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auto merge of #16718 : Sawyer47/rust/bool-cast, r=pcwalton 

Current version of rust fails when casting from bool, e.g.
```rust
fn main() {
    let _a = false as uint;
    let _b = true as uint;
    let _c: [bool, ..false as uint];
    let _d: [bool, ..true as uint];
    // _a and _b work, but _c and _d result in an error
    // error: expected constant expr for vector length: can't cast str to uint
}
```
This commit makes it work as expected.
This commit is contained in:
bors 2014-08-24 20:30:59 +00:00
parent 17f79af31c 46cf384ba9
commit 9e8c30c553
2 changed files with 8 additions and 4 deletions
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11
src/librustc/middle/const_eval.rs
View File

@ -517,26 +517,29 @@ pub fn eval_const_expr_partial<T: ty::ExprTyProvider>(tcx: &T, e: &Expr)
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 float to str".to_string()),
_ => Err("can't cast this type to float".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 str to uint".to_string()),
_ => Err("can't cast this type to uint".to_string()),
}
}
ty::ty_int(_) | ty::ty_bool => {
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 str to int".to_string()),
_ => Err("can't cast this type to int".to_string()),
}
}
_ => Err("can't cast this type".to_string())

1
src/test/run-pass/cast-in-array-size.rs
View File

@ -16,4 +16,5 @@ fn main() {
let _a: [bool, ..1 as uint];
let _b: [int, ..SIZE as uint] = [1, ..SIZE as uint];
let _c: [bool, ..'\n' as uint] = [true, ..'\n' as uint];
let _d: [bool, ..true as uint] = [true, ..true as uint];
}