From 3ec7666a2ac99ccfa9de268a89d855ceb380024c Mon Sep 17 00:00:00 2001 From: Ada Alakbarova Date: Fri, 9 Jan 2026 20:43:26 +0100 Subject: [PATCH 1/6] clean-up --- clippy_lints/src/int_plus_one.rs | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/clippy_lints/src/int_plus_one.rs b/clippy_lints/src/int_plus_one.rs index 67ce57de254d..540f9bb1e260 100644 --- a/clippy_lints/src/int_plus_one.rs +++ b/clippy_lints/src/int_plus_one.rs @@ -100,7 +100,7 @@ impl IntPlusOne { _ => None, } }, - // case where `... >= y - 1` or `... >= -1 + y` + // case where `... <= y - 1` or `... <= -1 + y` (BinOpKind::Le, _, ExprKind::Binary(rhskind, rhslhs, rhsrhs)) => { match (rhskind.node, &rhslhs.kind, &rhsrhs.kind) { // `-1 + y` @@ -156,11 +156,11 @@ impl IntPlusOne { } impl EarlyLintPass for IntPlusOne { - fn check_expr(&mut self, cx: &EarlyContext<'_>, item: &Expr) { - if let ExprKind::Binary(ref kind, ref lhs, ref rhs) = item.kind + fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &Expr) { + if let ExprKind::Binary(kind, lhs, rhs) = &expr.kind && let Some(rec) = Self::check_binop(cx, kind.node, lhs, rhs) { - Self::emit_warning(cx, item, rec); + Self::emit_warning(cx, expr, rec); } } } From 0180ec4d5d9e47b1b36bf33d783ac72600c4abd4 Mon Sep 17 00:00:00 2001 From: Ada Alakbarova Date: Fri, 9 Jan 2026 22:38:08 +0100 Subject: [PATCH 2/6] fix: negative literals are not literals --- clippy_lints/src/int_plus_one.rs | 67 ++++++++++++++++++-------------- tests/ui/int_plus_one.fixed | 16 ++++---- tests/ui/int_plus_one.rs | 16 ++++---- tests/ui/int_plus_one.stderr | 26 ++++++++++++- 4 files changed, 78 insertions(+), 47 deletions(-) diff --git a/clippy_lints/src/int_plus_one.rs b/clippy_lints/src/int_plus_one.rs index 540f9bb1e260..c25821751b3f 100644 --- a/clippy_lints/src/int_plus_one.rs +++ b/clippy_lints/src/int_plus_one.rs @@ -1,7 +1,7 @@ use clippy_utils::diagnostics::span_lint_and_sugg; use clippy_utils::source::SpanRangeExt; -use rustc_ast::ast::{BinOpKind, Expr, ExprKind, LitKind}; -use rustc_ast::token; +use rustc_ast::ast::{BinOpKind, Expr, ExprKind, LitKind, UnOp}; +use rustc_data_structures::packed::Pu128; use rustc_errors::Applicability; use rustc_lint::{EarlyContext, EarlyLintPass}; use rustc_session::declare_lint_pass; @@ -50,25 +50,36 @@ enum Side { } impl IntPlusOne { - #[expect(clippy::cast_sign_loss)] - fn check_lit(token_lit: token::Lit, target_value: i128) -> bool { - if let Ok(LitKind::Int(value, ..)) = LitKind::from_token_lit(token_lit) { - return value == (target_value as u128); + fn is_one(expr: &Expr) -> bool { + if let ExprKind::Lit(token_lit) = expr.kind + && let Ok(LitKind::Int(Pu128(1), ..)) = LitKind::from_token_lit(token_lit) + { + return true; } false } + fn is_neg_one(expr: &Expr) -> bool { + if let ExprKind::Unary(UnOp::Neg, expr) = &expr.kind + && Self::is_one(expr) + { + true + } else { + false + } + } + fn check_binop(cx: &EarlyContext<'_>, binop: BinOpKind, lhs: &Expr, rhs: &Expr) -> Option { match (binop, &lhs.kind, &rhs.kind) { // case where `x - 1 >= ...` or `-1 + x >= ...