parser should not allow same symbol names import from different module

[kbkpbot]

Describe the bug

parser should not allow same symbol names import from different module

Reproduction Steps

a/a.v:

module a

pub struct Top {
        a int
}

b/b.v:

module b

pub struct Top {
        b int
}

fmt.v

module main

import a { Top }
import b { Top }

fn main() {
        x := Top{}
        dump(x)
}

Expected Behavior

parser should issue an error msg, that Top already registered by another module.

Current Behavior

$ v fmt.v
fmt.v:3:8: warning: module 'a' is imported but never used
    1 | module main
    2 |
    3 | import a { Top }
      |        ^
    4 | import b { Top }
    5 |

Possible Solution

Fix parser

Additional Information/Context

No response

V version

V 0.4.11 9e1273a

Environment details (OS name and version, etc.)

V full version	V 0.4.11 9e1273a
OS	linux, Ubuntu 24.04.3 LTS
Processor	8 cpus, 64bit, little endian, Intel(R) Core(TM) i7-9700 CPU @ 3.00GHz
Memory	10.7GB/15.51GB
V executable	/media/HD/github/lang/v/v
V last modified time	2025-08-29 03:37:07
V home dir	OK, value: /media/HD/github/lang/v
VMODULES	OK, value: /home/mars/.vmodules
VTMP	OK, value: /tmp/v_1000
Current working dir	OK, value: /home/mars/v/bug/comptime/top
Git version	git version 2.43.0
V git status	weekly.2025.35-9-g9e1273ae
.git/config present	true
cc version	cc (Ubuntu 13.3.0-6ubuntu2~24.04) 13.3.0
gcc version	gcc (Ubuntu 13.3.0-6ubuntu2~24.04) 13.3.0
clang version	Ubuntu clang version 18.1.3 (1ubuntu1)
tcc version	tcc version 0.9.28rc 2025-02-13 HEAD@f8bd136d (x86_64 Linux)
tcc git status	thirdparty-linux-amd64 696c1d84
emcc version	N/A
glibc version	ldd (Ubuntu GLIBC 2.39-0ubuntu8.5) 2.39

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[huly-for-github]

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