---

yaml
---
r: 188303
b: refs/heads/tmp
c: f1ea2b3
h: refs/heads/master
i:
  188301: d2b4e33
  188299: 0eca1fd
  188295: f8b2dbb
  188287: 787ea4e
v: v3

Author: pnkfelix

[refs]

@@ -34,5 +34,5 @@ refs/heads/building: 126db549b038c84269a1e4fe46f051b2c15d6970
 refs/heads/beta: 522d09dfecbeca1595f25ac58c6d0178bbd21d7d
 refs/heads/windistfix: 7608dbad651f02e837ed05eef3d74a6662a6e928
 refs/tags/1.0.0-alpha: e42bd6d93a1d3433c486200587f8f9e12590a4d7
-refs/heads/tmp: faf3bcd72c85774805ae0e84d0458aa3e67b20e4
+refs/heads/tmp: f1ea2b3094b1c28e64af30e187e31aa82f5ff004
 refs/tags/1.0.0-alpha.2: 4c705f6bc559886632d3871b04f58aab093bfa2f

branches/tmp/src/librustc/middle/const_eval.rs

@@ -25,6 +25,7 @@ use syntax::parse::token::InternedString;
 use syntax::ptr::P;
 use syntax::{ast_map, ast_util, codemap};
 
+use std::num::wrapping::OverflowingOps;
 use std::cmp::Ordering;
 use std::collections::hash_map::Entry::Vacant;
 use std::{i8, i16, i32, i64};
@@ -206,6 +207,33 @@ pub fn eval_const_expr(tcx: &ty::ctxt, e: &Expr) -> const_val {
     }
 }
 
+fn checked_add_int(a: i64, b: i64) -> Result<const_val, String> {
+    let (ret, oflo) = a.overflowing_add(b);
+    if !oflo { Ok(const_int(ret)) } else { Err(format!("constant arithmetic overflow")) }
+}
+fn checked_sub_int(a: i64, b: i64) -> Result<const_val, String> {
+    let (ret, oflo) = a.overflowing_sub(b);
+    if !oflo { Ok(const_int(ret)) } else { Err(format!("constant arithmetic overflow")) }
+}
+fn checked_mul_int(a: i64, b: i64) -> Result<const_val, String> {
+    let (ret, oflo) = a.overflowing_mul(b);
+    if !oflo { Ok(const_int(ret)) } else { Err(format!("constant arithmetic overflow")) }
+}
+
+fn checked_add_uint(a: u64, b: u64) -> Result<const_val, String> {
+    let (ret, oflo) = a.overflowing_add(b);
+    if !oflo { Ok(const_uint(ret)) } else { Err(format!("constant arithmetic overflow")) }
+}
+fn checked_sub_uint(a: u64, b: u64) -> Result<const_val, String> {
+    let (ret, oflo) = a.overflowing_sub(b);
+    if !oflo { Ok(const_uint(ret)) } else { Err(format!("constant arithmetic overflow")) }
+}
+fn checked_mul_uint(a: u64, b: u64) -> Result<const_val, String> {
+    let (ret, oflo) = a.overflowing_mul(b);
+    if !oflo { Ok(const_uint(ret)) } else { Err(format!("constant arithmetic overflow")) }
+}
+
+
 pub fn eval_const_expr_partial<'tcx>(tcx: &ty::ctxt<'tcx>,
                                      e: &Expr,
                                      ty_hint: Option<Ty<'tcx>>)
@@ -276,9 +304,9 @@ pub fn eval_const_expr_partial<'tcx>(tcx: &ty::ctxt<'tcx>,
                 }
             };
             match op.node {
-              ast::BiAdd => Ok(const_int(a + b)),
-              ast::BiSub => Ok(const_int(a - b)),
-              ast::BiMul => Ok(const_int(a * b)),
+              ast::BiAdd => checked_add_int(a, b),
+              ast::BiSub => checked_sub_int(a, b),
+              ast::BiMul => checked_mul_int(a, b),
               ast::BiDiv => {
                   if b == 0 {
                       Err("attempted to divide by zero".to_string())
@@ -312,9 +340,9 @@ pub fn eval_const_expr_partial<'tcx>(tcx: &ty::ctxt<'tcx>,
           }
           (Ok(const_uint(a)), Ok(const_uint(b))) => {
             match op.node {
-              ast::BiAdd => Ok(const_uint(a + b)),
-              ast::BiSub => Ok(const_uint(a - b)),
-              ast::BiMul => Ok(const_uint(a * b)),
+              ast::BiAdd => checked_add_uint(a, b),
+              ast::BiSub => checked_sub_uint(a, b),
+              ast::BiMul => checked_mul_uint(a, b),
               ast::BiDiv if b == 0 => {
                   Err("attempted to divide by zero".to_string())
               }