From 8a1d6d319b02f2da13622b148d7ff0559f836f8a Mon Sep 17 00:00:00 2001
From: Jamie Hill-Daniel <jamie@osec.io>
Date: Wed, 21 Jan 2026 20:02:57 +0000
Subject: [PATCH] Add test for malformed and misapplied `crate_type`

---
 tests/ui/attributes/crate-type-non-crate.rs   | 19 +++++
 .../ui/attributes/crate-type-non-crate.stderr | 70 +++++++++++++++++++
 2 files changed, 89 insertions(+)
 create mode 100644 tests/ui/attributes/crate-type-non-crate.rs
 create mode 100644 tests/ui/attributes/crate-type-non-crate.stderr

diff --git a/tests/ui/attributes/crate-type-non-crate.rs b/tests/ui/attributes/crate-type-non-crate.rs
new file mode 100644
index 000000000000..bd667b4b0a45
--- /dev/null
+++ b/tests/ui/attributes/crate-type-non-crate.rs
@@ -0,0 +1,19 @@
+//! Test the behavior of various malformed `crate_type` attributes applied to a non-crate target.
+#![allow(unused_attributes)]
+
+// No arguments
+#[crate_type]           //~ ERROR malformed `crate_type` attribute input
+// List/NameValue with/without strings
+#[crate_type(lib)]      //~ ERROR malformed `crate_type` attribute input
+#[crate_type("lib")]    //~ ERROR malformed `crate_type` attribute input
+#[crate_type = lib]     //~ ERROR attribute value must be a literal
+#[crate_type = "lib"]   //  OK
+// Same as above but with invalid names
+#[crate_type(foo)]      //~ ERROR malformed `crate_type` attribute input
+#[crate_type("foo")]    //~ ERROR malformed `crate_type` attribute input
+#[crate_type = foo]     //~ ERROR attribute value must be a literal
+#[crate_type = "foo"]   //  OK - we don't report errors on invalid crate types here
+// Non-string literals
+#[crate_type(1)]        //~ ERROR malformed `crate_type` attribute input
+#[crate_type = 1]       //~ ERROR malformed `crate_type` attribute input
+fn main() {}
diff --git a/tests/ui/attributes/crate-type-non-crate.stderr b/tests/ui/attributes/crate-type-non-crate.stderr
new file mode 100644
index 000000000000..433c1e3b71a2
--- /dev/null
+++ b/tests/ui/attributes/crate-type-non-crate.stderr
@@ -0,0 +1,70 @@
+error: malformed `crate_type` attribute input
+  --> $DIR/crate-type-non-crate.rs:5:1
+   |
+LL | #[crate_type]
+   | ^^^^^^^^^^^^^
+   |
+   = note: for more information, visit <https://doc.rust-lang.org/reference/linkage.html>
+
+error: malformed `crate_type` attribute input
+  --> $DIR/crate-type-non-crate.rs:7:1
+   |
+LL | #[crate_type(lib)]
+   | ^^^^^^^^^^^^^^^^^^
+   |
+   = note: for more information, visit <https://doc.rust-lang.org/reference/linkage.html>
+
+error: malformed `crate_type` attribute input
+  --> $DIR/crate-type-non-crate.rs:8:1
+   |
+LL | #[crate_type("lib")]
+   | ^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: for more information, visit <https://doc.rust-lang.org/reference/linkage.html>
+
+error: attribute value must be a literal
+  --> $DIR/crate-type-non-crate.rs:9:16
+   |
+LL | #[crate_type = lib]
+   |                ^^^
+
+error: malformed `crate_type` attribute input
+  --> $DIR/crate-type-non-crate.rs:12:1
+   |
+LL | #[crate_type(foo)]
+   | ^^^^^^^^^^^^^^^^^^
+   |
+   = note: for more information, visit <https://doc.rust-lang.org/reference/linkage.html>
+
+error: malformed `crate_type` attribute input
+  --> $DIR/crate-type-non-crate.rs:13:1
+   |
+LL | #[crate_type("foo")]
+   | ^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: for more information, visit <https://doc.rust-lang.org/reference/linkage.html>
+
+error: attribute value must be a literal
+  --> $DIR/crate-type-non-crate.rs:14:16
+   |
+LL | #[crate_type = foo]
+   |                ^^^
+
+error: malformed `crate_type` attribute input
+  --> $DIR/crate-type-non-crate.rs:17:1
+   |
+LL | #[crate_type(1)]
+   | ^^^^^^^^^^^^^^^^
+   |
+   = note: for more information, visit <https://doc.rust-lang.org/reference/linkage.html>
+
+error: malformed `crate_type` attribute input
+  --> $DIR/crate-type-non-crate.rs:18:1
+   |
+LL | #[crate_type = 1]
+   | ^^^^^^^^^^^^^^^^^
+   |
+   = note: for more information, visit <https://doc.rust-lang.org/reference/linkage.html>
+
+error: aborting due to 9 previous errors
+