89 lines
3.2 KiB
Rust
89 lines
3.2 KiB
Rust
use crate::utils::span_lint_and_sugg;
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use if_chain::if_chain;
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use rustc::hir;
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use rustc::hir::def::Def;
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use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
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use rustc::{declare_lint_pass, declare_tool_lint};
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use rustc_errors::Applicability;
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declare_clippy_lint! {
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/// **What it does:** Checks for usage of `ATOMIC_X_INIT`, `ONCE_INIT`, and
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/// `uX/iX::MIN/MAX`.
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///
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/// **Why is this bad?** `const fn`s exist
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///
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/// **Known problems:** None.
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///
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/// **Example:**
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/// ```rust
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/// static FOO: AtomicIsize = ATOMIC_ISIZE_INIT;
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/// ```
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///
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/// Could be written:
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///
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/// ```rust
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/// static FOO: AtomicIsize = AtomicIsize::new(0);
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/// ```
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pub REPLACE_CONSTS,
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pedantic,
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"Lint usages of standard library `const`s that could be replaced by `const fn`s"
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}
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declare_lint_pass!(ReplaceConsts => [REPLACE_CONSTS]);
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impl<'a, 'tcx> LateLintPass<'a, 'tcx> for ReplaceConsts {
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fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx hir::Expr) {
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if_chain! {
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if let hir::ExprKind::Path(ref qp) = expr.node;
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if let Def::Const(def_id) = cx.tables.qpath_def(qp, expr.hir_id);
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then {
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for &(const_path, repl_snip) in REPLACEMENTS {
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if cx.match_def_path(def_id, const_path) {
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span_lint_and_sugg(
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cx,
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REPLACE_CONSTS,
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expr.span,
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&format!("using `{}`", const_path.last().expect("empty path")),
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"try this",
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repl_snip.to_string(),
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Applicability::MachineApplicable,
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);
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return;
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}
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}
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}
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}
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}
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}
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const REPLACEMENTS: &[(&[&str], &str)] = &[
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// Once
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(&["core", "sync", "ONCE_INIT"], "Once::new()"),
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// Min
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(&["core", "isize", "MIN"], "isize::min_value()"),
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(&["core", "i8", "MIN"], "i8::min_value()"),
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(&["core", "i16", "MIN"], "i16::min_value()"),
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(&["core", "i32", "MIN"], "i32::min_value()"),
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(&["core", "i64", "MIN"], "i64::min_value()"),
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(&["core", "i128", "MIN"], "i128::min_value()"),
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(&["core", "usize", "MIN"], "usize::min_value()"),
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(&["core", "u8", "MIN"], "u8::min_value()"),
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(&["core", "u16", "MIN"], "u16::min_value()"),
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(&["core", "u32", "MIN"], "u32::min_value()"),
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(&["core", "u64", "MIN"], "u64::min_value()"),
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(&["core", "u128", "MIN"], "u128::min_value()"),
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// Max
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(&["core", "isize", "MAX"], "isize::max_value()"),
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(&["core", "i8", "MAX"], "i8::max_value()"),
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(&["core", "i16", "MAX"], "i16::max_value()"),
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(&["core", "i32", "MAX"], "i32::max_value()"),
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(&["core", "i64", "MAX"], "i64::max_value()"),
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(&["core", "i128", "MAX"], "i128::max_value()"),
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(&["core", "usize", "MAX"], "usize::max_value()"),
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(&["core", "u8", "MAX"], "u8::max_value()"),
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(&["core", "u16", "MAX"], "u16::max_value()"),
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(&["core", "u32", "MAX"], "u32::max_value()"),
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(&["core", "u64", "MAX"], "u64::max_value()"),
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(&["core", "u128", "MAX"], "u128::max_value()"),
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];
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