test: show runtime-dep and build-dep collides

See rust-lang/cargo 14253

tests/testsuite/rustflags.rs

@@ -1642,3 +1642,74 @@ fn target_applies_to_host_rustdocflags_works() {
         )
         .run();
 }
+
+#[cargo_test]
+fn host_config_shared_build_dep() {
+    // rust-lang/cargo#14253
+    Package::new("cc", "1.0.0").publish();
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+            [package]
+            name = "bootstrap"
+            edition = "2021"
+
+            [dependencies]
+            cc = "1.0.0"
+
+            [build-dependencies]
+            cc = "1.0.0"
+
+            [profile.dev]
+            debug = 0
+            "#,
+        )
+        .file("src/lib.rs", "")
+        .file("build.rs", "fn main() {}")
+        .file(
+            ".cargo/config.toml",
+            "
+            target-applies-to-host=false
+
+            [host]
+            rustflags = ['--cfg', 'from_host']
+
+            [build]
+            rustflags = ['--cfg', 'from_target']
+            ",
+        )
+        .build();
+
+    p.cargo("build -v")
+        .masquerade_as_nightly_cargo(&["target-applies-to-host"])
+        .arg("-Ztarget-applies-to-host")
+        .arg("-Zhost-config")
+        // Sometimes it compiles. Not deterministic...
+        .with_stderr_data(str![[r#"
+[UPDATING] `dummy-registry` index
+[LOCKING] 2 packages to latest compatible versions
+[DOWNLOADING] crates ...
+[DOWNLOADED] cc v1.0.0 (registry `dummy-registry`)
+[WARNING] output filename collision.
+The lib target `cc` in package `cc v1.0.0` has the same output filename as the lib target `cc` in package `cc v1.0.0`.
+Colliding filename is: [ROOT]/foo/target/debug/deps/libcc-[HASH].rlib
+The targets should have unique names.
+Consider changing their names to be unique or compiling them separately.
+This may become a hard error in the future; see <https://github.com/rust-lang/cargo/issues/6313>.
+[WARNING] output filename collision.
+The lib target `cc` in package `cc v1.0.0` has the same output filename as the lib target `cc` in package `cc v1.0.0`.
+Colliding filename is: [ROOT]/foo/target/debug/deps/libcc-[HASH].rmeta
+The targets should have unique names.
+Consider changing their names to be unique or compiling them separately.
+This may become a hard error in the future; see <https://github.com/rust-lang/cargo/issues/6313>.
+[COMPILING] cc v1.0.0
+[RUNNING] `rustc --crate-name cc [..]--cfg from_host[..]`
+[RUNNING] `rustc --crate-name cc [..]--cfg from_target[..]`
+[ERROR] failed to build archive: No such file or directory
+
+[ERROR] could not compile `cc` (lib) due to 1 previous error
+
+"#]])
+        .run();
+}