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Fix TryFrom for i128/u128

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Another case of `as` cast silent truncation being error prone.

This also adds a few missing TryFrom tests to libcoretest.
This commit is contained in:
Oliver Middleton
2017-02-04 23:10:28 +00:00
parent eb5cb9545c
commit a2de6e2285
2 changed files with 36 additions and 4 deletions
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8
src/libcore/num/mod.rs
View File

@@ -2626,8 +2626,8 @@ macro_rules! cross_sign_from_int_impl {
type Err = TryFromIntError;
fn try_from(u: $unsigned) -> Result<$signed, TryFromIntError> {
let max = <$signed as FromStrRadixHelper>::max_value() as u64;
if u as u64 > max {
let max = <$signed as FromStrRadixHelper>::max_value() as u128;
if u as u128 > max {
Err(TryFromIntError(()))
} else {
Ok(u as $signed)
@@ -2640,8 +2640,8 @@ macro_rules! cross_sign_from_int_impl {
type Err = TryFromIntError;
fn try_from(u: $signed) -> Result<$unsigned, TryFromIntError> {
let max = <$unsigned as FromStrRadixHelper>::max_value() as u64;
if u < 0 || u as u64 > max {
let max = <$unsigned as FromStrRadixHelper>::max_value() as u128;
if u < 0 || u as u128 > max {
Err(TryFromIntError(()))
} else {
Ok(u as $unsigned)

32
src/libcoretest/num/mod.rs
View File

@@ -366,3 +366,35 @@ test_impl_try_from_same_sign_err! { test_try_i32i16, i32, i16 }
test_impl_try_from_same_sign_err! { test_try_i64i8, i64, i8 }
test_impl_try_from_same_sign_err! { test_try_i64i16, i64, i16 }
test_impl_try_from_same_sign_err! { test_try_i64i32, i64, i32 }
macro_rules! test_impl_try_from_signed_to_unsigned_err {
($fn_name:ident, $source:ty, $target:ty) => {
#[test]
fn $fn_name() {
let max = <$source>::max_value();
let min = <$source>::min_value();
let zero: $source = 0;
let t_max = <$target>::max_value();
let t_min = <$target>::min_value();
assert!(<$target as TryFrom<$source>>::try_from(max).is_err());
assert!(<$target as TryFrom<$source>>::try_from(min).is_err());
assert_eq!(<$target as TryFrom<$source>>::try_from(zero).unwrap(),
zero as $target);
assert_eq!(<$target as TryFrom<$source>>::try_from(t_max as $source)
.unwrap(),
t_max as $target);
assert_eq!(<$target as TryFrom<$source>>::try_from(t_min as $source)
.unwrap(),
t_min as $target);
}
}
}
test_impl_try_from_signed_to_unsigned_err! { test_try_i16u8, i16, u8 }
test_impl_try_from_signed_to_unsigned_err! { test_try_i32u8, i32, u8 }
test_impl_try_from_signed_to_unsigned_err! { test_try_i32u16, i32, u16 }
test_impl_try_from_signed_to_unsigned_err! { test_try_i64u8, i64, u8 }
test_impl_try_from_signed_to_unsigned_err! { test_try_i64u16, i64, u16 }
test_impl_try_from_signed_to_unsigned_err! { test_try_i64u32, i64, u32 }