diff options
| -rw-r--r-- | clippy_lints/src/types.rs | 66 | ||||
| -rw-r--r-- | tests/ui/cast_size_32bit.stderr | 2 | ||||
| -rw-r--r-- | tests/ui/eq_op.rs | 1 | ||||
| -rw-r--r-- | tests/ui/eq_op.stderr | 54 | ||||
| -rw-r--r-- | tests/ui/unnecessary_cast_fixable.fixed | 19 | ||||
| -rw-r--r-- | tests/ui/unnecessary_cast_fixable.rs | 19 | ||||
| -rw-r--r-- | tests/ui/unnecessary_cast_fixable.stderr | 74 |
7 files changed, 190 insertions, 45 deletions
diff --git a/clippy_lints/src/types.rs b/clippy_lints/src/types.rs index 9a948af8bfc..6a33aaaaab2 100644 --- a/clippy_lints/src/types.rs +++ b/clippy_lints/src/types.rs @@ -11,7 +11,7 @@ use rustc_hir as hir; use rustc_hir::intravisit::{walk_body, walk_expr, walk_ty, FnKind, NestedVisitorMap, Visitor}; use rustc_hir::{ BinOpKind, Block, Body, Expr, ExprKind, FnDecl, FnRetTy, FnSig, GenericArg, GenericParamKind, HirId, ImplItem, - ImplItemKind, Item, ItemKind, Lifetime, Local, MatchSource, MutTy, Mutability, Node, QPath, Stmt, StmtKind, + ImplItemKind, Item, ItemKind, Lifetime, Lit, Local, MatchSource, MutTy, Mutability, Node, QPath, Stmt, StmtKind, TraitFn, TraitItem, TraitItemKind, TyKind, UnOp, }; use rustc_lint::{LateContext, LateLintPass, LintContext}; @@ -1224,7 +1224,8 @@ declare_clippy_lint! { } declare_clippy_lint! { - /// **What it does:** Checks for casts to the same type. + /// **What it does:** Checks for casts to the same type, casts of int literals to integer types + /// and casts of float literals to float types. /// /// **Why is this bad?** It's just unnecessary. /// @@ -1233,6 +1234,14 @@ declare_clippy_lint! { /// **Example:** /// ```rust /// let _ = 2i32 as i32; + /// let _ = 0.5 as f32; + /// ``` + /// + /// Better: + /// + /// ```rust + /// let _ = 2_i32; + /// let _ = 0.5_f32; /// ``` pub UNNECESSARY_CAST, complexity, @@ -1598,7 +1607,9 @@ impl<'tcx> LateLintPass<'tcx> for Casts { if let ExprKind::Cast(ref ex, _) = expr.kind { let (cast_from, cast_to) = (cx.typeck_results().expr_ty(ex), cx.typeck_results().expr_ty(expr)); lint_fn_to_numeric_cast(cx, expr, ex, cast_from, cast_to); - if let ExprKind::Lit(ref lit) = ex.kind { + if let Some(lit) = get_numeric_literal(ex) { + let literal_str = snippet_opt(cx, ex.span).unwrap_or_default(); + if_chain! { if let LitKind::Int(n, _) = lit.node; if let Some(src) = snippet_opt(cx, lit.span); @@ -1608,19 +1619,19 @@ impl<'tcx> LateLintPass<'tcx> for Casts { let to_nbits = fp_ty_mantissa_nbits(cast_to); if from_nbits != 0 && to_nbits != 0 && from_nbits <= to_nbits && num_lit.is_decimal(); then { - span_lint_and_sugg( - cx, - UNNECESSARY_CAST, - expr.span, - &format!("casting integer literal to `{}` is unnecessary", cast_to), - "try", - format!("{}_{}", n, cast_to), - Applicability::MachineApplicable, - ); + let literal_str = if is_unary_neg(ex) { format!("-{}", num_lit.integer) } else { num_lit.integer.into() }; + show_unnecessary_cast(cx, expr, &literal_str, cast_from, cast_to); return; } } + match lit.node { + LitKind::Int(_, LitIntType::Unsuffixed) if cast_to.is_integral() => { + show_unnecessary_cast(cx, expr, &literal_str, cast_from, cast_to); + }, + LitKind::Float(_, LitFloatType::Unsuffixed) if cast_to.is_floating_point() => { + show_unnecessary_cast(cx, expr, &literal_str, cast_from, cast_to); + }, LitKind::Int(_, LitIntType::Unsuffixed) | LitKind::Float(_, LitFloatType::Unsuffixed) => {}, _ => { if cast_from.kind() == cast_to.kind() && !in_external_macro(cx.sess(), expr.span) { @@ -1646,6 +1657,37 @@ impl<'tcx> LateLintPass<'tcx> for Casts { } } +fn is_unary_neg(expr: &Expr<'_>) -> bool { + matches!