` (BinOpKind::Ge, ExprKind::Binary(lhskind, lhslhs, lhsrhs), _) => { - match (lhskind.node, &lhslhs.kind, &lhsrhs.kind) { + match lhskind.node { // `-1 + x` - (BinOpKind::Add, ExprKind::Lit(lit), _) if Self::check_lit(*lit, -1) => { + BinOpKind::Add if Self::is_neg_one(lhslhs) => { Self::generate_recommendation(cx, binop, lhsrhs, rhs, Side::Lhs) }, // `x - 1` - (BinOpKind::Sub, _, ExprKind::Lit(lit)) if Self::check_lit(*lit, 1) => { + BinOpKind::Sub if Self::is_one(lhsrhs) => { Self::generate_recommendation(cx, binop, lhslhs, rhs, Side::Lhs) }, _ => None, @@ -76,39 +87,35 @@ impl IntPlusOne { }, // case where `... >= y + 1` or `... >= 1 + y` (BinOpKind::Ge, _, ExprKind::Binary(rhskind, rhslhs, rhsrhs)) if rhskind.node == BinOpKind::Add => { - match (&rhslhs.kind, &rhsrhs.kind) { - // `y + 1` and `1 + y` - (ExprKind::Lit(lit), _) if Self::check_lit(*lit, 1) => { - Self::generate_recommendation(cx, binop, rhsrhs, lhs, Side::Rhs) - }, - (_, ExprKind::Lit(lit)) if Self::check_lit(*lit, 1) => { - Self::generate_recommendation(cx, binop, rhslhs, lhs, Side::Rhs) - }, - _ => None, + // `y + 1` and `1 + y` + if Self::is_one(rhslhs) { + Self::generate_recommendation(cx, binop, rhsrhs, lhs, Side::Rhs) + } else if Self::is_one(rhsrhs) { + Self::generate_recommendation(cx, binop, rhslhs, lhs, Side::Rhs) + } else { + None } }, // case where `x + 1 <= ...` or `1 + x <= ...` (BinOpKind::Le, ExprKind::Binary(lhskind, lhslhs, lhsrhs), _) if lhskind.node == BinOpKind::Add => { - match (&lhslhs.kind, &lhsrhs.kind) { - // `1 + x` and `x + 1` - (ExprKind::Lit(lit), _) if Self::check_lit(*lit, 1) => { - Self::generate_recommendation(cx, binop, lhsrhs, rhs, Side::Lhs) - }, - (_, ExprKind::Lit(lit)) if Self::check_lit(*lit, 1) => { - Self::generate_recommendation(cx, binop, lhslhs, rhs, Side::Lhs) - }, - _ => None, + // `1 + x` and `x + 1` + if Self::is_one(lhslhs) { + Self::generate_recommendation(cx, binop, lhsrhs, rhs, Side::Lhs) + } else if Self::is_one(lhsrhs) { + Self::generate_recommendation(cx, binop, lhslhs, rhs, Side::Lhs) + } else { + None } }, // case where `... <= y - 1` or `... <= -1 + y` (BinOpKind::Le, _, ExprKind::Binary(rhskind, rhslhs, rhsrhs)) => { - match (rhskind.node, &rhslhs.kind, &rhsrhs.kind) { + match rhskind.node { // `-1 + y` - (BinOpKind::Add, ExprKind::Lit(lit), _) if Self::check_lit(*lit, -1) => { + BinOpKind::Add if Self::is_neg_one(rhslhs) => { Self::generate_recommendation(cx, binop, rhsrhs, lhs, Side::Rhs) }, // `y - 1` - (BinOpKind::Sub, _, ExprKind::Lit(lit)) if Self::check_lit(*lit, 1) => { + BinOpKind::Sub if Self::is_one(rhsrhs) => { Self::generate_recommendation(cx, binop, rhslhs, lhs, Side::Rhs) }, _ => None, diff --git a/tests/ui/int_plus_one.fixed b/tests/ui/int_plus_one.fixed index a1aba6bf7f64..cdd19515e9a7 100644 --- a/tests/ui/int_plus_one.fixed +++ b/tests/ui/int_plus_one.fixed @@ -4,15 +4,15 @@ fn main() { let x = 1i32; let y = 0i32; - let _ = x > y; - //~^ int_plus_one - let _ = y < x; - //~^ int_plus_one + let _ = x > y; //~ int_plus_one + let _ = x > y; //~ int_plus_one + let _ = y < x; //~ int_plus_one + let _ = y < x; //~ int_plus_one - let _ = x > y; - //~^ int_plus_one - let _ = y < x; - //~^ int_plus_one + let _ = x > y; //~ int_plus_one + let _ = x > y; //~ int_plus_one + let _ = y < x; //~ int_plus_one + let _ = y < x; //~ int_plus_one let _ = x > y; // should