implemented as_conversions lint

Author: basil-cow

CHANGELOG.md

@@ -929,6 +929,7 @@ Released 2018-09-13
 [`absurd_extreme_comparisons`]: https://rust-lang.github.io/rust-clippy/master/index.html#absurd_extreme_comparisons
 [`almost_swapped`]: https://rust-lang.github.io/rust-clippy/master/index.html#almost_swapped
 [`approx_constant`]: https://rust-lang.github.io/rust-clippy/master/index.html#approx_constant
+[`as_conversions`]: https://rust-lang.github.io/rust-clippy/master/index.html#as_conversions
 [`assertions_on_constants`]: https://rust-lang.github.io/rust-clippy/master/index.html#assertions_on_constants
 [`assign_op_pattern`]: https://rust-lang.github.io/rust-clippy/master/index.html#assign_op_pattern
 [`assign_ops`]: https://rust-lang.github.io/rust-clippy/master/index.html#assign_ops

README.md

@@ -6,7 +6,7 @@
 
 A collection of lints to catch common mistakes and improve your [Rust](https://github.com/rust-lang/rust) code.
 
-[There are 333 lints included in this crate!](https://rust-lang.github.io/rust-clippy/master/index.html)
+[There are 334 lints included in this crate!](https://rust-lang.github.io/rust-clippy/master/index.html)
 
 We have a bunch of lint categories to allow you to choose how much Clippy is supposed to ~~annoy~~ help you:
 

clippy_lints/src/lib.rs

@@ -156,6 +156,7 @@ mod utils;
 // begin lints modules, do not remove this comment, it’s used in `update_lints`
 pub mod approx_const;
 pub mod arithmetic;
+pub mod as_conversions;
 pub mod assertions_on_constants;
 pub mod assign_ops;
 pub mod attrs;
@@ -447,6 +448,7 @@ pub fn register_plugins(store: &mut lint::LintStore, sess: &Session, conf: &Conf
         &approx_const::APPROX_CONSTANT,
         &arithmetic::FLOAT_ARITHMETIC,
         &arithmetic::INTEGER_ARITHMETIC,
+        &as_conversions::AS_CONVERSIONS,
         &assertions_on_constants::ASSERTIONS_ON_CONSTANTS,
         &assign_ops::ASSIGN_OP_PATTERN,
         &assign_ops::MISREFACTORED_ASSIGN_OP,
@@ -951,6 +953,7 @@ pub fn register_plugins(store: &mut lint::LintStore, sess: &Session, conf: &Conf
     store.register_late_pass(|| box mutable_debug_assertion::DebugAssertWithMutCall);
     store.register_late_pass(|| box exit::Exit);
     store.register_late_pass(|| box to_digit_is_some::ToDigitIsSome);
+    store.register_early_pass(|| box as_conversions::AsConversions);
 
     store.register_group(true, "clippy::restriction", Some("clippy_restriction"), vec![
         LintId::of(&arithmetic::FLOAT_ARITHMETIC),
@@ -987,6 +990,7 @@ pub fn register_plugins(store: &mut lint::LintStore, sess: &Session, conf: &Conf
     ]);
 
     store.register_group(true, "clippy::pedantic", Some("clippy_pedantic"), vec![
+        LintId::of(&as_conversions::AS_CONVERSIONS),
         LintId::of(&attrs::INLINE_ALWAYS),
         LintId::of(&checked_conversions::CHECKED_CONVERSIONS),
         LintId::of(&copies::MATCH_SAME_ARMS),

src/lintlist/mod.rs

@@ -6,7 +6,7 @@ pub use lint::Lint;
 pub use lint::LINT_LEVELS;
 
 // begin lint list, do not remove this comment, it’s used in `update_lints`
-pub const ALL_LINTS: [Lint; 333] = [
+pub const ALL_LINTS: [Lint; 334] = [
     Lint {
         name: "absurd_extreme_comparisons",
         group: "correctness",
@@ -28,6 +28,13 @@ pub const ALL_LINTS: [Lint; 333] = [
         deprecation: None,
         module: "approx_const",
     },
+    Lint {
+        name: "as_conversions",
+        group: "pedantic",
+        desc: "a potentially dangerous silent `as` conversion",
+        deprecation: None,
+        module: "as_conversions",
+    },
     Lint {
         name: "assertions_on_constants",
         group: "style",

tests/ui/types.fixed

@@ -1,7 +1,7 @@
 // run-rustfix
 
 #![allow(dead_code, unused_variables)]
-#![warn(clippy::all, clippy::pedantic)]
+#![warn(clippy::cast_lossless)]
 
 // should not warn on lossy casting in constant types
 // because not supported yet

tests/ui/types.rs

@@ -1,7 +1,7 @@
 // run-rustfix
 
 #![allow(dead_code, unused_variables)]
-#![warn(clippy::all, clippy::pedantic)]
+#![warn(clippy::cast_lossless)]
 
 // should not warn on lossy casting in constant types
 // because not supported yet