Merge pull request #1999 from sunfishcode/master

Enable the cast_lossless warning by default.

Author: oli-obk

README.md

@@ -198,7 +198,7 @@ name
 [box_vec](https://github.com/rust-lang-nursery/rust-clippy/wiki#box_vec)                                                     | warn    | usage of `Box<Vec<T>>`, vector elements are already on the heap
 [boxed_local](https://github.com/rust-lang-nursery/rust-clippy/wiki#boxed_local)                                             | warn    | using `Box<T>` where unnecessary
 [builtin_type_shadow](https://github.com/rust-lang-nursery/rust-clippy/wiki#builtin_type_shadow)                             | warn    | shadowing a builtin type
-[cast_lossless](https://github.com/rust-lang-nursery/rust-clippy/wiki#cast_lossless)                                         | allow   | casts using `as` that are known to be lossless, e.g. `x as u64` where `x: u8`
+[cast_lossless](https://github.com/rust-lang-nursery/rust-clippy/wiki#cast_lossless)                                         | warn    | casts using `as` that are known to be lossless, e.g. `x as u64` where `x: u8`
 [cast_possible_truncation](https://github.com/rust-lang-nursery/rust-clippy/wiki#cast_possible_truncation)                   | allow   | casts that may cause truncation of the value, e.g. `x as u8` where `x: u32`, or `x as i32` where `x: f32`
 [cast_possible_wrap](https://github.com/rust-lang-nursery/rust-clippy/wiki#cast_possible_wrap)                               | allow   | casts that may cause wrapping around the value, e.g. `x as i32` where `x: u32` and `x > i32::MAX`
 [cast_precision_loss](https://github.com/rust-lang-nursery/rust-clippy/wiki#cast_precision_loss)                             | allow   | casts that cause loss of precision, e.g. `x as f32` where `x: u64`

clippy_lints/src/lib.rs

@@ -358,7 +358,6 @@ pub fn register_plugins(reg: &mut rustc_plugin::Registry) {
         shadow::SHADOW_UNRELATED,
         strings::STRING_ADD,
         strings::STRING_ADD_ASSIGN,
-        types::CAST_LOSSLESS,
         types::CAST_POSSIBLE_TRUNCATION,
         types::CAST_POSSIBLE_WRAP,
         types::CAST_PRECISION_LOSS,
@@ -530,6 +529,7 @@ pub fn register_plugins(reg: &mut rustc_plugin::Registry) {
         types::ABSURD_EXTREME_COMPARISONS,
         types::BORROWED_BOX,
         types::BOX_VEC,
+        types::CAST_LOSSLESS,
         types::CHAR_LIT_AS_U8,
         types::LET_UNIT_VALUE,
         types::LINKEDLIST,

clippy_lints/src/types.rs

@@ -499,7 +499,7 @@ declare_lint! {
 /// ```
 declare_lint! {
     pub CAST_LOSSLESS,
-    Allow,
+    Warn,
     "casts using `as` that are known to be lossless, e.g. `x as u64` where `x: u8`"
 }
 

tests/ui/absurd-extreme-comparisons.rs

@@ -38,12 +38,12 @@ pub struct U(u64);
 
 impl PartialEq<u32> for U {
     fn eq(&self, other: &u32) -> bool {
-        self.eq(&U(*other as u64))
+        self.eq(&U(u64::from(*other)))
     }
 }
 impl PartialOrd<u32> for U {
     fn partial_cmp(&self, other: &u32) -> Option<Ordering> {
-        self.partial_cmp(&U(*other as u64))
+        self.partial_cmp(&U(u64::from(*other)))
     }
 }
 

tests/ui/float_cmp.rs

@@ -2,7 +2,7 @@
 #![plugin(clippy)]
 
 #![warn(float_cmp)]
-#![allow(unused, no_effect, unnecessary_operation)]
+#![allow(unused, no_effect, unnecessary_operation, cast_lossless)]
 
 use std::ops::Add;
 

tests/ui/invalid_upcast_comparisons.rs

@@ -2,7 +2,7 @@
 #![plugin(clippy)]
 
 #![warn(invalid_upcast_comparisons)]
-#![allow(unused, eq_op, no_effect, unnecessary_operation)]
+#![allow(unused, eq_op, no_effect, unnecessary_operation, cast_lossless)]
 
 fn mk_value<T>() -> T { unimplemented!() }