mirror of
https://github.com/rust-lang/rust-clippy
synced 2024-11-24 21:53:23 +00:00
Move unnecessary_cast to its own module
This commit is contained in:
Yoshitomo Nakanishi
parent
a383e034dc
commit
9709993e41
2 changed files with 127 additions and 97 deletions
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@ -3,17 +3,18 @@ mod cast_possible_truncation;
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mod cast_possible_wrap;
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mod cast_precision_loss;
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mod cast_sign_loss;
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mod unnecessary_cast;
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mod utils;
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use std::borrow::Cow;
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use if_chain::if_chain;
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use rustc_ast::{LitFloatType, LitIntType, LitKind};
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use rustc_ast::LitKind;
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use rustc_errors::Applicability;
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use rustc_hir::{Expr, ExprKind, GenericArg, Lit, MutTy, Mutability, TyKind, UnOp};
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use rustc_hir::{Expr, ExprKind, GenericArg, MutTy, Mutability, TyKind, UnOp};
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use rustc_lint::{LateContext, LateLintPass, LintContext};
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use rustc_middle::lint::in_external_macro;
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use rustc_middle::ty::{self, FloatTy, InferTy, Ty, TypeAndMut, UintTy};
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use rustc_middle::ty::{self, Ty, TypeAndMut, UintTy};
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use rustc_semver::RustcVersion;
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use rustc_session::{declare_lint_pass, declare_tool_lint, impl_lint_pass};
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use rustc_span::symbol::sym;
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@ -21,8 +22,7 @@ use rustc_target::abi::LayoutOf;
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use crate::utils::sugg::Sugg;
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use crate::utils::{
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is_hir_ty_cfg_dependant, meets_msrv, numeric_literal::NumericLiteral, snippet_opt, snippet_with_applicability,
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span_lint, span_lint_and_sugg, span_lint_and_then,
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is_hir_ty_cfg_dependant, meets_msrv, snippet_with_applicability, span_lint, span_lint_and_sugg, span_lint_and_then,
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};
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use utils::int_ty_to_nbits;
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@ -284,72 +284,25 @@ fn is_c_void(cx: &LateContext<'_>, ty: Ty<'_>) -> bool {
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false
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}
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/// Returns the mantissa bits wide of a fp type.
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/// Will return 0 if the type is not a fp
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fn fp_ty_mantissa_nbits(typ: Ty<'_>) -> u32 {
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match typ.kind() {
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ty::Float(FloatTy::F32) => 23,
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ty::Float(FloatTy::F64) | ty::Infer(InferTy::FloatVar(_)) => 52,
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_ => 0,
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}
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}
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impl<'tcx> LateLintPass<'tcx> for Casts {
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fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
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if expr.span.from_expansion() {
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return;
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}
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if let ExprKind::Cast(ref ex, cast_to) = expr.kind {
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if let ExprKind::Cast(ref cast_expr, cast_to) = expr.kind {
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if is_hir_ty_cfg_dependant(cx, cast_to) {
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return;
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}
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let (cast_from, cast_to) = (cx.typeck_results().expr_ty(ex), cx.typeck_results().expr_ty(expr));
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lint_fn_to_numeric_cast(cx, expr, ex, cast_from, cast_to);
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if let Some(lit) = get_numeric_literal(ex) {
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let literal_str = snippet_opt(cx, ex.span).unwrap_or_default();
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let (cast_from, cast_to) = (
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cx.typeck_results().expr_ty(cast_expr),
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cx.typeck_results().expr_ty(expr),
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);
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if_chain! {
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if let LitKind::Int(n, _) = lit.node;
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if let Some(src) = snippet_opt(cx, lit.span);
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if cast_to.is_floating_point();
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if let Some(num_lit) = NumericLiteral::from_lit_kind(&src, &lit.node);
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let from_nbits = 128 - n.leading_zeros();
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let to_nbits = fp_ty_mantissa_nbits(cast_to);
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if from_nbits != 0 && to_nbits != 0 && from_nbits <= to_nbits && num_lit.is_decimal();
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then {
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let literal_str = if is_unary_neg(ex) { format!("-{}", num_lit.integer) } else { num_lit.integer.into() };
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show_unnecessary_cast(cx, expr, &literal_str, cast_from, cast_to);
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return;
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}
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}
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match lit.node {
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LitKind::Int(_, LitIntType::Unsuffixed) if cast_to.is_integral() => {
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show_unnecessary_cast(cx, expr, &literal_str, cast_from, cast_to);
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},
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LitKind::Float(_, LitFloatType::Unsuffixed) if cast_to.is_floating_point() => {
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show_unnecessary_cast(cx, expr, &literal_str, cast_from, cast_to);
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},
