CARGO_CRATE_NAME is set incorrectly for integration tests and examples

[ModProg]

rust-analyzer version: rust-analyzer 1 (2df30e1 2023-09-03)

rustc version: rustc 1.72.0 (5680fa18f 2023-08-23)

rust-analyzer sets CARGO_CRATE_NAME incorrectly for examples and integration tests. Possibly related to #8149.

# Cargo.toml
[package]
name = "crate"
version = "0.1.0"
edition = "2021"

[dependencies]
crate-name.path = "crate-name"

// crate-name/src/lib.rs
#[proc_macro]
pub fn crate_name(_: proc_macro::TokenStream) -> proc_macro::TokenStream {
    panic!("{}", std::env::var("CARGO_CRATE_NAME").unwrap(),)
}

Put crate_name::crate_name!{} in src/main.rs, tests/test.rs and example/example.rs.

cargo check prints:

#   Compiling crate v0.1.0 (/crate)
error: proc macro panicked
 --> tests/test.rs:1:1
  |
1 | crate_name::crate_name!();
  | ^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = help: message: test

error: proc macro panicked
 --> src/main.rs:2:5
  |
2 |     crate_name::crate_name!();
  |     ^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = help: message: crate

error: proc macro panicked
 --> examples/example.rs:2:5
  |
2 |     crate_name::crate_name!();
  |     ^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = help: message: example

error: could not compile `crate` (bin "crate") due to previous error
warning: build failed, waiting for other jobs to finish...
error: could not compile `crate` (test "test") due to previous error
error: could not compile `crate` (bin "crate" test) due to previous error
error: could not compile `crate` (example "example") due to previous error

While rust-analyzer reports crate for all of them, meaning that it did not run crate_name with the correct name.

[alibektas]

It seems that we use PKG_NAME as a replacement for the crate name.

rust-analyzer/crates/project-model/src/workspace.rs

Lines 1464 to 1466 in d5b6ab2

	// FIXME: This isn't really correct (a package can have many crates with different names), but
	// it's better than leaving the variable unset.
	env.set("CARGO_CRATE_NAME", CrateName::normalize_dashes(&package.name).to_string());