be ok let _ = y < x; // should be ok diff --git a/tests/ui/int_plus_one.rs b/tests/ui/int_plus_one.rs index f804fc9047de..8d7d2e8982d8 100644 --- a/tests/ui/int_plus_one.rs +++ b/tests/ui/int_plus_one.rs @@ -4,15 +4,15 @@ fn main() { let x = 1i32; let y = 0i32; - let _ = x >= y + 1; - //~^ int_plus_one - let _ = y + 1 <= x; - //~^ int_plus_one + let _ = x >= y + 1; //~ int_plus_one + let _ = x >= 1 + y; //~ int_plus_one + let _ = y + 1 <= x; //~ int_plus_one + let _ = 1 + y <= x; //~ int_plus_one - let _ = x - 1 >= y; - //~^ int_plus_one - let _ = y <= x - 1; - //~^ int_plus_one + let _ = x - 1 >= y; //~ int_plus_one + let _ = -1 + x >= y; //~ int_plus_one + let _ = y <= x - 1; //~ int_plus_one + let _ = y <= -1 + x; //~ int_plus_one let _ = x > y; // should be ok let _ = y < x; // should be ok diff --git a/tests/ui/int_plus_one.stderr b/tests/ui/int_plus_one.stderr index 052706028141..8bdff5680bdc 100644 --- a/tests/ui/int_plus_one.stderr +++ b/tests/ui/int_plus_one.stderr @@ -7,23 +7,47 @@ LL | let _ = x >= y + 1; = note: `-D clippy::int-plus-one` implied by `-D warnings` = help: to override `-D warnings` add `#[allow(clippy::int_plus_one)]` +error: unnecessary `>= y + 1` or `x - 1 >=` + --> tests/ui/int_plus_one.rs:8:13 + | +LL | let _ = x >= 1 + y; + | ^^^^^^^^^^ help: change it to: `x > y` + error: unnecessary `>= y + 1` or `x - 1 >=` --> tests/ui/int_plus_one.rs:9:13 | LL | let _ = y + 1 <= x; | ^^^^^^^^^^ help: change it to: `y < x` +error: unnecessary `>= y + 1` or `x - 1 >=` + --> tests/ui/int_plus_one.rs:10:13 + | +LL | let _ = 1 + y <= x; + | ^^^^^^^^^^ help: change it to: `y < x` + error: unnecessary `>= y + 1` or `x - 1 >=` --> tests/ui/int_plus_one.rs:12:13 | LL | let _ = x - 1 >= y; | ^^^^^^^^^^ help: change it to: `x > y` +error: unnecessary `>= y + 1` or `x - 1 >=` + --> tests/ui/int_plus_one.rs:13:13 + | +LL | let _ = -1 + x >= y; + | ^^^^^^^^^^^ help: change it to: `x > y` + error: unnecessary `>= y + 1` or `x - 1 >=` --> tests/ui/int_plus_one.rs:14:13 | LL | let _ = y <= x - 1; | ^^^^^^^^^^ help: change it to: `y < x` -error: aborting due to 4 previous errors +error: unnecessary `>= y + 1` or `x - 1 >=` + --> tests/ui/int_plus_one.rs:15:13 + | +LL | let _ = y <= -1 + x; + | ^^^^^^^^^^^ help: change it to: `y < x` + +error: aborting due to 8 previous errors From df65d1a6a8509f9167078aab372f59ac7762af6c Mon Sep 17 00:00:00 2001 From: Ada Alakbarova Date: Fri, 9 Jan 2026 20:39:42 +0100 Subject: [PATCH 3/6] introduce `LeOrGe` removes the need for a wildcard match --- clippy_lints/src/int_plus_one.rs | 63 ++++++++++++++++++++------------ 1 file changed, 40 insertions(+), 23 deletions(-) diff --git a/clippy_lints/src/int_plus_one.rs b/clippy_lints/src/int_plus_one.rs index c25821751b3f..8143dbad79e8 100644 --- a/clippy_lints/src/int_plus_one.rs +++ b/clippy_lints/src/int_plus_one.rs @@ -35,11 +35,11 @@ declare_clippy_lint! { declare_lint_pass!