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From: "redi at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/114265] Unhelpful message when var name is also a struct name Date: Thu, 07 Mar 2024 11:57:50 +0000 [thread overview] Message-ID: <bug-114265-4-ajroRbKkxz@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-114265-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114265 Jonathan Wakely <redi at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Last reconfirmed| |2024-03-07 Status|UNCONFIRMED |NEW Ever confirmed|0 |1 --- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> --- But it's valid to define Struct as a variable after also defining it as a type, the problem is only when you later refer to it as a type. That's why the error talks about the 'fn' being redeclared. When it sees `int fn(Struct*)` the second time, the language grammar says you are declaring an int variable, and initializing it with an arithmetic expression involving the Struct variable multiplied by a missing operand. The code would be valid if the use of Struct after its redefinition used an elaborated-type-specifier to refer to it (i.e. included the 'struct' keyword): int fn(struct Struct *) { return 0; } Maybe it would be possible for the "redeclared as a different kind of entity" to try to parse `int fn(Struct*)` again, excluding non-types from name lookup (except in unevaluated operands and default arguments?) and then if that succeeds, adda fix-it hint for the elaborated-type-specifier (with either 'struct', 'class', 'union', or 'enum' as appropriate): note: use 'struct Struct' to refer to the type int fn(struct Struct *) ^~~~~~ For comparison, other compilers give very similar results: Clang gives: s.cc:7:5: error: redefinition of 'fn' as different kind of symbol int fn(Struct *) ^ s.cc:3:5: note: previous definition is here int fn(Struct *); ^ s.cc:7:16: error: expected expression int fn(Struct *) ^ s.cc:7:17: error: expected ';' after top level declarator int fn(Struct *) ^ ; 3 errors generated. EDG gives: "s.cc", line 7: error: declaration is incompatible with "int fn(Struct *)" (declared at line 3) int fn(Struct *) ^ "s.cc", line 7: error: expected an expression int fn(Struct *) ^ "s.cc", line 8: error: expected a ";" { ^ 3 errors detected in the compilation of "s.cc". MSVC seems the least helpful: <source>(7): error C2059: syntax error: ')' <source>(8): error C2143: syntax error: missing ';' before '{' <source>(8): error C2447: '{': missing function header (old-style formal list?)
prev parent reply other threads:[~2024-03-07 11:57 UTC|newest] Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top 2024-03-07 9:12 [Bug c++/114265] New: " denis.campredon at gmail dot com 2024-03-07 11:57 ` redi at gcc dot gnu.org [this message]
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