From patchwork Wed Nov 6 20:33:00 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marek Polacek X-Patchwork-Id: 2007701 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=J/VbMilw; dkim-atps=neutral Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=gcc.gnu.org (client-ip=2620:52:3:1:0:246e:9693:128c; helo=server2.sourceware.org; envelope-from=gcc-patches-bounces~incoming=patchwork.ozlabs.org@gcc.gnu.org; receiver=patchwork.ozlabs.org) Received: from server2.sourceware.org (server2.sourceware.org [IPv6:2620:52:3:1:0:246e:9693:128c]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (secp384r1) server-digest SHA384) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4XkH3j5Q3Fz1xyd for ; Thu, 7 Nov 2024 07:33:51 +1100 (AEDT) Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id BD3813858423 for ; Wed, 6 Nov 2024 20:33:48 +0000 (GMT) X-Original-To: gcc-patches@gcc.gnu.org Delivered-To: gcc-patches@gcc.gnu.org Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by sourceware.org (Postfix) with ESMTP id 497243858D20 for ; Wed, 6 Nov 2024 20:33:09 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 497243858D20 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com ARC-Filter: OpenARC Filter v1.0.0 sourceware.org 497243858D20 Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1730925196; cv=none; b=AQUwt85BxBPV8IvhqnW8fC/zMtSCUSTnK9Vc1Xg8JRQWMgAnip+gHcCrVtArgc93vD0Fckdit76Rob+0/vaModbzEaM2Trbv59r6xFM5h0u8BiFDgjMAfE0xmktBggDaM74i5o3LviV4GZTKra6sH5FGOvYdIbN9dj6h0qANjas= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1730925196; c=relaxed/simple; bh=5LM/wlkK6o1ISePSy97dXP3fPw9/DNl5fkySXzoBic0=; h=DKIM-Signature:Date:From:To:Subject:Message-ID:MIME-Version; b=VfWYpuLGZHLQBT15TPWPFzLmhVF8ruTIvYpJjJ5TGDI0Cv7tdjWnHa1+9nBtg7lzn1ANDn2XQEet1d8eJxyxbRHAcfzVstNiB/vCyykdTM63QJRCNh0gmxZLDCSfPbxd9/fwDCwTZJ/nQ4cTr5ThdSKY3V90TnrKXoUVt/Srwtw= ARC-Authentication-Results: i=1; server2.sourceware.org DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1730925188; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=mGECsaR1pDmap7/OWFAT4J58WeUbUGzRbFYmbh/zOig=; b=J/VbMilwB1fk4iFV/3aoMFB8aBE4yJx4YQ/Z8Pih8XmAXAluLKjGLnJ1+8XsUyXsLEDqXW uB4yWZIPnf+NzMr4XqCTKXDkEc1vsJd/MZGqBqjdjur7fLkT92KUHb1LwVbdiZmJZiln9Z EENPhWzkL1HrLccyrYKWbJI2KQa9J+g= Received: from mail-qv1-f70.google.com (mail-qv1-f70.google.com [209.85.219.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-477-dzwlwyILOAiEwQQKGvtP8Q-1; Wed, 06 Nov 2024 15:33:06 -0500 X-MC-Unique: dzwlwyILOAiEwQQKGvtP8Q-1 X-Mimecast-MFC-AGG-ID: dzwlwyILOAiEwQQKGvtP8Q Received: by mail-qv1-f70.google.com with SMTP id 6a1803df08f44-6cbf039dccfso3016336d6.0 for ; Wed, 06 Nov 2024 12:33:06 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1730925186; x=1731529986; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=mGECsaR1pDmap7/OWFAT4J58WeUbUGzRbFYmbh/zOig=; b=a+dZXlgIHnGMRaAL0qzi3wyGpHKJOORx7DuT17JkUnymSsh2l6yZ5WpLvwS37/iBXr Kn4J09PjvGY6VUO3xMfp36CuWUC33yP/oa4D/ohQBcKu6xNmCHh8yMkhf8lCxpHcQf5E YQLE+tibSlgb4z72t9/L9OdXMvuWyK3VcJcwMmwSR9ajc60JPCHBHWLqA/X6ZflHvb1L ELM3dgkyyn536RoPirwoyuZLcHgXk4m7WPedHBW8ysfj7f1jIQJ+AHl3iYiviCV+1aKJ da7kX4EWVmQBNXifQleDoFBLySA4742iiW1gQmySlsVW7FTuNfyd90H9AODZGlTsDjPR lmgw== X-Forwarded-Encrypted: i=1; AJvYcCV3CL1IdJ0sH3bug1KlV8ta6YeI0XBo+N+5xzF+taeGi5NcKIX09wjtAlf2a0ZP9PIVAnHej1RXxB+u1A==@gcc.gnu.org X-Gm-Message-State: AOJu0Yycaa1s4lqX47zGkFQh9RyDrxkhLfuurzOyQpxu6wwXOzUwfg3i FjACxBwkjdGtGGi82fp7/cOnY2EQ2UqUukeVHiOhoEzk2ysl++8GFvwCipP7+V2CTao5IkW52ps 1Msv7qhrVapGRSy7oojlfR4EoSte1GuiwVU52rr7mGuGdIUEhyLTkvEk= X-Received: by 2002:a05:6214:3904:b0:6cb:f6de:3dc4 with SMTP id 6a1803df08f44-6d1857021a6mr610825106d6.28.1730925184818; Wed, 06 Nov 2024 12:33:04 -0800 (PST) X-Google-Smtp-Source: AGHT+IG/I/tdjj0VujJGsdsHHZSDRopuu2+kB2aJaGcdvdOJ5H+/O8WrCYUXQxaU2QjgdEZYrltzzg== X-Received: by 2002:a05:6214:3904:b0:6cb:f6de:3dc4 with SMTP id 6a1803df08f44-6d1857021a6mr610824186d6.28.1730925183344; Wed, 06 Nov 2024 12:33:03 -0800 (PST) Received: from redhat.com ([2603:7000:9500:34a5::1db4]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6d35415b2fesm77049146d6.92.2024.11.06.12.33.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 06 Nov 2024 12:33:02 -0800 (PST) Date: Wed, 6 Nov 2024 15:33:00 -0500 From: Marek Polacek To: Jason Merrill Cc: Patrick Palka , GCC Patches Subject: [PATCH v4] c++: Implement P2662R3, Pack Indexing [PR113798] Message-ID: References: <20241022192217.508500-1-polacek@redhat.com> <915bdf08-fcc8-493b-9767-9200e3743a13@redhat.com> <3b17171a-957f-45b6-8990-29f3d297ac9f@redhat.com> MIME-Version: 1.0 In-Reply-To: <3b17171a-957f-45b6-8990-29f3d297ac9f@redhat.com> User-Agent: Mutt/2.2.12 (2023-09-09) X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: B0t2VQ7VeryFRH6cErvZwHTNMYgSlXxeAvWMrGYlv7k_1730925186 X-Mimecast-Originator: redhat.com Content-Disposition: inline X-BeenThere: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.30 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: gcc-patches-bounces~incoming=patchwork.ozlabs.org@gcc.gnu.org On Mon, Nov 04, 2024 at 11:10:05PM -0500, Jason Merrill wrote: > On 10/30/24 4:59 PM, Marek Polacek wrote: > > On Wed, Oct 30, 2024 at 09:01:36AM -0400, Patrick Palka wrote: > > > On Tue, 29 Oct 2024, Marek Polacek wrote: > > --- a/gcc/cp/cp-tree.h > > +++ b/gcc/cp/cp-tree.h > > @@ -451,6 +451,7 @@ extern GTY(()) tree cp_global_trees[CPTI_MAX]; > > ATOMIC_CONSTR_MAP_INSTANTIATED_P (in ATOMIC_CONSTR) > > contract_semantic (in ASSERTION_, PRECONDITION_, POSTCONDITION_STMT) > > RETURN_EXPR_LOCAL_ADDR_P (in RETURN_EXPR) > > + PACK_INDEX_PARENTHESIZED_P (in PACK_INDEX_*) > > 1: IDENTIFIER_KIND_BIT_1 (in IDENTIFIER_NODE) > > TI_PENDING_TEMPLATE_FLAG. > > TEMPLATE_PARMS_FOR_INLINE. > > @@ -2258,7 +2259,8 @@ enum languages { lang_c, lang_cplusplus }; > > || TREE_CODE (T) == BOUND_TEMPLATE_TEMPLATE_PARM \ > > || TREE_CODE (T) == DECLTYPE_TYPE \ > > || TREE_CODE (T) == TRAIT_TYPE \ > > - || TREE_CODE (T) == DEPENDENT_OPERATOR_TYPE) > > + || TREE_CODE (T) == DEPENDENT_OPERATOR_TYPE \ > > + || PACK_INDEX_P (T)) > > Just PACK_INDEX_TYPE here, I think? I think so too. Done. > > /* Nonzero if T is a class (or struct or union) type. Also nonzero > > for template type parameters, typename types, and instantiated > > @@ -4001,6 +4003,9 @@ struct GTY(()) lang_decl { > > #define PACK_EXPANSION_CHECK(NODE) \ > > TREE_CHECK2 (NODE, TYPE_PACK_EXPANSION, EXPR_PACK_EXPANSION) > > +#define PACK_INDEX_CHECK(NODE) \ > > + TREE_CHECK2 (NODE, PACK_INDEX_TYPE, PACK_INDEX_EXPR) > > + > > /* Extracts the type or expression pattern from a TYPE_PACK_EXPANSION or > > EXPR_PACK_EXPANSION. */ > > #define PACK_EXPANSION_PATTERN(NODE) \ > > @@ -4025,6 +4030,22 @@ struct GTY(()) lang_decl { > > ? &TYPE_MAX_VALUE_RAW (NODE) \ > > : &TREE_OPERAND ((NODE), 2)) > > +/* True if NODE is a pack index. */ > > +#define PACK_INDEX_P(NODE) \ > > + (TREE_CODE (NODE) == PACK_INDEX_TYPE \ > > + || TREE_CODE (NODE) == PACK_INDEX_EXPR) > > + > > +/* For a pack index T...[N], the pack expansion T. */ > > "the pack expansion T..."? Done. > > +#define PACK_INDEX_PACK(NODE) \ > > + (TREE_CODE (PACK_INDEX_CHECK (NODE)) == PACK_INDEX_TYPE \ > > + ? TREE_TYPE (NODE) : TREE_OPERAND (NODE, 0)) > > + > > +/* For a pack index T...[N], the index N. */ > > +#define PACK_INDEX_INDEX(NODE) \ > > + *(TREE_CODE (PACK_INDEX_CHECK (NODE)) == PACK_INDEX_TYPE \ > > + ? &TYPE_MAX_VALUE_RAW (NODE) \ > > + : &TREE_OPERAND ((NODE), 1)) > > + > > /* True iff this pack expansion is within a function context. */ > > #define PACK_EXPANSION_LOCAL_P(NODE) \ > > TREE_LANG_FLAG_0 (PACK_EXPANSION_CHECK (NODE)) > > @@ -4042,6 +4063,11 @@ struct GTY(()) lang_decl { > > #define PACK_EXPANSION_FORCE_EXTRA_ARGS_P(NODE) \ > > TREE_LANG_FLAG_3 (PACK_EXPANSION_CHECK (NODE)) > > +/* Indicates whether a pack expansion has been parenthesized. Used for > > + a pack expansion in a decltype. */ > > +#define PACK_INDEX_PARENTHESIZED_P(NODE) \ > > + TREE_LANG_FLAG_1 (PACK_INDEX_CHECK (NODE)) > > This should only apply to PACK_INDEX_EXPR, I think? True, fixed. > > /* True iff the wildcard can match a template parameter pack. */ > > #define WILDCARD_PACK_P(NODE) TREE_LANG_FLAG_0 (NODE) > > @@ -7581,6 +7607,7 @@ extern bool template_parameter_pack_p (const_tree); > > extern bool function_parameter_pack_p (const_tree); > > extern bool function_parameter_expanded_from_pack_p (tree, tree); > > extern tree make_pack_expansion (tree, tsubst_flags_t = tf_warning_or_error); > > +extern tree make_pack_index (tree, tree); > > extern bool check_for_bare_parameter_packs (tree, location_t = UNKNOWN_LOCATION); > > extern tree build_template_info (tree, tree); > > extern tree get_template_info (const_tree); > > @@ -7906,6 +7933,8 @@ extern tree finish_underlying_type (tree); > > extern tree calculate_bases (tree, tsubst_flags_t); > > extern tree finish_bases (tree, bool); > > extern tree calculate_direct_bases (tree, tsubst_flags_t); > > +extern tree pack_index_element (tree, tree, bool, > > + tsubst_flags_t); > > extern tree finish_offsetof (tree, tree, location_t); > > extern void finish_decl_cleanup (tree, tree); > > extern void finish_eh_cleanup (tree); > > diff --git a/gcc/cp/cxx-pretty-print.cc b/gcc/cp/cxx-pretty-print.cc > > index f4203123737..15d41b55557 100644 > > --- a/gcc/cp/cxx-pretty-print.cc > > +++ b/gcc/cp/cxx-pretty-print.cc > > @@ -1220,6 +1220,13 @@ cxx_pretty_printer::expression (tree t) > > pp_cxx_ws_string (this, "..."); > > break; > > + case PACK_INDEX_EXPR: > > + expression (PACK_INDEX_PACK (t)); > > + pp_cxx_left_bracket (this); > > + expression (PACK_INDEX_INDEX (t)); > > + pp_cxx_right_bracket (this); > > + break; > > + > > case UNARY_LEFT_FOLD_EXPR: > > pp_cxx_unary_left_fold_expression (this, t); > > break; > > @@ -1920,6 +1927,13 @@ cxx_pretty_printer::type_id (tree t) > > pp_cxx_ws_string (this, "..."); > > break; > > + case PACK_INDEX_TYPE: > > + type_id (PACK_INDEX_PACK (t)); > > + pp_cxx_left_bracket (this); > > + expression (PACK_INDEX_INDEX (t)); > > + pp_cxx_right_bracket (this); > > + break; > > + > > case TYPE_ARGUMENT_PACK: > > { > > tree args = ARGUMENT_PACK_ARGS (t); > > diff --git a/gcc/cp/error.cc b/gcc/cp/error.cc > > index 7ef79b90868..c62c9d7312e 100644 > > --- a/gcc/cp/error.cc > > +++ b/gcc/cp/error.cc > > @@ -814,6 +814,13 @@ dump_type (cxx_pretty_printer *pp, tree t, int flags) > > pp_cxx_ws_string (pp, "..."); > > break; > > + case PACK_INDEX_TYPE: > > + dump_type (pp, PACK_INDEX_PACK (t), flags); > > + pp_cxx_left_bracket (pp); > > + dump_expr (pp, PACK_INDEX_INDEX (t), flags & ~TFF_EXPR_IN_PARENS); > > + pp_cxx_right_bracket (pp); > > + break; > > + > > case TYPE_ARGUMENT_PACK: > > dump_template_argument (pp, t, flags); > > break; > > @@ -1088,6 +1095,7 @@ dump_type_prefix (cxx_pretty_printer *pp, tree t, int flags) > > case TYPE_PACK_EXPANSION: > > case FIXED_POINT_TYPE: > > case NULLPTR_TYPE: > > + case PACK_INDEX_TYPE: > > dump_type (pp, t, flags); > > pp->set_padding (pp_before); > > break; > > @@ -1220,6 +1228,7 @@ dump_type_suffix (cxx_pretty_printer *pp, tree t, int flags) > > case TYPE_PACK_EXPANSION: > > case FIXED_POINT_TYPE: > > case NULLPTR_TYPE: > > + case PACK_INDEX_TYPE: > > break; > > default: > > @@ -3103,6 +3112,13 @@ dump_expr (cxx_pretty_printer *pp, tree t, int flags) > > pp->expression (t); > > break; > > + case PACK_INDEX_EXPR: > > + pp->expression (PACK_INDEX_PACK (t)); > > + pp_cxx_left_bracket (pp); > > + pp->expression (PACK_INDEX_INDEX (t)); > > + pp_cxx_right_bracket (pp); > > + break; > > + > > case TRUTH_AND_EXPR: > > case TRUTH_OR_EXPR: > > case TRUTH_XOR_EXPR: > > diff --git a/gcc/cp/mangle.cc b/gcc/cp/mangle.cc > > index 4d46c0917a9..c103b50b1f1 100644 > > --- a/gcc/cp/mangle.cc > > +++ b/gcc/cp/mangle.cc > > @@ -2669,6 +2669,12 @@ write_type (tree type) > > "use library traits instead", type); > > break; > > + case PACK_INDEX_TYPE: > > + /* TODO Mangle pack indexing > > + . */ > > + sorry ("mangling type pack index"); > > + break; > > + > > case LANG_TYPE: > > /* fall through. */ > > diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc > > index 9323023ff7f..2ef6d8a6d82 100644 > > --- a/gcc/cp/module.cc > > +++ b/gcc/cp/module.cc > > @@ -9209,6 +9209,11 @@ trees_out::type_node (tree type) > > tree_node (PACK_EXPANSION_EXTRA_ARGS (type)); > > break; > > + case PACK_INDEX_TYPE: > > + tree_node (PACK_INDEX_PACK (type)); > > + tree_node (PACK_INDEX_INDEX (type)); > > + break; > > + > > case TYPENAME_TYPE: > > { > > tree_node (TYPE_CONTEXT (type)); > > @@ -9776,6 +9781,15 @@ trees_in::tree_node (bool is_use) > > } > > break; > > + case PACK_INDEX_TYPE: > > + { > > + tree pack = tree_node (); > > + tree index = tree_node (); > > + if (!get_overrun ()) > > + res = make_pack_index (pack, index); > > + } > > + break; > > + > > case TYPENAME_TYPE: > > { > > tree ctx = tree_node (); > > diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc > > index c1375ecdbb5..e562ba723ad 100644 > > --- a/gcc/cp/parser.cc > > +++ b/gcc/cp/parser.cc > > @@ -5739,6 +5739,54 @@ cp_parser_fold_expression (cp_parser *parser, tree expr1) > > return finish_binary_fold_expr (loc, expr1, expr2, op); > > } > > +/* Parse a pack-index-specifier: > > + > > + pack-index-specifier: > > + typedef-name ... [ constant-expression ] > > + > > + or a pack-index-expression: > > + > > + pack-index-expression: > > + id-expression ... [ constant-expression ] > > + > > + PACK is the parsed typedef-name or the id-expression. Returns > > + either a PACK_INDEX_TYPE or PACK_INDEX_EXPR. */ > > + > > +static tree > > +cp_parser_pack_index (cp_parser *parser, tree pack) > > +{ > > + if (cxx_dialect < cxx26) > > + pedwarn (cp_lexer_peek_token (parser->lexer)->location, > > + OPT_Wc__26_extensions, "pack indexing only available with " > > + "%<-std=c++2c%> or %<-std=gnu++2c%>"); > > + /* Consume the '...' token. */ > > + cp_lexer_consume_token (parser->lexer); > > + /* Consume the '['. */ > > + cp_lexer_consume_token (parser->lexer); > > + > > + if (cp_lexer_next_token_is (parser->lexer, CPP_CLOSE_SQUARE)) > > + { > > + error_at (cp_lexer_peek_token (parser->lexer)->location, > > + "pack index missing"); > > Maybe cp_parser_error? Unsure. This: template void foo(Ts...[]); then generates: error: variable or field 'foo' declared void error: expected primary-expression before '...' token error: pack index missing before ']' token which doesn't seem better. > > + cp_lexer_consume_token (parser->lexer); > > + return error_mark_node; > > + } > > + > > + tree index = cp_parser_constant_expression (parser, > > + /*allow_non_constant_p=*/false, > > + /*non_constant_p=*/nullptr, > > + /*strict_p=*/true); > > + /* Consume the ']'. */ > > + cp_parser_require (parser, CPP_CLOSE_SQUARE, RT_CLOSE_SQUARE); > > + > > + if (TREE_CODE (pack) == TYPE_DECL) > > + pack = TREE_TYPE (pack); > > + pack = make_pack_expansion (pack); > > + if (pack == error_mark_node) > > + return error_mark_node; > > + return make_pack_index (pack, index); > > +} > > + > > /* Parse a primary-expression. > > primary-expression: > > @@ -6368,6 +6416,12 @@ cp_parser_primary_expression (cp_parser *parser, > > = make_location (caret_loc, start_loc, finish_loc); > > decl.set_location (combined_loc); > > + > > + /* "T...[constant-expression]" is a C++26 pack-index-expression. */ > > + if (cp_lexer_next_token_is (parser->lexer, CPP_ELLIPSIS) > > + && cp_lexer_nth_token_is (parser->lexer, 2, CPP_OPEN_SQUARE)) > > + decl = cp_parser_pack_index (parser, decl); > > Shouldn't this be in cp_parser_id_expression? It should, but I need to wait until after finish_id_expression, so that DECL isn't just an identifier node. > > return decl; > > } > > @@ -6411,6 +6465,7 @@ missing_template_diag (location_t loc, diagnostic_t diag_kind = DK_WARNING) > > id-expression: > > unqualified-id > > qualified-id > > + pack-index-expression > > qualified-id: > > :: [opt] nested-name-specifier template [opt] unqualified-id > > @@ -6593,7 +6648,9 @@ cp_parser_id_expression (cp_parser *parser, > > identifier > > operator-function-id > > conversion-function-id > > - ~ class-name > > + literal-operator-id > > + ~ type-name > > + ~ computed-type-specifier > > Hmm, seems we never implemented ~decltype. Looks like CWG 1753: . > > template-id > > If TEMPLATE_KEYWORD_P is TRUE, we have just seen the `template' > > @@ -6900,6 +6957,14 @@ cp_parser_unqualified_id (cp_parser* parser, > > "typedef-name %qD used as destructor declarator", > > type_decl); > > + /* "~T...[N]" is a C++26 pack-index-specifier. */ > > + if (cp_lexer_next_token_is (parser->lexer, CPP_ELLIPSIS) > > + && cp_lexer_nth_token_is (parser->lexer, 2, CPP_OPEN_SQUARE)) > > + { > > + type_decl = cp_parser_pack_index (parser, type_decl); > > + return build_min_nt_loc (loc, BIT_NOT_EXPR, type_decl); > > + } > > > return build_min_nt_loc (loc, BIT_NOT_EXPR, TREE_TYPE (type_decl)); > > } > > @@ -6970,9 +7035,10 @@ check_template_keyword_in_nested_name_spec (tree name) > > class-or-namespace-name :: nested-name-specifier [opt] > > class-or-namespace-name :: template nested-name-specifier [opt] > > - nested-name-specifier: [C++0x] > > + nested-name-specifier: [C++11] > > type-name :: > > namespace-name :: > > + computed-type-specifier :: > > nested-name-specifier identifier :: > > nested-name-specifier template [opt] simple-template-id :: > > @@ -7080,6 +7146,10 @@ cp_parser_nested_name_specifier_opt (cp_parser *parser, > > } > > if (token->type != CPP_SCOPE > > + /* See if a pack-index-specifier follows. */ > > + && !(token->type == CPP_ELLIPSIS > > + && cp_lexer_peek_nth_token (parser->lexer, 3)->type > > + == CPP_OPEN_SQUARE) > > Also update the comment a few lines up? Done. > > /* If the following token is neither a `<' (to begin a > > template-id), nor a `::', then we are not looking at a > > nested-name-specifier. */ > > > && !cp_parser_nth_token_starts_template_argument_list_p > > (parser, 2)) > > break; > > @@ -7127,6 +7197,12 @@ cp_parser_nested_name_specifier_opt (cp_parser *parser, > > check_dependency_p, > > type_p, > > is_declaration); > > + > > + /* "T...[constant-expression]" is a C++26 pack-index-specifier. */ > > + if (cp_lexer_next_token_is (parser->lexer, CPP_ELLIPSIS) > > + && cp_lexer_nth_token_is (parser->lexer, 2, CPP_OPEN_SQUARE)) > > + new_scope = cp_parser_pack_index (parser, new_scope); > > Shouldn't this be in cp_parser_qualifying_entity? It could. Moved. > > /* Look for the `::' token. */ > > cp_parser_require (parser, CPP_SCOPE, RT_SCOPE); > > @@ -17410,6 +17486,11 @@ cp_parser_decltype_expr (cp_parser *parser, > > /* Parse a full expression. */ > > expr = cp_parser_expression (parser, /*pidk=*/NULL, /*cast_p=*/false, > > /*decltype_p=*/true); > > + /* A pack indexing is an id-expression. cp_parser_expression does not > > + tell us if the pack indexing was wrapped in (), so we use the > > + PACK_INDEX_PARENTHESIZED_P flag to track that. */ > > + if (PACK_INDEX_P (expr)) > > + id_expression_or_member_access_p = true; > > Since it's an id-expression, I'd think it should have been handled in the > earlier call to cp_parser_id_expression. As mentioned above, I need to wait for the finish_id_expression call. But still, I shouldn't have to wait till the cp_parser_expression call; we should handle a pack indexing earlier in the function. Changed. > > return expr; > > @@ -17938,13 +18019,17 @@ cp_parser_mem_initializer (cp_parser* parser) > > /* Parse a mem-initializer-id. > > mem-initializer-id: > > - :: [opt] nested-name-specifier [opt] class-name > > - decltype-specifier (C++11) > > + class-or-decltype > > identifier > > + class-or-decltype: > > + nested-name-specifier [opt] type-name > > + nested-name-specifier template simple-template-id > > + computed-type-specifier > > > Returns a TYPE indicating the class to be initialized for the first > > - production (and the second in C++11). Returns an IDENTIFIER_NODE > > - indicating the data member to be initialized for the last production. */ > > + production. Returns an IDENTIFIER_NODE indicating the data member to > > + be initialized for the second production. */ > > static tree > > cp_parser_mem_initializer_id (cp_parser* parser) > > @@ -18015,10 +18100,16 @@ cp_parser_mem_initializer_id (cp_parser* parser) > > /*class_head_p=*/false, > > /*is_declaration=*/true); > > /* If we found one, we're done. */ > > - if (cp_parser_parse_definitely (parser)) > > - return id; > > - /* Otherwise, look for an ordinary identifier. */ > > - return cp_parser_identifier (parser); > > + if (!cp_parser_parse_definitely (parser)) > > + /* Otherwise, look for an ordinary identifier. */ > > + id = cp_parser_identifier (parser); > > + > > + /* ": T...[N]" is a C++26 pack-index-specifier. */ > > + if (cp_lexer_next_token_is (parser->lexer, CPP_ELLIPSIS) > > + && cp_lexer_nth_token_is (parser->lexer, 2, CPP_OPEN_SQUARE)) > > + id = cp_parser_pack_index (parser, id); > > + return id; > > } > > /* Overloading [gram.over] */ > > @@ -20436,11 +20527,11 @@ cp_parser_type_specifier (cp_parser* parser, > > C++11 Extension: > > simple-type-specifier: > > - auto > > - decltype ( expression ) > > char16_t > > char32_t > > __underlying_type ( type-id ) > > + computed-type-specifier > > + placeholder-type-specifier > > C++17 extension: > > @@ -20822,6 +20913,13 @@ cp_parser_simple_type_specifier (cp_parser* parser, > > type = NULL_TREE; > > } > > + /* "T...