https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93816
Bug ID: 93816
Summary: invalid typedef name with class key accepted
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: msebor at gcc dot gnu.org
Target Milestone: ---
The second typedef in the test case below is invalid for the same reason as the
first but only the first one is diagnosed and rejected. The second one is
silently accepted and has been since at least GCC 4.1.
$ cat t.C && gcc -S -Wall -Wextra -Wpedantic t.C
typedef struct { } A;
template <int> struct B { typedef struct { } C; };
typedef struct A A2; // correctly rejected
typedef struct B<0>::C C2; // incorrectly accepted
t.C:4:16: error: using typedef-name ‘A’ after ‘struct’
4 | typedef struct A A2; // correctly rejected
| ^
t.C:1:20: note: ‘A’ has a previous declaration here
1 | typedef struct { } A;
| ^
Clang (and ICC) diagnose both:
t.C:4:16: error: typedef 'A' cannot be referenced with a struct specifier
typedef struct A A2;
^
t.C:1:20: note: declared here
typedef struct { } A;
^
t.C:5:22: error: typedef 'C' cannot be referenced with a struct specifier
typedef struct B<0>::C C2;
^
t.C:2:46: note: declared here
template <int> struct B { typedef struct { } C; };
^
2 errors generated.
