I happened to be browsing the standard a bit later and noticed that we
incorrectly reject the example given below.
Bootstrapped on x86_64-pc-linux-gnu; regtesting ongoing but modules.exp
completed with no errors.
-- >8 --
A typedef doesn't create a new entity, and thus should be allowed to be
exported even if it has been previously declared un-exported. See the
example in [module.interface] p6:
export module M;
struct S { int n; };
typedef S S;
export typedef S S; // OK, does not redeclare an entity
PR c++/102341
gcc/cp/ChangeLog:
* decl.cc (duplicate_decls): Allow exporting a redeclaration of
a typedef.
gcc/testsuite/ChangeLog:
* g++.dg/modules/export-1.C: Adjust test.
Signed-off-by: Nathaniel Shead <nathanielosh...@gmail.com>
---
gcc/cp/decl.cc | 5 ++++-
gcc/testsuite/g++.dg/modules/export-1.C | 6 +++++-
2 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index bde9bd79d58..5e175d3e835 100644
--- a/gcc/cp/decl.cc
+++ b/gcc/cp/decl.cc
@@ -2231,7 +2231,10 @@ duplicate_decls (tree newdecl, tree olddecl, bool
hiding, bool was_hidden)
}
tree not_tmpl = STRIP_TEMPLATE (olddecl);
- if (DECL_LANG_SPECIFIC (not_tmpl) && DECL_MODULE_ATTACH_P (not_tmpl))
+ if (DECL_LANG_SPECIFIC (not_tmpl)
+ && DECL_MODULE_ATTACH_P (not_tmpl)
+ /* Typedefs are not entities and so can be exported later. */
+ && TREE_CODE (olddecl) != TYPE_DECL)
{
if (DECL_MODULE_EXPORT_P (STRIP_TEMPLATE (newdecl))
&& !DECL_MODULE_EXPORT_P (not_tmpl))
diff --git a/gcc/testsuite/g++.dg/modules/export-1.C
b/gcc/testsuite/g++.dg/modules/export-1.C
index 3f93814d270..598814370ec 100644
--- a/gcc/testsuite/g++.dg/modules/export-1.C
+++ b/gcc/testsuite/g++.dg/modules/export-1.C
@@ -9,8 +9,12 @@ export int x (); // { dg-error "conflicting exporting for
declaration" }
int y;
export extern int y; // { dg-error "conflicting exporting for declaration" }
+// A typedef is not an entity so the following is OK; see [module.interface]
example 4
typedef int z;
-export typedef int z; // { dg-error "conflicting exporting for declaration" }
+export typedef int z; // { dg-bogus "conflicting exporting for declaration" }
+
+template <typename T> using w = T;
+export template <typename T> using w = T; // { dg-error "conflicting
exporting for declaration" }
template <typename T> int f (T);
export template <typename T> int f (T); // { dg-error "conflicting exporting
for declaration" }
--
2.42.0
