Auto merge of #4809 - iankronquist:patch-1, 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 fac75cffeba6facee676ca726443594f747f0d81..123a0a9d18949d0cf071faed85376d1ad91112ec 100644 (file)
--- a/clippy_lints/src/approx_const.rs
+++ b/clippy_lints/src/approx_const.rs
@@ -1,10 +1,10 @@
 use crate::utils::span_lint;
-use rustc::hir::*;
-use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::{declare_lint_pass, declare_tool_lint};
+use rustc_hir::*;
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::symbol;
 use std::f64::consts as f64;
 use syntax::ast::{FloatTy, LitFloatType, LitKind};
-use syntax::symbol;
 
 declare_clippy_lint! {
     /// **What it does:** Checks for floating point literals that approximate
@@ -23,7 +23,13 @@
     ///
     /// **Example:**
     /// ```rust
+    /// // Bad
     /// let x = 3.14;
+    /// let y = 1_f64 / x;
+    ///
+    /// // Good
+    /// let x = std::f32::consts::PI;
+    /// let y = std::f64::consts::FRAC_1_PI;
     /// ```
     pub APPROX_CONSTANT,
     correctness,
@@ -53,14 +59,14 @@
 declare_lint_pass!(ApproxConstant => [APPROX_CONSTANT]);
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for ApproxConstant {
-    fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr) {
+    fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr<'_>) {
         if let ExprKind::Lit(lit) = &e.kind {
             check_lit(cx, &lit.node, e);
         }
     }
 }
 
-fn check_lit(cx: &LateContext<'_, '_>, lit: &LitKind, e: &Expr) {
+fn check_lit(cx: &LateContext<'_, '_>, lit: &LitKind, e: &Expr<'_>) {
     match *lit {
         LitKind::Float(s, LitFloatType::Suffixed(fty)) => match fty {
             FloatTy::F32 => check_known_consts(cx, e, s, "f32"),
@@ -71,7 +77,7 @@ fn check_lit(cx: &LateContext<'_, '_>, lit: &LitKind, e: &Expr) {
     }
 }
 
-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 {