Add 'library/portable-simd/' from commit '1ce1c645cf27c4acdefe6ec8a11d1f0491954a99'

[rust.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 e07518b25868795c691291bc01e28b8d9315e59b..c5a5cde4b110fccbb874801a53cd72dcc9b2e747 100644 (file)
--- a/src/tools/clippy/clippy_lints/src/no_effect.rs
+++ b/src/tools/clippy/clippy_lints/src/no_effect.rs
@@ -3,7 +3,7 @@
 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;
@@ -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
@@ -94,28 +96,63 @@ fn check_stmt(&mut self, cx: &LateContext<'tcx>, stmt: &'tcx Stmt<'_>) {
             if has_no_effect(cx, expr) {
                 span_lint_hir(cx, NO_EFFECT, expr.hir_id, stmt.span, "statement with no effect");
             } else if let Some(reduced) = reduce_expression(cx, expr) {
-                let mut snippet = String::new();
-                for e in reduced {
+                for e in &reduced {
                     if e.span.from_expansion() {
                         return;
                     }
-                    if let Some(snip) = snippet_opt(cx, e.span) {
-                        snippet.push_str(&snip);
-                        snippet.push(';');
-                    } else {
-                        return;
+                }
+                if let ExprKind::Index(..) = &expr.kind {
+                    let snippet;
+                    if_chain! {
+                        if let Some(arr) = snippet_opt(cx, reduced[0].span);
+                        if let Some(func) = snippet_opt(cx, reduced[1].span);
+                        then {
+                            snippet = format!("assert!({}.len() > {});", &arr, &func);
+                        } else {
+                            return;
+                        }
+                    }
+                    span_lint_hir_and_then(
+                        cx,
+                        UNNECESSARY_OPERATION,
+                        expr.hir_id,
+                        stmt.span,
+                        "unnecessary operation",
+                        |diag| {
+                            diag.span_suggestion(
+                                stmt.span,
+                                "statement can be written as",
+                                snippet,
+                                Applicability::MaybeIncorrect,
+                            );
+                        },
+                    );
+                } else {
+                    let mut snippet = String::new();
+                    for e in reduced {
+                        if let Some(snip) = snippet_opt(cx, e.span) {
+                            snippet.push_str(&snip);
+                            snippet.push(';');
+                        } else {
+                            return;
+                        }
                     }
+                    span_lint_hir_and_then(
+                        cx,
+                        UNNECESSARY_OPERATION,
+                        expr.hir_id,
+                        stmt.span,
+                        "unnecessary operation",
+                        |diag| {
+                            diag.span_suggestion(
+                                stmt.span,
+                                "statement can be reduced to",
+                                snippet,
+                                Applicability::MachineApplicable,
+                            );
+                        },
+                    );
                 }
-                span_lint_hir_and_then(
-                    cx,
-                    UNNECESSARY_OPERATION,
-                    expr.hir_id,
-                    stmt.span,
-                    "statement can be reduced",
-                    |diag| {
-                        diag.span_suggestion(stmt.span, "replace it with", snippet, Applicability::MachineApplicable);
-                    },
-                );
             }
         }
     }