improves duplicate lang item test

2 files changed, 36 insertions, 0 deletions

diff --git a/tests/ui/error-codes/E0152-duplicate-lang-items.rs b/tests/ui/error-codes/E0152-duplicate-lang-items.rs
new file mode 100644
index 00000000000..089810b1ad2
--- /dev/null
+++ b/tests/ui/error-codes/E0152-duplicate-lang-items.rs
@@ -0,0 +1,20 @@
+//! Validates the correct printing of E0152 in the case of duplicate "lang_item" function
+//! definitions.
+//!
+//! Issue: <https://github.com/rust-lang/rust/issues/31788>
+
+//@ error-pattern: first defined in crate `std`
+//@ normalize-stderr: "loaded from .*libstd-.*.rlib" -> "loaded from SYSROOT/libstd-*.rlib"
+#![feature(lang_items)]
+
+extern crate core;
+
+use core::panic::PanicInfo;
+
+#[lang = "panic_impl"]
+fn panic_impl(info: &PanicInfo) -> ! {
+    //~^ ERROR: found duplicate lang item `panic_impl`
+    loop {}
+}
+
+fn main() {}
diff --git a/tests/ui/error-codes/E0152-duplicate-lang-items.stderr b/tests/ui/error-codes/E0152-duplicate-lang-items.stderr
new file mode 100644
index 00000000000..3c3d64322f3
--- /dev/null
+++ b/tests/ui/error-codes/E0152-duplicate-lang-items.stderr
@@ -0,0 +1,16 @@
+error[E0152]: found duplicate lang item `panic_impl`
+  --> $DIR/E0152-duplicate-lang-items.rs:15:1
+   |
+LL | / fn panic_impl(info: &PanicInfo) -> ! {
+LL | |
+LL | |     loop {}
+LL | | }
+   | |_^
+   |
+   = note: the lang item is first defined in crate `std` (which `E0152_duplicate_lang_items` depends on)
+   = note: first definition in `std` loaded from SYSROOT/libstd-*.rlib
+   = note: second definition in the local crate (`E0152_duplicate_lang_items`)
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0152`.