From 503fd56a423c8da7958aa3fc611b623270d02fde Mon Sep 17 00:00:00 2001 From: timvisee Date: Mon, 17 Apr 2023 20:25:42 +0200 Subject: [PATCH 1/3] Suggest applicable expression for manual slice size calculation lint --- .../src/manual_slice_size_calculation.rs | 22 ++++++++++++------ tests/ui/manual_slice_size_calculation.stderr | 23 +++++-------------- 2 files changed, 21 insertions(+), 24 deletions(-) diff --git a/clippy_lints/src/manual_slice_size_calculation.rs b/clippy_lints/src/manual_slice_size_calculation.rs index ba01fd085303..cef5b8361a4d 100644 --- a/clippy_lints/src/manual_slice_size_calculation.rs +++ b/clippy_lints/src/manual_slice_size_calculation.rs @@ -1,5 +1,7 @@ -use clippy_utils::diagnostics::span_lint_and_help; +use clippy_utils::diagnostics::span_lint_and_sugg; +use clippy_utils::source::snippet_with_context; use clippy_utils::{expr_or_init, in_constant}; +use rustc_errors::Applicability; use rustc_hir::{BinOpKind, Expr, ExprKind}; use rustc_lint::{LateContext, LateLintPass}; use rustc_middle::ty; @@ -42,15 +44,21 @@ impl<'tcx> LateLintPass<'tcx> for ManualSliceSizeCalculation { if !in_constant(cx, expr.hir_id) && let ExprKind::Binary(ref op, left, right) = expr.kind && BinOpKind::Mul == op.node - && let Some(_receiver) = simplify(cx, left, right) + && let Some(receiver) = simplify(cx, left, right) { - span_lint_and_help( + let ctxt = expr.span.ctxt(); + let mut app = Applicability::MachineApplicable; + let val_name = snippet_with_context(cx, receiver.span, ctxt, "slice", &mut app).0; + + span_lint_and_sugg( cx, MANUAL_SLICE_SIZE_CALCULATION, - expr.span, - "manual slice size calculation", - None, - "consider using std::mem::size_of_val instead"); + expr.span, + "manual slice size calculation", + "try", + format!("std::mem::size_of_val({val_name})"), + Applicability::MachineApplicable, + ); } } } diff --git a/tests/ui/manual_slice_size_calculation.stderr b/tests/ui/manual_slice_size_calculation.stderr index 7698d9782f0c..b88f523ddcfe 100644 --- a/tests/ui/manual_slice_size_calculation.stderr +++ b/tests/ui/manual_slice_size_calculation.stderr @@ -2,50 +2,39 @@ error: manual slice size calculation --> $DIR/manual_slice_size_calculation.rs:11:13 | LL | let _ = s_i32.len() * size_of::(); // WARNING - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `std::mem::size_of_val(s_i32)` | - = help: consider using std::mem::size_of_val instead = note: `-D clippy::manual-slice-size-calculation` implied by `-D warnings` error: manual slice size calculation --> $DIR/manual_slice_size_calculation.rs:12:13 | LL | let _ = size_of::() * s_i32.len(); // WARNING - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - | - = help: consider using std::mem::size_of_val instead + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `std::mem::size_of_val(s_i32)` error: manual slice size calculation --> $DIR/manual_slice_size_calculation.rs:13:13 | LL | let _ = size_of::() * s_i32.len() * 5; // WARNING - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - | - = help: consider using std::mem::size_of_val instead + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `std::mem::size_of_val(s_i32)` error: manual slice size calculation --> $DIR/manual_slice_size_calculation.rs:17:13 | LL | let _ = len * size_of::(); // WARNING - | ^^^^^^^^^^^^^^^^^^^^^^ - | - = help: consider using std::mem::size_of_val instead + | ^^^^^^^^^^^^^^^^^^^^^^ help: try: `std::mem::size_of_val(s_i32)` error: manual slice size calculation --> $DIR/manual_slice_size_calculation.rs:18:13 | LL | let _ = s_i32.len() * size; // WARNING - | ^^^^^^^^^^^^^^^^^^ - | - = help: consider using std::mem::size_of_val instead + | ^^^^^^^^^^^^^^^^^^ help: try: `std::mem::size_of_val(s_i32)` error: manual slice size calculation --> $DIR/manual_slice_size_calculation.rs:19:13 | LL | let _ = len * size; // WARNING - | ^^^^^^^^^^ - | - = help: consider using std::mem::size_of_val instead + | ^^^^^^^^^^ help: try: `std::mem::size_of_val(s_i32)` error: aborting due to 6 previous errors From b8fee8b5047f6a98992424c25f79468313044e1c Mon Sep 17 00:00:00 2001 From: timvisee Date: Mon, 17 Apr 2023 20:43:16 +0200 Subject: [PATCH 2/3] Add run-rustfix marker and test file --- .../src/manual_slice_size_calculation.rs | 1 + tests/ui/manual_slice_size_calculation.fixed | 37 +++++++++++++++++++ tests/ui/manual_slice_size_calculation.rs | 1 + tests/ui/manual_slice_size_calculation.stderr | 12 +++--- 4 files changed, 45 insertions(+), 6 deletions(-) create mode 100644 tests/ui/manual_slice_size_calculation.fixed diff --git a/clippy_lints/src/manual_slice_size_calculation.rs b/clippy_lints/src/manual_slice_size_calculation.rs index cef5b8361a4d..d87dbe0a0a43 100644 --- a/clippy_lints/src/manual_slice_size_calculation.rs +++ b/clippy_lints/src/manual_slice_size_calculation.rs @@ -1,3 +1,4 @@ +// run-rustfix use clippy_utils::diagnostics::span_lint_and_sugg; use clippy_utils::source::snippet_with_context; use clippy_utils::{expr_or_init, in_constant}; diff --git a/tests/ui/manual_slice_size_calculation.fixed b/tests/ui/manual_slice_size_calculation.fixed new file mode 100644 index 000000000000..2b18dd58c634 --- /dev/null +++ b/tests/ui/manual_slice_size_calculation.fixed @@ -0,0 +1,37 @@ +// run-rustfix +#![allow(unused)] +#![warn(clippy::manual_slice_size_calculation)] + +use core::mem::{align_of, size_of}; + +fn main() { + let v_i32 = Vec::::new(); + let s_i32 = v_i32.as_slice(); + + // True positives: + let _ = std::mem::size_of_val(s_i32); // WARNING + let _ = std::mem::size_of_val(s_i32); // WARNING + let _ = std::mem::size_of_val(s_i32) * 5; // WARNING + + let len = s_i32.len(); + let size = size_of::(); + let _ = std::mem::size_of_val(s_i32); // WARNING + let _ = std::mem::size_of_val(s_i32); // WARNING + let _ = std::mem::size_of_val(s_i32); // WARNING + + // True negatives: + let _ = size_of::() + s_i32.len(); // Ok, not a multiplication + let _ = size_of::() * s_i32.partition_point(|_| true); // Ok, not len() + let _ = size_of::() * v_i32.len(); // Ok, not a slice + let _ = align_of::() * s_i32.len(); // Ok, not size_of() + let _ = size_of::() * s_i32.len(); // Ok, different types + + // False negatives: + let _ = 5 * size_of::() * s_i32.len(); // Ok (MISSED OPPORTUNITY) + let _ = size_of::() * 5 * s_i32.len(); // Ok (MISSED OPPORTUNITY) +} + +const fn _const(s_i32: &[i32]) { + // True negative: + let _ = s_i32.len() * size_of::(); // Ok, can't use size_of_val in const +} diff --git a/tests/ui/manual_slice_size_calculation.rs b/tests/ui/manual_slice_size_calculation.rs index 5082f931f3c2..04adab76df25 100644 --- a/tests/ui/manual_slice_size_calculation.rs +++ b/tests/ui/manual_slice_size_calculation.rs @@ -1,3 +1,4 @@ +// run-rustfix #![allow(unused)] #![warn(clippy::manual_slice_size_calculation)] diff --git a/tests/ui/manual_slice_size_calculation.stderr