diff options
| -rw-r--r-- | CHANGELOG.md | 1 | ||||
| -rw-r--r-- | clippy_lints/src/bool_to_int_with_if.rs | 125 | ||||
| -rw-r--r-- | clippy_lints/src/lib.register_all.rs | 1 | ||||
| -rw-r--r-- | clippy_lints/src/lib.register_lints.rs | 1 | ||||
| -rw-r--r-- | clippy_lints/src/lib.register_style.rs | 1 | ||||
| -rw-r--r-- | clippy_lints/src/lib.rs | 2 | ||||
| -rw-r--r-- | clippy_lints/src/matches/single_match.rs | 8 | ||||
| -rw-r--r-- | clippy_lints/src/only_used_in_recursion.rs | 12 | ||||
| -rw-r--r-- | tests/ui/author/struct.rs | 7 | ||||
| -rw-r--r-- | tests/ui/bool_to_int_with_if.fixed | 85 | ||||
| -rw-r--r-- | tests/ui/bool_to_int_with_if.rs | 109 | ||||
| -rw-r--r-- | tests/ui/bool_to_int_with_if.stderr | 84 |
12 files changed, 419 insertions, 17 deletions
diff --git a/CHANGELOG.md b/CHANGELOG.md index c488c142e46..257add86b6e 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -3603,6 +3603,7 @@ Released 2018-09-13 [`blocks_in_if_conditions`]: https://rust-lang.github.io/rust-clippy/master/index.html#blocks_in_if_conditions [`bool_assert_comparison`]: https://rust-lang.github.io/rust-clippy/master/index.html#bool_assert_comparison [`bool_comparison`]: https://rust-lang.github.io/rust-clippy/master/index.html#bool_comparison +[`bool_to_int_with_if`]: https://rust-lang.github.io/rust-clippy/master/index.html#bool_to_int_with_if [`borrow_as_ptr`]: https://rust-lang.github.io/rust-clippy/master/index.html#borrow_as_ptr [`borrow_deref_ref`]: https://rust-lang.github.io/rust-clippy/master/index.html#borrow_deref_ref [`borrow_interior_mutable_const`]: https://rust-lang.github.io/rust-clippy/master/index.html#borrow_interior_mutable_const diff --git a/clippy_lints/src/bool_to_int_with_if.rs b/clippy_lints/src/bool_to_int_with_if.rs new file mode 100644 index 00000000000..a4b8cbb0d82 --- /dev/null +++ b/clippy_lints/src/bool_to_int_with_if.rs @@ -0,0 +1,125 @@ +use rustc_ast::{ExprPrecedence, LitKind}; +use rustc_hir::{Block, ExprKind}; +use rustc_lint::{LateContext, LateLintPass}; +use rustc_session::{declare_lint_pass, declare_tool_lint}; + +use clippy_utils::{diagnostics::span_lint_and_then, is_else_clause, source::snippet_block_with_applicability}; +use rustc_errors::Applicability; + +declare_clippy_lint! { + /// ### What it does + /// Instead of using an if statement to convert a bool to an int, + /// this lint suggests using a `from()` function or an `as` coercion. + /// + /// ### Why is this bad? + /// Coercion or `from()` is idiomatic way to convert bool to a number. + /// Both methods are guaranteed to return 1 for true, and 0 for false. + /// + /// See https://doc.rust-lang.org/std/primitive.bool.html#impl-From%3Cbool%3E + /// + /// ### Example + /// ```rust + /// # let condition = false; + /// if condition { + /// 1_i64 + /// } else { + /// 0 + /// }; + /// ``` + /// Use instead: + /// ```rust + /// # let condition = false; + /// i64::from(condition); + /// ``` + /// or + /// ```rust + /// # let condition = false; + /// condition as i64; + /// ``` + #[clippy::version = "1.65.0"] + pub BOOL_TO_INT_WITH_IF, + style, + "using if to convert bool to int" +} +declare_lint_pass!