Add #[rustc_legacy_const_generics]

src/test/ui/auxiliary/legacy-const-generics.rs

@@ -0,0 +1,6 @@
+#![feature(rustc_attrs)]
+
+#[rustc_legacy_const_generics(1)]
+pub fn foo<const Y: usize>(x: usize, z: usize) -> [usize; 3] {
+    [x, Y, z]
+}

src/test/ui/invalid-rustc_legacy_const_generics-arguments.rs

@@ -0,0 +1,35 @@
+#![feature(rustc_attrs)]
+
+#[rustc_legacy_const_generics(0)] //~ ERROR index exceeds number of arguments
+fn foo1() {}
+
+#[rustc_legacy_const_generics(1)] //~ ERROR index exceeds number of arguments
+fn foo2(_: u8) {}
+
+#[rustc_legacy_const_generics(2)] //~ ERROR index exceeds number of arguments
+fn foo3<const X: usize>(_: u8) {}
+
+#[rustc_legacy_const_generics(a)] //~ ERROR arguments should be non-negative integers
+fn foo4() {}
+
+#[rustc_legacy_const_generics(1, a, 2, b)] //~ ERROR arguments should be non-negative integers
+fn foo5(_: u8, _: u8, _: u8) {}
+
+#[rustc_legacy_const_generics(0)] //~ ERROR attribute should be applied to a function
+struct S;
+
+#[rustc_legacy_const_generics(0usize)] //~ ERROR suffixed literals are not allowed in attributes
+fn foo6(_: u8) {}
+
+extern {
+    #[rustc_legacy_const_generics(1)] //~ ERROR index exceeds number of arguments
+    fn foo7(_: u8);
+}
+
+#[rustc_legacy_const_generics] //~ ERROR malformed `rustc_legacy_const_generics` attribute
+fn bar1() {}
+
+#[rustc_legacy_const_generics = 1] //~ ERROR malformed `rustc_legacy_const_generics` attribute
+fn bar2() {}
+
+fn main() {}

src/test/ui/invalid-rustc_legacy_const_generics-arguments.stderr

@@ -0,0 +1,66 @@
+error: suffixed literals are not allowed in attributes
+  --> $DIR/invalid-rustc_legacy_const_generics-arguments.rs:21:31
+   |
+LL | #[rustc_legacy_const_generics(0usize)]
+   |                               ^^^^^^
+   |
+   = help: instead of using a suffixed literal (`1u8`, `1.0f32`, etc.), use an unsuffixed version (`1`, `1.0`, etc.)
+
+error: malformed `rustc_legacy_const_generics` attribute input
+  --> $DIR/invalid-rustc_legacy_const_generics-arguments.rs:29:1
+   |
+LL | #[rustc_legacy_const_generics]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: must be of the form: `#[rustc_legacy_const_generics(N)]`
+
+error: malformed `rustc_legacy_const_generics` attribute input
+  --> $DIR/invalid-rustc_legacy_const_generics-arguments.rs:32:1
+   |
+LL | #[rustc_legacy_const_generics = 1]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: must be of the form: `#[rustc_legacy_const_generics(N)]`
+
+error: index exceeds number of arguments
+  --> $DIR/invalid-rustc_legacy_const_generics-arguments.rs:3:31
+   |
+LL | #[rustc_legacy_const_generics(0)]
+   |                               ^ there are only 0 arguments
+
+error: index exceeds number of arguments
+  --> $DIR/invalid-rustc_legacy_const_generics-arguments.rs:6:31
+   |
+LL | #[rustc_legacy_const_generics(1)]
+   |                               ^ there is only 1 argument
+
+error: index exceeds number of arguments
+  --> $DIR/invalid-rustc_legacy_const_generics-arguments.rs:9:31
+   |
+LL | #[rustc_legacy_const_generics(2)]
+   |                               ^ there are only 2 arguments
+
+error: arguments should be non-negative integers
+  --> $DIR/invalid-rustc_legacy_const_generics-arguments.rs:12:31
+   |
+LL | #[rustc_legacy_const_generics(a)]
+   |                               ^
+
+error: arguments should be non-negative integers
+  --> $DIR/invalid-rustc_legacy_const_generics-arguments.rs:15:34
+   |
+LL | #[rustc_legacy_const_generics(1, a, 2, b)]
+   |                                  ^     ^
+
+error: attribute should be applied to a function
+  --> $DIR/invalid-rustc_legacy_const_generics-arguments.rs:18:1
+   |
+LL | #[rustc_legacy_const_generics(0)]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | struct S;
+   | --------- not a function
+
+error: index exceeds number of arguments
+  --> $DIR/invalid-rustc_legacy_const_generics-arguments.rs:25:35
+   |
+LL |     #[rustc_legacy_const_generics(1)]
+   |                                   ^ there is only 1 argument
+
+error: aborting due to 10 previous errors
+

src/test/ui/legacy-const-generics.rs

@@ -0,0 +1,18 @@
+// aux-build:legacy-const-generics.rs
+// run-pass
+
+#![feature(rustc_attrs)]
+
+extern crate legacy_const_generics;
+
+#[rustc_legacy_const_generics(1)]
+pub fn bar<const Y: usize>(x: usize, z: usize) -> [usize; 3] {
+    [x, Y, z]
+}
+
+fn main() {
+    assert_eq!(legacy_const_generics::foo(0 + 0, 1 + 1, 2 + 2), [0, 2, 4]);
+    assert_eq!(legacy_const_generics::foo::<{1 + 1}>(0 + 0, 2 + 2), [0, 2, 4]);
+    // TODO: Only works cross-crate
+    //assert_eq!(bar(0, 1, 2), [0, 1, 2]);
+}