"target type not found for 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, e) {