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Move cast_possible_truncation to its own module

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This commit is contained in:
Yoshitomo Nakanishi 2021-03-09 12:10:59 +09:00
parent b12d7515b1
commit 0534bf4698
2 changed files with 68 additions and 62 deletions
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54
clippy_lints/src/casts/cast_possible_truncation.rs Normal file
View File

@ -0,0 +1,54 @@
use rustc_hir::Expr;
use rustc_lint::LateContext;
use rustc_middle::ty::{self, FloatTy, Ty};
use crate::utils::{is_isize_or_usize, span_lint};
use super::{utils, CAST_POSSIBLE_TRUNCATION};
pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, cast_from: Ty<'_>, cast_to: Ty<'_>) {
let msg = match (cast_from.is_integral(), cast_to.is_integral()) {
(true, true) => {
let from_nbits = utils::int_ty_to_nbits(cast_from, cx.tcx);
let to_nbits = utils::int_ty_to_nbits(cast_to, cx.tcx);
let (should_lint, suffix) = match (is_isize_or_usize(cast_from), is_isize_or_usize(cast_to)) {
(true, true) | (false, false) => (to_nbits < from_nbits, ""),
(true, false) => (
to_nbits <= 32,
if to_nbits == 32 {
" on targets with 64-bit wide pointers"
} else {
""
},
),
(false, true) => (from_nbits == 64, " on targets with 32-bit wide pointers"),
};
if !should_lint {
return;
}
format!(
"casting `{}` to `{}` may truncate the value{}",
cast_from, cast_to, suffix,
)
},
(false, true) => {
format!("casting `{}` to `{}` may truncate the value", cast_from, cast_to)
},
(_, _) => {
if matches!(cast_from.kind(), &ty::Float(FloatTy::F64))
&& matches!(cast_to.kind(), &ty::Float(FloatTy::F32))
{
"casting `f64` to `f32` may truncate the value".to_string()
} else {
return;
}
},
};
span_lint(cx, CAST_POSSIBLE_TRUNCATION, expr.span, &msg);
}

76
clippy_lints/src/casts/mod.rs
View File

@ -1,4 +1,5 @@
mod cast_lossless;
mod cast_possible_truncation;
mod cast_precision_loss;
mod utils;
@ -312,52 +313,18 @@ fn check_truncation_and_wrapping(cx: &LateContext<'_>, expr: &Expr<'_>, cast_fro
let cast_unsigned_to_signed = !cast_from.is_signed() && cast_to.is_signed();
let from_nbits = int_ty_to_nbits(cast_from, cx.tcx);
let to_nbits = int_ty_to_nbits(cast_to, cx.tcx);
let (span_truncation, suffix_truncation, span_wrap, suffix_wrap) =
match (is_isize_or_usize(cast_from), is_isize_or_usize(cast_to)) {
(true, true) | (false, false) => (
to_nbits < from_nbits,
ArchSuffix::None,
to_nbits == from_nbits && cast_unsigned_to_signed,
ArchSuffix::None,
),
(true, false) => (
to_nbits <= 32,
if to_nbits == 32 {
ArchSuffix::_64
} else {
ArchSuffix::None
},
to_nbits <= 32 && cast_unsigned_to_signed,
ArchSuffix::_32,
),
(false, true) => (
from_nbits == 64,
ArchSuffix::_32,
cast_unsigned_to_signed,
if from_nbits == 64 {
ArchSuffix::_64
} else {
ArchSuffix::_32
},
),
};
if span_truncation {
span_lint(
cx,
CAST_POSSIBLE_TRUNCATION,
expr.span,
&format!(
"casting `{}` to `{}` may truncate the value{}",
cast_from,
cast_to,
match suffix_truncation {
ArchSuffix::_32 => arch_32_suffix,
ArchSuffix::_64 => arch_64_suffix,
ArchSuffix::None => "",
}
),
);
}
let (span_wrap, suffix_wrap) = match (is_isize_or_usize(cast_from), is_isize_or_usize(cast_to)) {
(true, true) | (false, false) => (to_nbits == from_nbits && cast_unsigned_to_signed, ArchSuffix::None),
(true, false) => (to_nbits <= 32 && cast_unsigned_to_signed, ArchSuffix::_32),
(false, true) => (
cast_unsigned_to_signed,
if from_nbits == 64 {
ArchSuffix::_64
} else {
ArchSuffix::_32
},
),
};
if span_wrap {
span_lint(
cx,
@ -529,14 +496,9 @@ fn lint_numeric_casts<'tcx>(
) {
cast_precision_loss::check(cx, expr, cast_from, cast_to);
cast_lossless::check(cx, expr, cast_expr, cast_from, cast_to);
cast_possible_truncation::check(cx, expr, cast_from, cast_to);
match (cast_from.is_integral(), cast_to.is_integral()) {
(false, true) => {
span_lint(
cx,
CAST_POSSIBLE_TRUNCATION,
expr.span,
&format!("casting `{}` to `{}` may truncate the value", cast_from, cast_to),
);
if !cast_to.is_signed() {
span_lint(
cx,
@ -553,16 +515,6 @@ fn lint_numeric_casts<'tcx>(
check_loss_of_sign(cx, expr, cast_expr, cast_from, cast_to);
check_truncation_and_wrapping(cx, expr, cast_from, cast_to);
},
(false, false) => {
if let (&ty::Float(FloatTy::F64), &ty::Float(FloatTy::F32)) = (&cast_from.kind(), &cast_to.kind()) {
span_lint(
cx,
CAST_POSSIBLE_TRUNCATION,
expr.span,
"casting `f64` to `f32` may truncate the value",
);
}
},
(_, _) => {},
}
}