Make the diagnostic for static variables in patterns better

Fixes #17933.

Author: Jakub Wieczorek

src/librustc/middle/resolve.rs

@@ -5112,10 +5112,15 @@ impl<'a> Resolver<'a> {
                         Some(def @ (DefFn(..), _))      |
                         Some(def @ (DefVariant(..), _)) |
                         Some(def @ (DefStruct(..), _))  |
-                        Some(def @ (DefConst(..), _))  |
-                        Some(def @ (DefStatic(..), _)) => {
+                        Some(def @ (DefConst(..), _)) => {
                             self.record_def(pattern.id, def);
                         }
+                        Some((DefStatic(..), _)) => {
+                            self.resolve_error(path.span,
+                                               "static variables cannot be \
+                                                referenced in a pattern, \
+                                                use a `const` instead");
+                        }
                         Some(_) => {
                             self.resolve_error(path.span,
                                 format!("`{}` is not an enum variant, struct or const",

src/test/compile-fail/issue-17933.rs

@@ -0,0 +1,19 @@
+// Copyright 2014 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.
+
+pub static X: uint = 1u;
+
+fn main() {
+    match 1u {
+        self::X => { },
+        //~^ ERROR static variables cannot be referenced in a pattern, use a `const` instead
+        _       => { },
+    }
+}