(BoolToIntWithIf => [BOOL_TO_INT_WITH_IF]); + +impl<'tcx> LateLintPass<'tcx> for BoolToIntWithIf { + fn check_expr(&mut self, ctx: &LateContext<'tcx>, expr: &'tcx rustc_hir::Expr<'tcx>) { + if !expr.span.from_expansion() { + check_if_else(ctx, expr); + } + } +} + +fn check_if_else<'tcx>(ctx: &LateContext<'tcx>, expr: &'tcx rustc_hir::Expr<'tcx>) { + if let ExprKind::If(check, then, Some(else_)) = expr.kind + && let Some(then_lit) = int_literal(then) + && let Some(else_lit) = int_literal(else_) + && check_int_literal_equals_val(then_lit, 1) + && check_int_literal_equals_val(else_lit, 0) + { + let mut applicability = Applicability::MachineApplicable; + let snippet = snippet_block_with_applicability(ctx, check.span, "..", None, &mut applicability); + let snippet_with_braces = { + let need_parens = should_have_parentheses(check); + let (left_paren, right_paren) = if need_parens {("(", ")")} else {("", "")}; + format!("{left_paren}{snippet}{right_paren}") + }; + + let ty = ctx.typeck_results().expr_ty(then_lit); // then and else must be of same type + + let suggestion = { + let wrap_in_curly = is_else_clause(ctx.tcx, expr); + let (left_curly, right_curly) = if wrap_in_curly {("{", "}")} else {("", "")}; + format!( + "{left_curly}{ty}::from({snippet}){right_curly}" + ) + }; // when used in else clause if statement should be wrapped in curly braces + + span_lint_and_then(ctx, + BOOL_TO_INT_WITH_IF, + expr.span, + "boolean to int conversion using if", + |diag| { + diag.span_suggestion( + expr.span, + "replace with from", + suggestion, + applicability, + ); + diag.note(format!("`{snippet_with_braces} as {ty}` or `{snippet_with_braces}.into()` can also be valid options")); + }); + }; +} + +// If block contains only a int literal expression, return literal expression +fn int_literal<'tcx>(expr: &'tcx rustc_hir::Expr<'tcx>) -> Option<&'tcx rustc_hir::Expr<'tcx>> { + if let ExprKind::Block(block, _) = expr.kind + && let Block { + stmts: [], // Shouldn't lint if statements with side effects + expr: Some(expr), + .. + } = block + && let ExprKind::Lit(lit) = &expr.kind + && let LitKind::Int(_, _) = lit.node + { + Some(expr) + } else { + None + } +} + +fn check_int_literal_equals_val<'tcx>(expr: &'tcx rustc_hir::Expr<'tcx>, expected_value: u128) -> bool { + if let ExprKind::Lit(lit) = &expr.kind + && let LitKind::Int(val, _) = lit.node + && val == expected_value + { + true + } else { + false + } +} + +fn should_have_parentheses<'tcx>(check: &'tcx rustc_hir::Expr<'tcx>) -> bool { + check.precedence().order() < ExprPrecedence::Cast.order() +} diff --git a/clippy_lints/src/lib.register_all.rs b/clippy_lints/src/lib.register_all.rs index 134cbbf7b5c..1f85382347a 100644 --- a/clippy_lints/src/lib.register_all.rs +++ b/clippy_lints/src/lib.register_all.rs @@ -17,6 +17,7 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![ LintId::of(await_holding_invalid::AWAIT_HOLDING_REFCELL_REF), LintId::of(blocks_in_if_conditions::BLOCKS_IN_IF_CONDITIONS), LintId::of(bool_assert_comparison::BOOL_ASSERT_COMPARISON), + LintId::of(bool_to_int_with_if::BOOL_TO_INT_WITH_IF), LintId::of(booleans::NONMINIMAL_BOOL), LintId::of(booleans::OVERLY_COMPLEX_BOOL_EXPR), LintId::of(borrow_deref_ref::BORROW_DEREF_REF), diff --git a/clippy_lints/src/lib.register_lints.rs b/clippy_lints/src/lib.register_lints.rs index fd20e016578..13b573beea1 100644 --- a/clippy_lints/src/lib.register_lints.rs +++ b/clippy_lints/src/lib.register_lints.rs @@ -56,6 +56,7 @@ store.register_lints(&[ await_holding_invalid::AWAIT_HOLDING_REFCELL_REF, blocks_in_if_conditions::BLOCKS_IN_IF_CONDITIONS, bool_assert_comparison::BOOL_ASSERT_COMPARISON, + bool_to_int_with_if::BOOL_TO_INT_WITH_IF, booleans::NONMINIMAL_BOOL, booleans::OVERLY_COMPLEX_BOOL_EXPR, borrow_deref_ref::BORROW_DEREF_REF, diff --git a/clippy_lints/src/lib.register_style.rs b/clippy_lints/src/lib.register_style.rs index b5cb078e7a3..05d2ec2e9e1 100644 --- a/clippy_lints/src/lib.register_style.rs +++ b/clippy_lints/src/lib.register_style.rs @@ -6,6 +6,7 @@ store.register_group(true, "clippy::style", Some("clippy_style"), vec![ LintId::of(assertions_on_constants::ASSERTIONS_ON_CONSTANTS), LintId::of(blocks_in_if_conditions::BLOCKS_IN_IF_CONDITIONS), LintId::of(bool_assert_comparison::BOOL_ASSERT_COMPARISON), + LintId::of(bool_to_int_with_if::BOOL_TO_INT_WITH_IF), LintId::of(casts::FN_TO_NUMERIC_CAST), LintId::of(casts::FN_TO_NUMERIC_CAST_WITH_TRUNCATION), LintId::of(collapsible_if::COLLAPSIBLE_ELSE_IF), diff --git a/clippy_lints/src/lib.rs b/clippy_lints/src/lib.rs index 178e57aaf61..a26e129f094 100644 --- a/clippy_lints/src/lib.rs +++ b/clippy_lints/src/lib.rs @@ -178,6 +178,7 @@ mod attrs; mod await_holding_invalid; mod blocks_in_if_conditions; mod bool_assert_comparison; +mod bool_to_int_with_if; mod booleans; mod borrow_deref_ref; mod cargo; @@ -900,6 +901,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: store.register_late_pass(|| Box::new(manual_string_new::ManualStringNew)); store.register_late_pass(|| Box::new(unused_peekable::UnusedPeekable)); store.register_early_pass(|| Box::new(multi_assignments::MultiAssignments)); + store.register_late_pass(|| Box::new(bool_to_int_with_if::BoolToIntWithIf)); // add lints here, do not remove this comment, it's used in `new_lint` } diff --git a/clippy_lints/src/matches/single_match.rs b/clippy_lints/src/matches/single_match.rs index 92091a0c339..52632e88b1b 100644 --- a/clippy_lints/src/matches/single_match.rs +++ b/clippy_lints/src/matches/single_match.rs @@ -201,12 +201,8 @@ fn form_exhaustive_matches<'a>(cx: &LateContext<'a>, ty: Ty<'a>, left: &Pat<'_>, // in the arms, so we need to evaluate the correct offsets here in order to iterate in // both arms at the same time. let len = max( - left_in.len() + { - if left_pos.is_some() { 1 } else { 0 } - }, - right_in.len() + { - if right_pos.is_some() { 1 } else { 0 } - }, + left_in.len() + usize::from(left_pos.is_some()), + right_in.len() + usize::from(right_pos.is_some()), ); let mut left_pos = left_pos.unwrap_or(usize::MAX); let mut