Auto merge of #3946 - rchaser53:issue-3920, r=flip1995

[rust.git] / clippy_lints / src / approx_const.rs

diff --git a/clippy_lints/src/approx_const.rs b/clippy_lints/src/approx_const.rs
index 704546a1eb3e94bbaa229e6100c5c4023ceaec13..fa586ad45c23c6bebde7edf3ac7dc062c4e59a93 100644 (file)
--- a/clippy_lints/src/approx_const.rs
+++ b/clippy_lints/src/approx_const.rs
@@ -1,32 +1,33 @@
+use crate::utils::span_lint;
 use rustc::hir::*;
-use rustc::lint::*;
+use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
+use rustc::{declare_tool_lint, lint_array};
 use std::f64::consts as f64;
 use syntax::ast::{FloatTy, Lit, LitKind};
 use syntax::symbol;
-use crate::utils::span_lint;
 
-/// **What it does:** Checks for floating point literals that approximate
-/// constants which are defined in
-/// [`std::f32::consts`](https://doc.rust-lang.org/stable/std/f32/consts/#constants)
-/// or
-/// [`std::f64::consts`](https://doc.rust-lang.org/stable/std/f64/consts/#constants),
-/// respectively, suggesting to use the predefined constant.
-///
-/// **Why is this bad?** Usually, the definition in the standard library is more
-/// precise than what people come up with. If you find that your definition is
-/// actually more precise, please [file a Rust
-/// issue](https://github.com/rust-lang/rust/issues).
-///
-/// **Known problems:** If you happen to have a value that is within 1/8192 of a
-/// known constant, but is not *and should not* be the same, this lint will
-/// report your value anyway. We have not yet noticed any false positives in
-/// code we tested clippy with (this includes servo), but YMMV.
-///
-/// **Example:**
-/// ```rust
-/// let x = 3.14;
-/// ```
 declare_clippy_lint! {
+    /// **What it does:** Checks for floating point literals that approximate
+    /// constants which are defined in
+    /// [`std::f32::consts`](https://doc.rust-lang.org/stable/std/f32/consts/#constants)
+    /// or
+    /// [`std::f64::consts`](https://doc.rust-lang.org/stable/std/f64/consts/#constants),
+    /// respectively, suggesting to use the predefined constant.
+    ///
+    /// **Why is this bad?** Usually, the definition in the standard library is more
+    /// precise than what people come up with. If you find that your definition is
+    /// actually more precise, please [file a Rust
+    /// issue](https://github.com/rust-lang/rust/issues).
+    ///
+    /// **Known problems:** If you happen to have a value that is within 1/8192 of a
+    /// known constant, but is not *and should not* be the same, this lint will
+    /// report your value anyway. We have not yet noticed any false positives in
+    /// code we tested clippy with (this includes servo), but YMMV.
+    ///
+    /// **Example:**
+    /// ```rust
+    /// let x = 3.14;
+    /// ```
     pub APPROX_CONSTANT,
     correctness,
     "the approximate of a known float constant (in `std::fXX::consts`)"
@@ -59,26 +60,30 @@ impl LintPass for Pass {
     fn get_lints(&self) -> LintArray {
         lint_array!(APPROX_CONSTANT)
     }
+
+    fn name(&self) -> &'static str {
+        "ApproxConstant"
+    }
 }
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
     fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr) {
-        if let ExprLit(ref lit) = e.node {
+        if let ExprKind::Lit(lit) = &e.node {
             check_lit(cx, lit, e);
         }
     }
 }
 
-fn check_lit(cx: &LateContext, lit: &Lit, e: &Expr) {
+fn check_lit(cx: &LateContext<'_, '_>, lit: &Lit, e: &Expr) {
     match lit.node {
-        LitKind::Float(ref s, FloatTy::F32) => check_known_consts(cx, e, s, "f32"),
-        LitKind::Float(ref s, FloatTy::F64) => check_known_consts(cx, e, s, "f64"),
-        LitKind::FloatUnsuffixed(ref s) => check_known_consts(cx, e, s, "f{32, 64}"),
+        LitKind::Float(s, FloatTy::F32) => check_known_consts(cx, e, s, "f32"),
+        LitKind::Float(s, FloatTy::F64) => check_known_consts(cx, e, s, "f64"),
+        LitKind::FloatUnsuffixed(s) => check_known_consts(cx, e, s, "f{32, 64}"),
         _ => (),
     }
 }
 
-fn check_known_consts(cx: &LateContext, e: &Expr, s: &symbol::Symbol, module: &str) {
+fn check_known_consts(cx: &LateContext<'_, '_>, e: &Expr, s: symbol::Symbol, module: &str) {
     let s = s.as_str();
     if s.parse::<f64>().is_ok() {
         for &(constant, name, min_digits) in KNOWN_CONSTS {
@@ -99,7 +104,7 @@ fn check_known_consts(cx: &LateContext, e: &Expr, s: &symbol::Symbol, module: &s
     }
 }
 
-/// Returns false if the number of significant figures in `value` are
+/// Returns `false` if the number of significant figures in `value` are
 /// less than `min_digits`; otherwise, returns true if `value` is equal
 /// to `constant`, rounded to the number of digits present in `value`.
 fn is_approx_const(constant: f64, value: &str, min_digits: usize) -> bool {