Add a test case with infinite importable paths. (obi1kenobi#287)

* Add a test case with infinite importable paths.

* Make one more import public.

* Make the test crates `publish = false`.

test_crates/infinite_importable_paths/new/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+publish = false
+name = "infinite_importable_paths"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

test_crates/infinite_importable_paths/new/src/lib.rs

@@ -0,0 +1,23 @@
+//! This package exports the functions:
+//! - `foo`
+//! - `nested::foo`
+//! - `nested::nested::foo`
+//! etc. with arbitrarily many repetitions of `nested` allowed.
+//!
+//! This package uses a different way of achieving the same thing
+//! compared to its variant in the `old` directory.
+//! No semver issues should be reported when comparing the two.
+
+mod nested_other {
+    pub use super::nested;
+
+    pub fn foo() {}
+}
+
+pub mod nested {
+    pub use crate::nested_other::foo;
+
+    pub use crate::nested_other::nested;
+}
+
+pub use nested::foo;

test_crates/infinite_importable_paths/old/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+publish = false
+name = "infinite_importable_paths"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

test_crates/infinite_importable_paths/old/src/lib.rs

@@ -0,0 +1,13 @@
+//! This package exports the functions:
+//! - `foo`
+//! - `nested::foo`
+//! - `nested::nested::foo`
+//! etc. with arbitrarily many repetitions of `nested` allowed.
+
+pub mod nested {
+    pub use super::nested;
+
+    pub fn foo() {}
+}
+
+pub use nested::foo;