[gcc r14-8408] c++: Handle partial specialisations in GMF [PR113405]

[gcc r14-8408] c++: Handle partial specialisations in GMF [PR113405]

[Nathaniel Shead]

https://gcc.gnu.org/g:6ff54cc0be8dfa9d9bd5922ec65e86c9eb644711

commit r14-8408-g6ff54cc0be8dfa9d9bd5922ec65e86c9eb644711
Author: Nathaniel Shead <nathanieloshead@gmail.com>
Date:   Fri Jan 19 22:24:18 2024 +1100

    c++: Handle partial specialisations in GMF [PR113405]
    
    Currently, when exporting names from the GMF, or within header modules,
    for a set of constrained partial specialisations we only emit the first
    one. This is because the 'type_specialization' list only includes a
    single specialization per template+argument list; constraints are not
    considered here.
    
    The existing code uses a separate 'partial_specializations' list to
    track this instead, but currently it's only used for declarations in the
    module purview. This patch makes use of this list for all declarations.
    
            PR c++/113405
    
    gcc/cp/ChangeLog:
    
            * module.cc (set_defining_module): Track partial specialisations
            for all declarations.
    
    gcc/testsuite/ChangeLog:
    
            * g++.dg/modules/concept-9.h: New test.
            * g++.dg/modules/concept-9_a.C: New test.
            * g++.dg/modules/concept-9_b.C: New test.
            * g++.dg/modules/concept-10_a.H: New test.
            * g++.dg/modules/concept-10_b.C: New test.
    
    Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com>

Diff:
---
 gcc/cp/module.cc                            |  5 ++++-
 gcc/testsuite/g++.dg/modules/concept-10_a.H | 25 +++++++++++++++++++++++++
 gcc/testsuite/g++.dg/modules/concept-10_b.C |  8 ++++++++
 gcc/testsuite/g++.dg/modules/concept-9.h    | 18 ++++++++++++++++++
 gcc/testsuite/g++.dg/modules/concept-9_a.C  | 13 +++++++++++++
 gcc/testsuite/g++.dg/modules/concept-9_b.C  |  8 ++++++++
 6 files changed, 76 insertions(+), 1 deletion(-)

diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc
index 70785493561..f26b2265bce 100644
--- a/gcc/cp/module.cc
+++ b/gcc/cp/module.cc
@@ -18865,8 +18865,11 @@ set_defining_module (tree decl)
   gcc_checking_assert (!DECL_LANG_SPECIFIC (decl)
 		       || !DECL_MODULE_IMPORT_P (decl));
 
-  if (module_has_cmi_p ())
+  if (module_p ())
     {
+      /* We need to track all declarations within a module, not just those
+	 in the module purview, because we don't necessarily know yet if
+	 this module will require a CMI while in the global fragment.  */
       tree ctx = DECL_CONTEXT (decl);
       if (ctx
 	  && (TREE_CODE (ctx) == RECORD_TYPE || TREE_CODE (ctx) == UNION_TYPE)
diff --git a/gcc/testsuite/g++.dg/modules/concept-10_a.H b/gcc/testsuite/g++.dg/modules/concept-10_a.H
new file mode 100644
index 00000000000..c3a5fa727a7
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/concept-10_a.H
@@ -0,0 +1,25 @@
+// Also test header modules
+// PR c++/113405
+// { dg-additional-options "-fmodule-header" }
+// { dg-require-effective-target c++20 }
+// { dg-module-cmi {} }
+
+template <typename>
+concept foo = false;
+
+template <typename>
+concept bar = true;
+
+template <typename T>
+struct corge {};
+
+template <foo F>
+struct corge<F> {};
+
+template <bar B>
+struct corge<B> {
+  using alias = int;
+};
+
+template <typename T>
+using corge_alias = corge<T>::alias;
diff --git a/gcc/testsuite/g++.dg/modules/concept-10_b.C b/gcc/testsuite/g++.dg/modules/concept-10_b.C
new file mode 100644
index 00000000000..67be13d5995
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/concept-10_b.C
@@ -0,0 +1,8 @@
+// PR c++/113405
+// { dg-additional-options "-fmodules-ts" }
+// { dg-require-effective-target c++20 }
+
+import "concept-10_a.H";
+
+struct test {};
+using quux = corge_alias<test>;
diff --git a/gcc/testsuite/g++.dg/modules/concept-9.h b/gcc/testsuite/g++.dg/modules/concept-9.h
new file mode 100644
index 00000000000..1c7f003228c
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/concept-9.h
@@ -0,0 +1,18 @@
+// PR c++/113405
+
+template <typename>
+concept foo = false;
+
+template <typename>
+concept bar = true;
+
+template <typename T>
+struct corge {};
+
+template <foo F>
+struct corge<F> {};
+
+template <bar B>
+struct corge<B> {
+  using alias = int;
+};
diff --git a/gcc/testsuite/g++.dg/modules/concept-9_a.C b/gcc/testsuite/g++.dg/modules/concept-9_a.C
new file mode 100644
index 00000000000..9a055b6dcc9
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/concept-9_a.C
@@ -0,0 +1,13 @@
+// PR c++/113405
+// { dg-additional-options "-fmodules-ts" }
+// { dg-require-effective-target c++20 }
+// { dg-module-cmi M }
+
+module;
+
+#include "concept-9.h"
+
+export module M;
+
+export template<class T>
+using corge_alias = corge<T>::alias;
diff --git a/gcc/testsuite/g++.dg/modules/concept-9_b.C b/gcc/testsuite/g++.dg/modules/concept-9_b.C
new file mode 100644
index 00000000000..55a64a9a413
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/concept-9_b.C
@@ -0,0 +1,8 @@
+// PR c++/113405
+// { dg-additional-options "-fmodules-ts" }
+// { dg-require-effective-target c++20 }
+
+import M;
+
+struct test {};
+using quux = corge_alias<test>;