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LitKind::Int(_, LitIntType::Unsuffixed) | LitKind::Float(_, LitFloatType::Unsuffixed) => {},
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_ => {
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if cast_from.kind() == cast_to.kind() && !in_external_macro(cx.sess(), expr.span) {
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span_lint(
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cx,
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UNNECESSARY_CAST,
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expr.span,
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&format!(
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"casting to the same type is unnecessary (`{}` -> `{}`)",
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cast_from, cast_to
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),
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);
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}
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},
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}
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if unnecessary_cast::check(cx, expr, cast_expr, cast_from, cast_to) {
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return;
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}
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if cast_from.is_numeric() && cast_to.is_numeric() && !in_external_macro(cx.sess(), expr.span) {
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lint_numeric_casts(cx, expr, ex, cast_from, cast_to);
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}
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lint_fn_to_numeric_cast(cx, expr, cast_expr, cast_from, cast_to);
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lint_numeric_casts(cx, expr, cast_expr, cast_from, cast_to);
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lint_cast_ptr_alignment(cx, expr, cast_from, cast_to);
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} else if let ExprKind::MethodCall(method_path, _, args, _) = expr.kind {
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if_chain! {
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@ -368,37 +321,6 @@ impl<'tcx> LateLintPass<'tcx> for Casts {
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}
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}
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fn is_unary_neg(expr: &Expr<'_>) -> bool {
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matches!(expr.kind, ExprKind::Unary(UnOp::Neg, _))
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}
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fn get_numeric_literal<'e>(expr: &'e Expr<'e>) -> Option<&'e Lit> {
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match expr.kind {
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ExprKind::Lit(ref lit) => Some(lit),
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ExprKind::Unary(UnOp::Neg, e) => {
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if let ExprKind::Lit(ref lit) = e.kind {
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Some(lit)
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} else {
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None
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}
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},
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_ => None,
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}
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}
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fn show_unnecessary_cast(cx: &LateContext<'_>, expr: &Expr<'_>, literal_str: &str, cast_from: Ty<'_>, cast_to: Ty<'_>) {
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let literal_kind_name = if cast_from.is_integral() { "integer" } else { "float" };
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span_lint_and_sugg(
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cx,
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UNNECESSARY_CAST,
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expr.span,
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&format!("casting {} literal to `{}` is unnecessary", literal_kind_name, cast_to),
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"try",
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format!("{}_{}", literal_str.trim_end_matches('.'), cast_to),
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Applicability::MachineApplicable,
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);
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}
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fn lint_numeric_casts<'tcx>(
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cx: &LateContext<'tcx>,
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expr: &Expr<'tcx>,
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@ -406,11 +328,13 @@ fn lint_numeric_casts<'tcx>(
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cast_from: Ty<'tcx>,
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cast_to: Ty<'tcx>,
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) {
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cast_possible_truncation::check(cx, expr, cast_from, cast_to);
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cast_possible_wrap::check(cx, expr, cast_from, cast_to);
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cast_precision_loss::check(cx, expr, cast_from, cast_to);
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cast_lossless::check(cx, expr, cast_op, cast_from, cast_to);
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cast_sign_loss::check(cx, expr, cast_op, cast_from, cast_to);
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if cast_from.is_numeric() && cast_to.is_numeric() && !in_external_macro(cx.sess(), expr.span) {
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cast_possible_truncation::check(cx, expr, cast_from, cast_to);
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cast_possible_wrap::check(cx, expr, cast_from, cast_to);
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cast_precision_loss::check(cx, expr, cast_from, cast_to);
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cast_lossless::check(cx, expr, cast_op, cast_from, cast_to);
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cast_sign_loss::check(cx, expr, cast_op, cast_from, cast_to);
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}
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}
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fn lint_cast_ptr_alignment<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'_>, cast_from: Ty<'tcx>, cast_to: Ty<'tcx>) {
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106
clippy_lints/src/casts/unnecessary_cast.rs
Normal file
106
clippy_lints/src/casts/unnecessary_cast.rs
Normal file
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@ -0,0 +1,106 @@
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use rustc_ast::{LitFloatType, LitIntType, LitKind};
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use rustc_errors::Applicability;
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use rustc_hir::{Expr, ExprKind, Lit, UnOp};
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use rustc_lint::{LateContext, LintContext};
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use rustc_middle::lint::in_external_macro;
