diff --git a/clippy_lints/src/lib.rs b/clippy_lints/src/lib.rs index 9b598df4fa6..13760e8c0fb 100644 --- a/clippy_lints/src/lib.rs +++ b/clippy_lints/src/lib.rs @@ -150,6 +150,7 @@ pub mod ptr; pub mod ranges; pub mod reference; pub mod regex; +pub mod replace_consts; pub mod returns; pub mod serde_api; pub mod shadow; @@ -361,6 +362,7 @@ pub fn register_plugins(reg: &mut rustc_plugin::Registry) { reg.register_late_lint_pass(box types::ImplicitHasher); reg.register_early_lint_pass(box const_static_lifetime::StaticConst); reg.register_late_lint_pass(box fallible_impl_from::FallibleImplFrom); + reg.register_late_lint_pass(box replace_consts::ReplaceConsts); reg.register_lint_group("clippy_restrictions", vec![ arithmetic::FLOAT_ARITHMETIC, @@ -399,6 +401,7 @@ pub fn register_plugins(reg: &mut rustc_plugin::Registry) { print::PRINT_STDOUT, print::USE_DEBUG, ranges::RANGE_PLUS_ONE, + replace_consts::REPLACE_CONSTS, shadow::SHADOW_REUSE, shadow::SHADOW_SAME, shadow::SHADOW_UNRELATED, diff --git a/clippy_lints/src/replace_consts.rs b/clippy_lints/src/replace_consts.rs new file mode 100644 index 00000000000..511dbf7a40f --- /dev/null +++ b/clippy_lints/src/replace_consts.rs @@ -0,0 +1,102 @@ +use rustc::lint::*; +use rustc::hir; +use rustc::hir::def::Def; +use utils::{match_def_path, span_lint_and_sugg}; + +/// **What it does:** Checks for usage of `ATOMIC_X_INIT`, `ONCE_INIT`, and +/// `uX/iX::MIN/MAX`. +/// +/// **Why is this bad?** `const fn`s exist +/// +/// **Known problems:** None. +/// +/// **Example:** +/// ```rust +/// static FOO: AtomicIsize = ATOMIC_ISIZE_INIT; +/// ``` +/// +/// Could be written: +/// +/// ```rust +/// static FOO: AtomicIsize = AtomicIsize::new(0); +/// ``` +declare_lint! { + pub REPLACE_CONSTS, + Allow, + "Lint usages of standard library `const`s that could be replaced by `const fn`s" +} + +pub struct ReplaceConsts; + +impl LintPass for ReplaceConsts { + fn get_lints(&self) -> LintArray { + lint_array!(REPLACE_CONSTS) + } +} + +impl<'a, 'tcx> LateLintPass<'a, 'tcx> for ReplaceConsts { + fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx hir::Expr) { + if_chain! { + if let hir::ExprPath(ref qp) = expr.node; + if let Def::Const(def_id) = cx.tables.qpath_def(qp, expr.hir_id); + then { + for &(const_path, repl_snip) in REPLACEMENTS { + if match_def_path(cx.tcx, def_id, const_path) { + span_lint_and_sugg( + cx, + REPLACE_CONSTS, + expr.span, + &format!("using `{}`", const_path.last().expect("empty path")), + "try this", + repl_snip.to_string(), + ); + return; + } + } + } + } + } +} + +const REPLACEMENTS: &[(&[&str], &str)] = &[ + // Once + (&["core", "sync", "ONCE_INIT"], "Once::new()"), + // Atomic + (&["core", "sync", "atomic", "ATOMIC_BOOL_INIT"], "AtomicBool::new(false)"), + (&["core", "sync", "atomic", "ATOMIC_ISIZE_INIT"], "AtomicIsize::new(0)"), + (&["core", "sync", "atomic", "ATOMIC_I8_INIT"], "AtomicI8::new(0)"), + (&["core", "sync", "atomic", "ATOMIC_I16_INIT"], "AtomicI16::new(0)"), + (&["core", "sync", "atomic", "ATOMIC_I32_INIT"], "AtomicI32::new(0)"), + (&["core", "sync", "atomic", "ATOMIC_I64_INIT"], "AtomicI64::new(0)"), + (&["core", "sync", "atomic", "ATOMIC_USIZE_INIT"], "AtomicUsize::new(0)"), + (&["core", "sync", "atomic", "ATOMIC_U8_INIT"], "AtomicU8::new(0)"), + (&["core", "sync", "atomic", "ATOMIC_U16_INIT"], "AtomicU16::new(0)"), + (&["core", "sync", "atomic", "ATOMIC_U32_INIT"], "AtomicU32::new(0)"), + (&["core", "sync", "atomic", "ATOMIC_U64_INIT"], "AtomicU64::new(0)"), + // Min + (&["core", "isize", "MIN"], "isize::min_value()"), + (&["core", "i8", "MIN"], "i8::min_value()"), + (&["core", "i16", "MIN"], "i16::min_value()"), + (&["core", "i32", "MIN"], "i32::min_value()"), + (&["core", "i64", "MIN"], "i64::min_value()"), + (&["core", "i128", "MIN"], "i128::min_value()"), + (&["core", "usize", "MIN"], "usize::min_value()"), + (&["core", "u8", "MIN"], "u8::min_value()"), + (&["core", "u16", "MIN"], "u16::min_value()"), + (&["core", "u32", "MIN"], "u32::min_value()"), + (&["core", "u64", "MIN"], "u64::min_value()"), + (&["core", "u128", "MIN"], "u128::min_value()"), + // Max + (&["core", "isize", "MAX"], "isize::max_value()"), + (&["core", "i8", "MAX"], "i8::max_value()"), + (&["core", "i16", "MAX"], "i16::max_value()"), + (&["core", "i32", "MAX"], "i32::max_value()"), + (&["core", "i64", "MAX"], "i64::max_value()"), + (&["core", "i128", "MAX"], "i128::max_value()"), + (&["core", "usize", "MAX"], "usize::max_value()"), + (&["core", "u8", "MAX"], "u8::max_value()"), + (&["core", "u16", "MAX"], "u16::max_value()"), + (&["core", "u32", "MAX"], "u32::max_value()"), + (&["core", "u64", "MAX"], "u64::max_value()"), + (&["core", "u128", "MAX"], "u128::max_value()"), +]; diff --git a/tests/ui/replace_consts.rs b/tests/ui/replace_consts.rs new file mode 100644 index 00000000000..31c58b4bb4e --- /dev/null +++ b/tests/ui/replace_consts.rs @@ -0,0 +1,96 @@ +#![feature(integer_atomics, i128, i128_type)] +#![allow(blacklisted_name)] +#![deny(replace_consts)] +use std::sync::atomic::*; +use std::sync::{ONCE_INIT, Once}; + +fn bad() { + // Once + { let foo = ONCE_INIT; }; + // Atomic + { let foo = ATOMIC_BOOL_INIT; }; + { let foo = ATOMIC_ISIZE_INIT; }; + { let foo = ATOMIC_I8_INIT; }; + { let foo = ATOMIC_I16_INIT; }; + { let foo = ATOMIC_I32_INIT; }; + { let foo = ATOMIC_I64_INIT; }; + { let foo = ATOMIC_USIZE_INIT; }; + { let foo = ATOMIC_U8_INIT; }; + { let foo = ATOMIC_U16_INIT; }; + { let foo = ATOMIC_U32_INIT; }; + { let foo = ATOMIC_U64_INIT; }; + // Min + { let foo = std::isize::MIN; }; + { let foo = std::i8::MIN; }; + { let foo = std::i16::MIN; }; + { let foo = std::i32::MIN; }; + { let foo = std::i64::MIN; }; + { let foo = std::i128::MIN; }; + { let foo = std::usize::MIN; }; + { let foo = std::u8::MIN; }; + { let foo = std::u16::MIN; }; + { let foo = std::u32::MIN; }; + { let foo = std::u64::MIN; }; + { let foo = std::u128::MIN; }; + // Max + { let foo = std::isize::MAX; }; + { let foo = std::i8::MAX; }; + { let foo = std::i16::MAX; }; + { let foo = std::i32::MAX; }; + { let foo = std::i64::MAX; }; + { let foo = std::i128::MAX; }; + { let foo = std::usize::MAX; }; + { let foo = std::u8::MAX; }; + { let foo = std::u16::MAX; }; + { let foo = std::u32::MAX; }; + { let foo = std::u64::MAX; }; + { let foo = std::u128::MAX; }; +} + +fn good() { + // Once + { let foo = Once::new(); }; + // Atomic + { let foo = AtomicBool::new(false); }; + { let foo = AtomicIsize::new(0); }; + { let foo = AtomicI8::new(0); }; + { let foo = AtomicI16::new(0); }; + { let foo = AtomicI32::new(0); }; + { let foo = AtomicI64::new(0); }; + { let foo = AtomicUsize::new(0); }; + { let foo = AtomicU8::new(0); }; + { let foo = AtomicU16::new(0); }; + { let foo = AtomicU32::new(0); }; + { let