`--cfg=sqlx_macros_unstable` broken in recent rust nightly

[gpluscb]

I have found these related issues/pull requests

rust-lang/rust#149400
rust-lang/rust#99515

Description

rust-lang/rust#149400 restructured the nightly proc_macro_tracked_path feature (previously track_path), causing errors when compiling with --cfg=sqlx_macros_unstable on recent rust nightly:

error[E0433]: failed to resolve: could not find `tracked_path` in `proc_macro`
   --> /home/marrue/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/sqlx-macros-core-0.8.6/src/migrate.rs:119:21
    |
119 |         proc_macro::tracked_path::path(path);
    |                     ^^^^^^^^^^^^ could not find `tracked_path` in `proc_macro`

error[E0635]: unknown feature `track_path`
  --> /home/marrue/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/sqlx-macros-core-0.8.6/src/lib.rs:19:13
   |
19 |     feature(track_path)
   |             ^^^^^^^^^^

Some errors have detailed explanations: E0433, E0635.
For more information about an error, try `rustc --explain E0433`.
error: could not compile `sqlx-macros-core` (lib) due to 2 previous errors

The first error is because proc_macro::tracked_path::path was renamed to proc_macro::tracked::path, the second error is because the feature was renamed to proc_macro_tracked_path.

This affects at least sqlx 0.8.x and 0.9.0-alpha.1. On 0.9.0-alpha.1, the compiler additionally complains about the change from proc_macro::tracked_env::var to proc_macro::tracked::env_var as well as about a use of unresolved module or unlinked crate 'proc_macro'. I'm not sure whether the unresolved module issue is related to the feature structure changes:

error[E0433]: failed to resolve: use of unresolved module or unlinked crate `proc_macro`
  --> /home/marrue/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/sqlx-macros-core-0.9.0-alpha.1/src/query/cache.rs:74:13
   |
74 |             proc_macro::tracked_path::path(&path);
   |             ^^^^^^^^^^ use of unresolved module or unlinked crate `proc_macro`
   |
help: there is a crate or module with a similar name
   |
74 |             proc_macro2::tracked_path::path(&path);
   |                       +

error[E0433]: failed to resolve: could not find `tracked_path` in `proc_macro`
   --> /home/marrue/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/sqlx-macros-core-0.9.0-alpha.1/src/migrate.rs:135:21
    |
135 |         proc_macro::tracked_path::path(path);
    |                     ^^^^^^^^^^^^ could not find `tracked_path` in `proc_macro`

error[E0433]: failed to resolve: use of unresolved module or unlinked crate `proc_macro`
  --> /home/marrue/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/sqlx-macros-core-0.9.0-alpha.1/src/lib.rs:99:41
   |
99 |     let res: Result<String, VarError> = proc_macro::tracked_env::var(var);
   |                                         ^^^^^^^^^^ use of unresolved module or unlinked crate `proc_macro`
   |
help: there is a crate or module with a similar name
   |
99 |     let res: Result<String, VarError> = proc_macro2::tracked_env::var(var);
   |                                                   +

error[E0635]: unknown feature `track_path`
  --> /home/marrue/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/sqlx-macros-core-0.9.0-alpha.1/src/lib.rs:19:13
   |
19 |     feature(track_path)
   |             ^^^^^^^^^^

Some errors have detailed explanations: E0433, E0635.
For more information about an error, try `rustc --explain E0433`.
error: could not compile `sqlx-macros-core` (lib) due to 4 previous errors

Reproduction steps

As far as I can tell, compiling any crate using sqlx macros on latest nightly with --cfg=sqlx_macros_unstable should reproduce this.

SQLx version

Tested for 0.8.6, 0.9.0-alpha.1

Enabled SQLx features

"postgres", "runtime-tokio", "time"

Database server and version

PostgreSQL 18.0 (Debian 18.0-1.pgdg13+3)

Operating system

Linux

Rust version

rustc 1.95.0-nightly (d222ddc4d 2026-01-23)