cgen error: `could not find method`, for compiling a veb program with an app alias, with defined index route on the unaliased App type

[spytheman]

V version: V 0.4.11 930c84d, press to see full `v doctor` output

V full version	V 0.4.11 1820a55.930c84d
OS	linux, Ubuntu 20.04.6 LTS
Processor	4 cpus, 64bit, little endian, Intel(R) Core(TM) i3-3225 CPU @ 3.30GHz
Memory	0.98GB/15.05GB
V executable	/home/delian/v/v
V last modified time	2025-09-07 06:07:01
V home dir	OK, value: /home/delian/v
VMODULES	OK, value: /home/delian/.vmodules
VTMP	OK, value: /tmp/v_1000
Current working dir	OK, value: /home/delian/v
env VFLAGS	"-no-parallel"
Git version	git version 2.50.0
V git status	weekly.2025.36-27-g930c84db-dirty
.git/config present	true
cc version	cc (Ubuntu 10.5.0-1ubuntu1~20.04) 10.5.0
gcc version	gcc (Ubuntu 10.5.0-1ubuntu1~20.04) 10.5.0
clang version	N/A
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 2.31-0ubuntu9.18) 2.31

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

import veb

pub struct Context {
	veb.Context
}

pub struct App {
	veb.Middleware[Context]
	veb.Controller
	veb.StaticHandler
	started chan bool
}

pub fn (mut app App) index(mut ctx Context) veb.Result {
	return ctx.text('Hello V!')
}

type AliasApp = App
type AliasContext = Context

mut app := &AliasApp{}
veb.run_at[AliasApp, AliasContext](mut app,
	port: 12343
	family: .ip
)

What did you see?

vlib/veb/veb.v:746:13: cgen error: could not find method `index` on compile-time resolution
  744 | 
  745 |                             // println('m1')
  746 |                             app.$method(mut user_context, args)
      |                                  ~~~~~~
  747 |                         } else {
  748 |                             // println('m2')

What did you expect to see?

A compiled program, and the veb server should handle / and /index routes by responding with Hello V!.

This was found, while reviewing #25246 (which needed a simpler cgen change).

I expect that I would be able to define the route method on both the unaliased type, and on the aliased type too. If there are 2 definitions, the method route definition on the aliased type should be chosen over the unaliased method route. There should be no compile time errors.

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[huly-for-github]

Connected to Huly®: V_0.6-24911

[spytheman]

The compilation issue is gone, but there is still a compiler problem - the method defined on the alias type, is ignored in the generic function generate_routes in veb, which contains a
$for method in A.methods { loop.

If that is solved too, imho the issue will be fully resolved.