foo = AtomicU64::new(0); }; + // Min + { let foo = isize::min_value(); }; + { let foo = i8::min_value(); }; + { let foo = i16::min_value(); }; + { let foo = i32::min_value(); }; + { let foo = i64::min_value(); }; + { let foo = i128::min_value(); }; + { let foo = usize::min_value(); }; + { let foo = u8::min_value(); }; + { let foo = u16::min_value(); }; + { let foo = u32::min_value(); }; + { let foo = u64::min_value(); }; + { let foo = u128::min_value(); }; + // Max + { let foo = isize::max_value(); }; + { let foo = i8::max_value(); }; + { let foo = i16::max_value(); }; + { let foo = i32::max_value(); }; + { let foo = i64::max_value(); }; + { let foo = i128::max_value(); }; + { let foo = usize::max_value(); }; + { let foo = u8::max_value(); }; + { let foo = u16::max_value(); }; + { let foo = u32::max_value(); }; + { let foo = u64::max_value(); }; + { let foo = u128::max_value(); }; +} + +fn main() { + bad(); + good(); +} diff --git a/tests/ui/replace_consts.stderr b/tests/ui/replace_consts.stderr new file mode 100644 index 00000000000..a8e3dd2d00e --- /dev/null +++ b/tests/ui/replace_consts.stderr @@ -0,0 +1,216 @@ +error: using `ATOMIC_BOOL_INIT` + --> $DIR/replace_consts.rs:11:17 + | +11 | { let foo = ATOMIC_BOOL_INIT; }; + | ^^^^^^^^^^^^^^^^ help: try this: `AtomicBool::new(false)` + | +note: lint level defined here + --> $DIR/replace_consts.rs:3:9 + | +3 | #![deny(replace_consts)] + | ^^^^^^^^^^^^^^ + +error: using `ATOMIC_ISIZE_INIT` + --> $DIR/replace_consts.rs:12:17 + | +12 | { let foo = ATOMIC_ISIZE_INIT; }; + | ^^^^^^^^^^^^^^^^^ help: try this: `AtomicIsize::new(0)` + +error: using `ATOMIC_I8_INIT` + --> $DIR/replace_consts.rs:13:17 + | +13 | { let foo = ATOMIC_I8_INIT; }; + | ^^^^^^^^^^^^^^ help: try this: `AtomicI8::new(0)` + +error: using `ATOMIC_I16_INIT` + --> $DIR/replace_consts.rs:14:17 + | +14 | { let foo = ATOMIC_I16_INIT; }; + | ^^^^^^^^^^^^^^^ help: try this: `AtomicI16::new(0)` + +error: using `ATOMIC_I32_INIT` + --> $DIR/replace_consts.rs:15:17 + | +15 | { let foo = ATOMIC_I32_INIT; }; + | ^^^^^^^^^^^^^^^ help: try this: `AtomicI32::new(0)` + +error: using `ATOMIC_I64_INIT` + --> $DIR/replace_consts.rs:16:17 + | +16 | { let foo = ATOMIC_I64_INIT; }; + | ^^^^^^^^^^^^^^^ help: try this: `AtomicI64::new(0)` + +error: using `ATOMIC_USIZE_INIT` + --> $DIR/replace_consts.rs:17:17 + | +17 | { let foo = ATOMIC_USIZE_INIT; }; + | ^^^^^^^^^^^^^^^^^ help: try this: `AtomicUsize::new(0)` + +error: using `ATOMIC_U8_INIT` + --> $DIR/replace_consts.rs:18:17 + | +18 | { let foo = ATOMIC_U8_INIT; }; + | ^^^^^^^^^^^^^^ help: try this: `AtomicU8::new(0)` + +error: using `ATOMIC_U16_INIT` + --> $DIR/replace_consts.rs:19:17 + | +19 | { let foo = ATOMIC_U16_INIT; }; + | ^^^^^^^^^^^^^^^ help: try this: `AtomicU16::new(0)` + +error: using `ATOMIC_U32_INIT` + --> $DIR/replace_consts.rs:20:17 + | +20 | { let foo = ATOMIC_U32_INIT; }; + | ^^^^^^^^^^^^^^^ help: try this: `AtomicU32::new(0)` + +error: using `ATOMIC_U64_INIT` + --> $DIR/replace_consts.rs:21:17 + | +21 | { let foo = ATOMIC_U64_INIT; }; + | ^^^^^^^^^^^^^^^ help: try this: `AtomicU64::new(0)` + +error: using `MIN` + --> $DIR/replace_consts.rs:23:17 + | +23 | { let foo = std::isize::MIN; }; + | ^^^^^^^^^^^^^^^ help: try this: `isize::min_value()` + +error: using `MIN` + --> $DIR/replace_consts.rs:24:17 + | +24 | { let foo = std::i8::MIN; }; + | ^^^^^^^^^^^^ help: try this: `i8::min_value()` + +error: using `MIN` + --> $DIR/replace_consts.rs:25:17 + | +25 | { let foo = std::i16::MIN; }; + | ^^^^^^^^^^^^^ help: try this: `i16::min_value()` + +error: using `MIN` + --> $DIR/replace_consts.rs:26:17 + | +26 | { let foo = std::i32::MIN; }; + | ^^^^^^^^^^^^^ help: try this: `i32::min_value()` + +error: using `MIN` + --> $DIR/replace_consts.rs:27:17 + | +27 | { let foo = std::i64::MIN; }; + | ^^^^^^^^^^^^^ help: try this: `i64::min_value()` + +error: using `MIN` + --> $DIR/replace_consts.rs:28:17 + | +28 | { let foo = std::i128::MIN; }; + | ^^^^^^^^^^^^^^ help: try this: `i128::min_value()` + +error: using `MIN` + --> $DIR/replace_consts.rs:29:17 + | +29 | { let foo = std::usize::MIN; }; + | ^^^^^^^^^^^^^^^ help: try this: `usize::min_value()` + +error: using `MIN` + --> $DIR/replace_consts.rs:30:17 + | +30 | { let foo = std::u8::MIN; }; + | ^^^^^^^^^^^^ help: try this: `u8::min_value()` + +error: using `MIN` + --> $DIR/replace_consts.rs:31:17 + | +31 | { let foo = std::u16::MIN; }; + | ^^^^^^^^^^^^^ help: try this: `u16::min_value()` + +error: using `MIN` + --> $DIR/replace_consts.rs:32:17 + | +32 | { let foo = std::u32::MIN; }; + | ^^^^^^^^^^^^^ help: try this: `u32::min_value()` + +error: using `MIN` + --> $DIR/replace_consts.rs:33:17 + | +33 | { let foo = std::u64::MIN; }; + | ^^^^^^^^^^^^^ help: try this: `u64::min_value()` + +error: using `MIN` + --> $DIR/replace_consts.rs:34:17 + | +34 | { let foo = std::u128::MIN; }; + | ^^^^^^^^^^^^^^ help: try this: `u128::min_value()` + +error: using `MAX` + --> $DIR/replace_consts.rs:36:17 + | +36 | { let foo = std::isize::MAX; }; + | ^^^^^^^^^^^^^^^ help: try this: `isize::max_value()` + +error: using `MAX` + --> $DIR/replace_consts.rs:37:17 + | +37 | { let foo = std::i8::MAX; }; + | ^^^^^^^^^^^^ help: try this: `i8::max_value()` + +error: using `MAX` + --> $DIR/replace_consts.rs:38:17 + | +38 | { let foo = std::i16::MAX; }; + | ^^^^^^^^^^^^^ help: try this: `i16::max_value()` + +error: using `MAX` + --> $DIR/replace_consts.rs:39:17 + | +39 | { let foo = std::i32::MAX; }; + | ^^^^^^^^^^^^^ help: try this: `i32::max_value()` + +error: using `MAX` + --> $DIR/replace_consts.rs:40:17 + | +40 | { let foo = std::i64::MAX; }; + | ^^^^^^^^^^^^^ help: try this: `i64::max_value()` + +error: using `MAX` + --> $DIR/replace_consts.rs:41:17 + | +41 | { let foo = std::i128::MAX; }; + | ^^^^^^^^^^^^^^ help: try this: `i128::max_value()` + +error: using `MAX` + --> $DIR/replace_consts.rs:42:17 + | +42 | { let foo = std::usize::MAX; }; + | ^^^^^^^^^^^^^^^ help: try this: `usize::max_value()` + +error: using `MAX` + --> $DIR/replace_consts.rs:43:17 + | +43 | { let foo = std::u8::MAX; }; + | ^^^^^^^^^^^^ help: try this: `u8::max_value()` + +error: using `MAX` + --> $DIR/replace_consts.rs:44:17 + | +44 | { let foo = std::u16::MAX; }; + | ^^^^^^^^^^^^^ help: try this: `u16::max_value()` + +error: using `MAX` + --> $DIR/replace_consts.rs:45:17 + | +45 | { let foo = std::u32::MAX; }; + | ^^^^^^^^^^^^^ help: try this: `u32::max_value()` + +error: using `MAX` + --> $DIR/replace_consts.rs:46:17 + | +46 | { let foo = std::u64::MAX; }; + | ^^^^^^^^^^^^^ help: try this: `u64::max_value()` + +error: using `MAX` + --> $DIR/replace_consts.rs:47:17 + | +47 | { let foo = std::u128::MAX; }; + | ^^^^^^^^^^^^^^ help: try this: `u128::max_value()` +