On 2/12/25 1:07 PM, Nathaniel Shead wrote:
Bootstrapped and regtested on x86_64-pc-linux-gnu, OK for trunk?
OK.
-- >8 -- There are two separate issues making various template parameters behave as if they were TU-local. Firstly, the TU-local detection code uses WILDCARD_TYPE_P to check for types that are not yet concrete; for some reason UNBOUND_CLASS_TEMPLATE is not on that list. I don't see any particular reason why it shouldn't be, so this patch adds it; this may solve other latent issues as well. Secondly, the TEMPLATE_DECL for a type with expressions involving template template parameters is currently always constrained to internal linkage, because the result does not have TREE_PUBLIC set. Rather than messing with TREE_PUBLIC here, I think rather we just should ensure that we only attempt to constrain visiblity of templates of type, variable, or function decls. PR c++/118846 gcc/cp/ChangeLog: * cp-tree.h (WILDCARD_TYPE_P): Include UNBOUND_CLASS_TEMPLATE. * decl2.cc (min_vis_expr_r): Don't rely on TREE_PUBLIC always being accurate for the DECL_TEMPLATE_RESULT of a template. gcc/testsuite/ChangeLog: * g++.dg/modules/pr118846_a.C: New test. * g++.dg/modules/pr118846_b.C: New test. Signed-off-by: Nathaniel Shead <nathanielosh...@gmail.com> --- gcc/cp/cp-tree.h | 1 + gcc/cp/decl2.cc | 22 ++++++++++++++-------- gcc/testsuite/g++.dg/modules/pr118846_a.C | 18 ++++++++++++++++++ gcc/testsuite/g++.dg/modules/pr118846_b.C | 10 ++++++++++ 4 files changed, 43 insertions(+), 8 deletions(-) create mode 100644 gcc/testsuite/g++.dg/modules/pr118846_a.C create mode 100644 gcc/testsuite/g++.dg/modules/pr118846_b.C diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h index ec976928f5f..3d0349f66a3 100644 --- a/gcc/cp/cp-tree.h +++ b/gcc/cp/cp-tree.h @@ -2325,6 +2325,7 @@ enum languages { lang_c, lang_cplusplus }; || TREE_CODE (T) == TYPENAME_TYPE \ || TREE_CODE (T) == TYPEOF_TYPE \ || TREE_CODE (T) == BOUND_TEMPLATE_TEMPLATE_PARM \ + || TREE_CODE (T) == UNBOUND_CLASS_TEMPLATE \ || TREE_CODE (T) == DECLTYPE_TYPE \ || TREE_CODE (T) == TRAIT_TYPE \ || TREE_CODE (T) == DEPENDENT_OPERATOR_TYPE \ diff --git a/gcc/cp/decl2.cc b/gcc/cp/decl2.cc index 593dcaa4e2d..4415cea93e0 100644 --- a/gcc/cp/decl2.cc +++ b/gcc/cp/decl2.cc @@ -2786,6 +2786,19 @@ min_vis_expr_r (tree *tp, int */*walk_subtrees*/, void *data) tree t = *tp; if (TREE_CODE (t) == PTRMEM_CST) t = PTRMEM_CST_MEMBER (t); + + if (TREE_CODE (t) == TEMPLATE_DECL) + { + if (DECL_ALIAS_TEMPLATE_P (t) || concept_definition_p (t)) + /* FIXME: We don't maintain TREE_PUBLIC / DECL_VISIBILITY for + alias templates so we can't trust it here (PR107906). Ditto + for concepts. */ + return NULL_TREE; + t = DECL_TEMPLATE_RESULT (t); + if (!t) + return NULL_TREE; + } + switch (TREE_CODE (t)) { case CAST_EXPR: @@ -2797,17 +2810,10 @@ min_vis_expr_r (tree *tp, int */*walk_subtrees*/, void *data) case NEW_EXPR: case CONSTRUCTOR: case LAMBDA_EXPR: + case TYPE_DECL: tpvis = type_visibility (TREE_TYPE (t)); break;- case TEMPLATE_DECL:- if (DECL_ALIAS_TEMPLATE_P (t) || concept_definition_p (t)) - /* FIXME: We don't maintain TREE_PUBLIC / DECL_VISIBILITY for - alias templates so we can't trust it here (PR107906). Ditto - for concepts. */ - break; - t = DECL_TEMPLATE_RESULT (t); - /* Fall through. */ case VAR_DECL: case FUNCTION_DECL: if (decl_constant_var_p (t)) diff --git a/gcc/testsuite/g++.dg/modules/pr118846_a.C b/gcc/testsuite/g++.dg/modules/pr118846_a.C new file mode 100644 index 00000000000..bbbdde78457 --- /dev/null +++ b/gcc/testsuite/g++.dg/modules/pr118846_a.C @@ -0,0 +1,18 @@ +// PR c++/118846 +// { dg-additional-options "-fmodules" } +// { dg-module-cmi M } + +export module M; + +template <int N> struct integral_constant { static constexpr int value = N; }; +template <template <class> class> constexpr int cx_count_if() { return 0; } +template <template <class> class P> struct mp_count_if_impl { + using type = integral_constant<cx_count_if<P>()>; +}; + +template <template <class> class> struct consume { + static constexpr bool value = true; +}; +template <class P> struct use { + using type = consume<P::template fn>; +}; diff --git a/gcc/testsuite/g++.dg/modules/pr118846_b.C b/gcc/testsuite/g++.dg/modules/pr118846_b.C new file mode 100644 index 00000000000..a2f28894630 --- /dev/null +++ b/gcc/testsuite/g++.dg/modules/pr118846_b.C @@ -0,0 +1,10 @@ +// PR c++/118846 +// { dg-additional-options "-fmodules" } + +module M; + +template <typename> struct S { + template <typename> struct fn {}; +}; +static_assert(mp_count_if_impl<S>::type::value == 0); +static_assert(use<S<int>>::type::value);
