Auto merge of #4809 - iankronquist:patch-1, r=flip1995

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

diff --git a/clippy_lints/src/overflow_check_conditional.rs b/clippy_lints/src/overflow_check_conditional.rs
index 4177f4a3e73c01ce0aeed5ea30d499327f1e75a8..df3f588f38a15afa2e122e2bd42bb4a94b1eaf5d 100644 (file)
--- a/clippy_lints/src/overflow_check_conditional.rs
+++ b/clippy_lints/src/overflow_check_conditional.rs
@@ -1,54 +1,52 @@
-use rustc::lint::*;
-use rustc::hir::*;
-use utils::span_lint;
+use crate::utils::{span_lint, SpanlessEq};
+use if_chain::if_chain;
+use rustc_hir::*;
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
 
-/// **What it does:** Detects classic underflow/overflow checks.
-///
-/// **Why is this bad?** Most classic C underflow/overflow checks will fail in
-/// Rust. Users can use functions like `overflowing_*` and `wrapping_*` instead.
-///
-/// **Known problems:** None.
-///
-/// **Example:**
-/// ```rust
-/// a + b < a
-/// ```
-declare_lint! {
+declare_clippy_lint! {
+    /// **What it does:** Detects classic underflow/overflow checks.
+    ///
+    /// **Why is this bad?** Most classic C underflow/overflow checks will fail in
+    /// Rust. Users can use functions like `overflowing_*` and `wrapping_*` instead.
+    ///
+    /// **Known problems:** None.
+    ///
+    /// **Example:**
+    /// ```rust
+    /// # let a = 1;
+    /// # let b = 2;
+    /// a + b < a;
+    /// ```
     pub OVERFLOW_CHECK_CONDITIONAL,
-    Warn,
+    complexity,
     "overflow checks inspired by C which are likely to panic"
 }
 
-#[derive(Copy, Clone)]
-pub struct OverflowCheckConditional;
-
-impl LintPass for OverflowCheckConditional {
-    fn get_lints(&self) -> LintArray {
-        lint_array!(OVERFLOW_CHECK_CONDITIONAL)
-    }
-}
+declare_lint_pass!(OverflowCheckConditional => [OVERFLOW_CHECK_CONDITIONAL]);
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for OverflowCheckConditional {
     // a + b < a, a > a + b, a < a - b, a - b > a
-    fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
+    fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) {
+        let eq = |l, r| SpanlessEq::new(cx).eq_path_segment(l, r);
         if_chain! {
-            if let Expr_::ExprBinary(ref op, ref first, ref second) = expr.node;
-            if let Expr_::ExprBinary(ref op2, ref ident1, ref ident2) = first.node;
-            if let Expr_::ExprPath(QPath::Resolved(_, ref path1)) = ident1.node;
-            if let Expr_::ExprPath(QPath::Resolved(_, ref path2)) = ident2.node;
-            if let Expr_::ExprPath(QPath::Resolved(_, ref path3)) = second.node;
-            if path1.segments[0] == path3.segments[0] || path2.segments[0] == path3.segments[0];
+            if let ExprKind::Binary(ref op, ref first, ref second) = expr.kind;
+            if let ExprKind::Binary(ref op2, ref ident1, ref ident2) = first.kind;
+            if let ExprKind::Path(QPath::Resolved(_, ref path1)) = ident1.kind;
+            if let ExprKind::Path(QPath::Resolved(_, ref path2)) = ident2.kind;
+            if let ExprKind::Path(QPath::Resolved(_, ref path3)) = second.kind;
+            if eq(&path1.segments[0], &path3.segments[0]) || eq(&path2.segments[0], &path3.segments[0]);
             if cx.tables.expr_ty(ident1).is_integral();
             if cx.tables.expr_ty(ident2).is_integral();
             then {
-                if let BinOp_::BiLt = op.node {
-                    if let BinOp_::BiAdd = op2.node {
+                if let BinOpKind::Lt = op.node {
+                    if let BinOpKind::Add = op2.node {
                         span_lint(cx, OVERFLOW_CHECK_CONDITIONAL, expr.span,
                             "You are trying to use classic C overflow conditions that will fail in Rust.");
                     }
                 }
-                if let BinOp_::BiGt = op.node {
-                    if let BinOp_::BiSub = op2.node {
+                if let BinOpKind::Gt = op.node {
+                    if let BinOpKind::Sub = op2.node {
                         span_lint(cx, OVERFLOW_CHECK_CONDITIONAL, expr.span,
                             "You are trying to use classic C underflow conditions that will fail in Rust.");
                     }
@@ -57,23 +55,23 @@ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
         }
 
         if_chain! {
-            if let Expr_::ExprBinary(ref op, ref first, ref second) = expr.node;
-            if let Expr_::ExprBinary(ref op2, ref ident1, ref ident2) = second.node;
-            if let Expr_::ExprPath(QPath::Resolved(_, ref path1)) = ident1.node;
-            if let Expr_::ExprPath(QPath::Resolved(_, ref path2)) = ident2.node;
-            if let Expr_::ExprPath(QPath::Resolved(_, ref path3)) = first.node;
-            if path1.segments[0] == path3.segments[0] || path2.segments[0] == path3.segments[0];
+            if let ExprKind::Binary(ref op, ref first, ref second) = expr.kind;
+            if let ExprKind::Binary(ref op2, ref ident1, ref ident2) = second.kind;
+            if let ExprKind::Path(QPath::Resolved(_, ref path1)) = ident1.kind;
+            if let ExprKind::Path(QPath::Resolved(_, ref path2)) = ident2.kind;
+            if let ExprKind::Path(QPath::Resolved(_, ref path3)) = first.kind;
+            if eq(&path1.segments[0], &path3.segments[0]) || eq(&path2.segments[0], &path3.segments[0]);
             if cx.tables.expr_ty(ident1).is_integral();
             if cx.tables.expr_ty(ident2).is_integral();
             then {
-                if let BinOp_::BiGt = op.node {
-                    if let BinOp_::BiAdd = op2.node {
+                if let BinOpKind::Gt = op.node {
+                    if let BinOpKind::Add = op2.node {
                         span_lint(cx, OVERFLOW_CHECK_CONDITIONAL, expr.span,
                             "You are trying to use classic C overflow conditions that will fail in Rust.");
                     }
                 }
-                if let BinOp_::BiLt = op.node {
-                    if let BinOp_::BiSub = op2.node {
+                if let BinOpKind::Lt = op.node {
+                    if let BinOpKind::Sub = op2.node {
                         span_lint(cx, OVERFLOW_CHECK_CONDITIONAL, expr.span,
                             "You are trying to use classic C underflow conditions that will fail in Rust.");
                     }