access check on it. Access checks for dependent declarations need to wait until substitution, and enforce_access asserts this invariant. Skip the access check whenever the lookup result refers to a member of a dependent scope, not just when it remains a USING_DECL. gcc/cp/ChangeLog: PR c++/124983 * search.cc (lookup_member): Skip access checks for declarations from dependent scope. gcc/testsuite/ChangeLog: PR c++/124983 * g++.dg/template/pr124983.C: New test. Signed-off-by: Odysseas Georgoudis <[email protected]> Co-authored-by: Jason Merrill <[email protected]> (cherry picked from commit 151ded854245c1578706a9da4843f17f55de33d0) Diff: --- gcc/cp/search.cc | 7 +++-- gcc/testsuite/g++.dg/template/pr124983.C | 49 ++++++++++++++++++++++++++++++++ 2 files changed, 53 insertions(+), 3 deletions(-) diff --git a/gcc/cp/search.cc b/gcc/cp/search.cc index e098362fed77..c4c5e0aebecf 100644 --- a/gcc/cp/search.cc +++ b/gcc/cp/search.cc @@ -1277,9 +1277,10 @@ lookup_member (tree xbasetype, tree name, int protect, bool want_type, { tree decl = is_overloaded_fn (rval) ? get_first_fn (rval) : rval; decl = strip_using_decl (decl); - /* A dependent USING_DECL will be checked after tsubsting. */ - if (TREE_CODE (decl) != USING_DECL - && !DECL_IOBJ_MEMBER_FUNCTION_P (decl) + /* A dependent declaration will be checked after tsubsting. */ + if (!dependent_scope_p (DECL_CONTEXT (decl)) + && !(DECL_DECLARES_FUNCTION_P (decl) + && DECL_IOBJ_MEMBER_FUNCTION_P (decl)) && !perform_or_defer_access_check (basetype_path, decl, decl, complain, afi)) return error_mark_node; diff --git a/gcc/testsuite/g++.dg/template/pr124983.C b/gcc/testsuite/g++.dg/template/pr124983.C new file mode 100644 index 000000000000..72819af48c0e --- /dev/null +++ b/gcc/testsuite/g++.dg/template/pr124983.C @@ -0,0 +1,49 @@ +// PR c++/124983 +// { dg-do compile } + +template <class T> +struct A +{ + using typename T::Type; + + void f() + { + this->type(); // { dg-error "no member named 'type'; did you mean 'Type'" } + } +}; + +template <class T> +struct B +{ + typedef typename T::Type Type; + static T Value; + + void f() + { + this->type(); // { dg-error "no member named 'type'; did you mean 'Type'" } + this->value(); // { dg-error "no member named 'value'; did you mean 'Value'" } + } +}; + +struct X +{ + typedef int Type; +}; + +template <class T> +struct C +{ +private: + typedef typename T::Type Type; // { dg-message "declared private" } + static T Value; // { dg-message "declared private" } +}; + +template <class T> +void g() +{ + typename C<T>::Type t; // { dg-error "private within this context" } + (void) C<T>::Value; // { dg-error "private within this context" } + (void) t; +} + +template void g<X>(); // { dg-message "required from here" }
