From 19c4771eeb5fc8fb18bb2e9a3f16ee474d8e67e3 Mon Sep 17 00:00:00 2001 From: flip1995 Date: Thu, 22 Feb 2018 20:25:58 +0100 Subject: [PATCH] Implementing requested changes --- src/librustc_lint/types.rs | 141 +++++++++++++++---------------------- 1 file changed, 56 insertions(+), 85 deletions(-) diff --git a/src/librustc_lint/types.rs b/src/librustc_lint/types.rs index 4fabb5bafbf..db9dfedc656 100644 --- a/src/librustc_lint/types.rs +++ b/src/librustc_lint/types.rs @@ -153,18 +153,8 @@ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx hir::Expr) { if (negative && v > max + 1) || (!negative && v > max) { if let Some(repr_str) = get_bin_hex_repr(cx, lit) { let bits = int_ty_bits(t, cx.sess().target.isize_ty); - let mut actually = v as i128; - if bits < 128 { - // v & 0b0..01..1, |1| = bits - let trimmed = v & ((1 << bits) - 1); - actually = if v & (1 << (bits - 1)) == 0 { - // positive - trimmed as i128 - } else { - // negative -> two's complement - (((-1 as i128 as u128) << bits) | trimmed) as i128 - }; - } + let actually = + ((v << (128 - bits)) as i128) >> (128 - bits); let mut err = cx.struct_span_lint( OVERFLOWING_LITERALS, e.span, @@ -175,15 +165,11 @@ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx hir::Expr) { an `{:?}` and will become `{}{:?}`.", repr_str, v, t, actually, t )); - let sugg_ty = get_fitting_type( + let sugg_ty = get_type_suggestion( &cx.tables.node_id_to_type(e.hir_id).sty, v, negative, - ).map_or(String::new(), |ty| match ty { - ty::TyUint(t) => format!("Consider using `{:?}`", t), - ty::TyInt(t) => format!("Consider using `{:?}`", t), - _ => String::new(), - }); + ); if !sugg_ty.is_empty() { err.help(&sugg_ty); } @@ -221,24 +207,20 @@ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx hir::Expr) { if let hir::ExprCast(..) = parent_expr.node { if let ty::TyChar = cx.tables.expr_ty(parent_expr).sty { let mut err = cx.struct_span_lint( - OVERFLOWING_LITERALS, - parent_expr.span, - "only u8 can be casted into char", - ); - err.span_suggestion( - parent_expr.span, - &"use a char literal instead", - format!("'\\u{{{:X}}}'", lit_val), - ); + OVERFLOWING_LITERALS, + parent_expr.span, + "only u8 can be casted into char"); + err.span_suggestion(parent_expr.span, + &"use a char literal instead", + format!("'\\u{{{:X}}}'", lit_val)); err.emit(); - return; + return } } } if let Some(repr_str) = get_bin_hex_repr(cx, lit) { let bits = uint_ty_bits(t, cx.sess().target.usize_ty); - // u128 cannot be greater than max -> compiler error - let actually = lit_val & ((1 << bits) - 1); + let actually = (lit_val << (128 - bits)) >> (128 - bits); let mut err = cx.struct_span_lint( OVERFLOWING_LITERALS, e.span, @@ -249,19 +231,10 @@ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx hir::Expr) { an `{:?}` and will become `{}{:?}`.", repr_str, lit_val, t, actually, t )); - let sugg_ty = get_fitting_type( + let sugg_ty = get_type_suggestion( &cx.tables.node_id_to_type(e.hir_id).sty, lit_val, false, - ).map_or( - String::new(), - |ty| { - if let ty::TyUint(t) = ty { - format!("Consider using `{:?