diff options
| -rw-r--r-- | clippy_lints/src/casts/cast_possible_truncation.rs | 42 | ||||
| -rw-r--r-- | tests/ui/cast.rs | 6 | ||||
| -rw-r--r-- | tests/ui/cast.stderr | 112 |
3 files changed, 100 insertions, 60 deletions
diff --git a/clippy_lints/src/casts/cast_possible_truncation.rs b/clippy_lints/src/casts/cast_possible_truncation.rs index 823970e35ab..95c2ecbf791 100644 --- a/clippy_lints/src/casts/cast_possible_truncation.rs +++ b/clippy_lints/src/casts/cast_possible_truncation.rs @@ -2,8 +2,9 @@ use clippy_utils::consts::{constant, Constant}; use clippy_utils::diagnostics::{span_lint, span_lint_and_then}; use clippy_utils::expr_or_init; use clippy_utils::source::snippet; +use clippy_utils::sugg::Sugg; use clippy_utils::ty::{get_discriminant_value, is_isize_or_usize}; -use rustc_errors::{Applicability, SuggestionStyle}; +use rustc_errors::{Applicability, Diagnostic, SuggestionStyle}; use rustc_hir::def::{DefKind, Res}; use rustc_hir::{BinOpKind, Expr, ExprKind}; use rustc_lint::LateContext; @@ -163,19 +164,34 @@ pub(super) fn check( _ => return, }; - let name_of_cast_from = snippet(cx, cast_expr.span, ".."); - let cast_to_snip = snippet(cx, cast_to_span, ".."); - let suggestion = format!("{cast_to_snip}::try_from({name_of_cast_from})"); - span_lint_and_then(cx, CAST_POSSIBLE_TRUNCATION, expr.span, &msg, |diag| { diag.help("if this is intentional allow the lint with `#[allow(clippy::cast_possible_truncation)]` ..."); - diag.span_suggestion_with_style( - expr.span, - "... or use `try_from` and handle the error accordingly", - suggestion, - Applicability::Unspecified, - // always show the suggestion in a separate line - SuggestionStyle::ShowAlways, - ); + if !cast_from.is_floating_point() { + offer_suggestion(cx, expr, cast_expr, cast_to_span, diag); + } }); } + +fn offer_suggestion( + cx: &LateContext<'_>, + expr: &Expr<'_>, + cast_expr: &Expr<'_>, + cast_to_span: Span, + diag: &mut Diagnostic, +) { + let cast_to_snip = snippet(cx, cast_to_span, ".."); + let suggestion = if cast_to_snip == "_" { + format!("{}.try_into()", Sugg::hir(cx, cast_expr, "..").maybe_par()) + } else { + format!("{cast_to_snip}::try_from({})", Sugg::hir(cx, cast_expr, "..")) + }; + + diag.span_suggestion_with_style( + expr.span, + "... or use `try_from` and handle the error accordingly", + suggestion, + Applicability::Unspecified, + // always show the suggestion in a separate line + SuggestionStyle::ShowAlways, + ); +} diff --git a/tests/ui/cast.rs b/tests/ui/cast.rs index 8b2673c2a7f..a86b85706a3 100644 --- a/tests/ui/cast.rs +++ b/tests/ui/cast.rs @@ -29,6 +29,12 @@ fn main() { 1f64 as isize; 1f64 as usize; 1f32 as u32 as u16; + { + let _x: i8 = 1i32 as _; + 1f32 as i32; + 1f64 as i32; + 1f32 as u8; + } // Test clippy::cast_possible_wrap 1u8 as i8; 1u16 as i16; diff --git a/tests/ui/cast.stderr b/tests/ui/cast.stderr index 451078de23b..65ecf1aa37a 100644 --- a/tests/ui/cast.stderr +++ b/tests/ui/cast.stderr @@ -44,10 +44,6 @@ LL | 1f32 as i32; | = help: if this is intentional allow the lint with `#[allow(clippy::cast_possible_truncation)]` ... = note: `-D clippy::cast-possible-truncation` implied by `-D warnings` -help: ... or use `try_from` and handle the error accordingly - | -LL | i32::try_from(1f32); - | ~~~~~~~~~~~~~~~~~~~ error: casting `f32` to `u32` may truncate the value --> $DIR/cast.rs:25:5 @@ -56,10 +52,6 @@ LL | 1f32 as u32; | ^^^^^^^^^^^ | = help: if this is intentional allow the lint with `#[allow(clippy::cast_possible_truncation)]` ... -help: ... or use `try_from` and handle the error accordingly - | -LL | u32::try_from(1f32); - | ~~~~~~~~~~~~~~~~~~~ error: casting `f32` to `u32` may lose