Auto merge of #3596 - xfix:remove-crate-from-paths, r=flip1995

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

diff --git a/clippy_lints/src/minmax.rs b/clippy_lints/src/minmax.rs
index 91906241ff5b1cd30e7eb0de066f3974942d02cc..087aa94a7ecfad42ba9ed5d8548fa8ab747613f6 100644 (file)
--- a/clippy_lints/src/minmax.rs
+++ b/clippy_lints/src/minmax.rs
@@ -1,9 +1,18 @@
-use consts::{Constant, constant_simple};
-use rustc::lint::*;
+// Copyright 2014-2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use crate::consts::{constant_simple, Constant};
+use crate::utils::{match_def_path, opt_def_id, paths, span_lint};
 use rustc::hir::*;
-use std::cmp::{PartialOrd, Ordering};
-use syntax::ptr::P;
-use utils::{match_def_path, paths, span_lint};
+use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
+use rustc::{declare_tool_lint, lint_array};
+use std::cmp::Ordering;
 
 /// **What it does:** Checks for expressions where `std::cmp::min` and `max` are
 /// used to clamp values, but switched so that the result is constant.
@@ -19,13 +28,12 @@
 /// ```
 /// It will always be equal to `0`. Probably the author meant to clamp the value
 /// between 0 and 100, but has erroneously swapped `min` and `max`.
-declare_lint! {
+declare_clippy_lint! {
     pub MIN_MAX,
-    Warn,
+    correctness,
     "`min(_, max(_, _))` (or vice versa) with bounds clamping the result to a constant"
 }
 
-#[allow(missing_copy_implementations)]
 pub struct MinMaxPass;
 
 impl LintPass for MinMaxPass {
@@ -34,20 +42,26 @@ fn get_lints(&self) -> LintArray {
     }
 }
 
-impl LateLintPass for MinMaxPass {
-    fn check_expr(&mut self, cx: &LateContext, expr: &Expr) {
+impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MinMaxPass {
+    fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
         if let Some((outer_max, outer_c, oe)) = min_max(cx, expr) {
-            if let Some((inner_max, inner_c, _)) = min_max(cx, oe) {
+            if let Some((inner_max, inner_c, ie)) = min_max(cx, oe) {
                 if outer_max == inner_max {
                     return;
                 }
-                match (outer_max, outer_c.partial_cmp(&inner_c)) {
-                    (_, None) |
-                    (MinMax::Max, Some(Ordering::Less)) |
-                    (MinMax::Min, Some(Ordering::Greater)) => (),
+                match (
+                    outer_max,
+                    Constant::partial_cmp(cx.tcx, cx.tables.expr_ty(ie), &outer_c, &inner_c),
+                ) {
+                    (_, None) | (MinMax::Max, Some(Ordering::Less)) | (MinMax::Min, Some(Ordering::Greater)) => (),
                     _ => {
-                        span_lint(cx, MIN_MAX, expr.span, "this min/max combination leads to constant result");
-                    }
+                        span_lint(
+                            cx,
+                            MIN_MAX,
+                            expr.span,
+                            "this min/max combination leads to constant result",
+                        );
+                    },
                 }
             }
         }
@@ -60,18 +74,18 @@ enum MinMax {
     Max,
 }
 
-fn min_max<'a>(cx: &LateContext, expr: &'a Expr) -> Option<(MinMax, Constant, &'a Expr)> {
-    if let ExprCall(ref path, ref args) = expr.node {
-        if let ExprPath(None, _) = path.node {
-            let def_id = cx.tcx.expect_def(path.id).def_id();
-
-            if match_def_path(cx, def_id, &paths::CMP_MIN) {
-                fetch_const(args, MinMax::Min)
-            } else if match_def_path(cx, def_id, &paths::CMP_MAX) {
-                fetch_const(args, MinMax::Max)
-            } else {
-                None
-            }
+fn min_max<'a>(cx: &LateContext<'_, '_>, expr: &'a Expr) -> Option<(MinMax, Constant, &'a Expr)> {
+    if let ExprKind::Call(ref path, ref args) = expr.node {
+        if let ExprKind::Path(ref qpath) = path.node {
+            opt_def_id(cx.tables.qpath_def(qpath, path.hir_id)).and_then(|def_id| {
+                if match_def_path(cx.tcx, def_id, &paths::CMP_MIN) {
+                    fetch_const(cx, args, MinMax::Min)
+                } else if match_def_path(cx.tcx, def_id, &paths::CMP_MAX) {
+                    fetch_const(cx, args, MinMax::Max)
+                } else {
+                    None
+                }
+            })
         } else {
             None
         }
@@ -80,18 +94,18 @@ fn min_max<'a>(cx: &LateContext, expr: &'a Expr) -> Option<(MinMax, Constant, &'
     }
 }
 
-fn fetch_const(args: &[P<Expr>], m: MinMax) -> Option<(MinMax, Constant, &Expr)> {
+fn fetch_const<'a>(cx: &LateContext<'_, '_>, args: &'a [Expr], m: MinMax) -> Option<(MinMax, Constant, &'a Expr)> {
     if args.len() != 2 {
         return None;
     }
-    if let Some(c) = constant_simple(&args[0]) {
-        if constant_simple(&args[1]).is_none() {
+    if let Some(c) = constant_simple(cx, cx.tables, &args[0]) {
+        if constant_simple(cx, cx.tables, &args[1]).is_none() {
             // otherwise ignore
             Some((m, c, &args[1]))
         } else {
             None
         }
-    } else if let Some(c) = constant_simple(&args[1]) {
+    } else if let Some(c) = constant_simple(cx, cx.tables, &args[1]) {
         Some((m, c, &args[0]))
     } else {
         None