right_pos = right_pos.unwrap_or(usize::MAX); diff --git a/clippy_lints/src/only_used_in_recursion.rs b/clippy_lints/src/only_used_in_recursion.rs index 774a3540d1e..c55478b3441 100644 --- a/clippy_lints/src/only_used_in_recursion.rs +++ b/clippy_lints/src/only_used_in_recursion.rs @@ -234,11 +234,7 @@ impl<'tcx> LateLintPass<'tcx> for OnlyUsedInRecursion { })) => ( def_id.to_def_id(), FnKind::TraitFn, - if sig.decl.implicit_self.has_implicit_self() { - 1 - } else { - 0 - }, + usize::from(sig.decl.implicit_self.has_implicit_self()), ), Some(Node::ImplItem(&ImplItem { kind: ImplItemKind::Fn(ref sig, _), @@ -253,11 +249,7 @@ impl<'tcx> LateLintPass<'tcx> for OnlyUsedInRecursion { ( trait_item_id, FnKind::ImplTraitFn(cx.tcx.erase_regions(trait_ref.substs) as *const _ as usize), - if sig.decl.implicit_self.has_implicit_self() { - 1 - } else { - 0 - }, + usize::from(sig.decl.implicit_self.has_implicit_self()), ) } else { (def_id.to_def_id(), FnKind::Fn, 0) diff --git a/tests/ui/author/struct.rs b/tests/ui/author/struct.rs index 5fdf3433a37..a99bdfc1313 100644 --- a/tests/ui/author/struct.rs +++ b/tests/ui/author/struct.rs @@ -1,4 +1,9 @@ -#[allow(clippy::unnecessary_operation, clippy::single_match)] +#![allow( + clippy::unnecessary_operation, + clippy::single_match, + clippy::no_effect, + clippy::bool_to_int_with_if +)] fn main() { struct Test { field: u32, diff --git a/tests/ui/bool_to_int_with_if.fixed b/tests/ui/bool_to_int_with_if.fixed new file mode 100644 index 00000000000..9c1098dc4c1 --- /dev/null +++ b/tests/ui/bool_to_int_with_if.fixed @@ -0,0 +1,85 @@ +// run-rustfix + +#![warn(clippy::bool_to_int_with_if)] +#![allow(unused, dead_code, clippy::unnecessary_operation, clippy::no_effect)] + +fn main() { + let a = true; + let b = false; + + let x = 1; + let y = 2; + + // Should lint + // precedence + i32::from(a); + i32::from(!a); + i32::from(a || b); + i32::from(cond(a, b)); + i32::from(x + y < 4); + + // if else if + if a { + 123 + } else {i32::from(b)}; + + // Shouldn't lint + + if a { + 1 + } else if b { + 0 + } else { + 3 + }; + + if a { + 3 + } else if b { + 1 + } else { + -2 + }; + + if a { + 3 + } else { + 0 + }; + if a { + side_effect(); + 1 + } else { + 0 + }; + if a { + 1 + } else { + side_effect(); + 0 + }; + + // multiple else ifs + if a { + 123 + } else if b { + 1 + } else if a | b { + 0 + } else { + 123 + }; + + some_fn(a); +} + +// Lint returns and type inference +fn some_fn(a: bool) -> u8 { + u8::from(a) +} + +fn side_effect() {} + +fn cond(a: bool, b: bool) -> bool { + a || b +} diff --git a/tests/ui/bool_to_int_with_if.rs b/tests/ui/bool_to_int_with_if.rs new file mode 100644 index 00000000000..0c967dac6e2 --- /dev/null +++ b/tests/ui/bool_to_int_with_if.rs @@ -0,0 +1,109 @@ +// run-rustfix + +#![warn(clippy::bool_to_int_with_if)] +#![allow(unused, dead_code, clippy::unnecessary_operation, clippy::no_effect)] + +fn main() { + let a = true; + let b = false; + + let x = 1; + let y = 2; + + // Should lint + // precedence + if a { + 1 + } else { + 0 + }; + if !a { + 1 + } else { + 0 + }; + if