Hi!
The C++26 P2662R3 Pack indexing paper mentions that both GCC
and MSVC don't handle T...[10] parameter declaration when T
is a pack. While that will change meaning in C++26, in C++11 .. C++23
this ought to be valid. Also, T...(args) as well.
The following patch handles those in cp_parser_direct_declarator.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2024-05-09 Jakub Jelinek <ja...@redhat.com>
PR c++/115012
* parser.cc (cp_parser_direct_declarator): Handle
abstract declarator starting with ... followed by [
or (.
* g++.dg/cpp0x/variadic185.C: New test.
* g++.dg/cpp0x/variadic186.C: New test.
--- gcc/cp/parser.cc.jj 2024-05-09 10:30:58.000000000 +0200
+++ gcc/cp/parser.cc 2024-05-09 16:44:01.250777325 +0200
@@ -23916,7 +23916,12 @@ cp_parser_direct_declarator (cp_parser*
{
/* Peek at the next token. */
token = cp_lexer_peek_token (parser->lexer);
- if (token->type == CPP_OPEN_PAREN)
+ if (token->type == CPP_OPEN_PAREN
+ || (first
+ && dcl_kind != CP_PARSER_DECLARATOR_NAMED
+ && token->type == CPP_ELLIPSIS
+ && cxx_dialect > cxx98
+ && cp_lexer_nth_token_is (parser->lexer, 2, CPP_OPEN_PAREN)))
{
/* This is either a parameter-declaration-clause, or a
parenthesized declarator. When we know we are parsing a
@@ -23955,6 +23960,11 @@ cp_parser_direct_declarator (cp_parser*
Thus again, we try a parameter-declaration-clause, and if
that fails, we back out and return. */
+ bool pack_expansion_p = token->type == CPP_ELLIPSIS;
+
+ if (pack_expansion_p)
+ /* Consume the `...' */
+ cp_lexer_consume_token (parser->lexer);
if (!first || dcl_kind != CP_PARSER_DECLARATOR_NAMED)
{
@@ -24098,6 +24108,7 @@ cp_parser_direct_declarator (cp_parser*
attrs,
parens_loc);
declarator->attributes = gnu_attrs;
+ declarator->parameter_pack_p |= pack_expansion_p;
/* Any subsequent parameter lists are to do with
return type, so are not those of the declared
function. */
@@ -24121,7 +24132,7 @@ cp_parser_direct_declarator (cp_parser*
/* If this is the first, we can try a parenthesized
declarator. */
- if (first)
+ if (first && !pack_expansion_p)
{
bool saved_in_type_id_in_expr_p;
@@ -24156,16 +24167,27 @@ cp_parser_direct_declarator (cp_parser*
else
break;
}
- else if ((!first || dcl_kind != CP_PARSER_DECLARATOR_NAMED)
- && token->type == CPP_OPEN_SQUARE
- && !cp_next_tokens_can_be_attribute_p (parser))
+ else if (((!first || dcl_kind != CP_PARSER_DECLARATOR_NAMED)
+ && token->type == CPP_OPEN_SQUARE
+ && !cp_next_tokens_can_be_attribute_p (parser))
+ || (first
+ && dcl_kind != CP_PARSER_DECLARATOR_NAMED
+ && token->type == CPP_ELLIPSIS
+ && cp_lexer_nth_token_is (parser->lexer, 2, CPP_OPEN_SQUARE)
+ && cxx_dialect > cxx98
+ && !cp_nth_tokens_can_be_std_attribute_p (parser, 2)))
{
/* Parse an array-declarator. */
tree bounds, attrs;
+ bool pack_expansion_p = token->type == CPP_ELLIPSIS;
if (ctor_dtor_or_conv_p)
*ctor_dtor_or_conv_p = 0;
+ if (pack_expansion_p)
+ /* Consume the `...' */
+ cp_lexer_consume_token (parser->lexer);
+
open_paren = NULL;
first = false;
parser->default_arg_ok_p = false;
@@ -24220,6 +24242,7 @@ cp_parser_direct_declarator (cp_parser*
attrs = cp_parser_std_attribute_spec_seq (parser);
declarator = make_array_declarator (declarator, bounds);
declarator->std_attributes = attrs;
+ declarator->parameter_pack_p |= pack_expansion_p;
}
else if (first && dcl_kind != CP_PARSER_DECLARATOR_ABSTRACT)
{
--- gcc/testsuite/g++.dg/cpp0x/variadic185.C.jj 2024-05-09 15:08:49.070651189
+0200
+++ gcc/testsuite/g++.dg/cpp0x/variadic185.C 2024-05-09 15:07:40.045583153
+0200
@@ -0,0 +1,39 @@
+// PR c++/115012
+// { dg-do compile { target { c++11 && c++23_down } } }
+// { dg-final { scan-assembler "_Z3fooILi10EJidEEvDpAT__T0_" } }
+// { dg-final { scan-assembler "_Z3barILi10EiEvPT0_" } }
+// { dg-final { scan-assembler "_Z3bazILi10EJidEEvDpAT__T0_" } }
+// { dg-final { scan-assembler "_Z3quxILi5EJifEEvDpAT__AT__T0_" } }
+
+template <int N, typename ...T>
+void
+foo (T... x[N])
+{
+}
+
+template <int N, typename T>
+void
+bar (T [N])
+{
+}
+
+template <int N, typename ...T>
+void
+baz (T... [N])
+{
+}
+
+template <int N, typename ...T>
+void
+qux (T... [N][N])
+{
+}
+
+void
+corge (int a[10], double b[10], int c[5][5], float d[5][5])
+{
+ foo <10, int, double> (a, b);
+ bar <10, int> (a);
+ baz <10, int, double> (a, b);
+ qux <5, int, float> (c, d);
+}
--- gcc/testsuite/g++.dg/cpp0x/variadic186.C.jj 2024-05-09 16:39:50.409153099
+0200
+++ gcc/testsuite/g++.dg/cpp0x/variadic186.C 2024-05-09 15:37:22.469569809
+0200
@@ -0,0 +1,43 @@
+// PR c++/115012
+// { dg-do compile { target { c++11 } } }
+// { dg-final { scan-assembler "_Z3fooIJidEEvDpFT_iE" } }
+// { dg-final { scan-assembler "_Z3barIiEvPFT_iE" } }
+// { dg-final { scan-assembler "_Z3bazIJidEEvDpFT_iE" } }
+
+template <typename ...T>
+void
+foo (T... x (int))
+{
+}
+
+template <typename T>
+void
+bar (T (int))
+{
+}
+
+template <typename ...T>
+void
+baz (T... (int))
+{
+}
+
+int
+f1 (int)
+{
+ return 0;
+}
+
+double
+f2 (int)
+{
+ return 0;
+}
+
+void
+corge ()
+{
+ foo <int, double> (f1, f2);
+ bar <int> (f1);
+ baz <int, double> (f1, f2);
+}
Jakub