the sign of the value --> $DIR/cast.rs:25:5 @@ -76,10 +68,6 @@ LL | 1f64 as f32; | ^^^^^^^^^^^ | = help: if this is intentional allow the lint with `#[allow(clippy::cast_possible_truncation)]` ... -help: ... or use `try_from` and handle the error accordingly - | -LL | f32::try_from(1f64); - | ~~~~~~~~~~~~~~~~~~~ error: casting `i32` to `i8` may truncate the value --> $DIR/cast.rs:27:5 @@ -112,10 +100,6 @@ LL | 1f64 as isize; | ^^^^^^^^^^^^^ | = help: if this is intentional allow the lint with `#[allow(clippy::cast_possible_truncation)]` ... -help: ... or use `try_from` and handle the error accordingly - | -LL | isize::try_from(1f64); - | ~~~~~~~~~~~~~~~~~~~~~ error: casting `f64` to `usize` may truncate the value --> $DIR/cast.rs:30:5 @@ -124,10 +108,6 @@ LL | 1f64 as usize; | ^^^^^^^^^^^^^ | = help: if this is intentional allow the lint with `#[allow(clippy::cast_possible_truncation)]` ... -help: ... or use `try_from` and handle the error accordingly - | -LL | usize::try_from(1f64); - | ~~~~~~~~~~~~~~~~~~~~~ error: casting `f64` to `usize` may lose the sign of the value --> $DIR/cast.rs:30:5 @@ -154,10 +134,6 @@ LL | 1f32 as u32 as u16; | ^^^^^^^^^^^ | = help: if this is intentional allow the lint with `#[allow(clippy::cast_possible_truncation)]` ... -help: ... or use `try_from` and handle the error accordingly - | -LL | u32::try_from(1f32) as u16; - | ~~~~~~~~~~~~~~~~~~~ error: casting `f32` to `u32` may lose the sign of the value --> $DIR/cast.rs:31:5 @@ -165,8 +141,50 @@ error: casting `f32` to `u32` may lose the sign of the value LL | 1f32 as u32 as u16; | ^^^^^^^^^^^ +error: casting `i32` to `i8` may truncate the value + --> $DIR/cast.rs:33:22 + | +LL | let _x: i8 = 1i32 as _; + | ^^^^^^^^^ + | + = help: if this is intentional allow the lint with `#[allow(clippy::cast_possible_truncation)]` ... +help: ... or use `try_from` and handle the error accordingly + | +LL | let _x: i8 = 1i32.try_into(); + | ~~~~~~~~~~~~~~~ + +error: casting `f32` to `i32` may truncate the value + --> $DIR/cast.rs:34:9 + | +LL | 1f32 as i32; + | ^^^^^^^^^^^ + | + = help: if this is intentional allow the lint with `#[allow(clippy::cast_possible_truncation)]` ... + +error: casting `f64` to `i32` may truncate the value + --> $DIR/cast.rs:35:9 + | +LL | 1f64 as i32; + | ^^^^^^^^^^^ + | + = help: if this is intentional allow the lint with `#[allow(clippy::cast_possible_truncation)]` ... + +error: casting `f32` to `u8` may truncate the value + --> $DIR/cast.rs:36:9 + | +LL | 1f32 as u8; + | ^^^^^^^^^^ + | + = help: if this is intentional allow the lint with `#[allow(clippy::cast_possible_truncation)]` ... + +error: casting `f32` to `u8` may lose the sign of the value + --> $DIR/cast.rs:36:9 + | +LL | 1f32 as u8; + | ^^^^^^^^^^ + error: casting `u8` to `i8` may wrap around the value - --> $DIR/cast.rs:33:5 + --> $DIR/cast.rs:39:5 | LL | 1u8 as i8; | ^^^^^^^^^ @@ -174,43 +192,43 @@ LL | 1u8 as i8; = note: `-D clippy::cast-possible-wrap` implied by `-D warnings` error: casting `u16` to `i16` may wrap around the value - --> $DIR/cast.rs:34:5 + --> $DIR/cast.rs:40:5 | LL | 1u16 as i16; | ^^^^^^^^^^^ error: casting `u32` to `i32` may wrap around the value - --> $DIR/cast.rs:35:5 + --> $DIR/cast.rs:41:5 | LL | 1u32 as i32; | ^^^^^^^^^^^ error: casting `u64` to `i64` may wrap around the value - --> $DIR/cast.rs:36:5 + --> $DIR/cast.rs:42:5 | LL | 1u64 as i64; | ^^^^^^^^^^^ error: casting `usize` to `isize` may wrap around the value - --> $DIR/cast.rs:37:5 + --> $DIR/cast.rs:43:5 | LL | 1usize as isize; | ^^^^^^^^^^^^^^^ error: casting `i32` to `u32` may lose the sign of the value - --> $DIR/cast.rs:40:5 + --> $DIR/cast.rs:46:5 | LL | -1i32 as u32; | ^^^^^^^^^^^^ error: casting `isize` to `usize` may lose the sign of the value - --> $DIR/cast.rs:42:5 + --> $DIR/cast.rs:48:5 | LL | -1isize as usize; | ^^^^^^^^^^^^^^^^ error: casting `i64` to `i8` may truncate the value - --> $DIR/cast.rs:109:5 + --> $DIR/cast.rs:115:5 | LL | (-99999999999i64).min(1) as i8; // should be linted because signed | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -222,7 +240,7 @@ LL | i8::try_from((-99999999999i64).min(1)); // should be linted because sig | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ error: casting `u64` to `u8` may truncate the value - --> $DIR/cast.rs:121:5 + --> $DIR/cast.rs:127:5 | LL | 999999u64.clamp(0, 256) as u8; // should still be linted | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -234,7 +252,7 @@ LL | u8::try_from(999999u64.clamp(0, 256)); // should still be linted | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ error: casting `main::E2` to `u8` may truncate the value - --> $DIR/cast.rs:142:21 + --> $DIR/cast.rs:148:21 | LL | let _ = self as u8; | ^^^^^^^^^^ @@ -246,7 +264,7 @@ LL | let _ = u8::try_from(self); | ~~~~~~~~~~~~~~~~~~ error: casting `main::E2::B` to `u8` will truncate the value - --> $DIR/cast.rs:143:21 + --> $DIR/cast.rs:149:21 | LL | let _ = Self::B as u8; | ^^^^^^^^^^^^^ @@ -254,7 +272,7 @@ LL | let _ = Self::B as u8; = note: `-D clippy::cast-enum-truncation` implied by `-D warnings` error: casting `main::E5` to `i8` may truncate the value - --> $DIR/cast.rs:179:21 + --> $DIR/cast.rs:185:21 | LL | let _ = self as i8; | ^^^^^^^^^^ @@ -266,13 +284,13 @@ LL | let _ = i8::try_from(self); | ~~~~~~~~~~~~~~~~~~ error: casting `main::E5::A` to `i8` will truncate the value - --> $DIR/cast.rs:180:21 + --> $DIR/cast.rs:186:21 | LL | let _ = Self::A as i8; | ^^^^^^^^^^^^^ error: casting `main::E6` to `i16` may truncate the value - --> $DIR/cast.rs:194:21 + --> $DIR/cast.rs:200:21 | LL | let _ = self as i16; | ^^^^^^^^^^^ @@ -284,7 +302,7 @@ LL | let _ = i16::try_from(self); | ~~~~~~~~~~~~~~~~~~~ error: casting `main::E7` to `usize` may truncate the value on targets with 32-bit wide pointers - --> $DIR/cast.rs:209:21 + --> $DIR/cast.rs:215:21 | LL | let _ = self as usize; | ^^^^^^^^^^^^^ @@ -296,7 +314,7 @@ LL | let _ = usize::try_from(self); | ~~~~~~~~~~~~~~~~~~~~~ error: casting `main::E10` to `u16` may truncate the value - --> $DIR/cast.rs:250:21 + --> $DIR/cast.rs:256:21 | LL | let _ = self as u16; | ^^^^^^^^^^^ @@ -308,7 +326,7 @@ LL | let _ = u16::try_from(self); | ~~~~~~~~~~~~~~~~~~~ error: casting `u32` to `u8` may truncate the value - --> $DIR/cast.rs:258:13 + --> $DIR/cast.rs:264:13 | LL | let c = (q >> 16) as u8; | ^^^^^^^^^^^^^^^ @@ -316,11 +334,11 @@ LL | let c = (q >> 16) as u8; = help: if this is intentional allow the lint with `#[allow(clippy::cast_possible_truncation)]` ... help: ... or use `try_from` and handle the error accordingly | -LL | let c = u8::try_from((q >> 16)); - | ~~~~~~~~~~~~~~~~~~~~~~~ +LL | let c = u8::try_from(q >> 16); + | ~~~~~~~~~~~~~~~~~~~~~ error: casting `u32` to `u8` may truncate the value - --> $DIR/cast.rs:261:13 + --> $DIR/cast.rs:267:13 | LL | let c = (q / 1000) as u8; | ^^^^^^^^^^^^^^^^ @@ -328,8 +346,8 @@ LL | let c = (q / 1000) as u8; = help: if this is intentional allow the lint with `#[allow(clippy::cast_possible_truncation)]` ... help: ... or use `try_from` and handle the error accordingly | -LL | let c = u8::try_from((q / 1000)); - | ~~~~~~~~~~~~~~~~~~~~~~~~ +LL | let c = u8::try_from(q / 1000); + | ~~~~~~~~~~~~~~~~~~~~~~ -error: aborting due to 36 previous errors +error: aborting due to 41 previous errors |