(expr.kind, ExprKind::Unary(UnOp::UnNeg, _)) +} + +fn get_numeric_literal<'e>(expr: &'e Expr<'e>) -> Option<&'e Lit> { + match expr.kind { + ExprKind::Lit(ref lit) => Some(lit), + ExprKind::Unary(UnOp::UnNeg, e) => { + if let ExprKind::Lit(ref lit) = e.kind { + Some(lit) + } else { + None + } + }, + _ => None, + } +} + +fn show_unnecessary_cast(cx: &LateContext<'_>, expr: &Expr<'_>, literal_str: &str, cast_from: Ty<'_>, cast_to: Ty<'_>) { + let literal_kind_name = if cast_from.is_integral() { "integer" } else { "float" }; + span_lint_and_sugg( + cx, + UNNECESSARY_CAST, + expr.span, + &format!("casting {} literal to `{}` is unnecessary", literal_kind_name, cast_to), + "try", + format!("{}_{}", literal_str, cast_to), + Applicability::MachineApplicable, + ); +} + fn lint_numeric_casts<'tcx>( cx: &LateContext<'tcx>, expr: &Expr<'tcx>, diff --git a/tests/ui/cast_size_32bit.stderr b/tests/ui/cast_size_32bit.stderr index 2eec51895f5..140676a5ffc 100644 --- a/tests/ui/cast_size_32bit.stderr +++ b/tests/ui/cast_size_32bit.stderr @@ -124,7 +124,7 @@ error: casting integer literal to `f64` is unnecessary --> $DIR/cast_size_32bit.rs:34:5 | LL | 3_999_999_999usize as f64; - | ^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `3999999999_f64` + | ^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `3_999_999_999_f64` | = note: `-D clippy::unnecessary-cast` implied by `-D warnings` diff --git a/tests/ui/eq_op.rs b/tests/ui/eq_op.rs index 272b0900a31..4e09d19ea21 100644 --- a/tests/ui/eq_op.rs +++ b/tests/ui/eq_op.rs @@ -6,6 +6,7 @@ #[allow(clippy::no_effect, unused_variables, clippy::unnecessary_operation, clippy::short_circuit_statement)] #[allow(clippy::nonminimal_bool)] #[allow(unused)] +#[allow(clippy::unnecessary_cast)] fn main() { // simple values and comparisons 1 == 1; diff --git a/tests/ui/eq_op.stderr b/tests/ui/eq_op.stderr index 5b80e6078ee..ad81b35a766 100644 --- a/tests/ui/eq_op.stderr +++ b/tests/ui/eq_op.stderr @@ -1,5 +1,5 @@ error: equal expressions as operands to `==` - --> $DIR/eq_op.rs:11:5 + --> $DIR/eq_op.rs:12:5 | LL | 1 == 1; | ^^^^^^ @@ -7,157 +7,157 @@ LL | 1 == 1; = note: `-D clippy::eq-op` implied by `-D warnings` error: equal expressions as operands to `==` - --> $DIR/eq_op.rs:12:5 + --> $DIR/eq_op.rs:13:5 | LL | "no" == "no"; | ^^^^^^^^^^^^ error: equal expressions as operands to `!=` - --> $DIR/eq_op.rs:14:5 + --> $DIR/eq_op.rs:15:5 | LL | false != false; | ^^^^^^^^^^^^^^ error: equal expressions as operands to `<` - --> $DIR/eq_op.rs:15:5 + --> $DIR/eq_op.rs:16:5 | LL | 1.5 < 1.5; | ^^^^^^^^^ error: equal expressions as operands to `>=` - --> $DIR/eq_op.rs:16:5 + --> $DIR/eq_op.rs:17:5 | LL | 1u64 >= 1u64; | ^^^^^^^^^^^^ error: equal expressions as operands to `&` - --> $DIR/eq_op.rs:19:5 + --> $DIR/eq_op.rs:20:5 | LL | (1 as u64) & (1 as u64); | ^^^^^^^^^^^^^^^^^^^^^^^ error: equal expressions as operands to `^` - --> $DIR/eq_op.rs:20:5 + --> $DIR/eq_op.rs:21:5 | LL | 1 ^ ((((((1)))))); | ^^^^^^^^^^^^^^^^^ error: equal expressions as