[constant-expression]" is a C++26 pack-index-specifier. */ > > + if (type > > + && type != error_mark_node > > + && cp_lexer_next_token_is (parser->lexer, CPP_ELLIPSIS) > > + && cp_lexer_nth_token_is (parser->lexer, 2, CPP_OPEN_SQUARE)) > > + type = cp_parser_pack_index (parser, type); > > + > > if (!type && flag_concepts && decl_specs) > > { > > /* Try for a type-constraint with template arguments. We check > > @@ -29103,12 +29201,21 @@ cp_parser_base_clause (cp_parser* parser) > > /* Parse a base-specifier. > > base-specifier: > > - attribute-specifier-seq [opt] :: [opt] nested-name-specifier [opt] > > - class-name > > - attribute-specifier-seq [opt] virtual access-specifier [opt] :: [opt] > > - nested-name-specifier [opt] class-name > > - attribute-specifier-seq [opt] access-specifier virtual [opt] :: [opt] > > - nested-name-specifier [opt] class-name > > + attribute-specifier-seq [opt] class-or-decltype > > + attribute-specifier-seq [opt] virtual access-specifier [opt] > > + class-or-decltype > > + attribute-specifier-seq [opt] access-specifier virtual [opt] > > + class-or-decltype > > + > > + class-or-decltype: > > + nested-name-specifier [opt] type-name > > + nested-name-specifier template simple-template-id > > + computed-type-specifier > > + > > + access-specifier: > > + private > > + protected > > + public > > Returns a TREE_LIST. The TREE_PURPOSE will be one of > > ACCESS_{DEFAULT,PUBLIC,PROTECTED,PRIVATE}_[VIRTUAL]_NODE to > > @@ -29237,6 +29344,10 @@ cp_parser_base_specifier (cp_parser* parser) > > /*class_head_p=*/false, > > /*is_declaration=*/true); > > type = TREE_TYPE (type); > > + /* ": T...[constant-expression]" is a C++26 pack-index-specifier. */ > > + if (cp_lexer_next_token_is (parser->lexer, CPP_ELLIPSIS) > > + && cp_lexer_nth_token_is (parser->lexer, 2, CPP_OPEN_SQUARE)) > > + type = cp_parser_pack_index (parser, type); > > Seems like we could replace a lot of this function with a call to > cp_parser_class_or_decltype, if it existed. But that doesn't need to happen > in this patch. That would be nice. > > } > > if (type == error_mark_node) > > diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc > > index 15d6d82f32f..6a8d275c4a7 100644 > > --- a/gcc/cp/pt.cc > > +++ b/gcc/cp/pt.cc > > @@ -1789,6 +1789,11 @@ iterative_hash_template_arg (tree arg, hashval_t val) > > val = iterative_hash_template_arg (PACK_EXPANSION_PATTERN (arg), val); > > return iterative_hash_template_arg (PACK_EXPANSION_EXTRA_ARGS (arg), val); > > + case PACK_INDEX_TYPE: > > + case PACK_INDEX_EXPR: > > + val = iterative_hash_template_arg (PACK_INDEX_PACK (arg), val); > > + return iterative_hash_template_arg (PACK_INDEX_INDEX (arg), val); > > + > > case TYPE_ARGUMENT_PACK: > > case NONTYPE_ARGUMENT_PACK: > > return iterative_hash_template_arg (ARGUMENT_PACK_ARGS (arg), val); > > @@ -4031,6 +4036,15 @@ find_parameter_packs_r (tree *tp, int *walk_subtrees, void* data) > > *walk_subtrees = 0; > > return NULL_TREE; > > + case PACK_INDEX_TYPE: > > + case PACK_INDEX_EXPR: > > + /* We can have an expansion of an expansion, such as "Ts...[Is]...", > > + so do look into the index. */ > > + cp_walk_tree (&PACK_INDEX_INDEX (t), &find_parameter_packs_r, ppd, > > + ppd->visited); > > + *walk_subtrees = 0; > > + return NULL_TREE; > > Do we need to handle these specifically here? I'd think the handling in > cp_walk_subtrees would be enough. I think I do, otherwise the Ts...[Is]... test doesn't work. It is used when calling check_for_bare_parameter_packs. > > case INTEGER_TYPE: > > cp_walk_tree (&TYPE_MAX_VALUE (t), &find_parameter_packs_r, > > ppd, ppd->visited); > > @@ -4257,6 +4271,33 @@ make_pack_expansion (tree arg, tsubst_flags_t complain) > > return result; > > } > > +/* Create a PACK_INDEX_* using the pack expansion PACK and index INDEX. */ > > + > > +tree > > +make_pack_index (tree pack, tree index) > > +{ > > + bool for_types; > > + if (TREE_CODE (pack) == TYPE_PACK_EXPANSION) > > + for_types = true; > > + else if (TREE_CODE (pack) == EXPR_PACK_EXPANSION) > > + for_types = false; > > + else > > + { > > + /* Maybe we've already partially substituted the pack. */ > > + gcc_checking_assert (TREE_CODE (pack) == TREE_VEC); > > + for_types = TYPE_P (TREE_VEC_ELT (pack, 0)); > > + } > > + > > + tree t = (for_types > > + ? cxx_make_type (PACK_INDEX_TYPE) > > + : make_node (PACK_INDEX_EXPR)); > > + PACK_INDEX_PACK (t) = pack; > > + PACK_INDEX_INDEX (t) = index; > > + if (TREE_CODE (t) == PACK_INDEX_TYPE) > > + SET_TYPE_STRUCTURAL_EQUALITY (t); > > + return t; > > +} > > + > > /* Checks T for any "bare" parameter packs, which have not yet been > > expanded, and issues an error if any are found. This operation can > > only be done on full expressions or types (e.g., an expression > > @@ -13645,11 +13686,12 @@ add_extra_args (tree extra, tree args, tsubst_flags_t complain, tree in_decl) > > return args; > > } > > -/* Substitute ARGS into T, which is an pack expansion > > - (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a > > +/* Substitute ARGS into T, which is a pack expansion > > + (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a > > TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node > > (if only a partial substitution could be performed) or > > ERROR_MARK_NODE if there was an error. */ > > + > > tree > > tsubst_pack_expansion (tree t, tree args, tsubst_flags_t complain, > > tree in_decl) > > @@ -13950,6 +13992,25 @@ tsubst_pack_expansion (tree t, tree args, tsubst_flags_t complain, > > return result; > > } > > +/* Substitute ARGS into T, which is a pack index (i.e., PACK_INDEX_TYPE or > > + PACK_INDEX_EXPR). Returns a single type or expression, a PACK_INDEX_* > > + node if only a partial substitution could be performed, or ERROR_MARK_NODE > > + if there was an error. */ > > + > > +tree > > +tsubst_pack_index (tree t, tree args, tsubst_flags_t complain, tree in_decl) > > +{ > > + tree pack = PACK_INDEX_PACK (t); > > + if (PACK_EXPANSION_P (pack)) > > + pack = tsubst_pack_expansion (pack, args, complain, in_decl); > > + tree index = tsubst_expr (PACK_INDEX_INDEX (t), args, complain, in_decl); > > + if (!value_dependent_expression_p (index) && TREE_CODE (pack) == TREE_VEC) > > + return pack_index_element (index, pack, PACK_INDEX_PARENTHESIZED_P (t), > > + complain); > > + else > > + return make_pack_index (pack, index); > > +} > > + > > /* Make an argument pack out of the TREE_VEC VEC. */ > > static tree > > @@ -16338,7 +16399,8 @@ tsubst (tree t, tree args, tsubst_flags_t complain, tree in_decl) > > && code != TEMPLATE_PARM_INDEX > > && code != IDENTIFIER_NODE > > && code != FUNCTION_TYPE > > - && code != METHOD_TYPE) > > + && code != METHOD_TYPE > > + && code != PACK_INDEX_TYPE) > > type = tsubst (type, args, complain, in_decl); > > if (type == error_mark_node) > > return error_mark_node; > > @@ -16898,9 +16960,15 @@ tsubst (tree t, tree args, tsubst_flags_t complain, tree in_decl) > > ctx = tsubst_pack_expansion (ctx, args, > > complain | tf_qualifying_scope, > > in_decl); > > - if (ctx == error_mark_node > > - || TREE_VEC_LENGTH (ctx) > 1) > > + if (ctx == error_mark_node) > > return error_mark_node; > > + if (TREE_VEC_LENGTH (ctx) > 1) > > + { > > + if (complain & tf_error) > > + error ("%qD expanded to more than one element", > > + TYPENAME_TYPE_FULLNAME (t)); > > + return error_mark_node; > > + } > > if (TREE_VEC_LENGTH (ctx) == 0) > > { > > if (complain & tf_error) > > @@ -17042,12 +17110,17 @@ tsubst (tree t, tree args, tsubst_flags_t complain, tree in_decl) > > else > > { > > bool id = DECLTYPE_TYPE_ID_EXPR_OR_MEMBER_ACCESS_P (t); > > - if (id && TREE_CODE (DECLTYPE_TYPE_EXPR (t)) == BIT_NOT_EXPR > > - && EXPR_P (type)) > > - /* In a template ~id could be either a complement expression > > - or an unqualified-id naming a destructor; if instantiating > > - it produces an expression, it's not an id-expression or > > - member access. */ > > + tree op = DECLTYPE_TYPE_EXPR (t); > > + if (id > > + /* In a template ~id could be either a complement expression > > + or an unqualified-id naming a destructor; if instantiating > > + it produces an expression, it's not an id-expression or > > + member access. */ > > + && ((TREE_CODE (op) == BIT_NOT_EXPR && EXPR_P (type)) > > + /* If the pack indexing was wrapped in (), it's not an > > + id-expression, either. */ > > + || (PACK_INDEX_P (op) > > + && PACK_INDEX_PARENTHESIZED_P (op)))) > > I still think DECLTYPE_TYPE_ID_EXPR_OR_MEMBER_ACCESS_P should be enough in > this case; I would think we only need PACK_INDEX_PARENTHESIZED_P for > tsubst_pack_index to pass to pack_index_element. Looks like I don't need this change anymore. Yay! > > id = false; > > type = finish_decltype_type (type, id, complain); > > } > > @@ -17075,6 +17148,9 @@ tsubst (tree t, tree args, tsubst_flags_t complain, tree in_decl) > > case NONTYPE_ARGUMENT_PACK: > > return tsubst_argument_pack (t, args, complain, in_decl); > > + case PACK_INDEX_TYPE: > > + return tsubst_pack_index (t, args, complain, in_decl); > > + > > case VOID_CST: > > case INTEGER_CST: > > case REAL_CST: > > @@ -21776,6 +21852,9 @@ tsubst_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl) > > RETURN (r); > > } > > + case PACK_INDEX_EXPR: > > + RETURN (tsubst_pack_index (t, args, complain, in_decl)); > > + > > case EXPR_PACK_EXPANSION: > > error ("invalid use of pack expansion expression"); > > RETURN (error_mark_node); > > @@ -28116,8 +28195,9 @@ dependent_type_p_r (tree type) > > } > > /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must > > - be template parameters. */ > > - if (TREE_CODE (type) == TYPE_PACK_EXPANSION) > > + be template parameters. This includes pack-index-specifiers. */ > > + if (TREE_CODE (type) == TYPE_PACK_EXPANSION > > + || TREE_CODE (type) == PACK_INDEX_TYPE) > > return true; > > if (TREE_CODE (type) == DEPENDENT_OPERATOR_TYPE) > > @@ -28740,8 +28820,10 @@ type_dependent_expression_p (tree expression) > > && uses_outer_template_parms_in_constraints (expression)) > > return true; > > - /* Always dependent, on the number of arguments if nothing else. */ > > - if (TREE_CODE (expression) == EXPR_PACK_EXPANSION) > > + /* Always dependent, on the number of arguments if nothing else. This > > + includes pack-index-expressions. */ > > + if (TREE_CODE (expression) == EXPR_PACK_EXPANSION > > + || TREE_CODE (expression) == PACK_INDEX_EXPR) > > return true; > > if (TREE_TYPE (expression) == unknown_type_node) > > diff --git a/gcc/cp/ptree.cc b/gcc/cp/ptree.cc > > index 95c7a69e27c..74152c9476d 100644 > > --- a/gcc/cp/ptree.cc > > +++ b/gcc/cp/ptree.cc > > @@ -193,6 +193,11 @@ cxx_print_type (FILE *file, tree node, int indent) > > print_node (file, "args", PACK_EXPANSION_EXTRA_ARGS (node), indent + 4); > > return; > > + case PACK_INDEX_TYPE: > > + print_node (file, "pack", PACK_INDEX_PACK (node), indent + 4); > > + print_node (file, "index", PACK_INDEX_INDEX (node), indent + 4); > > + return; > > + > > default: > > return; > > } > > diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc > > index ab8614e376d..0b7cd514742 100644 > > --- a/gcc/cp/semantics.cc > > +++ b/gcc/cp/semantics.cc > > @@ -2453,6 +2453,8 @@ finish_parenthesized_expr (cp_expr expr) > > tree stripped_expr = tree_strip_any_location_wrapper (expr); > > if (TREE_CODE (stripped_expr) == STRING_CST) > > PAREN_STRING_LITERAL_P (stripped_expr) = 1; > > + else if (PACK_INDEX_P (stripped_expr)) > > + PACK_INDEX_PARENTHESIZED_P (stripped_expr) = true; > > expr = cp_expr (force_paren_expr (expr), expr.get_location ()); > > @@ -4848,24 +4850,38 @@ finish_type_pack_element (tree idx, tree types, tsubst_flags_t complain) > > if (TREE_CODE (idx) != INTEGER_CST || !INTEGRAL_TYPE_P (TREE_TYPE (idx))) > > { > > if (complain & tf_error) > > - error ("%<__type_pack_element%> index is not an integral constant"); > > + error ("pack index is not an integral constant"); > > return error_mark_node; > > } > > if (tree_int_cst_sgn (idx) < 0) > > { > > if (complain & tf_error) > > - error ("%<__type_pack_element%> index is negative"); > > + error ("pack index is negative"); > > return error_mark_node; > > } > > if (wi::to_widest (idx) >= TREE_VEC_LENGTH (types)) > > { > > if (complain & tf_error) > > - error ("%<__type_pack_element%> index is out of range"); > > + error ("pack index is out of range"); > > return error_mark_node; > > } > > return TREE_VEC_ELT (types, tree_to_shwi (idx)); > > } > > +/* In a pack-index T...