C error when embedding C.Structs into V struct

[islonely]

V doctor:

V full version: V 0.4.9 4225a34.7b9b3dd
OS: macos, macOS, 15.1.1, 24B91
Processor: 8 cpus, 64bit, little endian, Apple M3

getwd: /Users/adamoates/Documents/v_tests
vexe: /Users/adamoates/v/v
vexe mtime: 2025-01-01 01:32:40

vroot: OK, value: /Users/adamoates/v
VMODULES: OK, value: /Users/adamoates/.vmodules
VTMP: OK, value: /tmp/v_501

Git version: git version 2.39.5 (Apple Git-154)
Git vroot status: weekly.2024.52-38-g7b9b3dd9
.git/config present: true

CC version: Apple clang version 16.0.0 (clang-1600.0.26.4)
emcc version: N/A
thirdparty/tcc status: thirdparty-macos-arm64 713692d4

What did you do?
./v -g -o vdbg cmd/v && ./vdbg test2.v

test.h

struct Position {
	int x, y;
};

struct Size {
	int width, height;
};

main.v

#include "test.h"
#flag -I ./

type Pos = C.Pos
type Size = C.Size

struct C.Pos {
__global:
	x int
	y int
}

struct C.Size {
__global:
	width int
	height int
}

struct Rectangle {
	C.Pos
	C.Size
}

fn main() {
    println(Rectangle{
		x: 400
		y: 100
		width: 800
		height: 600
	})
}

What did you expect to see?

Expected code to compile and print Rectangle{}.

What did you see instead?

================== C compilation error (from cc): ==============
cc: /tmp/v_501/test2.01JGG7XGNFZXDC952EJBWZNSH3.tmp.c:1047:13: error: field has incomplete type 'struct Pos'
cc:  1047 |         struct Pos Pos;
cc:       |                    ^
cc: /tmp/v_501/test2.01JGG7XGNFZXDC952EJBWZNSH3.tmp.c:834:16: note: forward declaration of 'struct Pos'
cc:   834 | typedef struct Pos main__Pos;
cc:       |                ^
cc: /tmp/v_501/test2.01JGG7XGNFZXDC952EJBWZNSH3.tmp.c:1697:95: error: incomplete definition of type 'struct Pos'
cc:  1697 |                 {_SLIT0, 0xfe10, {.d_s=indents}}, {_SLIT("    x: "), 0, {.d_c=0}}, {_SLIT(""), 7, {.d_i32=it->x}}, {_SLIT(""), 0, {.d_c=0}},
cc:       |                                                                                                           ~~^
cc: /tmp/v_501/test2.01JGG7XGNFZXDC952EJBWZNSH3.tmp.c:834:16: note: forward declaration of 'struct Pos'
cc:   834 | typedef struct Pos main__Pos;
cc:       |                ^
... (the original output was 25 lines long, and was truncated to 12 lines)
================================================================
(You can pass `-cg`, or `-show-c-output` as well, to print all the C error messages).
builder error: 
==================
C error found. It should never happen, when compiling pure V code.
This is a V compiler bug, please report it using `v bug file.v`,
or goto https://github.com/vlang/v/issues/new/choose .
You can also use #help on Discord: https://discord.gg/vlang .

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_{Huly®: V_0.6-21759}

[islonely]

This also causes a V panic when using aliases instead of C.Struct.

struct Rectangle {
	Pos
	Size
}

V panic: as cast: cannot cast `v.ast.Alias` to `v.ast.Struct`
v hash: 7b9b3dd
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:19135: at _v_panic: Backtrace
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:19603: by __as_cast
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:112106: by v__gen__c__Gen_struct_init
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:92130: by v__gen__c__Gen_expr
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:91214: by v__gen__c__Gen_expr_with_cast
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:111510: by v__gen__c__Gen_gen_expr_to_string
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:102946: by v__gen__c__Gen_fn_call
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:101363: by v__gen__c__Gen_call_expr
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:91788: by v__gen__c__Gen_expr
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:90613: by v__gen__c__Gen_stmt
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:90384: by v__gen__c__Gen_stmts_with_tmp_var
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:90259: by v__gen__c__Gen_stmts
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:100736: by v__gen__c__Gen_gen_fn_decl
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:100268: by v__gen__c__Gen_fn_decl
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:90572: by v__gen__c__Gen_stmt
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:90384: by v__gen__c__Gen_stmts_with_tmp_var
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:90259: by v__gen__c__Gen_stmts
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:89136: by v__gen__c__Gen_gen_file
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:89073: by v__gen__c__cgen_process_one_file_cb
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:32587: by sync__pool__process_in_thread
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:11474: by sync__pool__process_in_thread_thread_wrapper
0x19c3a32e4 : by ???
0x19c39e0fc : by ???
0x102552ab0 : at ???: RUNTIME ERROR: invalid memory access
0x102552554 : by ???
0x102552ebc : by ???
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:19135: by _v_panic
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:19603: by __as_cast
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:112106: by v__gen__c__Gen_struct_init
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:92130: by v__gen__c__Gen_expr
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:91214: by v__gen__c__Gen_expr_with_cast
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:111510: by v__gen__c__Gen_gen_expr_to_string
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:102946: by v__gen__c__Gen_fn_call
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:101363: by v__gen__c__Gen_call_expr
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:91788: by v__gen__c__Gen_expr
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:90613: by v__gen__c__Gen_stmt
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:90384: by v__gen__c__Gen_stmts_with_tmp_var
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:90259: by v__gen__c__Gen_stmts
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:100736: by v__gen__c__Gen_gen_fn_decl
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:100268: by v__gen__c__Gen_fn_decl
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:90572: by v__gen__c__Gen_stmt
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:90384: by v__gen__c__Gen_stmts_with_tmp_var
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:90259: by v__gen__c__Gen_stmts
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:89136: by v__gen__c__Gen_gen_file
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:89073: by v__gen__c__cgen_process_one_file_cb
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:32587: by sync__pool__process_in_thread
v2.01JGFQWM4SVD8YP682NHHPSDMM.tmp.c:11474: by sync__pool__process_in_thread_thread_wrapper
0x19c3a32e4 : by ???

[islonely]

I'm just being dumb again. The issue is C.Pos in the V code instead of C.Position.