Plugin adding a new warning for C: detection of suspicious variable assignment in struct initialization

[GRASSET Judicaël]

Hello, 

Find attached a plugin for GCC 14. It detects when the user forgets a dot and initialize by mistake a local variable instead of a struct member. 
I am not aware of any warning of gcc that can detect this mistake, but it would be nice to not have to use a plugin for that, so if you know any flag to check that please share it. 
It is helpful for me, so I am posting it thinking it might help someone else. 

I am not at all familiar with the gcc internals, so I did not write this plugin myself: *it has been vibe-coded with claude.ai* 
I have been able to compile and run it correctly on Debian 13, using GCC 14.2. 

Usage example: 

typedef struct { 
int a, b, c; 
} t; 

int c = 0; 

t f1() { 
return (t){.a=1, .c=c}; // OK 
} 

t f3() { 
return (t){.a=1, c=1}; // Should generate a warning 
} 

test.c: In function ‘f3’: 
test.c:16:23: warning: assignment 'c=...' in initializer context - did you mean '.c=...'? 
16 | return (t){.a=1, c=1}; // Should generate a warning 

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