[N], return the element at index IDX within TYPES. > > + PARENTHESIZED_P is true iff the pack index was wrapped in (). */ > > + > > +tree > > +pack_index_element (tree idx, tree types, bool parenthesized_p, > > + tsubst_flags_t complain) > > +{ > > + tree r = finish_type_pack_element (idx, types, complain); > > + if (parenthesized_p) > > + /* For the benefit of decltype(auto). */ > > + r = force_paren_expr (r); > > + return r; > > +} > > + > > /* Implement the __direct_bases keyword: Return the direct base classes > > of type. */ > > diff --git a/gcc/cp/tree.cc b/gcc/cp/tree.cc > > index 911260685f1..53fcbc7273e 100644 > > --- a/gcc/cp/tree.cc > > +++ b/gcc/cp/tree.cc > > @@ -4245,6 +4245,15 @@ cp_tree_equal (tree t1, tree t2) > > return false; > > return true; > > + case PACK_INDEX_EXPR: > > + if (!cp_tree_equal (PACK_INDEX_PACK (t1), > > + PACK_INDEX_PACK (t2))) > > + return false; > > + if (!cp_tree_equal (PACK_INDEX_INDEX (t1), > > + PACK_INDEX_INDEX (t2))) > > + return false; > > + return true; > > + > > case COMPONENT_REF: > > /* If we're comparing contract conditions of overrides, member references > > compare equal if they designate the same member. */ > > @@ -5585,6 +5594,13 @@ cp_walk_subtrees (tree *tp, int *walk_subtrees_p, walk_tree_fn func, > > *walk_subtrees_p = 0; > > break; > > + case PACK_INDEX_TYPE: > > + case PACK_INDEX_EXPR: > > + WALK_SUBTREE (PACK_INDEX_PACK (t)); > > + WALK_SUBTREE (PACK_INDEX_INDEX (t)); > > + *walk_subtrees_p = 0; > > + break; > > + > > case CAST_EXPR: > > case REINTERPRET_CAST_EXPR: > > case STATIC_CAST_EXPR: > > diff --git a/gcc/cp/typeck.cc b/gcc/cp/typeck.cc > > index 6ce1bb61fe7..06c632b9ee2 100644 > > --- a/gcc/cp/typeck.cc > > +++ b/gcc/cp/typeck.cc > > @@ -1623,6 +1623,12 @@ structural_comptypes (tree t1, tree t2, int strict) > > && comp_template_args (PACK_EXPANSION_EXTRA_ARGS (t1), > > PACK_EXPANSION_EXTRA_ARGS (t2))); > > + case PACK_INDEX_TYPE: > > + return (cp_tree_equal (PACK_INDEX_PACK (t1), > > + PACK_INDEX_PACK (t2)) > > + && cp_tree_equal (PACK_INDEX_INDEX (t1), > > + PACK_INDEX_INDEX (t2))); > > + > > case DECLTYPE_TYPE: > > if (DECLTYPE_TYPE_ID_EXPR_OR_MEMBER_ACCESS_P (t1) > > != DECLTYPE_TYPE_ID_EXPR_OR_MEMBER_ACCESS_P (t2)) > > ...testsuite... > > I'm not seeing a test for https://eel.is/c++draft/diff#cpp23.dcl.dcl-2 or > the code to handle this case differently in C++23 vs 26. Ah, right. I've added the test (pack-indexing11.C) but we don't compile it C++23 as we should due to: pack-indexing11.C:7:13: error: expected ',' or '...' before '[' token 7 | void f(T... [1]); | ^ which seems like a bug. Opened . Is fixing that a requirement for this patch? > > diff --git a/gcc/testsuite/g++.dg/cpp26/pack-indexing7.C b/gcc/testsuite/g++.dg/cpp26/pack-indexing7.C > > new file mode 100644 > > index 00000000000..06e2a3d0dc7 > > --- /dev/null > > +++ b/gcc/testsuite/g++.dg/cpp26/pack-indexing7.C > > @@ -0,0 +1,16 @@ > > +// P2662R3 - Pack Indexing > > +// PR c++/113798 > > +// { dg-do compile { target c++26 } } > > + > > +template > > +decltype(Ts...[I]) > > +foo () // { dg-message "sorry, unimplemented: mangling" } > > This should be dg-bogus/xfail. Done. > > +{ > > + return Ts...[I]; > > +} > > + > > +int > > +g () > > +{ > > + return foo<2, 0, 1, 42>(); > > +} > > diff --git a/gcc/testsuite/g++.dg/cpp26/pack-indexing8.C b/gcc/testsuite/g++.dg/cpp26/pack-indexing8.C > > new file mode 100644 > > index 00000000000..2b1b67c0841 > > --- /dev/null > > +++ b/gcc/testsuite/g++.dg/cpp26/pack-indexing8.C > > @@ -0,0 +1,23 @@ > > +// P2662R3 - Pack Indexing > > +// PR c++/113798 > > +// { dg-do run { target c++26 } } > > + > > +#include > > + > > +template > > +int > > +g (auto... Is) > > +{ > > + std::initializer_list l{ Is...[0], Is...[1], Is...[2], Is...[3], Is...[4] }; > > + int sum = 0; > > + for (auto x : l) > > + sum += x; > > + return sum; > > +} > > + > > +int > > +main () > > +{ > > + if (g (1, 2, 3, 4, 5) != 15) > > + __builtin_abort (); > > +} > > diff --git a/gcc/testsuite/g++.dg/cpp26/pack-indexing9.C b/gcc/testsuite/g++.dg/cpp26/pack-indexing9.C > > new file mode 100644 > > index 00000000000..468ae9dc4d1 > > --- /dev/null > > +++ b/gcc/testsuite/g++.dg/cpp26/pack-indexing9.C > > @@ -0,0 +1,27 @@ > > +// P2662R3 - Pack Indexing > > +// PR c++/113798 > > +// { dg-do compile { target c++26 } } > > +// From . > > + > > +template struct tuple { > > + template T...[I] get(); // { dg-message "sorry, unimplemented: mangling" } > > dg-bogus/xfail again. Done. Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk? -- >8 -- This patch implements C++26 Pack Indexing, as described in . The issue discussing how to mangle pack indexes has not been resolved yet and I've made no attempt to address it so far. Unlike v1, which used augmented TYPE/EXPR_PACK_EXPANSION codes, this version introduces two new codes: PACK_INDEX_EXPR and PACK_INDEX_TYPE. Both carry two operands: the pack expansion and the index. They are handled in tsubst_pack_index: substitute the index and the pack and then extract the element from the vector (if possible). To handle pack indexing in a decltype or with decltype(auto), there is also the new PACK_INDEX_PARENTHESIZED_P flag. With this feature, it's valid to write something like using U = tmpl; where we first expand the template argument into Ts...[Is#0], Ts...[Is#1], ... and then substitute each individual pack index. PR c++/113798 gcc/cp/ChangeLog: * constexpr.cc (potential_constant_expression_1) : New case. * cp-objcp-common.cc (cp_common_init_ts): Mark PACK_INDEX_TYPE and PACK_INDEX_EXPR. * cp-tree.def (PACK_INDEX_TYPE): New. (PACK_INDEX_EXPR): New. * cp-tree.h (WILDCARD_TYPE_P): Also check PACK_INDEX_TYPE. (PACK_INDEX_CHECK): Define. (PACK_INDEX_P): Define. (PACK_INDEX_PACK): Define. (PACK_INDEX_INDEX): Define. (PACK_INDEX_PARENTHESIZED_P): Define. (make_pack_index): Declare. (pack_index_element): Declare. * cxx-pretty-print.cc (cxx_pretty_printer::expression) : New case. (cxx_pretty_printer::type_id) : New case. * error.cc (dump_type) : New case. (dump_type_prefix): Handle PACK_INDEX_TYPE. (dump_type_suffix): Likewise. (dump_expr) : New case. * mangle.cc (write_type) : New case. * module.cc (trees_out::type_node) : New case. (trees_in::tree_node) : New case. * parser.cc (cp_parser_pack_index): New. (cp_parser_primary_expression): Handle a C++26 pack-index-expression. (cp_parser_unqualified_id): Handle a C++26 pack-index-specifier. (cp_parser_nested_name_specifier_opt): See if a pack-index-specifier follows. (cp_parser_qualifying_entity): Handle a C++26 pack-index-specifier. (cp_parser_decltype_expr): Set id_expression_or_member_access_p for pack indexing. (cp_parser_mem_initializer_id): Handle a C++26 pack-index-specifier. (cp_parser_simple_type_specifier): Likewise. (cp_parser_base_specifier): Likewise. * pt.cc (iterative_hash_template_arg) : New case. (find_parameter_packs_r) : New case. (make_pack_index): New. (tsubst_pack_index): New. (tsubst): Avoid tsubst on PACK_INDEX_TYPE. : Add a call to error. : New case. (tsubst_expr) : New case. (dependent_type_p_r): Return true for PACK_INDEX_TYPE. (type_dependent_expression_p): Return true for PACK_INDEX_EXPR. * ptree.cc (cxx_print_type) : New case. * semantics.cc (finish_parenthesized_expr): Set PACK_INDEX_PARENTHESIZED_P for PACK_INDEX_EXPR. (finish_type_pack_element): Adjust error messages. (pack_index_element): New. * tree.cc (cp_tree_equal) : New case. (cp_walk_subtrees) : New case. * typeck.cc (structural_comptypes) : New case. libstdc++-v3/ChangeLog: * testsuite/20_util/tuple/element_access/get_neg.cc: Adjust dg-prune-output. gcc/testsuite/ChangeLog: * g++.dg/cpp26/pack-indexing1.C: New test. * g++.dg/cpp26/pack-indexing2.C: New test. * g++.dg/cpp26/pack-indexing3.C: New test. * g++.dg/cpp26/pack-indexing4.C: New test. * g++.dg/cpp26/pack-indexing5.C: New test. * g++.dg/cpp26/pack-indexing6.C: New test. * g++.dg/cpp26/pack-indexing7.C: New test. * g++.dg/cpp26/pack-indexing8.C: New test. * g++.dg/cpp26/pack-indexing9.C: New test. * g++.dg/cpp26/pack-indexing10.C: New test. * g++.dg/cpp26/pack-indexing11.C: New test. * g++.dg/modules/pack-index-1_a.C: New test. * g++.dg/modules/pack-index-1_b.C: New test. --- gcc/cp/constexpr.cc | 3 + gcc/cp/cp-objcp-common.cc | 2 + gcc/cp/cp-tree.def | 8 + gcc/cp/cp-tree.h | 31 +++- gcc/cp/cxx-pretty-print.cc | 14 ++ gcc/cp/error.cc | 16 ++ gcc/cp/mangle.cc | 6 + gcc/cp/module.cc | 14 ++ gcc/cp/parser.cc | 167 +++++++++++++++--- gcc/cp/pt.cc | 96 +++++++++- gcc/cp/ptree.cc | 5 + gcc/cp/semantics.cc | 22 ++- gcc/cp/tree.cc | 16 ++ gcc/cp/typeck.cc | 6 + gcc/testsuite/g++.dg/cpp26/pack-indexing1.C | 102 +++++++++++ gcc/testsuite/g++.dg/cpp26/pack-indexing10.C | 15 ++ gcc/testsuite/g++.dg/cpp26/pack-indexing11.C | 13 ++ gcc/testsuite/g++.dg/cpp26/pack-indexing2.C | 111 ++++++++++++ gcc/testsuite/g++.dg/cpp26/pack-indexing3.C | 41 +++++ gcc/testsuite/g++.dg/cpp26/pack-indexing4.C | 65 +++++++ gcc/testsuite/g++.dg/cpp26/pack-indexing5.C | 41 +++++ gcc/testsuite/g++.dg/cpp26/pack-indexing6.C | 51 ++++++ gcc/testsuite/g++.dg/cpp26/pack-indexing7.C | 16 ++ gcc/testsuite/g++.dg/cpp26/pack-indexing8.C | 23 +++ gcc/testsuite/g++.dg/cpp26/pack-indexing9.C | 27 +++ gcc/testsuite/g++.dg/modules/pack-index-1_a.C | 18 ++ gcc/testsuite/g++.dg/modules/pack-index-1_b.C | 15 ++ .../20_util/tuple/element_access/get_neg.cc | 2 +- 28 files changed, 906 insertions(+), 40 deletions(-) create mode 100644 gcc/testsuite/g++.dg/cpp26/pack-indexing1.C create mode 100644 gcc/testsuite/g++.dg/cpp26/pack-indexing10.C create mode 100644 gcc/testsuite/g++.dg/cpp26/pack-indexing11.C create mode 100644 gcc/testsuite/g++.dg/cpp26/pack-indexing2.C create mode 100644 gcc/testsuite/g++.dg/cpp26/pack-indexing3.C create mode 100644 gcc/testsuite/g++.dg/cpp26/pack-indexing4.C create mode 100644 