diff --git a/src/rustc/middle/check_alt.rs b/src/rustc/middle/check_alt.rs
index 31ef3703c0b..1a97b276afe 100644
--- a/src/rustc/middle/check_alt.rs
+++ b/src/rustc/middle/check_alt.rs
@@ -1,7 +1,7 @@
 
 import syntax::ast::*;
-import syntax::ast_util::{variant_def_ids, dummy_sp, compare_lit_exprs,
-        lit_expr_eq, unguarded_pat};
+import syntax::ast_util::{variant_def_ids, dummy_sp, unguarded_pat};
+import middle::const_eval::{compare_lit_exprs, lit_expr_eq};
 import syntax::codemap::span;
 import pat_util::*;
 import syntax::visit;
diff --git a/src/rustc/middle/const_eval.rs b/src/rustc/middle/const_eval.rs
new file mode 100644
index 00000000000..ca066b127bc
--- /dev/null
+++ b/src/rustc/middle/const_eval.rs
@@ -0,0 +1,167 @@
+import syntax::ast::*;
+
+// FIXME this doesn't handle big integer/float literals correctly (nor does
+// the rest of our literal handling)
+enum const_val {
+    const_float(float),
+    const_int(i64),
+    const_uint(u64),
+    const_str(str),
+}
+
+// FIXME: issue #1417
+fn eval_const_expr(tcx: middle::ty::ctxt, e: @expr) -> const_val {
+    import middle::ty;
+    fn fromb(b: bool) -> const_val { const_int(b as i64) }
+    alt check e.node {
+      expr_unary(neg, inner) {
+        alt check eval_const_expr(tcx, inner) {
+          const_float(f) { const_float(-f) }
+          const_int(i) { const_int(-i) }
+          const_uint(i) { const_uint(-i) }
+        }
+      }
+      expr_unary(not, inner) {
+        alt check eval_const_expr(tcx, inner) {
+          const_int(i) { const_int(!i) }
+          const_uint(i) { const_uint(!i) }
+        }
+      }
+      expr_binary(op, a, b) {
+        alt check (eval_const_expr(tcx, a), eval_const_expr(tcx, b)) {
+          (const_float(a), const_float(b)) {
+            alt check op {
+              add { const_float(a + b) } subtract { const_float(a - b) }
+              mul { const_float(a * b) } div { const_float(a / b) }
+              rem { const_float(a % b) } eq { fromb(a == b) }
+              lt { fromb(a < b) } le { fromb(a <= b) } ne { fromb(a != b) }
+              ge { fromb(a >= b) } gt { fromb(a > b) }
+            }
+          }
+          (const_int(a), const_int(b)) {
+            alt check op {
+              add { const_int(a + b) } subtract { const_int(a - b) }
+              mul { const_int(a * b) } div { const_int(a / b) }
+              rem { const_int(a % b) } and | bitand { const_int(a & b) }
+              or | bitor { const_int(a | b) } bitxor { const_int(a ^ b) }
+              lsl { const_int(a << b) } lsr { const_int(a >> b) }
+              asr { const_int(a >>> b) }
+              eq { fromb(a == b) } lt { fromb(a < b) }
+              le { fromb(a <= b) } ne { fromb(a != b) }
+              ge { fromb(a >= b) } gt { fromb(a > b) }
+            }
+
+          }
+          (const_uint(a), const_uint(b)) {
+            alt check op {
+              add { const_uint(a + b) } subtract { const_uint(a - b) }
+              mul { const_uint(a * b) } div { const_uint(a / b) }
+              rem { const_uint(a % b) } and | bitand { const_uint(a & b) }
+              or | bitor { const_uint(a | b) } bitxor { const_uint(a ^ b) }
+              lsl { const_int((a << b) as i64) }
+              lsr { const_int((a >> b) as i64) }
+              asr { const_int((a >>> b) as i64) }
+              eq { fromb(a == b) } lt { fromb(a < b) }
+              le { fromb(a <= b) } ne { fromb(a != b) }
+              ge { fromb(a >= b) } gt { fromb(a > b) }
+            }
+          }
+        }
+      }
+      expr_cast(base, _) {
+        let ety = ty::expr_ty(tcx, e);
+        let base = eval_const_expr(tcx, base);
+        alt check ty::get(ety).struct {
+          ty::ty_float(_) {
+            alt check base {
+              const_uint(u) { const_float(u as f64) }
+              const_int(i) { const_float(i as f64) }
