Change:
<ins> // 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. // This compiler pass detects static items that refer to themselves // recursively. use driver::session::Session; use middle::resolve; use middle::def::DefStatic; use syntax::ast::{Crate, Expr, ExprPath, Item, ItemStatic, NodeId}; use syntax::{ast_util, ast_map}; use syntax::visit::Visitor; use syntax::visit; struct CheckCrateVisitor<'a, 'ast: 'a> { sess: &'a Session, def_map: &'a resolve::DefMap, ast_map: &'a ast_map::Map<'ast> } impl<'v, 'a, 'ast> Visitor<'v> for CheckCrateVisitor<'a, 'ast> { fn visit_item(&mut self, i: &Item) { check_item(self, i); } } pub fn check_crate<'ast>(sess: &Session, krate: &Crate, def_map: &resolve::DefMap, ast_map: &ast_map::Map<'ast>) { let mut visitor = CheckCrateVisitor { sess: sess, def_map: def_map, ast_map: ast_map }; visit::walk_crate(&mut visitor, krate); sess.abort_if_errors(); } fn check_item(v: &mut CheckCrateVisitor, it: &Item) { match it.node { ItemStatic(_, _, ref ex) => { check_item_recursion(v.sess, v.ast_map, v.def_map, it); visit::walk_expr(v, &**ex) }, _ => visit::walk_item(v, it) } } struct CheckItemRecursionVisitor<'a, 'ast: 'a> { root_it: &'a Item, sess: &'a Session, ast_map: &'a ast_map::Map<'ast>, def_map: &'a resolve::DefMap, idstack: Vec<NodeId> } // Make sure a const item doesn't recursively refer to itself // FIXME: Should use the dependency graph when it's available (#1356) pub fn check_item_recursion<'a>(sess: &'a Session, ast_map: &'a ast_map::Map, def_map: &'a resolve::DefMap, it: &'a Item) { let mut visitor = CheckItemRecursionVisitor { root_it: it, sess: sess, ast_map: ast_map, def_map: def_map, idstack: Vec::new() }; visitor.visit_item(it); } impl<'a, 'ast, 'v> Visitor<'v> for CheckItemRecursionVisitor<'a, 'ast> { fn visit_item(&mut self, it: &Item) { if self.idstack.iter().any(|x| x == &(it.id)) { self.sess.span_err(self.root_it.span, "recursive constant"); return; } self.idstack.push(it.id); visit::walk_item(self, it); self.idstack.pop(); } fn visit_expr(&mut self, e: &Expr) { match e.node { ExprPath(..) => { match self.def_map.borrow().find(&e.id) { Some(&DefStatic(def_id, _)) if ast_util::is_local(def_id) => { self.visit_item(&*self.ast_map.expect_item(def_id.node)); } _ => () } }, _ => () } visit::walk_expr(self, e); } } </ins>

Discussion:
Normally when a static variable has a recursive the definition, the compiler issues an error. However, if the static is used (and not just defined) rustc overflows its stack. This program causes a stack overflow: Stack trace:
Constant checking -- which detects this recursion -- occurs after type checking in the phase order, but type checking needs to evaluate the constant expression in order to find the length of the array type. It looks like strategically inserting a call to in the appropriate place would fix this at the cost of potentially performing the check many times.
After some chatting on IRC, it looks like the best way to fix this is to break the item recursion check out into a separate pass that comes before type checking. This is my first time looking at this part of the compiler, but I'll give it a shot.
This approach looks promising. I need to do a full build/test run and then I can submit a PR.
Fixed.