gcc/testsuite/g++.dg/cpp26/pack-indexing5.C create mode 100644 gcc/testsuite/g++.dg/cpp26/pack-indexing6.C create mode 100644 gcc/testsuite/g++.dg/cpp26/pack-indexing7.C create mode 100644 gcc/testsuite/g++.dg/cpp26/pack-indexing8.C create mode 100644 gcc/testsuite/g++.dg/cpp26/pack-indexing9.C create mode 100644 gcc/testsuite/g++.dg/modules/pack-index-1_a.C create mode 100644 gcc/testsuite/g++.dg/modules/pack-index-1_b.C base-commit: 345eb9b795d9728733bd0e472529e259ce796ff6 diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc index 71e6dc4ef32..818b9aa93ca 100644 --- a/gcc/cp/constexpr.cc +++ b/gcc/cp/constexpr.cc @@ -9947,6 +9947,9 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, case EXPR_PACK_EXPANSION: return RECUR (PACK_EXPANSION_PATTERN (t), want_rval); + case PACK_INDEX_EXPR: + return true; + case INDIRECT_REF: { tree x = TREE_OPERAND (t, 0); diff --git a/gcc/cp/cp-objcp-common.cc b/gcc/cp/cp-objcp-common.cc index 7a0636f1653..fe663ecaeb6 100644 --- a/gcc/cp/cp-objcp-common.cc +++ b/gcc/cp/cp-objcp-common.cc @@ -642,6 +642,7 @@ cp_common_init_ts (void) MARK_TS_TYPE_NON_COMMON (TEMPLATE_TEMPLATE_PARM); MARK_TS_TYPE_NON_COMMON (TEMPLATE_TYPE_PARM); MARK_TS_TYPE_NON_COMMON (TYPE_PACK_EXPANSION); + MARK_TS_TYPE_NON_COMMON (PACK_INDEX_TYPE); /* Statements. */ MARK_TS_EXP (CLEANUP_STMT); @@ -700,6 +701,7 @@ cp_common_init_ts (void) MARK_TS_EXP (NONTYPE_ARGUMENT_PACK); MARK_TS_EXP (UNARY_LEFT_FOLD_EXPR); MARK_TS_EXP (UNARY_RIGHT_FOLD_EXPR); + MARK_TS_EXP (PACK_INDEX_EXPR); /* Constraints. */ MARK_TS_EXP (COMPOUND_REQ); diff --git a/gcc/cp/cp-tree.def b/gcc/cp/cp-tree.def index 3de6923f771..fa445ec2781 100644 --- a/gcc/cp/cp-tree.def +++ b/gcc/cp/cp-tree.def @@ -397,6 +397,14 @@ DEFTREECODE (TYPE_PACK_EXPANSION, "type_pack_expansion", tcc_type, 0) but will be used for expressions. */ DEFTREECODE (EXPR_PACK_EXPANSION, "expr_pack_expansion", tcc_expression, 3) +/* Represents a pack index Ts...[I], yielding a type. PACK_INDEX_PACK is + the pack expansion Ts, PACK_INDEX_INDEX the index I. */ +DEFTREECODE (PACK_INDEX_TYPE, "pack_index_type", tcc_type, 0) + +/* Represents a pack index Ts...[I], yielding an expression. PACK_INDEX_PACK + is the pack expansion Ts, PACK_INDEX_INDEX the index I. */ +DEFTREECODE (PACK_INDEX_EXPR, "pack_index_expr", tcc_expression, 2) + /* Selects the Ith parameter out of an argument pack. This node will be used when instantiating pack expansions; see tsubst_pack_expansion. diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h index 92d1dba6a5c..c0b6cd0260a 100644 --- a/gcc/cp/cp-tree.h +++ b/gcc/cp/cp-tree.h @@ -451,6 +451,7 @@ extern GTY(()) tree cp_global_trees[CPTI_MAX]; ATOMIC_CONSTR_MAP_INSTANTIATED_P (in ATOMIC_CONSTR) contract_semantic (in ASSERTION_, PRECONDITION_, POSTCONDITION_STMT) RETURN_EXPR_LOCAL_ADDR_P (in RETURN_EXPR) + PACK_INDEX_PARENTHESIZED_P (in PACK_INDEX_*) 1: IDENTIFIER_KIND_BIT_1 (in IDENTIFIER_NODE) TI_PENDING_TEMPLATE_FLAG. TEMPLATE_PARMS_FOR_INLINE. @@ -2258,7 +2259,8 @@ enum languages { lang_c, lang_cplusplus }; || TREE_CODE (T) == BOUND_TEMPLATE_TEMPLATE_PARM \ || TREE_CODE (T) == DECLTYPE_TYPE \ || TREE_CODE (T) == TRAIT_TYPE \ - || TREE_CODE (T) == DEPENDENT_OPERATOR_TYPE) + || TREE_CODE (T) == DEPENDENT_OPERATOR_TYPE \ + || TREE_CODE (T) == PACK_INDEX_TYPE) /* Nonzero if T is a class (or struct or union) type. Also nonzero for template type parameters, typename types, and instantiated @@ -4001,6 +4003,9 @@ struct GTY(()) lang_decl { #define PACK_EXPANSION_CHECK(NODE) \ TREE_CHECK2 (NODE, TYPE_PACK_EXPANSION, EXPR_PACK_EXPANSION) +#define PACK_INDEX_CHECK(NODE) \ + TREE_CHECK2 (NODE, PACK_INDEX_TYPE, PACK_INDEX_EXPR) + /* Extracts the type or expression pattern from a TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION. */ #define PACK_EXPANSION_PATTERN(NODE) \ @@ -4025,6 +4030,22 @@ struct GTY(()) lang_decl { ? &TYPE_MAX_VALUE_RAW (NODE) \ : &TREE_OPERAND ((NODE), 2)) +/* True if NODE is a pack index. */ +#define PACK_INDEX_P(NODE) \ + (TREE_CODE (NODE) == PACK_INDEX_TYPE \ + || TREE_CODE (NODE) == PACK_INDEX_EXPR) + +/* For a pack index T...[N], the pack expansion 'T...'. */ +#define PACK_INDEX_PACK(NODE) \ + (TREE_CODE (PACK_INDEX_CHECK (NODE)) == PACK_INDEX_TYPE \ + ? TREE_TYPE (NODE) : TREE_OPERAND (NODE, 0)) + +/* For a pack index T...[N], the index N. */ +#define PACK_INDEX_INDEX(NODE) \ + *(TREE_CODE (PACK_INDEX_CHECK (NODE)) == PACK_INDEX_TYPE \ + ? &TYPE_MAX_VALUE_RAW (NODE) \ + : &TREE_OPERAND ((NODE), 1)) + /* True iff this pack expansion is within a function context. */ #define PACK_EXPANSION_LOCAL_P(NODE) \ TREE_LANG_FLAG_0 (PACK_EXPANSION_CHECK (NODE)) @@ -4042,6 +4063,11 @@ struct GTY(()) lang_decl { #define PACK_EXPANSION_FORCE_EXTRA_ARGS_P(NODE) \ TREE_LANG_FLAG_3 (PACK_EXPANSION_CHECK (NODE)) +/* Indicates whether a pack expansion has been parenthesized. Used for + a pack expansion in a decltype. */ +#define PACK_INDEX_PARENTHESIZED_P(NODE) \ + TREE_LANG_FLAG_1 (TREE_CHECK (NODE, PACK_INDEX_EXPR)) + /* True iff the wildcard can match a template parameter pack. */ #define WILDCARD_PACK_P(NODE) TREE_LANG_FLAG_0 (NODE) @@ -7581,6 +7607,7 @@ extern bool template_parameter_pack_p (const_tree); extern bool function_parameter_pack_p (const_tree); extern bool function_parameter_expanded_from_pack_p (tree, tree); extern tree make_pack_expansion (tree, tsubst_flags_t = tf_warning_or_error); +extern tree make_pack_index (tree, tree); extern bool check_for_bare_parameter_packs (tree, location_t = UNKNOWN_LOCATION); extern tree build_template_info (tree, tree); extern tree get_template_info (const_tree); @@ -7906,6 +7933,8 @@ extern tree finish_underlying_type (tree); extern tree calculate_bases (tree, tsubst_flags_t); extern tree finish_bases (tree, bool); extern tree calculate_direct_bases (tree, tsubst_flags_t); +extern tree pack_index_element (tree, tree, bool, + tsubst_flags_t); extern tree finish_offsetof (tree, tree, location_t); extern void finish_decl_cleanup (tree, tree); extern void finish_eh_cleanup (tree); diff --git a/gcc/cp/cxx-pretty-print.cc b/gcc/cp/cxx-pretty-print.cc index f4203123737..15d41b55557 100644 --- a/gcc/cp/cxx-pretty-print.cc +++ b/gcc/cp/cxx-pretty-print.cc @@ -1220,6 +1220,13 @@ cxx_pretty_printer::expression (tree t) pp_cxx_ws_string (this, "..."); break; + case PACK_INDEX_EXPR: + expression (PACK_INDEX_PACK (t)); + pp_cxx_left_bracket (this); + expression (PACK_INDEX_INDEX (t)); + pp_cxx_right_bracket (this); + break; + case UNARY_LEFT_FOLD_EXPR: pp_cxx_unary_left_fold_expression (this, t); break; @@ -1920,6 +1927,13 @@ cxx_pretty_printer::type_id (tree t) pp_cxx_ws_string (this, "..."); break; + case PACK_INDEX_TYPE: + type_id (PACK_INDEX_PACK (t)); + pp_cxx_left_bracket (this); + expression (PACK_INDEX_INDEX (t)); + pp_cxx_right_bracket (this); + break; + case TYPE_ARGUMENT_PACK: { tree args = ARGUMENT_PACK_ARGS (t); diff --git a/gcc/cp/error.cc b/gcc/cp/error.cc index 7ef79b90868..c62c9d7312e 100644 --- a/gcc/cp/error.cc +++ b/gcc/cp/error.cc @@ -814,6 +814,13 @@ dump_type (cxx_pretty_printer *pp, tree t, int flags) pp_cxx_ws_string (pp, "..."); break; + case PACK_INDEX_TYPE: + dump_type (pp, PACK_INDEX_PACK (t), flags); + pp_cxx_left_bracket (pp); + dump_expr (pp, PACK_INDEX_INDEX (t), flags & ~TFF_EXPR_IN_PARENS); + pp_cxx_right_bracket (pp); + break; + case TYPE_ARGUMENT_PACK: dump_template_argument (pp, t, flags); break; @@ -1088,6 +1095,7 @@ dump_type_prefix (cxx_pretty_printer *pp, tree t, int flags) case TYPE_PACK_EXPANSION: case FIXED_POINT_TYPE: case NULLPTR_TYPE: + case PACK_INDEX_TYPE: dump_type (pp, t, flags); pp->set_padding (pp_before); break; @@ -1220,6 +1228,7 @@ dump_type_suffix (cxx_pretty_printer *pp, tree t, int flags) case TYPE_PACK_EXPANSION: case FIXED_POINT_TYPE: case NULLPTR_TYPE: + case PACK_INDEX_TYPE: break; default: @@ -3103,6 +3112,13 @@ dump_expr (cxx_pretty_printer *pp, tree t, int flags) pp->expression (t); break; + case PACK_INDEX_EXPR: + pp->expression (PACK_INDEX_PACK (t)); + pp_cxx_left_bracket (pp); + pp->expression (PACK_INDEX_INDEX (t)); + pp_cxx_right_bracket (pp); + break; + case TRUTH_AND_EXPR: case TRUTH_OR_EXPR: case TRUTH_XOR_EXPR: diff --git a/gcc/cp/mangle.cc b/gcc/cp/mangle.cc index 4d46c0917a9..c103b50b1f1 100644 --- a/gcc/cp/mangle.cc +++ b/gcc/cp/mangle.cc @@ -2669,6 +2669,12 @@ write_type (tree type) "use library traits instead", type); break; + case PACK_INDEX_TYPE: + /* TODO Mangle pack indexing + . */ + sorry ("mangling type pack index"); + break; + case LANG_TYPE: /* fall through. */ diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc index 4eefb2d3584..f6f87b7d80b 100644 --- a/gcc/cp/module.cc +++ b/gcc/cp/module.cc @@ -9240,6 +9240,11 @@ trees_out::type_node (tree type) tree_node (PACK_EXPANSION_EXTRA_ARGS (type)); break; + case PACK_INDEX_TYPE: + tree_node (PACK_INDEX_PACK (type)); + tree_node (PACK_INDEX_INDEX (type)); + break; + case TYPENAME_TYPE: { tree_node (TYPE_CONTEXT (type)); @@ -9807,6 +9812,15 @@ trees_in::tree_node (bool is_use) } break; + case PACK_INDEX_TYPE: + { + tree pack = tree_node (); + tree index = tree_node (); + if (!get_overrun ()) + res = make_pack_index (pack, index); + } + break; + case TYPENAME_TYPE: { tree ctx = tree_node (); diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc index c1375ecdbb5..082456491a6 100644 --- a/gcc/cp/parser.cc +++ b/gcc/cp/parser.cc @@ -5739,6 +5739,54 @@ cp_parser_fold_expression (cp_parser *parser, tree expr1) return finish_binary_fold_expr (loc, expr1, expr2, op); } +/* Parse a pack-index-specifier: + + pack-index-specifier: + typedef-name ... [ constant-expression ] + + or a pack-index-expression: + + pack-index-expression: + id-expression ... [ constant-expression ] + + PACK is the parsed typedef-name or the id-expression. Returns + either a PACK_INDEX_TYPE or PACK_INDEX_EXPR. */ + +static tree +cp_parser_pack_index (cp_parser *parser, tree pack) +{ + if (cxx_dialect < cxx26) + pedwarn (cp_lexer_peek_token (parser->lexer)->location, + OPT_Wc__26_extensions, "pack indexing only available with " + "%<-std=c++2c%> or %<-std=gnu++2c%>"); + /* Consume the '...' token. */ + cp_lexer_consume_token (parser->lexer); + /* Consume the '['. */ + cp_lexer_consume_token (parser->lexer); + + if (cp_lexer_next_token_is (parser->lexer, CPP_CLOSE_SQUARE)) + { + error_at (cp_lexer_peek_token (parser->lexer)->location, + "pack index missing"); + cp_lexer_consume_token (parser->lexer); + return error_mark_node; + } + + tree index = cp_parser_constant_expression (parser, + /*allow_non_constant_p=*/false, + /*non_constant_p=*/nullptr, + /*strict_p=*/true); + /* Consume the ']'. */ + cp_parser_require (parser, CPP_CLOSE_SQUARE, RT_CLOSE_SQUARE); + + if (TREE_CODE (pack) == TYPE_DECL) + pack = TREE_TYPE (pack); + pack = make_pack_expansion (pack); + if (pack == error_mark_node) + return error_mark_node; + return make_pack_index (pack, index); +} + /* Parse a primary-expression. primary-expression: @@ -6368,6 +6416,12 @@ cp_parser_primary_expression (cp_parser *parser, = make_location (caret_loc, start_loc, finish_loc); decl.set_location (combined_loc); + + /* "T...