(IntPlusOne => [INT_PLUS_ONE]); // cases: -// BinOpKind::Ge +// LeOrGe::Ge // x >= y + 1 // x - 1 >= y // -// BinOpKind::Le +// LeOrGe::Le // x + 1 <= y // x <= y - 1 @@ -49,6 +49,23 @@ enum Side { Rhs, } +#[derive(Copy, Clone)] +enum LeOrGe { + Le, + Ge, +} + +impl TryFrom for LeOrGe { + type Error = (); + fn try_from(value: BinOpKind) -> Result { + match value { + BinOpKind::Le => Ok(Self::Le), + BinOpKind::Ge => Ok(Self::Ge), + _ => Err(()), + } + } +} + impl IntPlusOne { fn is_one(expr: &Expr) -> bool { if let ExprKind::Lit(token_lit) = expr.kind @@ -69,54 +86,54 @@ impl IntPlusOne { } } - fn check_binop(cx: &EarlyContext<'_>, binop: BinOpKind, lhs: &Expr, rhs: &Expr) -> Option { - match (binop, &lhs.kind, &rhs.kind) { + fn check_binop(cx: &EarlyContext<'_>, le_or_ge: LeOrGe, lhs: &Expr, rhs: &Expr) -> Option { + match (le_or_ge, &lhs.kind, &rhs.kind) { // case where `x - 1 >= ...` or `-1 + x >= ...` - (BinOpKind::Ge, ExprKind::Binary(lhskind, lhslhs, lhsrhs), _) => { + (LeOrGe::Ge, ExprKind::Binary(lhskind, lhslhs, lhsrhs), _) => { match lhskind.node { // `-1 + x` BinOpKind::Add if Self::is_neg_one(lhslhs) => { - Self::generate_recommendation(cx, binop, lhsrhs, rhs, Side::Lhs) + Self::generate_recommendation(cx, le_or_ge, lhsrhs, rhs, Side::Lhs) }, // `x - 1` BinOpKind::Sub if Self::is_one(lhsrhs) => { - Self::generate_recommendation(cx, binop, lhslhs, rhs, Side::Lhs) + Self::generate_recommendation(cx, le_or_ge, lhslhs, rhs, Side::Lhs) }, _ => None, } }, // case where `... >= y + 1` or `... >= 1 + y` - (BinOpKind::Ge, _, ExprKind::Binary(rhskind, rhslhs, rhsrhs)) if rhskind.node == BinOpKind::Add => { + (LeOrGe::Ge, _, ExprKind::Binary(rhskind, rhslhs, rhsrhs)) if rhskind.node == BinOpKind::Add => { // `y + 1` and `1 + y` if Self::is_one(rhslhs) { - Self::generate_recommendation(cx, binop, rhsrhs, lhs, Side::Rhs) + Self::generate_recommendation(cx, le_or_ge, rhsrhs, lhs, Side::Rhs) } else if Self::is_one(rhsrhs) { - Self::generate_recommendation(cx, binop, rhslhs, lhs, Side::Rhs) + Self::generate_recommendation(cx, le_or_ge, rhslhs, lhs, Side::Rhs) } else { None } }, // case where `x + 1 <= ...` or `1 + x <= ...` - (BinOpKind::Le, ExprKind::Binary(lhskind, lhslhs, lhsrhs), _) if lhskind.node == BinOpKind::Add => { + (LeOrGe::Le, ExprKind::Binary(lhskind, lhslhs, lhsrhs), _) if lhskind.node == BinOpKind::Add => { // `1 + x` and `x + 1` if Self::is_one(lhslhs) { - Self::generate_recommendation(cx, binop, lhsrhs, rhs, Side::Lhs) + Self::generate_recommendation(cx, le_or_ge, lhsrhs, rhs, Side::Lhs) } else if Self::is_one(lhsrhs) { - Self::generate_recommendation(cx, binop, lhslhs, rhs, Side::Lhs) + Self::generate_recommendation(cx, le_or_ge, lhslhs, rhs, Side::Lhs) } else { None } }, // case where `... <= y - 1` or `... <= -1 + y` - (BinOpKind::Le, _, ExprKind::Binary(rhskind, rhslhs, rhsrhs)) => { + (LeOrGe::Le, _, ExprKind::Binary(rhskind, rhslhs, rhsrhs)) => { match rhskind.node { // `-1 + y` BinOpKind::Add if Self::is_neg_one(rhslhs) => { - Self::generate_recommendation(cx, binop, rhsrhs, lhs, Side::Rhs) + Self::generate_recommendation(cx, le_or_ge, rhsrhs, lhs, Side::Rhs) }, // `y - 1` BinOpKind::Sub if Self::is_one(rhsrhs) => { - Self::generate_recommendation(cx, binop, rhslhs, lhs, Side::Rhs) + Self::generate_recommendation(cx, le_or_ge, rhslhs, lhs, Side::Rhs) }, _ => None, } @@ -127,15 +144,14 @@ impl IntPlusOne { fn generate_recommendation( cx: &EarlyContext<'_>, - binop: BinOpKind, + le_or_ge: LeOrGe, node: &Expr, other_side: &Expr, side: Side, ) -> Option { - let binop_string = match binop { - BinOpKind::Ge => ">", - BinOpKind::Le => "<", - _ => return None, + let binop_string = match le_or_ge { + LeOrGe::Ge => ">", + LeOrGe::Le => "<", }; if let Some(snippet) = node.span.get_source_text(cx) && let Some(other_side_snippet) = other_side.span.get_source_text(cx) @@ -164,8 +180,9 @@ impl IntPlusOne { impl EarlyLintPass for IntPlusOne { fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &Expr) { - if let ExprKind::Binary(kind, lhs, rhs) = &expr.kind - && let Some(rec) = Self::check_binop(cx, kind.node, lhs, rhs) + if let ExprKind::Binary(binop, lhs, rhs) = &expr.kind + && let Ok(le_or_ge) = LeOrGe::try_from(binop.node) + && let Some(rec) = Self::check_binop(cx, le_or_ge, lhs, rhs) { Self::emit_warning(cx, expr, rec); } From d554092c27f0ad5cf8dc013b4fbcbd7853c40c0c Mon Sep 17 00:00:00 2001 From: Ada Alakbarova Date: Fri, 9 Jan 2026 21:01:55 +0100 Subject: [PATCH 4/6] get rid of `Side` --- clippy_lints/src/int_plus_one.rs | 33 +++++++++----------------------- 1 file changed, 9 insertions(+), 24 deletions(-) diff --git a/clippy_lints/src/int_plus_one.rs b/clippy_lints/src/int_plus_one.rs index 8143dbad79e8..97b7afb61d86 100644 --- a/clippy_lints/src/int_plus_one.rs +++ b/clippy_lints/src/int_plus_one.rs @@ -43,12 +43,6 @@ declare_lint_pass!(IntPlusOne => [INT_PLUS_ONE]); // x + 1 <= y // x <= y - 1 -#[derive(Copy, Clone)] -enum Side { - Lhs, - Rhs, -} - #[derive(Copy, Clone)] enum LeOrGe { Le, @@ -93,12 +87,10 @@ impl IntPlusOne { match lhskind.node { // `-1 + x` BinOpKind::Add if Self::is_neg_one(lhslhs) => { - Self::generate_recommendation(cx, le_or_ge, lhsrhs, rhs, Side::Lhs) + Self::generate_recommendation(cx, le_or_ge, lhsrhs, rhs) }, // `x - 1` - BinOpKind::Sub if Self::is_one(lhsrhs) => { - Self::generate_recommendation(cx, le_or_ge, lhslhs, rhs, Side::Lhs) - }, + BinOpKind::Sub if Self::is_one(lhsrhs) => Self::generate_recommendation(cx, le_or_ge, lhslhs, rhs), _ => None, } }, @@ -106,9 +98,9 @@ impl IntPlusOne { (LeOrGe::Ge, _, ExprKind::Binary(rhskind, rhslhs, rhsrhs)) if rhskind.node == BinOpKind::Add => { // `y + 1` and `1 + y` if Self::is_one(rhslhs) { - Self::generate_recommendation(cx, le_or_ge, rhsrhs, lhs, Side::Rhs) + Self::generate_recommendation(cx, le_or_ge, lhs, rhsrhs) } else if Self::is_one(rhsrhs) { - Self::generate_recommendation(cx, le_or_ge, rhslhs, lhs, Side::Rhs) + Self::generate_recommendation(cx, le_or_ge, lhs, rhslhs) } else { None } @@ -117,9 +109,9 @@ impl IntPlusOne { (LeOrGe::Le, ExprKind::Binary(lhskind, lhslhs, lhsrhs), _) if lhskind.node == BinOpKind::Add => { // `1 + x` and `x + 1` if Self::is_one(lhslhs) { - Self::generate_recommendation(cx, le_or_ge, lhsrhs, rhs, Side::Lhs) + Self::generate_recommendation(cx, le_or_ge, lhsrhs, rhs) } else if Self::is_one(lhsrhs) { - Self::generate_recommendation(cx, le_or_ge, lhslhs, rhs, Side::Lhs) + Self::generate_recommendation(cx, le_or_ge, lhslhs, rhs) } else { None } @@ -129,12 +121,10 @@ impl IntPlusOne { match rhskind.node { // `-1 + y` BinOpKind::Add if Self::is_neg_one(rhslhs) => { - Self::generate_recommendation(cx, le_or_ge, rhsrhs, lhs, Side::Rhs) + Self::generate_recommendation(cx, le_or_ge, lhs, rhsrhs) }, // `y - 1` - BinOpKind::Sub if Self::is_one(rhsrhs) => { - Self::generate_recommendation(cx, le_or_ge, rhslhs, lhs, Side::Rhs) - }, + BinOpKind::Sub if Self::is_one(rhsrhs) => Self::generate_recommendation(cx, le_or_ge, lhs, rhslhs), _ => None, } }, @@ -147,7 +137,6 @@ impl IntPlusOne { le_or_ge: LeOrGe, node: &Expr, other_side: &Expr, - side: Side, ) -> Option { let binop_string = match le_or_ge { LeOrGe::Ge => ">", @@ -156,11 +145,7 @@ impl IntPlusOne { if let Some(snippet) = node.span.get_source_text(cx) && let Some(other_side_snippet) = other_side.span.get_source_text(cx) { - let rec = match side { - Side::Lhs => Some(format!("{snippet} {binop_string} {other_side_snippet}")), - Side::Rhs => Some(format!("{other_side_snippet} {binop_string} {snippet}")), - }; - return rec; + return Some(format!("{snippet} {binop_string} {other_side_snippet}")); } None } From ccaa2fa9841447092bfe96111629747a27fa419a Mon Sep 17 00:00:00 2001 From: Ada Alakbarova Date: Fri, 9 Jan 2026 20:30:20 +0100 Subject: [PATCH 5/6] fix: respect reduced applicability By building the whole suggestion in `emit_suggestion`, we avoid the need to thread `Applicability` through `check_binop` into `generate_suggestion` --- clippy_lints/src/int_plus_one.rs | 69 +++++++++++++------------------- 1 file changed, 28 insertions(+), 41 deletions(-) diff --git a/clippy_lints/src/int_plus_one.rs b/clippy_lints/src/int_plus_one.rs index 97b7afb61d86..b82ca0205a9f 100644 --- a/clippy_lints/src/int_plus_one.rs +++ b/clippy_lints/src/int_plus_one.rs @@ -1,5 +1,5 @@ -use clippy_utils::diagnostics::span_lint_and_sugg; -use clippy_utils::source::SpanRangeExt; +use clippy_utils::diagnostics::span_lint_and_then; +use clippy_utils::sugg; use rustc_ast::ast::{BinOpKind, Expr, ExprKind, LitKind, UnOp}; use rustc_data_structures::packed::Pu128; use rustc_errors::Applicability; @@ -80,17 +80,15 @@ impl IntPlusOne { } } - fn check_binop(cx: &EarlyContext<'_>, le_or_ge: LeOrGe, lhs: &Expr, rhs: &Expr) -> Option { + fn check_binop<'tcx>(le_or_ge: LeOrGe, lhs: &'tcx Expr, rhs: &'tcx Expr) -> Option<(&'tcx Expr, &'tcx Expr)> { match (le_or_ge, &lhs.kind, &rhs.kind) { // case where `x - 1 >= ...` or `-1 + x >= ...` (LeOrGe::Ge, ExprKind::Binary(lhskind, lhslhs, lhsrhs), _) => { match lhskind.node { // `-1 + x` - BinOpKind::Add if Self::is_neg_one(lhslhs) => { - Self::generate_recommendation(cx, le_or_ge, lhsrhs, rhs) - }, + BinOpKind::Add if Self::is_neg_one(lhslhs) => Some((lhsrhs, rhs)), // `x - 1` - BinOpKind::Sub if Self::is_one(lhsrhs) => Self::generate_recommendation(cx, le_or_ge, lhslhs, rhs), + BinOpKind::Sub if Self::is_one(lhsrhs) => Some((lhslhs, rhs)), _ => None, } }, @@ -98,9 +96,9 @@ impl IntPlusOne { (LeOrGe::Ge, _, ExprKind::Binary(rhskind, rhslhs, rhsrhs)) if rhskind.node == BinOpKind::Add => { // `y + 1` and `1 + y` if Self::is_one(rhslhs) { - Self::generate_recommendation(cx, le_or_ge, lhs, rhsrhs) + Some((lhs, rhsrhs)) } else if Self::is_one(rhsrhs) { - Self::generate_recommendation(cx, le_or_ge, lhs, rhslhs) + Some((lhs, rhslhs)) } else { None } @@ -109,9 +107,9 @@ impl IntPlusOne { (LeOrGe::Le, ExprKind::Binary(lhskind, lhslhs, lhsrhs), _) if