Auto merge of #8487 - dswij:8478, r=giraffate

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

diff --git a/clippy_lints/src/get_last_with_len.rs b/clippy_lints/src/get_last_with_len.rs
index 57a7fbb56567913ffd82f66c27ba847a7ba54bbc..df29d9308e7124da07b112998729023abbba7e17 100644 (file)
--- a/clippy_lints/src/get_last_with_len.rs
+++ b/clippy_lints/src/get_last_with_len.rs
@@ -1,6 +1,9 @@
 //! lint on using `x.get(x.len() - 1)` instead of `x.last()`
 
-use crate::utils::{is_type_diagnostic_item, snippet_with_applicability, span_lint_and_sugg, SpanlessEq};
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::source::snippet_with_applicability;
+use clippy_utils::ty::is_type_diagnostic_item;
+use clippy_utils::SpanlessEq;
 use if_chain::if_chain;
 use rustc_ast::ast::LitKind;
 use rustc_errors::Applicability;
@@ -8,12 +11,15 @@
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::source_map::Spanned;
+use rustc_span::sym;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for using `x.get(x.len() - 1)` instead of
+    /// ### What it does
+    /// Checks for using `x.get(x.len() - 1)` instead of
     /// `x.last()`.
     ///
-    /// **Why is this bad?** Using `x.last()` is easier to read and has the same
+    /// ### Why is this bad?
+    /// Using `x.last()` is easier to read and has the same
     /// result.
     ///
     /// Note that using `x[x.len() - 1]` is semantically different from
@@ -23,10 +29,7 @@
     /// There is another lint (get_unwrap) that covers the case of using
     /// `x.get(index).unwrap()` instead of `x[index]`.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
-    ///
+    /// ### Example
     /// ```rust
     /// // Bad
     /// let x = vec![2, 3, 5];
@@ -36,6 +39,7 @@
     /// let x = vec![2, 3, 5];
     /// let last_element = x.last();
     /// ```
+    #[clippy::version = "1.37.0"]
     pub GET_LAST_WITH_LEN,
     complexity,
     "Using `x.get(x.len() - 1)` when `x.last()` is correct and simpler"
@@ -43,19 +47,19 @@
 
 declare_lint_pass!(GetLastWithLen => [GET_LAST_WITH_LEN]);
 
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for GetLastWithLen {
-    fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) {
+impl<'tcx> LateLintPass<'tcx> for GetLastWithLen {
+    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
         if_chain! {
             // Is a method call
-            if let ExprKind::MethodCall(ref path, _, ref args, _) = expr.kind;
+            if let ExprKind::MethodCall(path, args, _) = expr.kind;
 
             // Method name is "get"
             if path.ident.name == sym!(get);
 
             // Argument 0 (the struct we're calling the method on) is a vector
             if let Some(struct_calling_on) = args.get(0);
-            let struct_ty = cx.tables().expr_ty(struct_calling_on);
-            if is_type_diagnostic_item(cx, struct_ty, sym!(vec_type));
+            let struct_ty = cx.typeck_results().expr_ty(struct_calling_on);
+            if is_type_diagnostic_item(cx, struct_ty, sym::Vec);
 
             // Argument to "get" is a subtraction
             if let Some(get_index_arg) = args.get(1);
@@ -69,8 +73,8 @@ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) {
             ) = &get_index_arg.kind;
 
             // LHS of subtraction is "x.len()"
-            if let ExprKind::MethodCall(arg_lhs_path, _, lhs_args, _) = &lhs.kind;
-            if arg_lhs_path.ident.name == sym!(len);
+            if let ExprKind::MethodCall(arg_lhs_path, lhs_args, _) = &lhs.kind;
+            if arg_lhs_path.ident.name == sym::len;
             if let Some(arg_lhs_struct) = lhs_args.get(0);
 
             // The two vectors referenced (x in x.get(...) and in x.len())