tests/run-make-cargo/same-crate-name-and-macro-name: New regression test

tests/run-make-cargo/same-crate-name-and-macro-name/consumer/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "consumer"
+version = "0.1.0"
+
+[dependencies]
+mylib_v1 = { path = "../mylib_v1", package = "mylib" }
+mylib_v2 = { path = "../mylib_v2", package = "mylib" }
+
+# Avoid interference with root workspace when casually testing
+[workspace]

tests/run-make-cargo/same-crate-name-and-macro-name/consumer/src/main.rs

@@ -0,0 +1,7 @@
+fn main() {
+    let v1 = mylib_v1::my_macro!();
+    assert_eq!(v1, "version 1");
+
+    let v2 = mylib_v2::my_macro!();
+    assert_eq!(v2, "version 2");
+}

tests/run-make-cargo/same-crate-name-and-macro-name/mylib_v1/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "mylib"
+version = "1.0.0"
+
+# Avoid interference with root workspace when casually testing
+[workspace]

tests/run-make-cargo/same-crate-name-and-macro-name/mylib_v1/src/lib.rs

@@ -0,0 +1,6 @@
+#[macro_export]
+macro_rules! my_macro {
+    () => {
+        "version 1"
+    };
+}

tests/run-make-cargo/same-crate-name-and-macro-name/mylib_v2/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "mylib"
+version = "2.0.0"
+
+# Avoid interference with root workspace when casually testing
+[workspace]

tests/run-make-cargo/same-crate-name-and-macro-name/mylib_v2/src/lib.rs

@@ -0,0 +1,6 @@
+#[macro_export]
+macro_rules! my_macro {
+    () => {
+        "version 2"
+    };
+}

tests/run-make-cargo/same-crate-name-and-macro-name/rmake.rs

@@ -0,0 +1,13 @@
+//! Regression test for
+//! <https://github.com/rust-lang/rust/issues/71259#issuecomment-615879925>
+//! (that particular comment describes the issue well).
+//!
+//! We test that two library crates with the same name can export macros with
+//! the same name without causing interference when both are used in another
+//! crate.
+
+use run_make_support::cargo;
+
+fn main() {
+    cargo().current_dir("consumer").arg("run").run();
+}