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Rollup merge of #34497 - oli-obk:double_negation, r=eddyb

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Revert "skip double negation in const eval"

This reverts commit 735c018974.

fixes #34395

The original commit was based on a mis-understanding of the overflowing literal lint.

This needs to be ported to beta.

r? @eddyb
This commit is contained in:
Manish Goregaokar 2016-06-29 21:21:22 +05:30 • committed by GitHub
commit 2e893ea6de
2 changed files with 42 additions and 48 deletions
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89
src/librustc_const_eval/eval.rs
View file

@ -543,54 +543,47 @@ pub fn eval_const_expr_partial<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
let result = match e.node {
hir::ExprUnary(hir::UnNeg, ref inner) => {
// unary neg literals already got their sign during creation
match inner.node {
hir::ExprLit(ref lit) => {
use syntax::ast::*;
use syntax::ast::LitIntType::*;
const I8_OVERFLOW: u64 = ::std::i8::MAX as u64 + 1;
const I16_OVERFLOW: u64 = ::std::i16::MAX as u64 + 1;
const I32_OVERFLOW: u64 = ::std::i32::MAX as u64 + 1;
const I64_OVERFLOW: u64 = ::std::i64::MAX as u64 + 1;
match (&lit.node, ety.map(|t| &t.sty)) {
(&LitKind::Int(I8_OVERFLOW, Unsuffixed), Some(&ty::TyInt(IntTy::I8))) |
(&LitKind::Int(I8_OVERFLOW, Signed(IntTy::I8)), _) => {
return Ok(Integral(I8(::std::i8::MIN)))
},
(&LitKind::Int(I16_OVERFLOW, Unsuffixed), Some(&ty::TyInt(IntTy::I16))) |
(&LitKind::Int(I16_OVERFLOW, Signed(IntTy::I16)), _) => {
return Ok(Integral(I16(::std::i16::MIN)))
},
(&LitKind::Int(I32_OVERFLOW, Unsuffixed), Some(&ty::TyInt(IntTy::I32))) |
(&LitKind::Int(I32_OVERFLOW, Signed(IntTy::I32)), _) => {
return Ok(Integral(I32(::std::i32::MIN)))
},
(&LitKind::Int(I64_OVERFLOW, Unsuffixed), Some(&ty::TyInt(IntTy::I64))) |
(&LitKind::Int(I64_OVERFLOW, Signed(IntTy::I64)), _) => {
return Ok(Integral(I64(::std::i64::MIN)))
},
(&LitKind::Int(n, Unsuffixed), Some(&ty::TyInt(IntTy::Is))) |
(&LitKind::Int(n, Signed(IntTy::Is)), _) => {
match tcx.sess.target.int_type {
IntTy::I16 => if n == I16_OVERFLOW {
return Ok(Integral(Isize(Is16(::std::i16::MIN))));
},
IntTy::I32 => if n == I32_OVERFLOW {
return Ok(Integral(Isize(Is32(::std::i32::MIN))));
},
IntTy::I64 => if n == I64_OVERFLOW {
return Ok(Integral(Isize(Is64(::std::i64::MIN))));
},
_ => bug!(),
}
},
_ => {},
}
},
hir::ExprUnary(hir::UnNeg, ref inner) => {
// skip `--$expr`
return eval_const_expr_partial(tcx, inner, ty_hint, fn_args);
},
_ => {},
if let hir::ExprLit(ref lit) = inner.node {
use syntax::ast::*;
use syntax::ast::LitIntType::*;
const I8_OVERFLOW: u64 = ::std::i8::MAX as u64 + 1;
const I16_OVERFLOW: u64 = ::std::i16::MAX as u64 + 1;
const I32_OVERFLOW: u64 = ::std::i32::MAX as u64 + 1;
const I64_OVERFLOW: u64 = ::std::i64::MAX as u64 + 1;
match (&lit.node, ety.map(|t| &t.sty)) {
(&LitKind::Int(I8_OVERFLOW, Unsuffixed), Some(&ty::TyInt(IntTy::I8))) |
(&LitKind::Int(I8_OVERFLOW, Signed(IntTy::I8)), _) => {
return Ok(Integral(I8(::std::i8::MIN)))
},
(&LitKind::Int(I16_OVERFLOW, Unsuffixed), Some(&ty::TyInt(IntTy::I16))) |
(&LitKind::Int(I16_OVERFLOW, Signed(IntTy::I16)), _) => {
return Ok(Integral(I16(::std::i16::MIN)))
},
(&LitKind::Int(I32_OVERFLOW, Unsuffixed), Some(&ty::TyInt(IntTy::I32))) |
(&LitKind::Int(I32_OVERFLOW, Signed(IntTy::I32)), _) => {
return Ok(Integral(I32(::std::i32::MIN)))
},
(&LitKind::Int(I64_OVERFLOW, Unsuffixed), Some(&ty::TyInt(IntTy::I64))) |
(&LitKind::Int(I64_OVERFLOW, Signed(IntTy::I64)), _) => {
return Ok(Integral(I64(::std::i64::MIN)))
},
(&LitKind::Int(n, Unsuffixed), Some(&ty::TyInt(IntTy::Is))) |
(&LitKind::Int(n, Signed(IntTy::Is)), _) => {
match tcx.sess.target.int_type {
IntTy::I16 => if n == I16_OVERFLOW {
return Ok(Integral(Isize(Is16(::std::i16::MIN))));
},
IntTy::I32 => if n == I32_OVERFLOW {
return Ok(Integral(Isize(Is32(::std::i32::MIN))));
},
IntTy::I64 => if n == I64_OVERFLOW {
return Ok(Integral(Isize(Is64(::std::i64::MIN))));
},
_ => bug!(),
}
},
_ => {},
}
}
match eval_const_expr_partial(tcx, &inner, ty_hint, fn_args)? {
Float(f) => Float(-f),

1
src/test/compile-fail/lint-type-overflow2.rs
View file

@ -15,6 +15,7 @@
#[allow(unused_variables)]
fn main() {
let x2: i8 = --128; //~ error: literal out of range for i8
//~^ error: attempted to negate with overflow
let x = -3.40282348e+38_f32; //~ error: literal out of range for f32
let x = 3.40282348e+38_f32; //~ error: literal out of range for f32