lhskind.node == BinOpKind::Add => { // `1 + x` and `x + 1` if Self::is_one(lhslhs) { - Self::generate_recommendation(cx, le_or_ge, lhsrhs, rhs) + Some((lhsrhs, rhs)) } else if Self::is_one(lhsrhs) { - Self::generate_recommendation(cx, le_or_ge, lhslhs, rhs) + Some((lhslhs, rhs)) } else { None } @@ -120,11 +118,9 @@ impl IntPlusOne { (LeOrGe::Le, _, ExprKind::Binary(rhskind, rhslhs, rhsrhs)) => { match rhskind.node { // `-1 + y` - BinOpKind::Add if Self::is_neg_one(rhslhs) => { - Self::generate_recommendation(cx, le_or_ge, lhs, rhsrhs) - }, + BinOpKind::Add if Self::is_neg_one(rhslhs) => Some((lhs, rhsrhs)), // `y - 1` - BinOpKind::Sub if Self::is_one(rhsrhs) => Self::generate_recommendation(cx, le_or_ge, lhs, rhslhs), + BinOpKind::Sub if Self::is_one(rhsrhs) => Some((lhs, rhslhs)), _ => None, } }, @@ -132,33 +128,24 @@ impl IntPlusOne { } } - fn generate_recommendation( - cx: &EarlyContext<'_>, - le_or_ge: LeOrGe, - node: &Expr, - other_side: &Expr, - ) -> Option { - let binop_string = match le_or_ge { - LeOrGe::Ge => ">", - LeOrGe::Le => "<", - }; - if let Some(snippet) = node.span.get_source_text(cx) - && let Some(other_side_snippet) = other_side.span.get_source_text(cx) - { - return Some(format!("{snippet} {binop_string} {other_side_snippet}")); - } - None - } - - fn emit_warning(cx: &EarlyContext<'_>, block: &Expr, recommendation: String) { - span_lint_and_sugg( + fn emit_warning(cx: &EarlyContext<'_>, expr: &Expr, new_lhs: &Expr, le_or_ge: LeOrGe, new_rhs: &Expr) { + span_lint_and_then( cx, INT_PLUS_ONE, - block.span, + expr.span, "unnecessary `>= y + 1` or `x - 1 >=`", - "change it to", - recommendation, - Applicability::MachineApplicable, // snippet + |diag| { + let mut app = Applicability::MachineApplicable; + let ctxt = expr.span.ctxt(); + let new_lhs = sugg::Sugg::ast(cx, new_lhs, "_", ctxt, &mut app); + let new_rhs = sugg::Sugg::ast(cx, new_rhs, "_", ctxt, &mut app); + let new_binop = match le_or_ge { + LeOrGe::Ge => BinOpKind::Gt, + LeOrGe::Le => BinOpKind::Lt, + }; + let rec = sugg::make_binop(new_binop, &new_lhs, &new_rhs); + diag.span_suggestion(expr.span, "change it to", rec, app); + }, ); } } @@ -167,9 +154,9 @@ impl EarlyLintPass for IntPlusOne { fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &Expr) { if let ExprKind::Binary(binop, lhs, rhs) = &expr.kind && let Ok(le_or_ge) = LeOrGe::try_from(binop.node) - && let Some(rec) = Self::check_binop(cx, le_or_ge, lhs, rhs) + && let Some((new_lhs, new_rhs)) = Self::check_binop(le_or_ge, lhs, rhs) { - Self::emit_warning(cx, expr, rec); + Self::emit_warning(cx, expr, new_lhs, le_or_ge, new_rhs); } } } From e4dd9475234017adeda572d02320876f98e26775 Mon Sep 17 00:00:00 2001 From: Ada Alakbarova Date: Sat, 10 Jan 2026 19:57:28 +0100 Subject: [PATCH 6/6] introduce `Self::as_x_{plus,minus}_one` reduces duplication --- clippy_lints/src/int_plus_one.rs | 91 +++++++++++++++----------------- 1 file changed, 44 insertions(+), 47 deletions(-) diff --git a/clippy_lints/src/int_plus_one.rs b/clippy_lints/src/int_plus_one.rs index b82ca0205a9f..f8184b30f400 100644 --- a/clippy_lints/src/int_plus_one.rs +++ b/clippy_lints/src/int_plus_one.rs @@ -63,7 +63,7 @@ impl TryFrom for LeOrGe { impl IntPlusOne { fn is_one(expr: &Expr) -> bool { if let ExprKind::Lit(token_lit) = expr.kind - && let Ok(LitKind::Int(Pu128(1), ..)) = LitKind::from_token_lit(token_lit) + && matches!