Correct the polymorphic extern fn error for const parameters

2 files changed, 37 insertions, 0 deletions

diff --git a/src/test/ui/const-generics/foreign-item-const-parameter.rs b/src/test/ui/const-generics/foreign-item-const-parameter.rs
new file mode 100644
index 00000000000..4673c8606c3
--- /dev/null
+++ b/src/test/ui/const-generics/foreign-item-const-parameter.rs
@@ -0,0 +1,10 @@
+#![feature(const_generics)]
+//~^ WARN the feature `const_generics` is incomplete and may cause the compiler to crash
+
+extern "C" {
+    fn foo<const X: usize>(); //~ ERROR foreign items may not have const parameters
+
+    fn bar<T, const X: usize>(_: T); //~ ERROR foreign items may not have type or const parameters
+}
+
+fn main() {}
diff --git a/src/test/ui/const-generics/foreign-item-const-parameter.stderr b/src/test/ui/const-generics/foreign-item-const-parameter.stderr
new file mode 100644
index 00000000000..0a74537dfef
--- /dev/null
+++ b/src/test/ui/const-generics/foreign-item-const-parameter.stderr
@@ -0,0 +1,27 @@
+warning: the feature `const_generics` is incomplete and may cause the compiler to crash
+  --> $DIR/foreign-item-const-parameter.rs:1:12
+   |
+LL | #![feature(const_generics)]
+   |            ^^^^^^^^^^^^^^
+   |
+   = note: `#[warn(incomplete_features)]` on by default
+
+error[E0044]: foreign items may not have const parameters
+  --> $DIR/foreign-item-const-parameter.rs:5:5
+   |
+LL |     fn foo<const X: usize>();
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^ can't have const parameters
+   |
+   = help: use specialization instead of const parameters by replacing them with concrete consts
+
+error[E0044]: foreign items may not have type or const parameters
+  --> $DIR/foreign-item-const-parameter.rs:7:5
+   |
+LL |     fn bar<T, const X: usize>(_: T);
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ can't have type or const parameters
+   |
+   = help: use specialization instead of type or const parameters by replacing them with concrete types or consts
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0044`.