Add a test for an incorrect number of const args

Author: varkor

src/test/ui/const_generics/incorrect-number-of-const-args.rs

@@ -0,0 +1,16 @@
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+fn foo<const X: usize>() -> usize { 0 }
+
+fn main() {
+    foo(); //~ ERROR too few const parameters provided
+    foo::<0, 0>(); //~ ERROR too many const parameters provided
+}

src/test/ui/const_generics/incorrect-number-of-const-args.stderr

@@ -0,0 +1,16 @@
+error[E0086]: too few const parameters provided: expected 1 const parameter, found 0 const parameters
+  --> $DIR/incorrect-number-of-const-args.rs:14:5
+   |
+LL |     foo(); //~ ERROR too few const parameters provided
+   |     ^^^ expected 1 const parameter
+
+error[E0085]: too many const parameters provided: expected at most 1 const parameter, found 2 const parameters
+  --> $DIR/incorrect-number-of-const-args.rs:15:14
+   |
+LL |     foo::<0, 0>(); //~ ERROR too many const parameters provided
+   |              ^ expected 1 const parameter
+
+error: aborting due to 2 previous errors
+
+Some errors occurred: E0085, E0086.
+For more information about an error, try `rustc --explain E0085`.