bjoernager/rust
bjoernager/rust
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This commit is contained in:
Bastian Kauschke 2020-10-23 09:33:47 +02:00
parent 40ab18d97d
commit e1c524cd45
1 changed files with 9 additions and 12 deletions
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21
compiler/rustc_middle/src/infer/unify_key.rs
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@ -175,19 +175,15 @@ impl<'tcx> UnifyKey for ty::ConstVid<'tcx> {
impl<'tcx> UnifyValue for ConstVarValue<'tcx> {
type Error = (&'tcx ty::Const<'tcx>, &'tcx ty::Const<'tcx>);
fn unify_values(value1: &Self, value2: &Self) -> Result<Self, Self::Error> {
let (val, origin) = match (value1.val, value2.val) {
fn unify_values(&value1: &Self, &value2: &Self) -> Result<Self, Self::Error> {
Ok(match (value1.val, value2.val) {
(ConstVariableValue::Known { .. }, ConstVariableValue::Known { .. }) => {
bug!("equating two const variables, both of which have known values")
}
// If one side is known, prefer that one.
(ConstVariableValue::Known { .. }, ConstVariableValue::Unknown { .. }) => {
(value1.val, value1.origin)
}
(ConstVariableValue::Unknown { .. }, ConstVariableValue::Known { .. }) => {
(value2.val, value2.origin)
}
(ConstVariableValue::Known { .. }, ConstVariableValue::Unknown { .. }) => value1,
(ConstVariableValue::Unknown { .. }, ConstVariableValue::Known { .. }) => value2,
// If both sides are *unknown*, it hardly matters, does it?
(
@ -200,11 +196,12 @@ impl<'tcx> UnifyValue for ConstVarValue<'tcx> {
// universe is the minimum of the two universes, because that is
// the one which contains the fewest names in scope.
let universe = cmp::min(universe1, universe2);
(ConstVariableValue::Unknown { universe }, value1.origin)
ConstVarValue {
val: ConstVariableValue::Unknown { universe },
origin: value1.origin,
}
};
Ok(ConstVarValue { origin, val })
}
})
}
}