Hi!
On Mon, Apr 10, 2017 at 04:48:43PM -0400, Jason Merrill wrote:
> On Mon, Apr 10, 2017 at 4:35 PM, Jakub Jelinek <ja...@redhat.com> wrote:
> > - store_decomp_type (v[i], eltype);
> > + if (!processing_template_decl)
> > + store_decomp_type (v[i], eltype);
>
> This spot shouldn't change; we do want to remember the decltype even
> in a template.
>
> > @@ -3935,7 +3935,10 @@ cxx_eval_constant_expression (const cons
> > return (*ctx->values->get (t));
> >
> > case VAR_DECL:
> > - if (DECL_HAS_VALUE_EXPR_P (t))
> > + if (DECL_HAS_VALUE_EXPR_P (t)
> > + /* Don't recurse on DECL_VALUE_EXPR of decomposition decls
> > + that have not been finalized yet. */
> > + && (!DECL_DECOMPOSITION_P (t) || TREE_TYPE (DECL_VALUE_EXPR (t))))
>
> Hmm, we shouldn't get here in this case. I think
> value_dependent_expression_p should return true for a VAR_DECL with
> type-dependent DECL_VALUE_EXPR.
So like this? Or just type_dependent_expression_p check rather than
both?
2017-04-11 Jakub Jelinek <ja...@redhat.com>
PR c++/80370
* decl.c (cp_finish_decomp): If processing_template_decl on
non-dependent decl, only set TREE_TYPE on the v[i] decls, but don't
change their DECL_VALUE_EXPR nor cp_finish_decl them. Instead make
sure DECL_VALUE_EXPR is the canonical NULL type ARRAY_REF for tsubst
processing.
* pt.c (value_dependent_expression_p) <case VAR_DECL>: For variables
with DECL_VALUE_EXPR, return true if DECL_VALUE_EXPR is type or
value dependent.
* g++.dg/cpp1z/decomp28.C: New test.
--- gcc/cp/decl.c.jj 2017-04-10 22:26:56.441388051 +0200
+++ gcc/cp/decl.c 2017-04-11 15:21:24.473163169 +0200
@@ -7473,6 +7473,8 @@ cp_finish_decomp (tree decl, tree first,
{
TREE_TYPE (v[i]) = eltype;
layout_decl (v[i], 0);
+ if (processing_template_decl)
+ continue;
tree t = unshare_expr (dexp);
t = build4_loc (DECL_SOURCE_LOCATION (v[i]), ARRAY_REF,
eltype, t, size_int (i), NULL_TREE,
@@ -7492,6 +7494,8 @@ cp_finish_decomp (tree decl, tree first,
{
TREE_TYPE (v[i]) = eltype;
layout_decl (v[i], 0);
+ if (processing_template_decl)
+ continue;
tree t = unshare_expr (dexp);
t = build1_loc (DECL_SOURCE_LOCATION (v[i]),
i ? IMAGPART_EXPR : REALPART_EXPR, eltype,
@@ -7510,6 +7514,8 @@ cp_finish_decomp (tree decl, tree first,
{
TREE_TYPE (v[i]) = eltype;
layout_decl (v[i], 0);
+ if (processing_template_decl)
+ continue;
tree t = unshare_expr (dexp);
convert_vector_to_array_for_subscript (DECL_SOURCE_LOCATION (v[i]),
&t, size_int (i));
@@ -7559,8 +7565,9 @@ cp_finish_decomp (tree decl, tree first,
SET_DECL_VALUE_EXPR (v[i], NULL_TREE);
DECL_HAS_VALUE_EXPR_P (v[i]) = 0;
}
- cp_finish_decl (v[i], init, /*constexpr*/false,
- /*asm*/NULL_TREE, LOOKUP_NORMAL);
+ if (!processing_template_decl)
+ cp_finish_decl (v[i], init, /*constexpr*/false,
+ /*asm*/NULL_TREE, LOOKUP_NORMAL);
}
}
else if (TREE_CODE (type) == UNION_TYPE)
@@ -7615,12 +7622,26 @@ cp_finish_decomp (tree decl, tree first,
tt = TREE_OPERAND (tt, 0);
TREE_TYPE (v[i]) = TREE_TYPE (tt);
layout_decl (v[i], 0);
- SET_DECL_VALUE_EXPR (v[i], tt);
- DECL_HAS_VALUE_EXPR_P (v[i]) = 1;
+ if (!processing_template_decl)
+ {
+ SET_DECL_VALUE_EXPR (v[i], tt);
+ DECL_HAS_VALUE_EXPR_P (v[i]) = 1;
+ }
i++;
}
}
- if (DECL_NAMESPACE_SCOPE_P (decl))
+ if (processing_template_decl)
+ {
+ for (unsigned int i = 0; i < count; i++)
+ if (!DECL_HAS_VALUE_EXPR_P (v[i]))
+ {
+ tree a = build_nt (ARRAY_REF, decl, size_int (i),
+ NULL_TREE, NULL_TREE);
+ SET_DECL_VALUE_EXPR (v[i], a);
+ DECL_HAS_VALUE_EXPR_P (v[i]) = 1;
+ }
+ }
+ else if (DECL_NAMESPACE_SCOPE_P (decl))
SET_DECL_ASSEMBLER_NAME (decl, mangle_decomp (decl, v));
}
--- gcc/cp/pt.c.jj 2017-04-10 08:18:51.000000000 +0200
+++ gcc/cp/pt.c 2017-04-11 15:37:59.727673709 +0200
@@ -23576,6 +23576,13 @@ value_dependent_expression_p (tree expre
|| type_dependent_expression_p (DECL_INITIAL (expression))
|| value_dependent_expression_p (DECL_INITIAL (expression))))
return true;
+ if (DECL_HAS_VALUE_EXPR_P (expression))
+ {
+ tree value_expr = DECL_VALUE_EXPR (expression);
+ if (type_dependent_expression_p (value_expr)
+ || value_dependent_expression_p (value_expr))
+ return true;
+ }
return false;
case DYNAMIC_CAST_EXPR:
--- gcc/testsuite/g++.dg/cpp1z/decomp28.C.jj 2017-04-11 15:21:24.473163169
+0200
+++ gcc/testsuite/g++.dg/cpp1z/decomp28.C 2017-04-11 15:21:24.473163169
+0200
@@ -0,0 +1,39 @@
+// PR c++/80370
+// { dg-do compile { target c++14 } }
+// { dg-options "" }
+
+namespace std {
+ template <typename> struct tuple_size;
+ template <long, typename> struct tuple_element;
+ template <typename...> struct tuple {};
+ template <typename... T> struct tuple_size<tuple<T...>> { static constexpr
int value = 1; };
+ template <typename T, typename... U> struct tuple_element<0, tuple<T, U...>>
{ typedef T type; };
+ template <int, typename... T> int& get (tuple<T...>);
+}
+
+template <int N>
+void
+foo (std::tuple<int> b)
+{
+ auto [c] = b; // { dg-warning "decomposition declaration only
available with" "" { target c++14_down } }
+}
+
+template <typename T>
+void
+bar (std::tuple<T> b)
+{
+ auto [c] = b; // { dg-warning "decomposition declaration only
available with" "" { target c++14_down } }
+}
+
+void
+baz (std::tuple<int> b)
+{
+ foo <5> (b);
+ bar (b);
+}
+
+int
+main ()
+{
+ [](auto) { [](std::tuple<int> b) { auto[c] = b; }; } (0); // { dg-warning
"decomposition declaration only available with" "" { target c++14_down } }
+}
Jakub
