bjoernager/rust
bjoernager/rust
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Relate identical parameters in array lengths

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This commit is contained in:
varkor 2019-05-11 18:01:50 +01:00
parent 7212685837
commit 73f7e426be
1 changed files with 17 additions and 21 deletions
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38
src/librustc/ty/relate.rs
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@ -9,7 +9,6 @@ use crate::ty::subst::{Kind, UnpackedKind, SubstsRef};
use crate::ty::{self, Ty, TyCtxt, TypeFoldable};
use crate::ty::error::{ExpectedFound, TypeError};
use crate::mir::interpret::{GlobalId, ConstValue, Scalar};
use crate::util::common::ErrorReported;
use syntax_pos::DUMMY_SP;
use std::rc::Rc;
use std::iter;
@ -474,8 +473,9 @@ pub fn super_relate_tys<'a, 'gcx, 'tcx, R>(relation: &mut R,
(&ty::Array(a_t, sz_a), &ty::Array(b_t, sz_b)) =>
{
let t = relation.relate(&a_t, &b_t)?;
let to_u64 = |x: ty::Const<'tcx>| -> Result<u64, ErrorReported> {
match x.val {
let to_u64 = |ct: &'tcx ty::Const<'tcx>| -> Option<u64> {
match ct.val {
// FIXME(const_generics): this doesn't work right now,
// because it tries to relate an `Infer` to a `Param`.
ConstValue::Unevaluated(def_id, substs) => {
@ -493,26 +493,18 @@ pub fn super_relate_tys<'a, 'gcx, 'tcx, R>(relation: &mut R,
instance,
promoted: None,
};
if let Some(s) = tcx.const_eval(param_env.and(cid))
.ok()
.map(|c| c.unwrap_usize(tcx)) {
return Ok(s)
}
return tcx.const_eval(param_env.and(cid))
.ok()
.map(|c| c.unwrap_usize(tcx));
}
}
tcx.sess.delay_span_bug(tcx.def_span(def_id),
"array length could not be evaluated");
Err(ErrorReported)
None
}
_ => x.assert_usize(tcx).ok_or_else(|| {
tcx.sess.delay_span_bug(DUMMY_SP,
"array length could not be evaluated");
ErrorReported
})
_ => ct.assert_usize(tcx),
}
};
match (to_u64(*sz_a), to_u64(*sz_b)) {
(Ok(sz_a_u64), Ok(sz_b_u64)) => {
match (to_u64(sz_a), to_u64(sz_b)) {
(Some(sz_a_u64), Some(sz_b_u64)) => {
if sz_a_u64 == sz_b_u64 {
Ok(tcx.mk_ty(ty::Array(t, sz_a)))
} else {
@ -520,9 +512,13 @@ pub fn super_relate_tys<'a, 'gcx, 'tcx, R>(relation: &mut R,
expected_found(relation, &sz_a_u64, &sz_b_u64)))
}
}
// We reported an error or will ICE, so we can return Error.
(Err(ErrorReported), _) | (_, Err(ErrorReported)) => {
Ok(tcx.types.err)
_ => {
if let Ok(sz) = relation.relate(&sz_a, &sz_b) {
Ok(tcx.mk_ty(ty::Array(t, sz)))
} else {
tcx.sess.delay_span_bug(DUMMY_SP, "array length could not be evaluated");
Ok(tcx.types.err)
}
}
}
}