a || b { + 1 + } else { + 0 + }; + if cond(a, b) { + 1 + } else { + 0 + }; + if x + y < 4 { + 1 + } else { + 0 + }; + + // if else if + if a { + 123 + } else if b { + 1 + } else { + 0 + }; + + // Shouldn't lint + + if a { + 1 + } else if b { + 0 + } else { + 3 + }; + + if a { + 3 + } else if b { + 1 + } else { + -2 + }; + + if a { + 3 + } else { + 0 + }; + if a { + side_effect(); + 1 + } else { + 0 + }; + if a { + 1 + } else { + side_effect(); + 0 + }; + + // multiple else ifs + if a { + 123 + } else if b { + 1 + } else if a | b { + 0 + } else { + 123 + }; + + some_fn(a); +} + +// Lint returns and type inference +fn some_fn(a: bool) -> u8 { + if a { 1 } else { 0 } +} + +fn side_effect() {} + +fn cond(a: bool, b: bool) -> bool { + a || b +} diff --git a/tests/ui/bool_to_int_with_if.stderr b/tests/ui/bool_to_int_with_if.stderr new file mode 100644 index 00000000000..8647a9cffbe --- /dev/null +++ b/tests/ui/bool_to_int_with_if.stderr @@ -0,0 +1,84 @@ +error: boolean to int conversion using if + --> $DIR/bool_to_int_with_if.rs:15:5 + | +LL | / if a { +LL | | 1 +LL | | } else { +LL | | 0 +LL | | }; + | |_____^ help: replace with from: `i32::from(a)` + | + = note: `-D clippy::bool-to-int-with-if` implied by `-D warnings` + = note: `a as i32` or `a.into()` can also be valid options + +error: boolean to int conversion using if + --> $DIR/bool_to_int_with_if.rs:20:5 + | +LL | / if !a { +LL | | 1 +LL | | } else { +LL | | 0 +LL | | }; + | |_____^ help: replace with from: `i32::from(!a)` + | + = note: `!a as i32` or `!a.into()` can also be valid options + +error: boolean to int conversion using if + --> $DIR/bool_to_int_with_if.rs:25:5 + | +LL | / if a || b { +LL | | 1 +LL | | } else { +LL | | 0 +LL | | }; + | |_____^ help: replace with from: `i32::from(a || b)` + | + = note: `(a || b) as i32` or `(a || b).into()` can also be valid options + +error: boolean to int conversion using if + --> $DIR/bool_to_int_with_if.rs:30:5 + | +LL | / if cond(a, b) { +LL | | 1 +LL | | } else { +LL | | 0 +LL | | }; + | |_____^ help: replace with from: `i32::from(cond(a, b))` + | + = note: `cond(a, b) as i32` or `cond(a, b).into()` can also be valid options + +error: boolean to int conversion using if + --> $DIR/bool_to_int_with_if.rs:35:5 + | +LL | / if x + y < 4 { +LL | | 1 +LL | | } else { +LL | | 0 +LL | | }; + | |_____^ help: replace with from: `i32::from(x + y < 4)` + | + = note: `(x + y < 4) as i32` or `(x + y < 4).into()` can also be valid options + +error: boolean to int conversion using if + --> $DIR/bool_to_int_with_if.rs:44:12 + | +LL | } else if b { + | ____________^ +LL | | 1 +LL | | } else { +LL | | 0 +LL | | }; + | |_____^ help: replace with from: `{i32::from(b)}` + | + = note: `b as i32` or `b.into()` can also be valid options + +error: boolean to int conversion using if + --> $DIR/bool_to_int_with_if.rs:102:5 + | +LL | if a { 1 } else { 0 } + | ^^^^^^^^^^^^^^^^^^^^^ help: replace with from: `u8::from(a)` + | + = note: `a as u8` or `a.into()` can also be valid options + +error: aborting due to 7 previous errors + |