| Message ID | 20220429141218.41850-1-polacek@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | c++: pedwarn for empty unnamed enum in decl [PR67048] | expand |
On 4/29/22 10:12, Marek Polacek wrote: > [dcl.dcl]/5 says that > > enum { }; > > is ill-formed, and since r197742 we issue a pedwarn. However, the > pedwarn also fires for > > enum { } x; > > which is well-formed. So only warn when {} is followed by a ;. This > should be correct since you can't have "enum {}, <whatever>" -- that > produces "expected unqualified-id before ',' token". > > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk? I think > this could go to 12.2 and 11.4 too. OK. > PR c++/67048 > > gcc/cp/ChangeLog: > > * parser.cc (cp_parser_enum_specifier): Warn about empty unnamed enum > only when it's followed by a semicolon. > > gcc/testsuite/ChangeLog: > > * g++.dg/cpp0x/enum42.C: New test. > --- > gcc/cp/parser.cc | 4 +++- > gcc/testsuite/g++.dg/cpp0x/enum42.C | 7 +++++++ > 2 files changed, 10 insertions(+), 1 deletion(-) > create mode 100644 gcc/testsuite/g++.dg/cpp0x/enum42.C > > diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc > index 2235da10c7c..0fa37fdfb66 100644 > --- a/gcc/cp/parser.cc > +++ b/gcc/cp/parser.cc > @@ -21007,7 +21007,9 @@ cp_parser_enum_specifier (cp_parser* parser) > /* If the next token is not '}', then there are some enumerators. */ > else if (cp_lexer_next_token_is (parser->lexer, CPP_CLOSE_BRACE)) > { > - if (is_unnamed && !scoped_enum_p) > + if (is_unnamed && !scoped_enum_p > + /* Don't warn for enum {} a; here. */ > + && cp_lexer_nth_token_is (parser->lexer, 2, CPP_SEMICOLON)) > pedwarn (type_start_token->location, OPT_Wpedantic, > "ISO C++ forbids empty unnamed enum"); > } > diff --git a/gcc/testsuite/g++.dg/cpp0x/enum42.C b/gcc/testsuite/g++.dg/cpp0x/enum42.C > new file mode 100644 > index 00000000000..05b372a1947 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/cpp0x/enum42.C > @@ -0,0 +1,7 @@ > +// PR c++/67048 > +// { dg-do compile { target c++11 } } > +// { dg-options -Wpedantic } > + > +typedef enum {} X; > +enum {} x; > +enum {} y, z; > > base-commit: 9ae8b993cd362e8aea4f65580aaf1453120207f2
diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc index 2235da10c7c..0fa37fdfb66 100644 --- a/gcc/cp/parser.cc +++ b/gcc/cp/parser.cc @@ -21007,7 +21007,9 @@ cp_parser_enum_specifier (cp_parser* parser) /* If the next token is not '}', then there are some enumerators. */ else if (cp_lexer_next_token_is (parser->lexer, CPP_CLOSE_BRACE)) { - if (is_unnamed && !scoped_enum_p) + if (is_unnamed && !scoped_enum_p + /* Don't warn for enum {} a; here. */ + && cp_lexer_nth_token_is (parser->lexer, 2, CPP_SEMICOLON)) pedwarn (type_start_token->location, OPT_Wpedantic, "ISO C++ forbids empty unnamed enum"); } diff --git a/gcc/testsuite/g++.dg/cpp0x/enum42.C b/gcc/testsuite/g++.dg/cpp0x/enum42.C new file mode 100644 index 00000000000..05b372a1947 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp0x/enum42.C @@ -0,0 +1,7 @@ +// PR c++/67048 +// { dg-do compile { target c++11 } } +// { dg-options -Wpedantic } + +typedef enum {} X; +enum {} x; +enum {} y, z;
[dcl.dcl]/5 says that enum { }; is ill-formed, and since r197742 we issue a pedwarn. However, the pedwarn also fires for enum { } x; which is well-formed. So only warn when {} is followed by a ;. This should be correct since you can't have "enum {}, <whatever>" -- that produces "expected unqualified-id before ',' token". Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk? I think this could go to 12.2 and 11.4 too. PR c++/67048 gcc/cp/ChangeLog: * parser.cc (cp_parser_enum_specifier): Warn about empty unnamed enum only when it's followed by a semicolon. gcc/testsuite/ChangeLog: * g++.dg/cpp0x/enum42.C: New test. --- gcc/cp/parser.cc | 4 +++- gcc/testsuite/g++.dg/cpp0x/enum42.C | 7 +++++++ 2 files changed, 10 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/g++.dg/cpp0x/enum42.C base-commit: 9ae8b993cd362e8aea4f65580aaf1453120207f2