[constant-expression]" is a C++26 pack-index-expression. */ + if (cp_lexer_next_token_is (parser->lexer, CPP_ELLIPSIS) + && cp_lexer_nth_token_is (parser->lexer, 2, CPP_OPEN_SQUARE)) + decl = cp_parser_pack_index (parser, decl); + return decl; } @@ -6411,6 +6465,7 @@ missing_template_diag (location_t loc, diagnostic_t diag_kind = DK_WARNING) id-expression: unqualified-id qualified-id + pack-index-expression qualified-id: :: [opt] nested-name-specifier template [opt] unqualified-id @@ -6593,7 +6648,9 @@ cp_parser_id_expression (cp_parser *parser, identifier operator-function-id conversion-function-id - ~ class-name + literal-operator-id + ~ type-name + ~ computed-type-specifier template-id If TEMPLATE_KEYWORD_P is TRUE, we have just seen the `template' @@ -6900,6 +6957,14 @@ cp_parser_unqualified_id (cp_parser* parser, "typedef-name %qD used as destructor declarator", type_decl); + /* "~T...[N]" is a C++26 pack-index-specifier. */ + if (cp_lexer_next_token_is (parser->lexer, CPP_ELLIPSIS) + && cp_lexer_nth_token_is (parser->lexer, 2, CPP_OPEN_SQUARE)) + { + type_decl = cp_parser_pack_index (parser, type_decl); + return build_min_nt_loc (loc, BIT_NOT_EXPR, type_decl); + } + return build_min_nt_loc (loc, BIT_NOT_EXPR, TREE_TYPE (type_decl)); } @@ -6970,9 +7035,10 @@ check_template_keyword_in_nested_name_spec (tree name) class-or-namespace-name :: nested-name-specifier [opt] class-or-namespace-name :: template nested-name-specifier [opt] - nested-name-specifier: [C++0x] + nested-name-specifier: [C++11] type-name :: namespace-name :: + computed-type-specifier :: nested-name-specifier identifier :: nested-name-specifier template [opt] simple-template-id :: @@ -7061,8 +7127,8 @@ cp_parser_nested_name_specifier_opt (cp_parser *parser, if (token->type != CPP_NAME) break; /* If the following token is neither a `<' (to begin a - template-id), nor a `::', then we are not looking at a - nested-name-specifier. */ + template-id), a `...[' (to begin a pack-index-specifier), + nor a `::', then we are not looking at a nested-name-specifier. */ token = cp_lexer_peek_nth_token (parser->lexer, 2); if (token->type == CPP_COLON @@ -7080,6 +7146,10 @@ cp_parser_nested_name_specifier_opt (cp_parser *parser, } if (token->type != CPP_SCOPE + /* See if a pack-index-specifier follows. */ + && !(token->type == CPP_ELLIPSIS + && cp_lexer_peek_nth_token (parser->lexer, 3)->type + == CPP_OPEN_SQUARE) && !cp_parser_nth_token_starts_template_argument_list_p (parser, 2)) break; @@ -7444,6 +7514,13 @@ cp_parser_qualifying_entity (cp_parser *parser, is_declaration, /*enum_ok=*/cxx_dialect > cxx98); successful_parse_p = only_class_p || cp_parser_parse_definitely (parser); + + /* "T...[constant-expression]" is a C++26 pack-index-specifier. */ + if (successful_parse_p + && cp_lexer_next_token_is (parser->lexer, CPP_ELLIPSIS) + && cp_lexer_nth_token_is (parser->lexer, 2, CPP_OPEN_SQUARE)) + scope = cp_parser_pack_index (parser, scope); + /* If that didn't work, try for a namespace-name. */ if (!only_class_p && !successful_parse_p) { @@ -17332,6 +17409,12 @@ cp_parser_decltype_expr (cp_parser *parser, tree id_expression = expr; cp_id_kind idk; const char *error_msg; + const bool pack_index_p + = (cp_lexer_next_token_is (parser->lexer, CPP_ELLIPSIS) + && cp_lexer_nth_token_is (parser->lexer, 2, CPP_OPEN_SQUARE)); + const bool have_id_expr_p + = (pack_index_p + || cp_lexer_peek_token (parser->lexer)->type == CPP_CLOSE_PAREN); if (identifier_p (expr)) /* Lookup the name we got back from the id-expression. */ @@ -17343,7 +17426,7 @@ cp_parser_decltype_expr (cp_parser *parser, && TREE_CODE (expr) != TYPE_DECL && (TREE_CODE (expr) != BIT_NOT_EXPR || !TYPE_P (TREE_OPERAND (expr, 0))) - && cp_lexer_peek_token (parser->lexer)->type == CPP_CLOSE_PAREN) + && have_id_expr_p) { /* Complete lookup of the id-expression. */ expr = (finish_id_expression @@ -17371,11 +17454,13 @@ cp_parser_decltype_expr (cp_parser *parser, } } - if (expr - && expr != error_mark_node - && cp_lexer_peek_token (parser->lexer)->type == CPP_CLOSE_PAREN) - /* We have an id-expression. */ - id_expression_or_member_access_p = true; + if (expr && expr != error_mark_node && have_id_expr_p) + { + /* We have an id-expression. */ + id_expression_or_member_access_p = true; + if (pack_index_p) + expr = cp_parser_pack_index (parser, expr); + } } if (!id_expression_or_member_access_p) @@ -17938,13 +18023,17 @@ cp_parser_mem_initializer (cp_parser* parser) /* Parse a mem-initializer-id. mem-initializer-id: - :: [opt] nested-name-specifier [opt] class-name - decltype-specifier (C++11) + class-or-decltype identifier + class-or-decltype: + nested-name-specifier [opt] type-name + nested-name-specifier template simple-template-id + computed-type-specifier + Returns a TYPE indicating the class to be initialized for the first - production (and the second in C++11). Returns an IDENTIFIER_NODE - indicating the data member to be initialized for the last production. */ + production. Returns an IDENTIFIER_NODE indicating the data member to + be initialized for the second production. */ static tree cp_parser_mem_initializer_id (cp_parser* parser) @@ -18015,10 +18104,16 @@ cp_parser_mem_initializer_id (cp_parser* parser) /*class_head_p=*/false, /*is_declaration=*/true); /* If we found one, we're done. */ - if (cp_parser_parse_definitely (parser)) - return id; - /* Otherwise, look for an ordinary identifier. */ - return cp_parser_identifier (parser); + if (!cp_parser_parse_definitely (parser)) + /* Otherwise, look for an ordinary identifier. */ + id = cp_parser_identifier (parser); + + /* ": T...[N]" is a C++26 pack-index-specifier. */ + if (cp_lexer_next_token_is (parser->lexer, CPP_ELLIPSIS) + && cp_lexer_nth_token_is (parser->lexer, 2, CPP_OPEN_SQUARE)) + id = cp_parser_pack_index (parser, id); + + return id; } /* Overloading [gram.over] */ @@ -20436,11 +20531,11 @@ cp_parser_type_specifier (cp_parser* parser, C++11 Extension: simple-type-specifier: - auto - decltype ( expression ) char16_t char32_t __underlying_type ( type-id ) + computed-type-specifier + placeholder-type-specifier C++17 extension: @@ -20822,6 +20917,13 @@ cp_parser_simple_type_specifier (cp_parser* parser, type = NULL_TREE; } + /* "T...[constant-expression]" is a C++26 pack-index-specifier. */ + if (type + && type != error_mark_node + && cp_lexer_next_token_is (parser->lexer, CPP_ELLIPSIS) + && cp_lexer_nth_token_is (parser->lexer, 2, CPP_OPEN_SQUARE)) + type = cp_parser_pack_index (parser, type); + if (!type && flag_concepts && decl_specs) { /* Try for a type-constraint with template arguments. We check @@ -29103,12 +29205,21 @@ cp_parser_base_clause (cp_parser* parser) /* Parse a base-specifier. base-specifier: - attribute-specifier-seq [opt] :: [opt] nested-name-specifier [opt] - class-name - attribute-specifier-seq [opt] virtual access-specifier [opt] :: [opt] - nested-name-specifier [opt] class-name - attribute-specifier-seq [opt] access-specifier virtual [opt] :: [opt] - nested-name-specifier [opt] class-name + attribute-specifier-seq [opt] class-or-decltype + attribute-specifier-seq [opt] virtual access-specifier [opt] + class-or-decltype + attribute-specifier-seq [opt] access-specifier virtual [opt] + class-or-decltype + + class-or-decltype: + nested-name-specifier [opt] type-name + nested-name-specifier template simple-template-id + computed-type-specifier + + access-specifier: + private + protected + public Returns a TREE_LIST. The TREE_PURPOSE will be one of ACCESS_{DEFAULT,PUBLIC,PROTECTED,PRIVATE}_[VIRTUAL]_NODE to @@ -29237,6 +29348,10 @@ cp_parser_base_specifier (cp_parser* parser) /*class_head_p=*/false, /*is_declaration=*/true); type = TREE_TYPE (type); + /* ": T...[constant-expression]" is a C++26 pack-index-specifier. */ + if (cp_lexer_next_token_is (parser->lexer, CPP_ELLIPSIS) + && cp_lexer_nth_token_is (parser->lexer, 2, CPP_OPEN_SQUARE)) + type = cp_parser_pack_index (parser, type); } if (type == error_mark_node) diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc index f4213f88b99..e7347c0b730 100644 --- a/gcc/cp/pt.cc +++ b/gcc/cp/pt.cc @@ -1789,6 +1789,11 @@ iterative_hash_template_arg (tree arg, hashval_t val) val = iterative_hash_template_arg (PACK_EXPANSION_PATTERN (arg), val); return iterative_hash_template_arg (PACK_EXPANSION_EXTRA_ARGS (arg), val); + case PACK_INDEX_TYPE: + case PACK_INDEX_EXPR: + val = iterative_hash_template_arg (PACK_INDEX_PACK (arg), val); + return iterative_hash_template_arg (PACK_INDEX_INDEX (arg), val); + case TYPE_ARGUMENT_PACK: case NONTYPE_ARGUMENT_PACK: return iterative_hash_template_arg (ARGUMENT_PACK_ARGS (arg), val); @@ -4031,6 +4036,15 @@ find_parameter_packs_r (tree *tp, int *walk_subtrees, void* data) *walk_subtrees = 0; return NULL_TREE; + case PACK_INDEX_TYPE: + case PACK_INDEX_EXPR: + /* We can have an expansion of an expansion, such as "Ts...[Is]...", + so do look into the index. */ + cp_walk_tree (&PACK_INDEX_INDEX (t), &find_parameter_packs_r, ppd, + ppd->visited); + *walk_subtrees = 0; + return NULL_TREE; + case INTEGER_TYPE: cp_walk_tree (&TYPE_MAX_VALUE (t), &find_parameter_packs_r, ppd, ppd->visited); @@ -4257,6 +4271,33 @@ make_pack_expansion (tree arg, tsubst_flags_t complain) return result; } +/* Create a PACK_INDEX_* using the pack expansion PACK and index INDEX. */ + +tree +make_pack_index (tree pack, tree index) +{ + bool for_types; + if (TREE_CODE (pack) == TYPE_PACK_EXPANSION) + for_types = true; + else if (TREE_CODE (pack) == EXPR_PACK_EXPANSION) + for_types = false; + else + { + /* Maybe we've already partially substituted the pack. */ + gcc_checking_assert (TREE_CODE (pack) == TREE_VEC); + for_types = TYPE_P (TREE_VEC_ELT (pack, 0)); + } + + tree t = (for_types + ? cxx_make_type (PACK_INDEX_TYPE) + : make_node (PACK_INDEX_EXPR)); + PACK_INDEX_PACK (t) = pack; + PACK_INDEX_INDEX (t) = index; + if (TREE_CODE (t) == PACK_INDEX_TYPE) + SET_TYPE_STRUCTURAL_EQUALITY (t); + return t; +} + /* Checks T for any "bare" parameter packs, which have not yet been expanded, and issues an error if any are found. This operation can only be done on full expressions or types (e.g., an expression @@ -13648,11 +13689,12 @@ add_extra_args (tree extra, tree args, tsubst_flags_t complain, tree in_decl) return args; } -/* Substitute ARGS into T, which is an pack expansion - (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a +/* Substitute ARGS into T, which is a pack expansion + (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node (if only a partial substitution could be performed) or ERROR_MARK_NODE if there was an error. */ + tree tsubst_pack_expansion (tree t, tree args, tsubst_flags_t complain, tree in_decl) @@ -13953,6 +13995,26 @@ tsubst_pack_expansion (tree t, tree args, tsubst_flags_t complain, return result; } +/* Substitute ARGS into T, which is a pack index (i.e., PACK_INDEX_TYPE or + PACK_INDEX_EXPR). Returns a single type or expression, a PACK_INDEX_* + node if only a partial substitution could be performed, or ERROR_MARK_NODE + if there was an error. */ + +tree +tsubst_pack_index (tree t, tree args, tsubst_flags_t complain, tree in_decl) +{ + tree pack = PACK_INDEX_PACK (t); + if (PACK_EXPANSION_P (pack)) + pack = tsubst_pack_expansion (pack, args, complain, in_decl); + tree index = tsubst_expr (PACK_INDEX_INDEX (t), args, complain, in_decl); + const bool parenthesized_p = (TREE_CODE (t) == PACK_INDEX_EXPR + && PACK_INDEX_PARENTHESIZED_P (t)); + if (!value_dependent_expression_p (index) && TREE_CODE (pack) == TREE_VEC) + return pack_index_element (index, pack, parenthesized_p, complain); + else + return make_pack_index (pack, index); +} + /* Make an argument pack out of the TREE_VEC VEC. */ static tree @@ -16341,7 +16403,8 @@ tsubst (tree t, tree args, tsubst_flags_t complain, tree in_decl) && code != TEMPLATE_PARM_INDEX && code != IDENTIFIER_NODE && code != FUNCTION_TYPE - && code != METHOD_TYPE) + && code != METHOD_TYPE + && code != PACK_INDEX_TYPE) type = tsubst (type, args, complain, in_decl); if (type == error_mark_node) return error_mark_node; @@ -16901,9 +16964,15 @@ tsubst (tree t, tree args, tsubst_flags_t complain, tree in_decl) ctx = tsubst_pack_expansion (ctx, args, complain | tf_qualifying_scope, in_decl); - if (ctx == error_mark_node - || TREE_VEC_LENGTH (ctx) > 1) + if (ctx == error_mark_node) return error_mark_node; + if (TREE_VEC_LENGTH (ctx) > 1) + { + if (complain & tf_error) + error ("%qD expanded to more than one element", + TYPENAME_TYPE_FULLNAME (t)); + return error_mark_node; + } if (TREE_VEC_LENGTH (ctx) == 0) { if (complain & tf_error) @@ -17078,6 +17147,9 @@ tsubst (tree t, tree args, tsubst_flags_t complain, tree in_decl) case NONTYPE_ARGUMENT_PACK: return tsubst_argument_pack (t, args, complain, in_decl); + case PACK_INDEX_TYPE: + return tsubst_pack_index (t, args, complain, in_decl); + case VOID_CST: case INTEGER_CST: case REAL_CST: @@ -21779,6 +21851,9 @@ tsubst_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl) RETURN (r); } + case PACK_INDEX_EXPR: + RETURN (tsubst_pack_index (t, args, complain, in_decl)); + case EXPR_PACK_EXPANSION: error ("invalid use of pack expansion expression"); RETURN (error_mark_node); @@ -28119,8 +28194,9 @@ dependent_type_p_r (tree type) } /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must - be template parameters. */ - if (TREE_CODE (type) == TYPE_PACK_EXPANSION) + be template parameters. This includes pack-index-specifiers. */ + if (TREE_CODE (type) == TYPE_PACK_EXPANSION + || TREE_CODE (type) == PACK_INDEX_TYPE) return true; if (TREE_CODE (type) == DEPENDENT_OPERATOR_TYPE) @@ -28743,8 +28819,10 @@ type_dependent_expression_p (tree expression) && uses_outer_template_parms_in_constraints (expression)) return true; - /* Always dependent, on the number of arguments if nothing else. */ - if (TREE_CODE (expression) == EXPR_PACK_EXPANSION) + /* Always dependent, on the number of arguments if nothing else. This + includes pack-index-expressions. */ + if (TREE_CODE (expression) == EXPR_PACK_EXPANSION + || TREE_CODE (expression) == PACK_INDEX_EXPR) return true; if (TREE_TYPE (expression) == unknown_type_node) diff --git a/gcc/cp/ptree.cc b/gcc/cp/ptree.cc index 95c7a69e27c..74152c9476d 100644 --- a/gcc/cp/ptree.cc +++ b/gcc/cp/ptree.cc @@ -193,6 +193,11 @@ cxx_print_type (FILE *file, tree node, int indent) print_node (file, "args", PACK_EXPANSION_EXTRA_ARGS (node), indent + 4); return; + case PACK_INDEX_TYPE: + print_node (file, "pack", PACK_INDEX_PACK (node), indent + 4); + print_node (file, "index", PACK_INDEX_INDEX (node), indent + 4); + return; + default: return; } diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc index ab8614e376d..6e80717cde7 100644 --- a/gcc/cp/semantics.cc +++ b/gcc/cp/semantics.cc @@ -2453,6 +2453,8 @@ finish_parenthesized_expr (cp_expr expr) tree stripped_expr = tree_strip_any_location_wrapper (expr); if (TREE_CODE (stripped_expr) == STRING_CST) PAREN_STRING_LITERAL_P (stripped_expr) = 1; + else if (TREE_CODE (stripped_expr) == PACK_INDEX_EXPR) + PACK_INDEX_PARENTHESIZED_P (stripped_expr) = true; expr = cp_expr (force_paren_expr (expr), expr.get_location ()); @@ -4848,24 +4850,38 @@ finish_type_pack_element (tree idx, tree types, tsubst_flags_t complain) if (TREE_CODE (idx) != INTEGER_CST || !INTEGRAL_TYPE_P (TREE_TYPE (idx))) { if (complain & tf_error) - error ("%<__type_pack_element%> index is not an integral constant"); + error ("pack index is not an integral constant"); return error_mark_node; } if (tree_int_cst_sgn (idx) < 0) { if (complain & tf_error) - error ("%<__type_pack_element%> index is negative"); + error ("pack index is negative"); return error_mark_node; } if (wi::to_widest (idx) >= TREE_VEC_LENGTH (types)) { if (complain & tf_error) - error ("%<__type_pack_element%> index is out of range"); + error ("pack index is out of range"); return error_mark_node; } return TREE_VEC_ELT (types, tree_to_shwi (idx)); } +/* In a pack-index T...[N], return the element at index IDX within TYPES. + PARENTHESIZED_P is true iff the pack index was wrapped in (). */ + +tree +pack_index_element (tree idx, tree types, bool parenthesized_p, + tsubst_flags_t complain) +{ + tree r = finish_type_pack_element (idx, types, complain); + if (parenthesized_p) + /* For the benefit of decltype(auto). */ + r = force_paren_expr (r); + return r; +} + /* Implement the __direct_bases keyword: Return the direct base classes of type. */ diff --git a/gcc/cp/tree.cc b/gcc/cp/tree.cc index 8e566cadcaf..73c97c35046 100644 --- a/gcc/cp/tree.cc +++ b/gcc/cp/tree.cc @@ -4278,6 +4278,15 @@ cp_tree_equal (tree t1, tree t2) return false; return true; + case PACK_INDEX_EXPR: + if (!cp_tree_equal (PACK_INDEX_PACK (t1), + PACK_INDEX_PACK (t2))) + return false; + if (!cp_tree_equal (PACK_INDEX_INDEX (t1), + PACK_INDEX_INDEX (t2))) + return false; + return true; + case COMPONENT_REF: /* If we're comparing contract conditions of overrides, member references compare equal if they designate the same member. */ @@ -5618,6 +5627,13 @@ cp_walk_subtrees (tree *tp, int *walk_subtrees_p, walk_tree_fn func, *walk_subtrees_p = 0; break; + case PACK_INDEX_TYPE: + case PACK_INDEX_EXPR: + WALK_SUBTREE (PACK_INDEX_PACK (t)); + WALK_SUBTREE (PACK_INDEX_INDEX (t)); + *walk_subtrees_p = 0; + break; + case CAST_EXPR: case REINTERPRET_CAST_EXPR: case STATIC_CAST_EXPR: diff --git a/gcc/cp/typeck.cc b/gcc/cp/typeck.cc index 4c15e26f692..50c53dad9c5 100644 --- a/gcc/cp/typeck.cc +++ b/gcc/cp/typeck.cc @@ -1623,6 +1623,12 @@ structural_comptypes (tree t1, tree t2, int strict) && comp_template_args (PACK_EXPANSION_EXTRA_ARGS (t1), PACK_EXPANSION_EXTRA_ARGS (t2))); + case PACK_INDEX_TYPE: + return (cp_tree_equal (PACK_INDEX_PACK (t1), + PACK_INDEX_PACK (t2)) + && cp_tree_equal (PACK_INDEX_INDEX (t1), + PACK_INDEX_INDEX (t2))); + case DECLTYPE_TYPE: if (DECLTYPE_TYPE_ID_EXPR_OR_MEMBER_ACCESS_P (t1) != DECLTYPE_TYPE_ID_EXPR_OR_MEMBER_ACCESS_P (t2)) diff --git a/gcc/testsuite/g++.dg/cpp26/pack-indexing1.C b/gcc/testsuite/g++.dg/cpp26/pack-indexing1.C new file mode 100644 index 00000000000..e8c7a90ae58 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp26/pack-indexing1.C @@ -0,0 +1,102 @@ +// P2662R3 - Pack Indexing +// PR c++/113798 +// { dg-do compile { target c++17 } } +// { dg-options "" } + +template struct same_type; +template struct same_type {}; + +template +using Type = Ts...[I]; // { dg-warning "pack indexing only available with" "" { target c++23_down } } + +template +constexpr auto Var = Ts...[I]; // { dg-warning "pack indexing only available with" "" { target c++23_down } } + +template +int +foo () +{ + return Ts...[I]; // { dg-warning "pack indexing only available with" "" { target c++23_down } } +} + +template +struct S { + Ts...[0] a; // { dg-warning "pack indexing only available with" "" { target c++23_down } } +#if __cpp_concepts >= 201907L + void foo (auto... Vs) { + decltype(Vs...[1]) d1 = Vs...[1]; // { dg-warning "pack indexing only available with" "" { target { c++20 && c++23_down } } } + } +#endif +}; + +int +g () +{ + using U = Type<1, char, int, float>; + using U = int; + + constexpr auto V = Var<2, 0, 1, 42>; + static_assert (V == 42); + + U r = foo<2, 0, 1, 42>(); + + return r; +} + +void +fn1 () +{ + int i = 0; + [&i](auto... pack) { + // type is int + decltype(pack...[0]) x5 = 42; // { dg-warning "pack indexing only available with" "" { target c++23_down } } + // type is int& + [[maybe_unused]] decltype((pack...[0])) x6 = i; // { dg-warning "pack indexing only available with" "" { target c++23_down } } + }(0); +} + +#if __cpp_concepts >= 201907L +int +bar (auto... pack) +{ + (void) pack...[0]; // { dg-warning "pack indexing only available with" "" { target { c++20 && c++23_down } } } + int x = pack...[0]; // { dg-warning "pack indexing only available with" "" { target { c++20 && c++23_down } } } + return x; +} +#endif + +template +void +fn2 () +{ + [[maybe_unused]] decltype(pack...[0]) x1; // { dg-warning "pack indexing only available with" "" { target c++23_down } } + [[maybe_unused]] decltype((pack...[0])) x2; // { dg-warning "pack indexing only available with" "" { target c++23_down } } + same_type(); + same_type(); +} + +template +void +fn3 (int p) +{ + T...[0] a = p; // { dg-warning "pack indexing only available with" "" { target c++23_down } } + (T...[0])(a); // { dg-warning "pack indexing only available with" "" { target c++23_down } } +} + +template +void fn4 () +{ + same_type(); // { dg-warning "pack indexing only available with" "" { target c++23_down } } + same_type(); // { dg-warning "pack indexing only available with" "" { target c++23_down } } +} + +void +g3 () +{ + fn2<0>(); +#if __cpp_concepts >= 201907L + bar (0); +#endif + S s; + fn4<0, 1, 2>(); +} diff --git a/gcc/testsuite/g++.dg/cpp26/pack-indexing10.C b/gcc/testsuite/g++.dg/cpp26/pack-indexing10.C new file mode 100644 index 00000000000..3cd348b3ec6 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp26/pack-indexing10.C @@ -0,0 +1,15 @@ +// P2662R3 - Pack Indexing +// PR c++/113798 +// { dg-do compile { target c++26 } } + +template +constexpr auto f() { + return []() { return Vs...[N]; }.template operator()<1>(); +} +static_assert(f<1, 2, 3>() == 2); + +template +constexpr auto g() { + return []() { return Vs...