(LitKind::from_token_lit(token_lit), Ok(LitKind::Int(Pu128(1), ..))) { return true; } @@ -71,60 +71,57 @@ impl IntPlusOne { } fn is_neg_one(expr: &Expr) -> bool { - if let ExprKind::Unary(UnOp::Neg, expr) = &expr.kind - && Self::is_one(expr) - { - true + if let ExprKind::Unary(UnOp::Neg, expr) = &expr.kind { + Self::is_one(expr) } else { false } } + /// Checks whether `expr` is `x + 1` or `1 + x`, and if so, returns `x` + fn as_x_plus_one(expr: &Expr) -> Option<&Expr> { + if let ExprKind::Binary(op, lhs, rhs) = &expr.kind + && op.node == BinOpKind::Add + { + if Self::is_one(rhs) { + // x + 1 + return Some(lhs); + } else if Self::is_one(lhs) { + // 1 + x + return Some(rhs); + } + } + None + } + + /// Checks whether `expr` is `x - 1` or `-1 + x`, and if so, returns `x` + fn as_x_minus_one(expr: &Expr) -> Option<&Expr> { + if let ExprKind::Binary(op, lhs, rhs) = &expr.kind { + if op.node == BinOpKind::Sub && Self::is_one(rhs) { + // x - 1 + return Some(lhs); + } else if op.node == BinOpKind::Add && Self::is_neg_one(lhs) { + // -1 + x + return Some(rhs); + } + } + None + } + fn check_binop<'tcx>(le_or_ge: LeOrGe, lhs: &'tcx Expr, rhs: &'tcx Expr) -> Option<(&'tcx Expr, &'tcx Expr)> { - match (le_or_ge, &lhs.kind, &rhs.kind) { - // case where `x - 1 >= ...` or `-1 + x >= ...` - (LeOrGe::Ge, ExprKind::Binary(lhskind, lhslhs, lhsrhs), _) => { - match lhskind.node { - // `-1 + x` - BinOpKind::Add if Self::is_neg_one(lhslhs) => Some((lhsrhs, rhs)), - // `x - 1` - BinOpKind::Sub if Self::is_one(lhsrhs) => Some((lhslhs, rhs)), - _ => None, - } + match le_or_ge { + LeOrGe::Ge => { + // case where `x - 1 >= ...` or `-1 + x >= ...` + (Self::as_x_minus_one(lhs).map(|new_lhs| (new_lhs, rhs))) + // case where `... >= y + 1` or `... >= 1 + y` + .or_else(|| Self::as_x_plus_one(rhs).map(|new_rhs| (lhs, new_rhs))) }, - // case where `... >= y + 1` or `... >= 1 + y` - (LeOrGe::Ge, _, ExprKind::Binary(rhskind, rhslhs, rhsrhs)) if rhskind.node == BinOpKind::Add => { - // `y + 1` and `1 + y` - if Self::is_one(rhslhs) { - Some((lhs, rhsrhs)) - } else if Self::is_one(rhsrhs) { - Some((lhs, rhslhs)) - } else { - None - } + LeOrGe::Le => { + // case where `x + 1 <= ...` or `1 + x <= ...` + (Self::as_x_plus_one(lhs).map(|new_lhs| (new_lhs, rhs))) + // case where `... <= y - 1` or `... <= -1 + y` + .or_else(|| Self::as_x_minus_one(rhs).map(|new_rhs| (lhs, new_rhs))) }, - // case where `x + 1 <= ...` or `1 + x <= ...` - (LeOrGe::Le, ExprKind::Binary(lhskind, lhslhs, lhsrhs), _) if lhskind.node == BinOpKind::Add => { - // `1 + x` and `x + 1` - if Self::is_one(lhslhs) { - Some((lhsrhs, rhs)) - } else if Self::is_one(lhsrhs) { - Some((lhslhs, rhs)) - } else { - None - } - }, - // case where `... <= y - 1` or `... <= -1 + y` - (LeOrGe::Le, _, ExprKind::Binary(rhskind, rhslhs, rhsrhs)) => { - match rhskind.node { - // `-1 + y` - BinOpKind::Add if Self::is_neg_one(rhslhs) => Some((lhs, rhsrhs)), - // `y - 1` - BinOpKind::Sub if Self::is_one(rhsrhs) => Some((lhs, rhslhs)), - _ => None, - } - }, - _ => None, } }