https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109654
Bug ID: 109654
Summary: unnecessary "cannot bind packed field to reference"
error when referenced type has aligned(1) attribute
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: richard-gccbugzilla at metafoo dot co.uk
Target Milestone: ---
As a workaround for people hitting #36566, I think GCC should accept cases like
this:
typedef __attribute__((aligned(1))) int packed_int;
struct __attribute__((packed)) Foo {
int i;
packed_int& get() { return i; }
};
Unfortunately GCC rejects:
<source>:5:32: error: cannot bind packed field '((Foo*)this)->Foo::i' to
'packed_int&' {aka 'int&'}
5 | packed_int& get() { return i; }
|
And conversely, GCC accepts this code, which has a genuine misalignment issue:
typedef __attribute__((aligned(1))) int packed_int;
struct __attribute__((packed)) Foo {
packed_int i;
int& get() { return i; }
};
I wonder if the check is mistakenly looking at the alignment of the source type
instead of the alignment of the referent of the reference type?
