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Resolve false positives for hex int cast.

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mlegner 2020-03-02 22:44:32 +01:00
parent 9ff4581cd3
commit 6673cc8329
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2 changed files with 29 additions and 18 deletions
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14
clippy_lints/src/literal_representation.rs
View file

@ -131,7 +131,7 @@ pub fn format_numeric_literal(lit: &str, type_suffix: Option<&str>, float: bool)
#[derive(Debug)]
pub(super) struct NumericLiteral<'a> {
/// Which radix the literal was represented in.
radix: Radix,
pub radix: Radix,
/// The radix prefix, if present.
prefix: Option<&'a str>,
@ -147,16 +147,20 @@ pub(super) struct NumericLiteral<'a> {
}
impl<'a> NumericLiteral<'a> {
fn from_lit(src: &'a str, lit: &Lit) -> Option<NumericLiteral<'a>> {
if lit.kind.is_numeric() && src.chars().next().map_or(false, |c| c.is_digit(10)) {
let (unsuffixed, suffix) = split_suffix(&src, &lit.kind);
let float = if let LitKind::Float(..) = lit.kind { true } else { false };
pub fn from_lit_kind(src: &'a str, lit_kind: &LitKind) -> Option<NumericLiteral<'a>> {
if lit_kind.is_numeric() && src.chars().next().map_or(false, |c| c.is_digit(10)) {
let (unsuffixed, suffix) = split_suffix(&src, lit_kind);
let float = if let LitKind::Float(..) = lit_kind { true } else { false };
Some(NumericLiteral::new(unsuffixed, suffix, float))
} else {
None
}
}
fn from_lit(src: &'a str, lit: &Lit) -> Option<NumericLiteral<'a>> {
NumericLiteral::from_lit_kind(src, &lit.kind)
}
#[must_use]
fn new(lit: &'a str, suffix: Option<&'a str>, float: bool) -> Self {
// Determine delimiter for radix prefix, if present, and radix.

33
clippy_lints/src/types.rs
View file

@ -27,6 +27,7 @@ use rustc_target::spec::abi::Abi;
use rustc_typeck::hir_ty_to_ty;
use crate::consts::{constant, Constant};
use crate::literal_representation::{NumericLiteral, Radix};
use crate::utils::paths;
use crate::utils::{
clip, comparisons, differing_macro_contexts, higher, in_constant, int_bits, last_path_segment, match_def_path,
@ -1210,21 +1211,27 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Casts {
let (cast_from, cast_to) = (cx.tables.expr_ty(ex), cx.tables.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 LitKind::Int(n, _) = lit.node {
if cast_to.is_floating_point() {
if_chain! {
if let LitKind::Int(n, _) = lit.node;
if let Some(src) = snippet_opt(cx, lit.span);
if cast_to.is_floating_point();
then {
let from_nbits = 128 - n.leading_zeros();
let to_nbits = fp_ty_mantissa_nbits(cast_to);
if from_nbits != 0 && to_nbits != 0 && from_nbits <= to_nbits {
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,
);
return;
if let Some(num_lit) = NumericLiteral::from_lit_kind(&src, &lit.node) {
if from_nbits != 0 && to_nbits != 0 && from_nbits <= to_nbits &&
num_lit.radix != Radix::Hexadecimal {
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,
);
return;
}
}
}
}