https://gcc.gnu.org/bugzilla/show_bug.cgi?id=72707
Bug ID: 72707
Summary: [4.6/4.7/4.8/4.9/5/6/7 regression] local anonymous
union member hides names in the same scope
Product: gcc
Version: 7.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: msebor at gcc dot gnu.org
Target Milestone: ---
In [class.union], all versions of the C++ standard starting with 1998 require
that:
The names of the members of an anonymous union shall be distinct from the
names of any other entity in the scope in which the anonymous union is
declared.
The following invalid test case is accepted by G++, implying that G++ fails to
conform to this requirement. The test case is rejected by Clang 3.8 and EDG
eccp 4.11.
Prior to version 4.6, GCC rejected this test case with
error: declaration of ‘int x’ shadows a parameter
This error was removed and the regression introduced in r159383.
$ cat xyz.c && /build/gcc-71912/gcc/xgcc -B /build/gcc-71912/gcc -S -Wall
-Wextra -Wpedantic -xc++ xyz.c
void f (double &x)
{
union { int x; };
x = 0;
}
xyz.c: In function ‘void f(double&)’:
xyz.c:1:17: warning: unused parameter ‘x’ [-Wunused-parameter]
void f (double &x)
^