b/tests/ui/manual_slice_size_calculation.stderr index b88f523ddcfe..a6217652b883 100644 --- a/tests/ui/manual_slice_size_calculation.stderr +++ b/tests/ui/manual_slice_size_calculation.stderr @@ -1,5 +1,5 @@ error: manual slice size calculation - --> $DIR/manual_slice_size_calculation.rs:11:13 + --> $DIR/manual_slice_size_calculation.rs:12:13 | LL | let _ = s_i32.len() * size_of::(); // WARNING | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `std::mem::size_of_val(s_i32)` @@ -7,31 +7,31 @@ LL | let _ = s_i32.len() * size_of::(); // WARNING = note: `-D clippy::manual-slice-size-calculation` implied by `-D warnings` error: manual slice size calculation - --> $DIR/manual_slice_size_calculation.rs:12:13 + --> $DIR/manual_slice_size_calculation.rs:13:13 | LL | let _ = size_of::() * s_i32.len(); // WARNING | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `std::mem::size_of_val(s_i32)` error: manual slice size calculation - --> $DIR/manual_slice_size_calculation.rs:13:13 + --> $DIR/manual_slice_size_calculation.rs:14:13 | LL | let _ = size_of::() * s_i32.len() * 5; // WARNING | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `std::mem::size_of_val(s_i32)` error: manual slice size calculation - --> $DIR/manual_slice_size_calculation.rs:17:13 + --> $DIR/manual_slice_size_calculation.rs:18:13 | LL | let _ = len * size_of::(); // WARNING | ^^^^^^^^^^^^^^^^^^^^^^ help: try: `std::mem::size_of_val(s_i32)` error: manual slice size calculation - --> $DIR/manual_slice_size_calculation.rs:18:13 + --> $DIR/manual_slice_size_calculation.rs:19:13 | LL | let _ = s_i32.len() * size; // WARNING | ^^^^^^^^^^^^^^^^^^ help: try: `std::mem::size_of_val(s_i32)` error: manual slice size calculation - --> $DIR/manual_slice_size_calculation.rs:19:13 + --> $DIR/manual_slice_size_calculation.rs:20:13 | LL | let _ = len * size; // WARNING | ^^^^^^^^^^ help: try: `std::mem::size_of_val(s_i32)` From a2580db6420aa6ea3ab34c467bb795e9e39ba449 Mon Sep 17 00:00:00 2001 From: timvisee Date: Mon, 17 Apr 2023 21:16:02 +0200 Subject: [PATCH 3/3] Use `clippy_utils::std_or_core` in manual slice size calculation lint --- clippy_lints/src/manual_slice_size_calculation.rs | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/clippy_lints/src/manual_slice_size_calculation.rs b/clippy_lints/src/manual_slice_size_calculation.rs index d87dbe0a0a43..a5bb1c6f9bcf 100644 --- a/clippy_lints/src/manual_slice_size_calculation.rs +++ b/clippy_lints/src/manual_slice_size_calculation.rs @@ -1,7 +1,7 @@ // run-rustfix use clippy_utils::diagnostics::span_lint_and_sugg; use clippy_utils::source::snippet_with_context; -use clippy_utils::{expr_or_init, in_constant}; +use clippy_utils::{expr_or_init, in_constant, std_or_core}; use rustc_errors::Applicability; use rustc_hir::{BinOpKind, Expr, ExprKind}; use rustc_lint::{LateContext, LateLintPass}; @@ -50,6 +50,7 @@ impl<'tcx> LateLintPass<'tcx> for ManualSliceSizeCalculation { let ctxt = expr.span.ctxt(); let mut app = Applicability::MachineApplicable; let val_name = snippet_with_context(cx, receiver.span, ctxt, "slice", &mut app).0; + let Some(sugg) = std_or_core(cx) else { return }; span_lint_and_sugg( cx, @@ -57,7 +58,7 @@ impl<'tcx> LateLintPass<'tcx> for ManualSliceSizeCalculation { expr.span, "manual slice size calculation", "try", - format!("std::mem::size_of_val({val_name})"), + format!("{sugg}::mem::size_of_val({val_name})"), Applicability::MachineApplicable, ); }