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[C++ PATCH] empty-declarations
- From: Nathan Sidwell <nathan at acm dot org>
- To: Jason Merrill <jason at redhat dot com>
- Cc: GCC Patches <gcc-patches at gcc dot gnu dot org>
- Date: Tue, 10 Apr 2018 11:06:07 -0400
- Subject: [C++ PATCH] empty-declarations
Jason,
thanks for looking up about empty-decls. This patch implements the
C++11 change.
At namespace-scope & class-scope we're now silent about empty
declarations, when not in C++-98 mode.
The class-scope change was a little more invasive, because we silently
accepted a semicolon after an in-class function definition:
class X {
void foo () {}; // semi-colon accepted
};
And we emitted a fixit for that case.
This isn't a regression. I don't think anyone's complained. Jason,
WDYT about committing this now?
nathan
--
Nathan Sidwell
2018-04-10 Nathan Sidwell <nathan@acm.org>
* parser.c (cp_parser_declaration_seq_opt): Permit
empty-declaration in c++11.
(cp_parser_member_declaration): Likewise.
* g++.dg/semicolon-fixits.C: Delete.
* g++.dg/cpp0x/semicolon.C: New.
* g++.dg/warn/Wextra-semi.C: C++98 only.
* g++.dg/warn/pedantic2.C: C++98 only.
* g++.old-deja/g++.bugs/900404_04.C: C++98 only.
* g++.old-deja/g++.jason/parse11.C: C++98 only.
* g++.old-deja/g++.law/missed-error2.C: C++98 only.
Index: cp/parser.c
===================================================================
--- cp/parser.c (revision 259268)
+++ cp/parser.c (working copy)
@@ -12614,9 +12614,9 @@ cp_parser_declaration_seq_opt (cp_parser
if (token->type == CPP_SEMICOLON)
{
/* A declaration consisting of a single semicolon is
- invalid. Allow it unless we're being pedantic. */
+ valid since C++11. */
cp_lexer_consume_token (parser->lexer);
- if (!in_system_header_at (input_location))
+ if (cxx_dialect < cxx11 && !in_system_header_at (input_location))
pedwarn (input_location, OPT_Wpedantic, "extra %<;%>");
continue;
}
@@ -23445,6 +23445,7 @@ cp_parser_member_specification_opt (cp_p
C++0x Extensions:
member-declaration:
+ empty-declaration
static_assert-declaration */
static void
@@ -23472,6 +23473,15 @@ cp_parser_member_declaration (cp_parser*
return;
}
+ if (cp_lexer_next_token_is (parser->lexer, CPP_SEMICOLON))
+ {
+ /* C++11 allow an empty-declaration. */
+ cp_lexer_consume_token (parser->lexer);
+ if (cxx_dialect < cxx11 && !in_system_header_at (input_location))
+ pedwarn (input_location, OPT_Wpedantic, "extra %<;%>");
+ return;
+ }
+
/* Check for a template-declaration. */
if (cp_lexer_next_token_is_keyword (parser->lexer, RID_TEMPLATE))
{
@@ -23912,8 +23922,9 @@ cp_parser_member_declaration (cp_parser*
finish_member_declaration (decl);
/* Peek at the next token. */
token = cp_lexer_peek_token (parser->lexer);
- /* If the next token is a semicolon, consume it. */
- if (token->type == CPP_SEMICOLON)
+ /* If the next token is a semicolon, consume it in
+ c++98. c++11 made this always ok. */
+ if (cxx_dialect < cxx11 && token->type == CPP_SEMICOLON)
{
location_t semicolon_loc
= cp_lexer_consume_token (parser->lexer)->location;
Index: testsuite/g++.dg/cpp0x/semicolon.C
===================================================================
--- testsuite/g++.dg/cpp0x/semicolon.C (revision 0)
+++ testsuite/g++.dg/cpp0x/semicolon.C (working copy)
@@ -0,0 +1,10 @@
+// { dg-do compile { target c++11 } }
+// C++11 allows empty decls
+
+; // OK
+
+
+struct X
+{
+ ; // OK
+};
Index: testsuite/g++.dg/semicolon-fixits.C
===================================================================
--- testsuite/g++.dg/semicolon-fixits.C (revision 259268)
+++ testsuite/g++.dg/semicolon-fixits.C (working copy)
@@ -1,17 +0,0 @@
-/* { dg-options "-fdiagnostics-show-caret -Wpedantic" } */
-
-/* Struct with extra semicolon. */
-struct s1 { int i;; }; /* { dg-warning "19: extra .;." } */
-/* { dg-begin-multiline-output "" }
- struct s1 { int i;; };
- ^
- -
- { dg-end-multiline-output "" } */
-
-/* Union with extra semicolon. */
-union u1 { int i;; }; /* { dg-warning "18: extra .;." } */
-/* { dg-begin-multiline-output "" }
- union u1 { int i;; };
- ^
- -
- { dg-end-multiline-output "" } */
Index: testsuite/g++.dg/warn/Wextra-semi.C
===================================================================
--- testsuite/g++.dg/warn/Wextra-semi.C (revision 259268)
+++ testsuite/g++.dg/warn/Wextra-semi.C (working copy)
@@ -1,3 +1,5 @@
+// { dg-do compile { target c++98_only } }
+
// { dg-options "-Wextra-semi -fdiagnostics-show-caret" }
struct A
Index: testsuite/g++.dg/warn/pedantic2.C
===================================================================
--- testsuite/g++.dg/warn/pedantic2.C (revision 259268)
+++ testsuite/g++.dg/warn/pedantic2.C (working copy)
@@ -1,3 +1,4 @@
+// { dg-do compile { target c++98_only } }
// { dg-options "-pedantic" }
class foo
Index: testsuite/g++.old-deja/g++.bugs/900404_04.C
===================================================================
--- testsuite/g++.old-deja/g++.bugs/900404_04.C (revision 259268)
+++ testsuite/g++.old-deja/g++.bugs/900404_04.C (working copy)
@@ -1,4 +1,4 @@
-// { dg-do assemble }
+// { dg-do assemble { target c++98_only } }
// g++ 1.37.1 bug 900404_04
// [dcl.dcl] explains that simple-declarations may omit the
@@ -13,6 +13,7 @@
int i;
+// Ok in C++11 up
; // { dg-error "extra ';'" }
int main () { return 0; }
Index: testsuite/g++.old-deja/g++.jason/parse11.C
===================================================================
--- testsuite/g++.old-deja/g++.jason/parse11.C (revision 259268)
+++ testsuite/g++.old-deja/g++.jason/parse11.C (working copy)
@@ -1,4 +1,4 @@
-// { dg-do assemble }
+// { dg-do assemble { target c++98_only } }
// PRMS Id: 6825
class aClass
Index: testsuite/g++.old-deja/g++.law/missed-error2.C
===================================================================
--- testsuite/g++.old-deja/g++.law/missed-error2.C (revision 259268)
+++ testsuite/g++.old-deja/g++.law/missed-error2.C (working copy)
@@ -1,10 +1,11 @@
-// { dg-do assemble }
+// { dg-do assemble { target c++98_only } }
// GROUPS passed missed-error
// missed-error file
// From: ndc!don@csvax.cs.caltech.edu (Don Erway)
// Date: Thu, 21 May 92 15:40:45 PDT
// Subject: More on [g++ 2.1 : overloaded function selection incorrect]
// Message-ID: <9205212240.AA17934@ndc.com>
+// naked semi-colons ok in C++11
#include <iostream>