vfmt removes selective import of interface when used only in implements clause

[Krotki]

Describe the bug

V fmt removes selective imports of an interface when a given interface is used only in implements clause.

The compiler will not complain after formatting, but I'm puzzled how compiler knows where the symbol 'Visitor' comes from as it does not contain qualifier nor such symbol exists in local scope. Might be that this is not checked.

Reproduction Steps

Given:

import v.ast.walker { Visitor }
import v.ast {Node}

struct Walker implements Visitor  {
	aaa  string
}

fn (mut n Walker) visit(node &Node) ! {
	panic('not implemented')
}

Run v fmt on it

Expected Behavior

Selective import not removed.

Current Behavior

First line will be transformed to import v.ast.walker.

Possible Solution

No response

Additional Information/Context

No response

V version

V 0.4.7 79bedff

Environment details (OS name and version, etc.)

V full version: V 0.4.7 a7db095.79bedff
OS: linux, Linux Mint 21.3
Processor: 20 cpus, 64bit, little endian, 12th Gen Intel(R) Core(TM) i9-12900H

getwd: /home/jakub/repos/V-ConsoleTest
vexe: /home/jakub/programy/v/v
vexe mtime: 2024-09-11 21:12:09

vroot: OK, value: /home/jakub/programy/v
VMODULES: OK, value: /home/jakub/.vmodules
VTMP: OK, value: /tmp/v_1000

Git version: git version 2.34.1
Git vroot status: weekly.2024.36-42-g79bedff1
.git/config present: true

CC version: cc (Ubuntu 11.4.0-1ubuntu1~22.04) 11.4.0
thirdparty/tcc status: thirdparty-linux-amd64 a0799a5

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[Krotki]

Actually there might be 2 separate issues.

1. v fmt does not see usage of the type used in implements clause
2. compiler does not check if a given interface exists

For the second one if I do:

struct Walker implements Abcdef {
	aaa string
}

Compiler does not complain that Abcdef type is not recognized, but continues with normal compilation.

[medvednikov]

Will fix today.

[spytheman]

I've reopened it, since #22209 fixes only the formatting issue, not the interface existence one.