}`", t) - } else { - String::new() - } - }, ); if !sugg_ty.is_empty() { err.help(&sugg_ty); @@ -279,19 +252,19 @@ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx hir::Expr) { } ty::TyFloat(t) => { let is_infinite = match lit.node { - ast::LitKind::Float(v, _) | ast::LitKind::FloatUnsuffixed(v) => match t - { - ast::FloatTy::F32 => v.as_str().parse().map(f32::is_infinite), - ast::FloatTy::F64 => v.as_str().parse().map(f64::is_infinite), - }, + ast::LitKind::Float(v, _) | + ast::LitKind::FloatUnsuffixed(v) => { + match t { + ast::FloatTy::F32 => v.as_str().parse().map(f32::is_infinite), + ast::FloatTy::F64 => v.as_str().parse().map(f64::is_infinite), + } + } _ => bug!(), }; if is_infinite == Ok(true) { - cx.span_lint( - OVERFLOWING_LITERALS, - e.span, - &format!("literal out of range for {:?}", t), - ); + cx.span_lint(OVERFLOWING_LITERALS, + e.span, + &format!("literal out of range for {:?}", t)); } } _ => (), @@ -421,26 +394,27 @@ fn is_comparison(binop: hir::BinOp) -> bool { } fn get_bin_hex_repr(cx: &LateContext, lit: &ast::Lit) -> Option { - if let Some(src) = cx.sess().codemap().span_to_snippet(lit.span).ok() { - if let Some(firstch) = src.chars().next() { - if let Some(0) = char::to_digit(firstch, 10) { - if let Some(base) = src.chars().nth(1) { - if base == 'x' || base == 'b' { - return Some(src); - } - } - } + let src = cx.sess().codemap().span_to_snippet(lit.span).ok()?; + let firstch = src.chars().next()?; + + if let Some(0) = char::to_digit(firstch, 10) { + match src.chars().nth(1) { + Some('x') | Some('b') => return Some(src), + _ => return None, } } None } - fn get_fitting_type<'a>( - t: &ty::TypeVariants, - val: u128, - negative: bool, - ) -> Option> { + // This function finds the next fitting type and generates a suggestion string. + // It searches for fitting types in the following way (`X < Y`): + // - `iX`: if literal fits in `uX` => `uX`, else => `iY` + // - `-iX` => `iY` + // - `uX` => `uY` + // + // No suggestion for: `isize`, `usize`. + fn get_type_suggestion<'a>(t: &ty::TypeVariants, val: u128, negative: bool) -> String { use syntax::ast::IntTy::*; use syntax::ast::UintTy::*; macro_rules! find_fit { @@ -451,36 +425,33 @@ macro_rules! find_fit { match $ty { $($type => { $(if !negative && val <= uint_ty_range($utypes).1 { - return Some(ty::TyUint($utypes)) + return format!("Consider using `{:?}`", $utypes) })* $(if val <= int_ty_range($itypes).1 as u128 + _neg { - return Some(ty::TyInt($itypes)) + return format!("Consider using `{:?}`", $itypes) })* - None + String::new() },)* - _ => None + _ => String::new() } } } } - if let &ty::TyInt(i) = t { - return find_fit!(i, val, negative, - I8 => [U8] => [I16, I32, I64, I128], - I16 => [U16] => [I32, I64, I128], - I32 => [U32] => [I64, I128], - I64 => [U64] => [I128], - I128 => [U128] => []); - } - if let &ty::TyUint(u) = t { - return find_fit!(u, val, negative, - U8 => [U8, U16, U32, U64, U128] => [], - U16 => [U16, U32, U64, U128] => [], - U32 => [U32, U64, U128] => [], - U64 => [U64, U128] => [], - U128 => [U128] => []); + match t { + &ty::TyInt(i) => find_fit!(i, val, negative, + I8 => [U8] => [I16, I32, I64, I128], + I16 => [U16] => [I32, I64, I128], + I32 => [U32] => [I64, I128], + I64 => [U64] => [I128], + I128 => [U128] => []), + &ty::TyUint(u) => find_fit!(u, val, negative, + U8 => [U8, U16, U32, U64, U128] => [], + U16 => [U16, U32, U64, U128] => [], + U32 => [U32, U64, U128] => [], + U64 => [U64, U128] => [], + U128 => [U128] => []), + _ => String::new(), } - - None } } } -- 2.44.0