Re: [PATCH] c++: templated static local var has value-dep addr [PR98930]

[Jason Merrill via Gcc-patches]

On 10/4/21 17:09, Patrick Palka wrote:

Here uses_template_parms is returning false for the dependent type
A<&impl::i>, which causes tsubst_aggr_type to think it's non-dependent
and not bothering substituting into it, leading to breakage.

This patch fixes this by making has_value_dependent_address also return
true for templated static local variables.

Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for
trunk?

OK.

        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.
---
  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(+)
  create mode 100644 gcc/testsuite/g++.dg/cpp1z/nontype4.C
  create mode 100644 gcc/testsuite/g++.dg/cpp1z/nontype4a.C

diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 5e819c9598c..06579e1be07 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -6763,8 +6763,15 @@ 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..3f345b339c6
--- /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> h;
+}
+
+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" }