Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK
for trunk? This fixes PR115358 whose testcase used a constexpr static
array variable, but it seems the general issue is not specific to
constexpr as illustrated by the below testcase. Note that Clang
currently rejects the testcase for a similar reason to GCC...
-- >8 --
For a non-dependent array variable of unknown bound, it seems we need to
try instantiating its definition upon use in a template context for sake
of proper checking and typing of its expression context. This seems
analogous to deducing the return type of a function which is similarly
done upon first use even in a template context.
PR c++/115358
gcc/cp/ChangeLog:
* decl2.cc (mark_used): Call maybe_instantiate_decl for an array
variable with unknown bound.
* semantics.cc (finish_decltype_type): Remove now redundant
handling of array variables with unknown bound.
* typeck.cc (cxx_sizeof_expr): Likewise.
gcc/testsuite/ChangeLog:
* g++.dg/template/array37.C: New test.
---
gcc/cp/decl2.cc | 2 ++
gcc/cp/semantics.cc | 7 -------
gcc/cp/typeck.cc | 7 -------
gcc/testsuite/g++.dg/template/array37.C | 16 ++++++++++++++++
4 files changed, 18 insertions(+), 14 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/template/array37.C
diff --git a/gcc/cp/decl2.cc b/gcc/cp/decl2.cc
index 6c3ef60d51f..cdd2b8aada2 100644
--- a/gcc/cp/decl2.cc
+++ b/gcc/cp/decl2.cc
@@ -6001,6 +6001,8 @@ mark_used (tree decl, tsubst_flags_t complain /* =
tf_warning_or_error */)
find out its type. For OpenMP user defined reductions, we need them
instantiated for reduction clauses which inline them by hand directly. */
if (undeduced_auto_decl (decl)
+ || (VAR_P (decl)
+ && VAR_HAD_UNKNOWN_BOUND (decl))
|| (TREE_CODE (decl) == FUNCTION_DECL
&& DECL_OMP_DECLARE_REDUCTION_P (decl)))
maybe_instantiate_decl (decl);
diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
index b4f626924af..3247521e03e 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -12002,13 +12002,6 @@ finish_decltype_type (tree expr, bool
id_expression_or_member_access_p,
return error_mark_node;
}
- /* To get the size of a static data member declared as an array of
- unknown bound, we need to instantiate it. */
- if (VAR_P (expr)
- && VAR_HAD_UNKNOWN_BOUND (expr)
- && DECL_TEMPLATE_INSTANTIATION (expr))
- instantiate_decl (expr, /*defer_ok*/true, /*expl_inst_mem*/false);
-
if (id_expression_or_member_access_p)
{
/* If e is an id-expression or a class member access (5.2.5
diff --git a/gcc/cp/typeck.cc b/gcc/cp/typeck.cc
index 5970ac3d398..9297948cfa5 100644
--- a/gcc/cp/typeck.cc
+++ b/gcc/cp/typeck.cc
@@ -2127,13 +2127,6 @@ cxx_sizeof_expr (location_t loc, tree e, tsubst_flags_t
complain)
location_t e_loc = cp_expr_loc_or_loc (e, loc);
STRIP_ANY_LOCATION_WRAPPER (e);
- /* To get the size of a static data member declared as an array of
- unknown bound, we need to instantiate it. */
- if (VAR_P (e)
- && VAR_HAD_UNKNOWN_BOUND (e)
- && DECL_TEMPLATE_INSTANTIATION (e))
- instantiate_decl (e, /*defer_ok*/true, /*expl_inst_mem*/false);
-
if (TREE_CODE (e) == PARM_DECL
&& DECL_ARRAY_PARAMETER_P (e)
&& (complain & tf_warning))
diff --git a/gcc/testsuite/g++.dg/template/array37.C
b/gcc/testsuite/g++.dg/template/array37.C
new file mode 100644
index 00000000000..ed03b955f05
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/array37.C
@@ -0,0 +1,16 @@
+// PR c++/115358
+// { dg-do compile { target c++14 } }
+
+template<class T>
+struct A { static int STR[]; };
+
+template<class T>
+int A<T>::STR[] = {1,2,3};
+
+void g(int(&)[3]);
+
+int main() {
+ [](auto) {
+ g(A<int>::STR); // { dg-bogus "int []" }
+ };
+}
--
2.45.2.606.g9005149a4a
