Improve divide-by-zero error messages

Author: brendanzab

src/librustc/middle/const_eval.rs

@@ -299,9 +299,9 @@ pub fn eval_const_expr_partial(tcx: middle::ty::ctxt, e: @expr)
               add => Ok(const_int(a + b)),
               subtract => Ok(const_int(a - b)),
               mul => Ok(const_int(a * b)),
-              quot if b == 0 => Err(~"quotient zero"),
+              quot if b == 0 => Err(~"attempted quotient with a divisor of zero"),
               quot => Ok(const_int(a / b)),
-              rem if b == 0 => Err(~"remainder zero"),
+              rem if b == 0 => Err(~"attempted remainder with a divisor of zero"),
               rem => Ok(const_int(a % b)),
               and | bitand => Ok(const_int(a & b)),
               or | bitor => Ok(const_int(a | b)),
@@ -321,9 +321,9 @@ pub fn eval_const_expr_partial(tcx: middle::ty::ctxt, e: @expr)
               add => Ok(const_uint(a + b)),
               subtract => Ok(const_uint(a - b)),
               mul => Ok(const_uint(a * b)),
-              quot if b == 0 => Err(~"quotient zero"),
+              quot if b == 0 => Err(~"attempted quotient with a divisor of zero"),
               quot => Ok(const_uint(a / b)),
-              rem if b == 0 => Err(~"remainder zero"),
+              rem if b == 0 => Err(~"attempted remainder with a divisor of zero"),
               rem => Ok(const_uint(a % b)),
               and | bitand => Ok(const_uint(a & b)),
               or | bitor => Ok(const_uint(a | b)),

src/librustc/middle/trans/base.rs

@@ -785,9 +785,9 @@ pub fn cast_shift_rhs(op: ast::binop,
 pub fn fail_if_zero(cx: block, span: span, quotrem: ast::binop,
                     rhs: ValueRef, rhs_t: ty::t) -> block {
     let text = if quotrem == ast::quot {
-        @~"quotient zero"
+        @~"attempted quotient with a divisor of zero"
     } else {
-        @~"remainder zero"
+        @~"attempted remainder with a divisor of zero"
     };
     let is_zero = match ty::get(rhs_t).sty {
       ty::ty_int(t) => {

src/test/compile-fail/eval-enum.rs

@@ -1,6 +1,6 @@
 enum test {
-    quot_zero = 1/0, //~ERROR expected constant: quotient zero
-    rem_zero = 1%0  //~ERROR expected constant: remainder zero
+    quot_zero = 1/0, //~ERROR expected constant: attempted quotient with a divisor of zero
+    rem_zero = 1%0  //~ERROR expected constant: attempted remainder with a divisor of zero
 }
 
 fn main() {}

src/test/run-fail/divide-by-zero.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// error-pattern:quotient zero
+// error-pattern:attempted quotient with a divisor of zero
 fn main() {
     let y = 0;
     let z = 1 / y;

src/test/run-fail/mod-zero.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// error-pattern:remainder zero
+// error-pattern:attempted remainder with a divisor of zero
 fn main() {
     let y = 0;
     let z = 1 % y;