operands to `<` - --> $DIR/eq_op.rs:23:5 + --> $DIR/eq_op.rs:24:5 | LL | (-(2) < -(2)); | ^^^^^^^^^^^^^ error: equal expressions as operands to `==` - --> $DIR/eq_op.rs:24:5 + --> $DIR/eq_op.rs:25:5 | LL | ((1 + 1) & (1 + 1) == (1 + 1) & (1 + 1)); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: equal expressions as operands to `&` - --> $DIR/eq_op.rs:24:6 + --> $DIR/eq_op.rs:25:6 | LL | ((1 + 1) & (1 + 1) == (1 + 1) & (1 + 1)); | ^^^^^^^^^^^^^^^^^ error: equal expressions as operands to `&` - --> $DIR/eq_op.rs:24:27 + --> $DIR/eq_op.rs:25:27 | LL | ((1 + 1) & (1 + 1) == (1 + 1) & (1 + 1)); | ^^^^^^^^^^^^^^^^^ error: equal expressions as operands to `==` - --> $DIR/eq_op.rs:25:5 + --> $DIR/eq_op.rs:26:5 | LL | (1 * 2) + (3 * 4) == 1 * 2 + 3 * 4; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: equal expressions as operands to `!=` - --> $DIR/eq_op.rs:28:5 + --> $DIR/eq_op.rs:29:5 | LL | ([1] != [1]); | ^^^^^^^^^^^^ error: equal expressions as operands to `!=` - --> $DIR/eq_op.rs:29:5 + --> $DIR/eq_op.rs:30:5 | LL | ((1, 2) != (1, 2)); | ^^^^^^^^^^^^^^^^^^ error: equal expressions as operands to `==` - --> $DIR/eq_op.rs:33:5 + --> $DIR/eq_op.rs:34:5 | LL | 1 + 1 == 2; | ^^^^^^^^^^ error: equal expressions as operands to `==` - --> $DIR/eq_op.rs:34:5 + --> $DIR/eq_op.rs:35:5 | LL | 1 - 1 == 0; | ^^^^^^^^^^ error: equal expressions as operands to `-` - --> $DIR/eq_op.rs:34:5 + --> $DIR/eq_op.rs:35:5 | LL | 1 - 1 == 0; | ^^^^^ error: equal expressions as operands to `-` - --> $DIR/eq_op.rs:36:5 + --> $DIR/eq_op.rs:37:5 | LL | 1 - 1; | ^^^^^ error: equal expressions as operands to `/` - --> $DIR/eq_op.rs:37:5 + --> $DIR/eq_op.rs:38:5 | LL | 1 / 1; | ^^^^^ error: equal expressions as operands to `&&` - --> $DIR/eq_op.rs:38:5 + --> $DIR/eq_op.rs:39:5 | LL | true && true; | ^^^^^^^^^^^^ error: equal expressions as operands to `||` - --> $DIR/eq_op.rs:40:5 + --> $DIR/eq_op.rs:41:5 | LL | true || true; | ^^^^^^^^^^^^ error: equal expressions as operands to `&&` - --> $DIR/eq_op.rs:46:5 + --> $DIR/eq_op.rs:47:5 | LL | a == b && b == a; | ^^^^^^^^^^^^^^^^ error: equal expressions as operands to `&&` - --> $DIR/eq_op.rs:47:5 + --> $DIR/eq_op.rs:48:5 | LL | a != b && b != a; | ^^^^^^^^^^^^^^^^ error: equal expressions as operands to `&&` - --> $DIR/eq_op.rs:48:5 + --> $DIR/eq_op.rs:49:5 | LL | a < b && b > a; | ^^^^^^^^^^^^^^ error: equal expressions as operands to `&&` - --> $DIR/eq_op.rs:49:5 + --> $DIR/eq_op.rs:50:5 | LL | a <= b && b >= a; | ^^^^^^^^^^^^^^^^ error: equal expressions as operands to `==` - --> $DIR/eq_op.rs:52:5 + --> $DIR/eq_op.rs:53:5 | LL | a == a; | ^^^^^^ error: equal expressions as operands to `/` - --> $DIR/eq_op.rs:62:20 + --> $DIR/eq_op.rs:63:20 | LL | const D: u32 = A / A; | ^^^^^ diff --git a/tests/ui/unnecessary_cast_fixable.fixed b/tests/ui/unnecessary_cast_fixable.fixed index fb89a9fce3d..350da4965d1 100644 --- a/tests/ui/unnecessary_cast_fixable.fixed +++ b/tests/ui/unnecessary_cast_fixable.fixed @@ -8,16 +8,31 @@ fn main() { 100_f32; 100_f64; 100_f64; + let _ = -100_f32; + let _ = -100_f64; + let _ = -100_f64; // Should not trigger #[rustfmt::skip] let v = vec!