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Fix casts in constant expressions

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Fixes #17074.
This commit is contained in:
Jakub Wieczorek 2014-09-07 20:45:12 +02:00
parent d7502ac2d6
commit c98a80e472
2 changed files with 57 additions and 35 deletions
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72
src/librustc/middle/const_eval.rs
View file

@ -502,42 +502,44 @@ pub fn eval_const_expr_partial<T: ty::ExprTyProvider>(tcx: &T, e: &Expr)
const cast")
});
let base = eval_const_expr_partial(tcx, &**base);
match base {
Err(_) => base,
Ok(val) => {
match ty::get(ety).sty {
ty::ty_float(_) => {
match val {
const_bool(b) => Ok(const_float(b as f64)),
const_uint(u) => Ok(const_float(u as f64)),
const_int(i) => Ok(const_float(i as f64)),
const_float(f) => Ok(const_float(f)),
_ => Err("can't cast this type to float".to_string()),
}
macro_rules! define_casts(
($val:ident, {
$($ty_pat:pat => (
$intermediate_ty:ty,
$const_type:ident,
$target_ty:ty
)),*
}) => (match ty::get(ety).sty {
$($ty_pat => {
match $val {
const_bool(b) => Ok($const_type(b as $intermediate_ty as $target_ty)),
const_uint(u) => Ok($const_type(u as $intermediate_ty as $target_ty)),
const_int(i) => Ok($const_type(i as $intermediate_ty as $target_ty)),
const_float(f) => Ok($const_type(f as $intermediate_ty as $target_ty)),
_ => Err(concat!(
"can't cast this type to ", stringify!($const_type)
).to_string())
}
ty::ty_uint(_) => {
match val {
const_bool(b) => Ok(const_uint(b as u64)),
const_uint(u) => Ok(const_uint(u)),
const_int(i) => Ok(const_uint(i as u64)),
const_float(f) => Ok(const_uint(f as u64)),
_ => Err("can't cast this type to uint".to_string()),
}
}
ty::ty_int(_) => {
match val {
const_bool(b) => Ok(const_int(b as i64)),
const_uint(u) => Ok(const_int(u as i64)),
const_int(i) => Ok(const_int(i)),
const_float(f) => Ok(const_int(f as i64)),
_ => Err("can't cast this type to int".to_string()),
}
}
_ => Err("can't cast this type".to_string())
}
}
}
},)*
_ => Err("can't cast this type".to_string())
})
)
eval_const_expr_partial(tcx, &**base)
.and_then(|val| define_casts!(val, {
ty::ty_int(ast::TyI) => (int, const_int, i64),
ty::ty_int(ast::TyI8) => (i8, const_int, i64),
ty::ty_int(ast::TyI16) => (i16, const_int, i64),
ty::ty_int(ast::TyI32) => (i32, const_int, i64),
ty::ty_int(ast::TyI64) => (i64, const_int, i64),
ty::ty_uint(ast::TyU) => (uint, const_uint, u64),
ty::ty_uint(ast::TyU8) => (u8, const_uint, u64),
ty::ty_uint(ast::TyU16) => (u16, const_uint, u64),
ty::ty_uint(ast::TyU32) => (u32, const_uint, u64),
ty::ty_uint(ast::TyU64) => (u64, const_uint, u64),
ty::ty_float(ast::TyF32) => (f32, const_float, f64),
ty::ty_float(ast::TyF64) => (f64, const_float, f64)
}))
}
ExprPath(_) => {
match lookup_const(tcx.ty_ctxt(), e) {

20
src/test/run-pass/issue-17074.rs Normal file
View file

@ -0,0 +1,20 @@
// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
static X: u64 = -1 as u16 as u64;
static Y: u64 = -1 as u32 as u64;
fn main() {
assert_eq!(match 1 {
X => unreachable!(),
Y => unreachable!(),
_ => 1i
}, 1);
}