Bug 47376

Summary: Duplicate member through anonymous unions not reported
Product: gcc Reporter: Jan Engelhardt <jengelh>
Component: cAssignee: Not yet assigned to anyone <unassigned>
Status: RESOLVED DUPLICATE    
Severity: normal    
Priority: P3    
Version: 4.5.0   
Target Milestone: 4.6.0   
Host: x86_64-suse-linux Target: x86_64-suse-linux
Build: x86_64-suse-linux Known to work:
Known to fail: Last reconfirmed:

Description Jan Engelhardt 2011-01-20 12:59:58 UTC
Given the following example:
---
struct foo {
        int a;
        union {
                int a;
                double b;
        };
};

int main(void)
{
        struct foo f;
        f.a = 123;
        return 0;
}
---

How it came to be:
Accidental error where I had forgotten to remove foo.a after having added foo.{anonymous}.a.

What has been observed:
It compiles fine, which caused this programming error of mine to go unnoticed for half a day. It seems gcc gives foo.a precedence over foo.{anonymous}.a when accessing it through f.a=....

What had been expected:
I would have liked that gcc emit at least a warning because f.a is ambiguous.
Comment 1 Joseph S. Myers 2011-02-07 01:59:50 UTC
Fixed in 4.6.
Comment 2 Joseph S. Myers 2011-02-07 02:00:15 UTC
Fixed in 4.6.

*** This bug has been marked as a duplicate of bug 4784 ***