(1); &v as &[i32]; - 1.0 as f64; - 1 as u64; 0x10 as f32; 0o10 as f32; 0b10 as f32; 0x11 as f64; 0o11 as f64; 0b11 as f64; + + 1_u32; + 0x10_i32; + 0b10_usize; + 0o73_u16; + 1_000_000_000_u32; + + 1.0_f64; + 0.5_f32; + + 1.0 as u16; + + let _ = -1_i32; + let _ = -1.0_f32; } diff --git a/tests/ui/unnecessary_cast_fixable.rs b/tests/ui/unnecessary_cast_fixable.rs index 4a0c8620dc1..ad2fb2e6289 100644 --- a/tests/ui/unnecessary_cast_fixable.rs +++ b/tests/ui/unnecessary_cast_fixable.rs @@ -8,16 +8,31 @@ fn main() { 100 as f32; 100 as f64; 100_i32 as f64; + let _ = -100 as f32; + let _ = -100 as f64; + let _ = -100_i32 as f64; // Should not trigger #[rustfmt::skip] let v = vec!(1); &v as &[i32]; - 1.0 as f64; - 1 as u64; 0x10 as f32; 0o10 as f32; 0b10 as f32; 0x11 as f64; 0o11 as f64; 0b11 as f64; + + 1 as u32; + 0x10 as i32; + 0b10 as usize; + 0o73 as u16; + 1_000_000_000 as u32; + + 1.0 as f64; + 0.5 as f32; + + 1.0 as u16; + + let _ = -1 as i32; + let _ = -1.0 as f32; } diff --git a/tests/ui/unnecessary_cast_fixable.stderr b/tests/ui/unnecessary_cast_fixable.stderr index 8ff1e5dea60..5a210fc8909 100644 --- a/tests/ui/unnecessary_cast_fixable.stderr +++ b/tests/ui/unnecessary_cast_fixable.stderr @@ -18,5 +18,77 @@ error: casting integer literal to `f64` is unnecessary LL | 100_i32 as f64; | ^^^^^^^^^^^^^^ help: try: `100_f64` -error: aborting due to 3 previous errors +error: casting integer literal to `f32` is unnecessary + --> $DIR/unnecessary_cast_fixable.rs:11:13 + | +LL | let _ = -100 as f32; + | ^^^^^^^^^^^ help: try: `-100_f32` + +error: casting integer literal to `f64` is unnecessary + --> $DIR/unnecessary_cast_fixable.rs:12:13 + | +LL | let _ = -100 as f64; + | ^^^^^^^^^^^ help: try: `-100_f64` + +error: casting integer literal to `f64` is unnecessary + --> $DIR/unnecessary_cast_fixable.rs:13:13 + | +LL | let _ = -100_i32 as f64; + | ^^^^^^^^^^^^^^^ help: try: `-100_f64` + +error: casting integer literal to `u32` is unnecessary + --> $DIR/unnecessary_cast_fixable.rs:25:5 + | +LL | 1 as u32; + | ^^^^^^^^ help: try: `1_u32` + +error: casting integer literal to `i32` is unnecessary + --> $DIR/unnecessary_cast_fixable.rs:26:5 + | +LL | 0x10 as i32; + | ^^^^^^^^^^^ help: try: `0x10_i32` + +error: casting integer literal to `usize` is unnecessary + --> $DIR/unnecessary_cast_fixable.rs:27:5 + | +LL | 0b10 as usize; + | ^^^^^^^^^^^^^ help: try: `0b10_usize` + +error: casting integer literal to `u16` is unnecessary + --> $DIR/unnecessary_cast_fixable.rs:28:5 + | +LL | 0o73 as u16; + | ^^^^^^^^^^^ help: try: `0o73_u16` + +error: casting integer literal to `u32` is unnecessary + --> $DIR/unnecessary_cast_fixable.rs:29:5 + | +LL | 1_000_000_000 as u32; + | ^^^^^^^^^^^^^^^^^^^^ help: try: `1_000_000_000_u32` + +error: casting float literal to `f64` is unnecessary + --> $DIR/unnecessary_cast_fixable.rs:31:5 + | +LL | 1.0 as f64; + | ^^^^^^^^^^ help: try: `1.0_f64` + +error: casting float literal to `f32` is unnecessary + --> $DIR/unnecessary_cast_fixable.rs:32:5 + | +LL | 0.5 as f32; + | ^^^^^^^^^^ help: try: `0.5_f32` + +error: casting integer literal to `i32` is unnecessary + --> $DIR/unnecessary_cast_fixable.rs:36:13 + | +LL | let _ = -1 as i32; + | ^^^^^^^^^ help: try: `-1_i32` + +error: casting float literal to `f32` is unnecessary + --> $DIR/unnecessary_cast_fixable.rs:37:13 + | +LL | let _ = -1.0 as f32; + | ^^^^^^^^^^^ help: try: `-1.0_f32` + +error: aborting due to 15 previous errors |