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_clippy_lint! { pub REPLACE_CONSTS, pedantic, "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()"), ];