Auto merge of #84373 - cjgillot:resolve-span, r=michaelwoerister,petrochenkov

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

diff --git a/clippy_lints/src/implicit_saturating_sub.rs b/clippy_lints/src/implicit_saturating_sub.rs
index b57fe8dc4269e341b7f6299cae07331aff409562..79d4d7ddcbcedfe8e0ad85116a98a76068dc6c46 100644 (file)
--- a/clippy_lints/src/implicit_saturating_sub.rs
+++ b/clippy_lints/src/implicit_saturating_sub.rs
@@ -1,20 +1,21 @@
-use crate::utils::{higher, in_macro, match_qpath, span_lint_and_sugg, SpanlessEq};
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::higher;
+use clippy_utils::{in_macro, SpanlessEq};
 use if_chain::if_chain;
 use rustc_ast::ast::LitKind;
 use rustc_errors::Applicability;
-use rustc_hir::{BinOpKind, Expr, ExprKind, QPath, StmtKind};
+use rustc_hir::{lang_items::LangItem, BinOpKind, Expr, ExprKind, QPath, StmtKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for implicit saturating subtraction.
+    /// ### What it does
+    /// Checks for implicit saturating subtraction.
     ///
-    /// **Why is this bad?** Simplicity and readability. Instead we can easily use an builtin function.
-    ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Why is this bad?
+    /// Simplicity and readability. Instead we can easily use an builtin function.
     ///
+    /// ### Example
     /// ```rust
     /// let end: u32 = 10;
     /// let start: u32 = 5;
@@ -42,25 +43,24 @@ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
             return;
         }
         if_chain! {
-            if let Some((ref cond, ref then, None)) = higher::if_block(&expr);
+            if let Some(higher::If { cond, then, .. }) = higher::If::hir(expr);
 
             // Check if the conditional expression is a binary operation
-            if let ExprKind::Binary(ref cond_op, ref cond_left, ref cond_right) = cond.kind;
+            if let ExprKind::Binary(ref cond_op, cond_left, cond_right) = cond.kind;
 
             // Ensure that the binary operator is >, != and <
             if BinOpKind::Ne == cond_op.node || BinOpKind::Gt == cond_op.node || BinOpKind::Lt == cond_op.node;
 
             // Check if the true condition block has only one statement
-            if let ExprKind::Block(ref block, _) = then.kind;
+            if let ExprKind::Block(block, _) = then.kind;
             if block.stmts.len() == 1 && block.expr.is_none();
 
             // Check if assign operation is done
-            if let StmtKind::Semi(ref e) = block.stmts[0].kind;
+            if let StmtKind::Semi(e) = block.stmts[0].kind;
             if let Some(target) = subtracts_one(cx, e);
 
             // Extracting out the variable name
-            if let ExprKind::Path(ref assign_path) = target.kind;
-            if let QPath::Resolved(_, ref ares_path) = assign_path;
+            if let ExprKind::Path(QPath::Resolved(_, ares_path)) = target.kind;
 
             then {
                 // Handle symmetric conditions in the if statement
@@ -87,7 +87,13 @@ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
 
                 // Get the variable name
                 let var_name = ares_path.segments[0].ident.name.as_str();
-                const INT_TYPES: [&str; 5] = ["i8", "i16", "i32", "i64", "i128"];
+                const INT_TYPES: [LangItem; 5] = [
+                    LangItem::I8,
+                    LangItem::I16,
+                    LangItem::I32,
+                    LangItem::I64,
+                    LangItem::Isize
+                ];
 
                 match cond_num_val.kind {
                     ExprKind::Lit(ref cond_lit) => {
@@ -99,17 +105,30 @@ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
                             };
                         }
                     },
-                    ExprKind::Path(ref cond_num_path) => {
-                        if INT_TYPES.iter().any(|int_type| match_qpath(cond_num_path, &[int_type, "MIN"])) {
-                            print_lint_and_sugg(cx, &var_name, expr);
-                        };
+                    ExprKind::Path(QPath::TypeRelative(_, name)) => {
+                        if_chain! {
+                            if name.ident.as_str() == "MIN";
+                            if let Some(const_id) = cx.typeck_results().type_dependent_def_id(cond_num_val.hir_id);
+                            if let Some(impl_id) = cx.tcx.impl_of_method(const_id);
+                            let mut int_ids = INT_TYPES.iter().filter_map(|&ty| cx.tcx.lang_items().require(ty).ok());
+                            if int_ids.any(|int_id| int_id == impl_id);
+                            then {
+                                print_lint_and_sugg(cx, &var_name, expr)
+                            }
+                        }
                     },
-                    ExprKind::Call(ref func, _) => {
-                        if let ExprKind::Path(ref cond_num_path) = func.kind {
-                            if INT_TYPES.iter().any(|int_type| match_qpath(cond_num_path, &[int_type, "min_value"])) {
-                                print_lint_and_sugg(cx, &var_name, expr);
+                    ExprKind::Call(func, []) => {
+                        if_chain! {
+                            if let ExprKind::Path(QPath::TypeRelative(_, name)) = func.kind;
+                            if name.ident.as_str() == "min_value";
+                            if let Some(func_id) = cx.typeck_results().type_dependent_def_id(func.hir_id);
+                            if let Some(impl_id) = cx.tcx.impl_of_method(func_id);
+                            let mut int_ids = INT_TYPES.iter().filter_map(|&ty| cx.tcx.lang_items().require(ty).ok());
+                            if int_ids.any(|int_id| int_id == impl_id);
+                            then {
+                                print_lint_and_sugg(cx, &var_name, expr)
                             }
-                        };
+                        }
                     },
                     _ => (),
                 }
@@ -120,7 +139,7 @@ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
 
 fn subtracts_one<'a>(cx: &LateContext<'_>, expr: &Expr<'a>) -> Option<&'a Expr<'a>> {
     match expr.kind {
-        ExprKind::AssignOp(ref op1, ref target, ref value) => {
+        ExprKind::AssignOp(ref op1, target, value) => {
             if_chain! {
                 if BinOpKind::Sub == op1.node;
                 // Check if literal being subtracted is one
@@ -133,9 +152,9 @@ fn subtracts_one<'a>(cx: &LateContext<'_>, expr: &Expr<'a>) -> Option<&'a Expr<'
                 }
             }
         },
-        ExprKind::Assign(ref target, ref value, _) => {
+        ExprKind::Assign(target, value, _) => {
             if_chain! {
-                if let ExprKind::Binary(ref op1, ref left1, ref right1) = value.kind;
+                if let ExprKind::Binary(ref op1, left1, right1) = value.kind;
                 if BinOpKind::Sub == op1.node;
 
                 if SpanlessEq::new(cx).eq_expr(left1, target);