[gcc r12-4186] c++: templated static local var has value-dep addr [PR98930]

[gcc r12-4186] c++: templated static local var has value-dep addr [PR98930]

[Patrick Palka]

https://gcc.gnu.org/g:f3930418cb82000fae3cb4e98e870428800cf295

commit r12-4186-gf3930418cb82000fae3cb4e98e870428800cf295
Author: Patrick Palka <ppalka@redhat.com>
Date:   Tue Oct 5 09:50:02 2021 -0400

    c++: templated static local var has value-dep addr [PR98930]
    
    Here uses_template_parms returns false for the dependent type A<&impl::i>,
    which causes tsubst_aggr_type to think it's non-dependent and not bother
    substituting into it, leading to breakage.
    
    This patch fixes this by making has_value_dependent_address also return
    true for templated static local variables.
    
            PR c++/98930
    
    gcc/cp/ChangeLog:
    
            * pt.c (has_value_dependent_address): Return true for a static
            local variable from a function template.
    
    gcc/testsuite/ChangeLog:
    
            * g++.dg/cpp1z/nontype4.C: New test.
            * g++.dg/cpp1z/nontype4a.C: New test.

Diff:
---
 gcc/cp/pt.c                            |  7 +++++++
 gcc/testsuite/g++.dg/cpp1z/nontype4.C  | 14 ++++++++++++++
 gcc/testsuite/g++.dg/cpp1z/nontype4a.C | 14 ++++++++++++++
 3 files changed, 35 insertions(+)

diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 1dcdffe322a..844b7c14fe4 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -6760,8 +6760,15 @@ has_value_dependent_address (tree op)
   if (DECL_P (op))
     {
       tree ctx = CP_DECL_CONTEXT (op);
+
       if (TYPE_P (ctx) && dependent_type_p (ctx))
 	return true;
+
+      if (VAR_P (op)
+	  && TREE_STATIC (op)
+	  && TREE_CODE (ctx) == FUNCTION_DECL
+	  && type_dependent_expression_p (ctx))
+	return true;
     }
 
   return false;
diff --git a/gcc/testsuite/g++.dg/cpp1z/nontype4.C b/gcc/testsuite/g++.dg/cpp1z/nontype4.C
new file mode 100644
index 00000000000..ff476dcf1df
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1z/nontype4.C
@@ -0,0 +1,14 @@
+// PR c++/98930
+// { dg-do compile { target c++17 } }
+
+template<int*>
+struct A { A() { } };
+
+template<class T>
+void impl() {
+  static int i;
+  static A<&i> a;
+}
+
+template void impl<int>();
+template void impl<char>();
diff --git a/gcc/testsuite/g++.dg/cpp1z/nontype4a.C b/gcc/testsuite/g++.dg/cpp1z/nontype4a.C
new file mode 100644
index 00000000000..5b742926b6d
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1z/nontype4a.C
@@ -0,0 +1,14 @@
+// PR c++/98930
+// { dg-do compile { target c++17 } }
+
+template<int*>
+struct A { };
+
+template<class T>
+auto impl() {
+  static int i;
+  return A<&i>();
+}
+
+using type = decltype(impl<int>());
+using type = decltype(impl<char>()); // { dg-error "conflicting declaration" }