+              const_float(_) { base }
+            }
+          }
+          ty::ty_uint(_) {
+            alt check base {
+              const_uint(_) { base }
+              const_int(i) { const_uint(i as u64) }
+              const_float(f) { const_uint(f as u64) }
+            }
+          }
+          ty::ty_int(_) | ty::ty_bool {
+            alt check base {
+              const_uint(u) { const_int(u as i64) }
+              const_int(_) { base }
+              const_float(f) { const_int(f as i64) }
+            }
+          }
+        }
+      }
+      expr_lit(lit) { lit_to_const(lit) }
+    }
+}
+
+fn lit_to_const(lit: @lit) -> const_val {
+    alt lit.node {
+      lit_str(s) { const_str(s) }
+      lit_int(n, _) { const_int(n) }
+      lit_uint(n, _) { const_uint(n) }
+      lit_float(n, _) { const_float(option::get(float::from_str(n))) }
+      lit_nil { const_int(0i64) }
+      lit_bool(b) { const_int(b as i64) }
+    }
+}
+
+fn compare_const_vals(a: const_val, b: const_val) -> int {
+  alt (a, b) {
+    (const_int(a), const_int(b)) {
+        if a == b {
+            0
+        } else if a < b {
+            -1
+        } else {
+            1
+        }
+    }
+    (const_uint(a), const_uint(b)) {
+        if a == b {
+            0
+        } else if a < b {
+            -1
+        } else {
+            1
+        }
+    }
+    (const_float(a), const_float(b)) {
+        if a == b {
+            0
+        } else if a < b {
+            -1
+        } else {
+            1
+        }
+    }
+    (const_str(a), const_str(b)) {
+        if a == b {
+            0
+        } else if a < b {
+            -1
+        } else {
+            1
+        }
+    }
+    _ {
+        fail "compare_const_vals: ill-typed comparison";
+    }
+  }
+}
+
+fn compare_lit_exprs(tcx: middle::ty::ctxt, a: @expr, b: @expr) -> int {
+  compare_const_vals(eval_const_expr(tcx, a), eval_const_expr(tcx, b))
+}
+
+fn lit_expr_eq(tcx: middle::ty::ctxt, a: @expr, b: @expr) -> bool {
+    compare_lit_exprs(tcx, a, b) == 0
+}
+
+fn lit_eq(a: @lit, b: @lit) -> bool {
+    compare_const_vals(lit_to_const(a), lit_to_const(b)) == 0
+}
diff --git a/src/rustc/middle/trans/alt.rs b/src/rustc/middle/trans/alt.rs
index a3d5dba565a..8b8ee1fe81b 100644
--- a/src/rustc/middle/trans/alt.rs
+++ b/src/rustc/middle/trans/alt.rs
@@ -25,10 +25,10 @@ enum opt {
 }
 fn opt_eq(tcx: ty::ctxt, a: opt, b: opt) -> bool {
     alt (a, b) {
-      (lit(a), lit(b)) { ast_util::compare_lit_exprs(tcx, a, b) == 0 }
+      (lit(a), lit(b)) { const_eval::compare_lit_exprs(tcx, a, b) == 0 }
       (range(a1, a2), range(b1, b2)) {
-        ast_util::compare_lit_exprs(tcx, a1, b1) == 0 &&
-        ast_util::compare_lit_exprs(tcx, a2, b2) == 0
+        const_eval::compare_lit_exprs(tcx, a1, b1) == 0 &&
+        const_eval::compare_lit_exprs(tcx, a2, b2) == 0
       }
       (var(a, _), var(b, _)) { a == b }
       _ { false }
diff --git a/src/rustc/middle/tstate/auxiliary.rs b/src/rustc/middle/tstate/auxiliary.rs
index b2ed35d8f13..c973d15b40d 100644
--- a/src/rustc/middle/tstate/auxiliary.rs
+++ b/src/rustc/middle/tstate/auxiliary.rs
@@ -676,7 +676,7 @@ fn pred_args_matches(pattern: [constr_arg_general_<inst>], desc: pred_args) ->
           carg_base { if n != carg_base { ret false; } }
           carg_lit(l) {
             alt n {
-              carg_lit(m) { if !lit_eq(l, m) { ret false; } }
+              carg_lit(m) { if !const_eval::lit_eq(l, m) { ret false; } }
               _ { ret false; }
             }
           }
diff --git a/src/rustc/middle/ty.rs b/src/rustc/middle/ty.rs
index 8fac6b536c0..deeef4f6826 100644
--- a/src/rustc/middle/ty.rs
+++ b/src/rustc/middle/ty.rs
@@ -1306,7 +1306,7 @@ fn arg_eq<T>(eq: fn(T, T) -> bool,
       }
       ast::carg_lit(l) {
         alt b.node {
-          ast::carg_lit(m) { ret ast_util::lit_eq(l, m); } _ { ret false; }
