Can we make taichi ignore annotation in annotated assignment when annotation is not a primitive type, or allow ti.template()/typing.Any to serve as a dummy annotation(without any compile-time or runtime effect, only edit-time effect for developer experience)?

[YouJiacheng]

With this we can improve developer experience leveraging the existing intelliSense(auto complete, jump to source, semantic highlight) infrastructure for Python.
Use case:

from typing import Generic, TypeVar

import taichi as ti
from taichi.lang.struct import StructType

T = TypeVar('T')

vec3 = ti.types.vector(3, ti.float32)
vec2 = ti.types.vector(2, ti.float32)

# make IntelliSense happy
class TypedStructType(Generic[T], StructType): ...

def ti_dataclass(cls: type[T]) -> TypedStructType[T]:
    return ti.dataclass(cls)

def typing(_: TypedStructType[T], obj) -> type[T]:
    return obj

@ti_dataclass
class Triangle:
    V0: vec3
    V1: vec3
    V2: vec3
TriangleT = typing(Triangle, ti.template())

@ti_dataclass
class TextureTriangle:
    V0: vec2
    V1: vec2
    V2: vec2
TextureTriangleT = typing(TextureTriangle, ti.template())

@ti_dataclass
class Primitive:
    position_triangle: Triangle
    texture_triangle: TextureTriangle
    material_index: ti.i32
PrimitiveT = typing(Primitive, ti.template())

@ti.func
def foo(p: PrimitiveT): # taichi allows ti.template() as argument annotation
    pos = p.position_triangle
    pos.V0
    pos2: TriangleT = p.position_triangle # taichi doesn't allow ti.template() as assignment annotation
    pos2.V0 # intelliSense enabled

Originally posted by @YouJiacheng in #2610 (comment)

[YouJiacheng]

I attempted to use ast to remove annotations in assignments. But taichi doesn't support ast transformation extension, and always require source as input(doesn't allow AST input) for ti.func and ti.kernel.

[ailzhang]

I guess this is pretty close to #6591 so let's track all the IDE experience progress there?
(feel free to reopen if I'm wrong)