Report error for non constant vector repeat count

Fix issue #3645

src/librustc/middle/ty.rs

@@ -4289,7 +4289,8 @@ pub fn eval_repeat_count(tcx: ctxt,
                          count_expr: @ast::expr,
                          span: span)
                       -> uint {
-    match const_eval::eval_const_expr(tcx, count_expr) {
+    match const_eval::eval_const_expr_partial(tcx, count_expr) {
+      Ok(ref const_val) => match *const_val {
         const_eval::const_int(count) => return count as uint,
         const_eval::const_uint(count) => return count as uint,
         const_eval::const_float(count) => {
@@ -4310,7 +4311,13 @@ pub fn eval_repeat_count(tcx: ctxt,
                                 repeat count but found boolean");
             return 0;
         }
-
+      },
+      Err(*) => {
+        tcx.sess.span_err(span,
+                          ~"expected constant integer for repeat count \
+                            but found variable");
+        return 0;
+      }
     }
 }
 

src/test/compile-fail/repeat_count.rs

@@ -0,0 +1,16 @@
+// Copyright 2013 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.
+
+// Regression test for issue #3645
+
+fn main() {
+    let n = 1;
+    let a = ~[0, ..n]; //~ ERROR expected constant integer for repeat count but found variable
+}