New upstream version 1.56.0~beta.4+dfsg1

[rustc.git] / src / tools / clippy / clippy_lints / src / no_effect.rs

diff --git a/src/tools/clippy/clippy_lints/src/no_effect.rs b/src/tools/clippy/clippy_lints/src/no_effect.rs
index 910b05360925d53dd6a6fd39aa14dbc8066d5cd0..28e9e6f438e3de59f8f63ef67acccbee8da82397 100644 (file)
--- a/src/tools/clippy/clippy_lints/src/no_effect.rs
+++ b/src/tools/clippy/clippy_lints/src/no_effect.rs
@@ -3,21 +3,21 @@ use clippy_utils::source::snippet_opt;
 use clippy_utils::ty::has_drop;
 use rustc_errors::Applicability;
 use rustc_hir::def::{DefKind, Res};
-use rustc_hir::{BinOpKind, BlockCheckMode, Expr, ExprKind, Stmt, StmtKind, UnsafeSource};
+use rustc_hir::{is_range_literal, BinOpKind, BlockCheckMode, Expr, ExprKind, Stmt, StmtKind, UnsafeSource};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use std::ops::Deref;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for statements which have no effect.
+    /// ### What it does
+    /// Checks for statements which have no effect.
     ///
-    /// **Why is this bad?** Similar to dead code, these statements are actually
+    /// ### Why is this bad?
+    /// Similar to dead code, these statements are actually
     /// executed. However, as they have no effect, all they do is make the code less
     /// readable.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// 0;
     /// ```
@@ -27,15 +27,15 @@ declare_clippy_lint! {
 }
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for expression statements that can be reduced to a
+    /// ### What it does
+    /// Checks for expression statements that can be reduced to a
     /// sub-expression.
     ///
-    /// **Why is this bad?** Expressions by themselves often have no side-effects.
+    /// ### Why is this bad?
+    /// Expressions by themselves often have no side-effects.
     /// Having such expressions reduces readability.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust,ignore
     /// compute_array()[0];
     /// ```
@@ -68,12 +68,14 @@ fn has_no_effect(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
         ExprKind::Call(callee, args) => {
             if let ExprKind::Path(ref qpath) = callee.kind {
                 let res = cx.qpath_res(qpath, callee.hir_id);
-                match res {
-                    Res::Def(DefKind::Struct | DefKind::Variant | DefKind::Ctor(..), ..) => {
-                        !has_drop(cx, cx.typeck_results().expr_ty(expr))
-                            && args.iter().all(|arg| has_no_effect(cx, arg))
-                    },
-                    _ => false,
+                let def_matched = matches!(
+                    res,
+                    Res::Def(DefKind::Struct | DefKind::Variant | DefKind::Ctor(..), ..)
+                );
+                if def_matched || is_range_literal(expr) {
+                    !has_drop(cx, cx.typeck_results().expr_ty(expr)) && args.iter().all(|arg| has_no_effect(cx, arg))
+                } else {
+                    false
                 }
             } else {
                 false