| use crate::utils::{match_def_path, span_lint_and_sugg}; |
| use if_chain::if_chain; |
| use rustc::hir; |
| use rustc::hir::def::{DefKind, Res}; |
| use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass}; |
| use rustc::{declare_lint_pass, declare_tool_lint}; |
| use rustc_errors::Applicability; |
| |
| declare_clippy_lint! { |
| /// **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 |
| /// # use core::sync::atomic::{ATOMIC_ISIZE_INIT, AtomicIsize}; |
| /// static FOO: AtomicIsize = ATOMIC_ISIZE_INIT; |
| /// ``` |
| /// |
| /// Could be written: |
| /// |
| /// ```rust |
| /// # use core::sync::atomic::AtomicIsize; |
| /// static FOO: AtomicIsize = AtomicIsize::new(0); |
| /// ``` |
| pub REPLACE_CONSTS, |
| pedantic, |
| "Lint usages of standard library `const`s that could be replaced by `const fn`s" |
| } |
| |
| declare_lint_pass!(ReplaceConsts => [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::ExprKind::Path(ref qp) = expr.kind; |
| if let Res::Def(DefKind::Const, def_id) = cx.tables.qpath_res(qp, expr.hir_id); |
| then { |
| for &(ref const_path, repl_snip) in &REPLACEMENTS { |
| if match_def_path(cx, 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(), |
| Applicability::MachineApplicable, |
| ); |
| return; |
| } |
| } |
| } |
| } |
| } |
| } |
| |
| const REPLACEMENTS: [([&str; 3], &str); 24] = [ |
| // 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()"), |
| ]; |