rust how to define an internal dependency? - rust

Question

I am trying to achieve the following, I have this project structure:
.
├── Cargo.lock
├── Cargo.toml
└── src
├── lib.rs
├── mesh
│ ├── gltf_loader
│ │ ├── Cargo.toml
│ │ ├── pluralize
│ │ └── src
│ └── mesh.rs
└── vulkan
├── core.rs
├── hardware_interface.rs
├── image.rs
├── memory.rs
├── mod.rs
├── pipeline.rs
├── renderer.rs
├── shader_program.rs
├── swapchain.rs
└── tools.rs
in here pluralize defines a procedural macro that is needed to compile gltf_loader but that needs to be kept hidden from all other dependencies. So I want to compile gltf loader as a "subcrate" then use that crate as a dependency for mesh.rs. Ideally without moving the directory structure.
To that effect I added this to the root toml:
[dependencies]
gltf_loader = { path = "src/mesh/gltf_loader" }
However if I do this and try to run an example, I get this error:
error: failed to get `gltf_loader` as a dependency of package `vulkan_bindings v0.1.0 (/home/makogan/rust_never_engine)`
Caused by:
failed to load source for dependency `gltf_loader`
Caused by:
Unable to update /home/makogan/rust_never_engine/src/mesh/gltf_loader
Caused by:
failed to parse manifest at `/home/makogan/rust_never_engine/src/mesh/gltf_loader/Cargo.toml`
Caused by:
can't find `proc-macros` bin at `src/bin/proc-macros.rs` or `src/bin/proc-macros/main.rs`. Please specify bin.path if you want to use a non-default path.
Why does this happen?
This id the full .toml:
[package]
name = "vulkan_bindings"
version = "0.1.0"
edition = "2021"
[lib]
name = "vulkan_bindings"
path = "src/lib.rs"
[dependencies]
# Rendering
ash = { version = "0.37.0" }
glfw = { version = "0.45.0", features = ["vulkan"] }
gpu-allocator = "0.18.0"
spirv_cross = { version = "0.23.1", features = ["glsl"] }
shaderc = "0.8.0"
# Math
nalgebra = "*"
nalgebra-glm = "0.3"
nalgebra-sparse = "0.1"
# json
serde_json = "1.0"
serde = { version = "1.0", features = ["derive"] }
data-url = "0.1.1"
# misc
paste = "1.0.8"
termcolor = "1.1.3"
regex = "1.6.0"
add_getters_setters = "1.1.2"
# internal
gltf_loader = { path = "src/mesh/gltf_loader" }