+          ast::carg_lit(m) { ret const_eval::lit_eq(l, m); } _ { ret false; }
         }
       }
     }
@@ -1894,8 +1894,8 @@ fn enum_variants(cx: ctxt, id: ast::def_id) -> @[variant_info] {
                 alt variant.node.disr_expr {
                   some (ex) {
                     // FIXME: issue #1417
-                    disr_val = alt syntax::ast_util::eval_const_expr(cx, ex) {
-                      ast_util::const_int(val) {val as int}
+                    disr_val = alt const_eval::eval_const_expr(cx, ex) {
+                      const_eval::const_int(val) {val as int}
                       _ { cx.sess.bug("tag_variants: bad disr expr"); }
                     }
                   }
diff --git a/src/rustc/middle/typeck.rs b/src/rustc/middle/typeck.rs
index 165ca33a15f..8ef8841754c 100644
--- a/src/rustc/middle/typeck.rs
+++ b/src/rustc/middle/typeck.rs
@@ -1645,7 +1645,7 @@ fn check_lit(ccx: @crate_ctxt, lit: @ast::lit) -> ty::t {
 
 fn valid_range_bounds(tcx: ty::ctxt, from: @ast::expr, to: @ast::expr)
     -> bool {
-    ast_util::compare_lit_exprs(tcx, from, to) <= 0
+    const_eval::compare_lit_exprs(tcx, from, to) <= 0
 }
 
 type pat_ctxt = {
@@ -3404,8 +3404,8 @@ fn check_enum_variants(ccx: @crate_ctxt, sp: span, vs: [ast::variant],
             // Also, check_expr (from check_const pass) doesn't guarantee that
             // the expression in an form that eval_const_expr can handle, so
             // we may still get an internal compiler error
-            alt syntax::ast_util::eval_const_expr(ccx.tcx, e) {
-              syntax::ast_util::const_int(val) {
+            alt const_eval::eval_const_expr(ccx.tcx, e) {
+              const_eval::const_int(val) {
                 disr_val = val as int;
               }
               _ {
diff --git a/src/rustc/rustc.rc b/src/rustc/rustc.rc
index 0c780f15b8b..4993f63cfc0 100644
--- a/src/rustc/rustc.rc
+++ b/src/rustc/rustc.rc
@@ -50,6 +50,7 @@ mod middle {
     mod pat_util;
     mod region;
     mod regionck;
+    mod const_eval;
 
     mod tstate {
         mod ck;
diff --git a/src/rustc/syntax/ast_util.rs b/src/rustc/syntax/ast_util.rs
index 308b13be882..4ab7c325a69 100644
--- a/src/rustc/syntax/ast_util.rs
+++ b/src/rustc/syntax/ast_util.rs
@@ -242,172 +242,6 @@ fn default_block(stmts1: [@stmt], expr1: option<@expr>, id1: node_id) ->
     {view_items: [], stmts: stmts1, expr: expr1, id: id1, rules: default_blk}
 }
 
-// FIXME this doesn't handle big integer/float literals correctly (nor does
-// the rest of our literal handling)
-enum const_val {
-    const_float(float),
-    const_int(i64),
-    const_uint(u64),
-    const_str(str),
-}
-
-// FIXME: issue #1417
-fn eval_const_expr(tcx: middle::ty::ctxt, e: @expr) -> const_val {
-    import middle::ty;
-    fn fromb(b: bool) -> const_val { const_int(b as i64) }
-    alt check e.node {
-      expr_unary(neg, inner) {
-        alt check eval_const_expr(tcx, inner) {
-          const_float(f) { const_float(-f) }
-          const_int(i) { const_int(-i) }
-          const_uint(i) { const_uint(-i) }
-        }
-      }
-      expr_unary(not, inner) {
-        alt check eval_const_expr(tcx, inner) {
-          const_int(i) { const_int(!i) }
-          const_uint(i) { const_uint(!i) }
-        }
-      }
-      expr_binary(op, a, b) {
-        alt check (eval_const_expr(tcx, a), eval_const_expr(tcx, b)) {
-          (const_float(a), const_float(b)) {
-            alt check op {
-              add { const_float(a + b) } subtract { const_float(a - b) }
-              mul { const_float(a * b) } div { const_float(a / b) }
-              rem { const_float(a % b) } eq { fromb(a == b) }
-              lt { fromb(a < b) } le { fromb(a <= b) } ne { fromb(a != b) }
-              ge { fromb(a >= b) } gt { fromb(a > b) }
-            }
-          }
-          (const_int(a), const_int(b)) {
-            alt check op {