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use rustc_middle::ty::{self, FloatTy, InferTy, Ty};
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use if_chain::if_chain;
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use crate::utils::{numeric_literal::NumericLiteral, snippet_opt, span_lint, span_lint_and_sugg};
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use super::UNNECESSARY_CAST;
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pub(super) fn check(
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cx: &LateContext<'_>,
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expr: &Expr<'_>,
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cast_expr: &Expr<'_>,
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cast_from: Ty<'_>,
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cast_to: Ty<'_>,
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) -> bool {
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if let Some(lit) = get_numeric_literal(cast_expr) {
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let literal_str = snippet_opt(cx, cast_expr.span).unwrap_or_default();
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if_chain! {
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if let LitKind::Int(n, _) = lit.node;
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if let Some(src) = snippet_opt(cx, lit.span);
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if cast_to.is_floating_point();
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if let Some(num_lit) = NumericLiteral::from_lit_kind(&src, &lit.node);
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let from_nbits = 128 - n.leading_zeros();
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let to_nbits = fp_ty_mantissa_nbits(cast_to);
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if from_nbits != 0 && to_nbits != 0 && from_nbits <= to_nbits && num_lit.is_decimal();
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then {
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let literal_str = if is_unary_neg(cast_expr) { format!("-{}", num_lit.integer) } else { num_lit.integer.into() };
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lint_unnecessary_cast(cx, expr, &literal_str, cast_from, cast_to);
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return true
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}
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}
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match lit.node {
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LitKind::Int(_, LitIntType::Unsuffixed) if cast_to.is_integral() => {
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lint_unnecessary_cast(cx, expr, &literal_str, cast_from, cast_to);
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},
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LitKind::Float(_, LitFloatType::Unsuffixed) if cast_to.is_floating_point() => {
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lint_unnecessary_cast(cx, expr, &literal_str, cast_from, cast_to);
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},
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LitKind::Int(_, LitIntType::Unsuffixed) | LitKind::Float(_, LitFloatType::Unsuffixed) => {},
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_ => {
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if cast_from.kind() == cast_to.kind() && !in_external_macro(cx.sess(), expr.span) {
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span_lint(
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cx,
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UNNECESSARY_CAST,
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expr.span,
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&format!(
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"casting to the same type is unnecessary (`{}` -> `{}`)",
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cast_from, cast_to
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),
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);
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return true;
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}
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},
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}
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}
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false
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}
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fn lint_unnecessary_cast(cx: &LateContext<'_>, expr: &Expr<'_>, literal_str: &str, cast_from: Ty<'_>, cast_to: Ty<'_>) {
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let literal_kind_name = if cast_from.is_integral() { "integer" } else { "float" };
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span_lint_and_sugg(
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cx,
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UNNECESSARY_CAST,
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expr.span,
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&format!("casting {} literal to `{}` is unnecessary", literal_kind_name, cast_to),
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"try",
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format!("{}_{}", literal_str.trim_end_matches('.'), cast_to),
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Applicability::MachineApplicable,
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);
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}
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fn get_numeric_literal<'e>(expr: &'e Expr<'e>) -> Option<&'e Lit> {
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match expr.kind {
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ExprKind::Lit(ref lit) => Some(lit),
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ExprKind::Unary(UnOp::Neg, e) => {
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if let ExprKind::Lit(ref lit) = e.kind {
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Some(lit)
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} else {
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None
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}
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},
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_ => None,
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}
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}
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/// Returns the mantissa bits wide of a fp type.
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/// Will return 0 if the type is not a fp
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fn fp_ty_mantissa_nbits(typ: Ty<'_>) -> u32 {
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match typ.kind() {
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ty::Float(FloatTy::F32) => 23,
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ty::Float(FloatTy::F64) | ty::Infer(InferTy::FloatVar(_)) => 52,
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_ => 0,
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}
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}
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fn is_unary_neg(expr: &Expr<'_>) -> bool {
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matches!(expr.kind, ExprKind::Unary(UnOp::Neg, _))
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}
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