auto merge of #8483 : luqmana/rust/rexprs, r=catamorphism

Fixes #8152.

Author: bors

src/librustc/middle/check_const.rs

@@ -160,6 +160,7 @@ pub fn check_expr(sess: Session,
           expr_field(*) |
           expr_index(*) |
           expr_tup(*) |
+          expr_repeat(*) |
           expr_struct(*) => { }
           expr_addr_of(*) => {
                 sess.span_err(

src/librustc/middle/const_eval.rs

@@ -153,6 +153,8 @@ pub fn classify(e: &expr,
                 lookup_constness(tcx, e)
               }
 
+              ast::expr_repeat(*) => general_const,
+
               _ => non_const
             };
         tcx.ccache.insert(did, cn);

src/librustc/middle/trans/consts.rs

@@ -32,6 +32,7 @@ use middle::trans::type_::Type;
 
 use std::c_str::ToCStr;
 use std::libc::c_uint;
+use std::vec;
 use syntax::{ast, ast_util, ast_map};
 
 pub fn const_lit(cx: &mut CrateContext, e: &ast::expr, lit: ast::lit)
@@ -540,6 +541,23 @@ fn const_expr_unadjusted(cx: @mut CrateContext, e: &ast::expr) -> ValueRef {
               _ => cx.sess.span_bug(e.span, "bad const-slice expr")
             }
           }
+          ast::expr_repeat(elem, count, _) => {
+            let vec_ty = ty::expr_ty(cx.tcx, e);
+            let unit_ty = ty::sequence_element_type(cx.tcx, vec_ty);
+            let llunitty = type_of::type_of(cx, unit_ty);
+            let n = match const_eval::eval_const_expr(cx.tcx, count) {
+                const_eval::const_int(i)  => i as uint,
+                const_eval::const_uint(i) => i as uint,
+                _ => cx.sess.span_bug(count.span, "count must be integral const expression.")
+            };
+            let vs = vec::from_elem(n, const_expr(cx, elem));
+            let v = if vs.iter().any(|vi| val_ty(*vi) != llunitty) {
+                C_struct(vs)
+            } else {
+                C_array(llunitty, vs)
+            };
+            v
+          }
           ast::expr_path(ref pth) => {
             assert_eq!(pth.types.len(), 0);
             let tcx = cx.tcx;

src/test/compile-fail/static-vec-repeat-not-constant.rs

@@ -0,0 +1,15 @@
+// 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.
+
+fn foo() -> int { 23 }
+
+static a: [int, ..2] = [foo(), ..2]; //~ ERROR: function calls in constants are limited to struct and enum constructors
+
+fn main() {}

src/test/run-pass/repeat-expr-in-static.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.
+
+static FOO: [int, ..4] = [32, ..4];
+static BAR: [int, ..4] = [32, 32, 32, 32];
+
+pub fn main() {
+    assert_eq!(FOO, BAR);
+}