-              add { const_int(a + b) } subtract { const_int(a - b) }
-              mul { const_int(a * b) } div { const_int(a / b) }
-              rem { const_int(a % b) } and | bitand { const_int(a & b) }
-              or | bitor { const_int(a | b) } bitxor { const_int(a ^ b) }
-              lsl { const_int(a << b) } lsr { const_int(a >> b) }
-              asr { const_int(a >>> b) }
-              eq { fromb(a == b) } lt { fromb(a < b) }
-              le { fromb(a <= b) } ne { fromb(a != b) }
-              ge { fromb(a >= b) } gt { fromb(a > b) }
-            }
-
-          }
-          (const_uint(a), const_uint(b)) {
-            alt check op {
-              add { const_uint(a + b) } subtract { const_uint(a - b) }
-              mul { const_uint(a * b) } div { const_uint(a / b) }
-              rem { const_uint(a % b) } and | bitand { const_uint(a & b) }
-              or | bitor { const_uint(a | b) } bitxor { const_uint(a ^ b) }
-              lsl { const_int((a << b) as i64) }
-              lsr { const_int((a >> b) as i64) }
-              asr { const_int((a >>> b) as i64) }
-              eq { fromb(a == b) } lt { fromb(a < b) }
-              le { fromb(a <= b) } ne { fromb(a != b) }
-              ge { fromb(a >= b) } gt { fromb(a > b) }
-            }
-          }
-        }
-      }
-      expr_cast(base, _) {
-        let ety = ty::expr_ty(tcx, e);
-        let base = eval_const_expr(tcx, base);
-        alt check ty::get(ety).struct {
-          ty::ty_float(_) {
-            alt check base {
-              const_uint(u) { const_float(u as f64) }
-              const_int(i) { const_float(i as f64) }
-              const_float(_) { base }
-            }
-          }
-          ty::ty_uint(_) {
-            alt check base {
-              const_uint(_) { base }
-              const_int(i) { const_uint(i as u64) }
-              const_float(f) { const_uint(f as u64) }
-            }
-          }
-          ty::ty_int(_) | ty::ty_bool {
-            alt check base {
-              const_uint(u) { const_int(u as i64) }
-              const_int(_) { base }
-              const_float(f) { const_int(f as i64) }
-            }
-          }
-        }
-      }
-      expr_lit(lit) { lit_to_const(lit) }
-    }
-}
-
-fn lit_to_const(lit: @lit) -> const_val {
-    alt lit.node {
-      lit_str(s) { const_str(s) }
-      lit_int(n, _) { const_int(n) }
-      lit_uint(n, _) { const_uint(n) }
-      lit_float(n, _) { const_float(option::get(float::from_str(n))) }
-      lit_nil { const_int(0i64) }
-      lit_bool(b) { const_int(b as i64) }
-    }
-}
-
-fn compare_const_vals(a: const_val, b: const_val) -> int {
-  alt (a, b) {
-    (const_int(a), const_int(b)) {
-        if a == b {
-            0
-        } else if a < b {
-            -1
-        } else {
-            1
-        }
-    }
-    (const_uint(a), const_uint(b)) {
-        if a == b {
-            0
-        } else if a < b {
-            -1
-        } else {
-            1
-        }
-    }
-    (const_float(a), const_float(b)) {
-        if a == b {
-            0
-        } else if a < b {
-            -1
-        } else {
-            1
-        }
-    }
-    (const_str(a), const_str(b)) {
-        if a == b {
-            0
-        } else if a < b {
-            -1
-        } else {
-            1
-        }
-    }
-    _ {
-        fail "compare_const_vals: ill-typed comparison";
-    }
-  }
-}
-
-fn compare_lit_exprs(tcx: middle::ty::ctxt, a: @expr, b: @expr) -> int {
-  compare_const_vals(eval_const_expr(tcx, a), eval_const_expr(tcx, b))
-}
-
-fn lit_expr_eq(tcx: middle::ty::ctxt, a: @expr, b: @expr) -> bool {
-    compare_lit_exprs(tcx, a, b) == 0
-}
-
-fn lit_eq(a: @lit, b: @lit) -> bool {
-    compare_const_vals(lit_to_const(a), lit_to_const(b)) == 0
-}
-
 fn ident_to_path(s: span, i: ident) -> @path {
     @respan(s, {global: false, idents: [i], types: []})
 }