[N]; }.template operator()<1, 2, 3>(); +} +static_assert(g<1>() == 2); diff --git a/gcc/testsuite/g++.dg/cpp26/pack-indexing11.C b/gcc/testsuite/g++.dg/cpp26/pack-indexing11.C new file mode 100644 index 00000000000..81e4da8603a --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp26/pack-indexing11.C @@ -0,0 +1,13 @@ +// P2662R3 - Pack Indexing +// PR c++/113798 +// { dg-do compile { target c++26 } } +// Test case from [diff.cpp23.dcl.dcl]. + +template +void f(T... [1]); +template +void g(T... ptr[1]); +int main() { + f(nullptr, nullptr); // { dg-error "no matching function" } + g(nullptr, nullptr); // ok +} diff --git a/gcc/testsuite/g++.dg/cpp26/pack-indexing2.C b/gcc/testsuite/g++.dg/cpp26/pack-indexing2.C new file mode 100644 index 00000000000..ec32527ed80 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp26/pack-indexing2.C @@ -0,0 +1,111 @@ +// P2662R3 - Pack Indexing +// PR c++/113798 +// { dg-do compile { target c++26 } } +// Test invalid cases. + +template +using Type = Typo...[I]; // { dg-error "does not name a type" } + +template +constexpr auto Var = Typo...[I]; // { dg-error "no parameter packs" } + +template +void foo(Ts...[]); // { dg-error "pack index missing" } + +template +void f(Ts...[1]); + +template +int f2 (X... [N]); // { dg-error "contains no parameter packs" } + +struct X; + +template +struct TX; + +template typename Tp> +void +bad (int i) +{ + i...[0]; // { dg-error "no parameter packs" } + V...[0]; // { dg-error "no parameter packs" } + X...[0] x; // { dg-error "no parameter packs" } + T...[0] t; // { dg-error "no parameter packs" } + Tp...[0] tp; // { dg-error "expected" } + + X...[0] xarr[1]; // { dg-error "no parameter packs" } + T...[0] tarr[1]; // { dg-error "no parameter packs" } + Tp...[0] tparr[1]; // { dg-error "expected" } +} + +template +int +getT (auto... Ts) +{ + return Ts...[N]; // { dg-error "pack index is out of range" } +} + +template +int +getT2 (auto... Ts) +{ + return Ts...[N]; // { dg-error "pack index is negative" } +} + +template +void +badtype () +{ + Ts...[N] t; // { dg-error "pack index is out of range" } +} + +template +void +badtype2 () +{ + Ts...[N] t; // { dg-error "pack index is negative" } +} + +int nonconst () { return 42; } + +template +void +badindex () +{ + Ts...[nonconst ()] t; // { dg-error "pack index is not an integral constant" } + // { dg-error "non-.constexpr. function" "" { target *-*-* } .-1 } +} + +template +struct broken { + Ts...1; // { dg-error "expected" } + Ts...[; // { dg-error "invalid" } + Ts...[1; // { dg-error "invalid" } + Ts...[]; // { dg-error "pack index missing" } + + void foo (auto...Vs) { + decltype(Vs...[1]) d1 = Vs...[]; // { dg-error "pack index missing" } + decltype(Vs...[1]) d2 = Vs...[; // { dg-error "expected" } + } +}; + +int main() +{ + // void f(int [1], double [1]) + f(nullptr, nullptr); // { dg-error "no matching function" } + bad(42); + + getT<0>(); // { dg-message "required from here" } + getT<1>(); // { dg-message "required from here" } + getT2<-1>(); // { dg-message "required from here" } + + badtype<0>(); // { dg-message "required from here" } + badtype<1, int>(); // { dg-message "required from here" } + badtype2<-1>(); // { dg-message "required from here" } + badtype2<-1, int>(); // { dg-message "required from here" } + + badindex(); + + bool b = nothere...[0]; // { dg-error "no parameter packs" } + using E = nothere...[0]; // { dg-error "does not name a type" } +} diff --git a/gcc/testsuite/g++.dg/cpp26/pack-indexing3.C b/gcc/testsuite/g++.dg/cpp26/pack-indexing3.C new file mode 100644 index 00000000000..8c10b307f3a --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp26/pack-indexing3.C @@ -0,0 +1,41 @@ +// P2662R3 - Pack Indexing +// PR c++/113798 +// { dg-do compile { target c++26 } } +// From LLVM's cxx2c-pack-indexing.cpp. + +template +struct X { }; + +template +requires requires(T...[0]) { {T...[0](0)}; } +struct S : T...[1] { + [[maybe_unused]] T...[1] base = {}; + using foo = T...[1]; + S() : T...[1]() { } + X x; + const T...[0] f(T...[0]&& parm) noexcept((T...[0])0) { + T...[0] (*test)(const volatile T...[0]**); + thread_local T...[0] d; + [[maybe_unused]] T...[0] a = parm; + auto ptr = new T...[0](0); + (*ptr).~T...[0](); + return T...[0](0); + typename T...[1]::foo b = 0; + T...[1]::i = 0; + return (T...[0])(a); + new T...[0]; + [[maybe_unused]] auto l = [](T...[0][1]) -> T...[0]{ return {}; }; + [[maybe_unused]] auto _ = l.template operator()({0}); + } + operator T...[0]() const { } +}; + +struct base { + using foo = int; + static inline int i = 42; +}; + +int main() +{ + S().f(0); +} diff --git a/gcc/testsuite/g++.dg/cpp26/pack-indexing4.C b/gcc/testsuite/g++.dg/cpp26/pack-indexing4.C new file mode 100644 index 00000000000..8decf3064bc --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp26/pack-indexing4.C @@ -0,0 +1,65 @@ +// P2662R3 - Pack Indexing +// PR c++/113798 +// { dg-do compile { target c++26 } } +// From LLVM's cxx2c-pack-indexing.cpp. + +template +constexpr bool is_same = false; +template +constexpr bool is_same = true; + +template +constexpr bool +f (auto&&... p) +{ + return is_same; +} + +void +g () +{ + int a = 0; + const int b = 0; + static_assert(f(0)); + static_assert(f(a)); + static_assert(f(b)); +} + +template +struct A { + enum E { + x = p...[0] + }; +}; +static_assert(A<42>::x == 42); + +struct S { }; +template +constexpr auto constant_initializer = p...[0]; +constexpr auto InitOk = constant_initializer; + +consteval int evaluate(auto... p) { + return p...[0]; +} +constexpr int x = evaluate(42, S{}); +static_assert(x == 42); + +template +struct IL{}; + +template +struct TL{}; + +template +struct SpliceImpl; + +template +struct SpliceImpl, IL> +{ + using type = TL; +}; + +template +using Splice = typename SpliceImpl::type; +using type = Splice, IL<1, 2>>; +static_assert(is_same>); diff --git a/gcc/testsuite/g++.dg/cpp26/pack-indexing5.C b/gcc/testsuite/g++.dg/cpp26/pack-indexing5.C new file mode 100644 index 00000000000..901956e2dae --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp26/pack-indexing5.C @@ -0,0 +1,41 @@ +// P2662R3 - Pack Indexing +// PR c++/113798 +// { dg-do compile { target c++26 } } + +template struct same_type; +template struct same_type {}; + +void +fn1 (auto... Ts) +{ + same_type(); + same_type(); + same_type(); + same_type(); +} + +template +void +fn2 () +{ + same_type(); + same_type(); + same_type(); + same_type(); + same_type(); + same_type(); + same_type(); + same_type(); + same_type(); + same_type(); +} + +static constexpr unsigned char c = 'A'; + +void +g () +{ + int i = 42; + fn1 (i, 42u); + fn2<0, 1u, 2.0, 3.f, c>(); +} diff --git a/gcc/testsuite/g++.dg/cpp26/pack-indexing6.C b/gcc/testsuite/g++.dg/cpp26/pack-indexing6.C new file mode 100644 index 00000000000..9af88765254 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp26/pack-indexing6.C @@ -0,0 +1,51 @@ +// P2662R3 - Pack Indexing +// PR c++/113798 +// { dg-do compile { target c++26 } } + +template struct same_type; +template struct same_type {}; + +void +fn1 (auto... Ts) +{ + decltype(auto) a1 = Ts...[0]; + same_type(); + decltype(auto) a2 = (Ts...[0]); + same_type(); +} + +template +void +fn2 () +{ + decltype(auto) a1 = Is...[0]; + same_type(); + decltype(auto) a2 = (Is...[0]); + same_type(); + decltype(auto) a3 = Is...[1]; + same_type(); + decltype(auto) a4 = (Is...[1]); + same_type(); + decltype(auto) a5 = Is...[2]; + same_type(); + decltype(auto) a6 = (Is...[2]); + same_type(); + decltype(auto) a7 = Is...[3]; + same_type(); + decltype(auto) a8 = (Is...[3]); + same_type(); + decltype(auto) a9 = Is...[4]; + same_type(); + decltype(auto) a10 = (Is...[4]); + same_type(); +} + +static constexpr unsigned char c = 'A'; + +void +g () +{ + int i = 42; + fn1 (i, 42u); + fn2<0, 1u, 2.0, 3.f, c>(); +} diff --git a/gcc/testsuite/g++.dg/cpp26/pack-indexing7.C b/gcc/testsuite/g++.dg/cpp26/pack-indexing7.C new file mode 100644 index 00000000000..de50f7758e3 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp26/pack-indexing7.C @@ -0,0 +1,16 @@ +// P2662R3 - Pack Indexing +// PR c++/113798 +// { dg-do compile { target c++26 } } + +template +decltype(Ts...[I]) +foo () // { dg-bogus "sorry, unimplemented: mangling" "" { xfail *-*-* } } +{ + return Ts...[I]; +} + +int +g () +{ + return foo<2, 0, 1, 42>(); +} diff --git a/gcc/testsuite/g++.dg/cpp26/pack-indexing8.C b/gcc/testsuite/g++.dg/cpp26/pack-indexing8.C new file mode 100644 index 00000000000..2b1b67c0841 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp26/pack-indexing8.C @@ -0,0 +1,23 @@ +// P2662R3 - Pack Indexing +// PR c++/113798 +// { dg-do run { target c++26 } } + +#include + +template +int +g (auto... Is) +{ + std::initializer_list l{ Is...[0], Is...[1], Is...[2], Is...[3], Is...[4] }; + int sum = 0; + for (auto x : l) + sum += x; + return sum; +} + +int +main () +{ + if (g (1, 2, 3, 4, 5) != 15) + __builtin_abort (); +} diff --git a/gcc/testsuite/g++.dg/cpp26/pack-indexing9.C b/gcc/testsuite/g++.dg/cpp26/pack-indexing9.C new file mode 100644 index 00000000000..afd8a2f9ed6 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp26/pack-indexing9.C @@ -0,0 +1,27 @@ +// P2662R3 - Pack Indexing +// PR c++/113798 +// { dg-do compile { target c++26 } } +// From . + +template struct tuple { + template T...[I] get(); // { dg-bogus "sorry, unimplemented: mangling" "" { xfail *-*-* } } +}; + +int +g () +{ + tuple t; + return t.get<0>(); +} + +template concept C = true; +template struct A { + template void f(T...[I], U...[I]) requires C; // { dg-message "sorry, unimplemented: mangling" } +}; + +void +h () +{ + A a; + a.f<1, int, int, char>(1, 2); +} diff --git a/gcc/testsuite/g++.dg/modules/pack-index-1_a.C b/gcc/testsuite/g++.dg/modules/pack-index-1_a.C new file mode 100644 index 00000000000..30ae189711c --- /dev/null +++ b/gcc/testsuite/g++.dg/modules/pack-index-1_a.C @@ -0,0 +1,18 @@ +// { dg-module-do run } +// { dg-additional-options { -std=c++26 -fmodules-ts } } + +export module packing1; +// { dg-module-cmi "packing1" } + +export template +using Type = Ts...[I]; + +export template +constexpr auto Var = Ts...[I]; + +export template +int +foo () +{ + return Ts...[I]; +} diff --git a/gcc/testsuite/g++.dg/modules/pack-index-1_b.C b/gcc/testsuite/g++.dg/modules/pack-index-1_b.C new file mode 100644 index 00000000000..dce6f5774d3 --- /dev/null +++ b/gcc/testsuite/g++.dg/modules/pack-index-1_b.C @@ -0,0 +1,15 @@ +// { dg-additional-options { -std=c++26 -fmodules-ts } } + +import packing1; + +int +main () +{ + using U = Type<1, char, int, float>; + using U = int; + + U r = foo<2, 0, 1, 42>(); + + constexpr auto V = Var<2, 0, 1, 42>; + static_assert (V == 42); +} diff --git a/libstdc++-v3/testsuite/20_util/tuple/element_access/get_neg.cc b/libstdc++-v3/testsuite/20_util/tuple/element_access/get_neg.cc index 2346c29b80f..9e002f4d47a 100644 --- a/libstdc++-v3/testsuite/20_util/tuple/element_access/get_neg.cc +++ b/libstdc++-v3/testsuite/20_util/tuple/element_access/get_neg.cc @@ -61,4 +61,4 @@ test03() // { dg-error "tuple index must be in range" "" { target *-*-* } 0 } // { dg-prune-output "no type named 'type' in .*_Nth_type" } -// { dg-prune-output "'__type_pack_element' index is out of range" } +// { dg-prune-output "pack index is out of range" }