X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;ds=sidebyside;f=compiler%2Frustc_middle%2Fsrc%2Fty%2Fconsts%2Fkind.rs;h=d9721863a58c801fa49c21594cfc26309a2dc47d;hb=2cd2070af7643ad88d280a4933bc4fb60451e521;hp=de63dae8a3df6455eb311d18c3eef5b717535591;hpb=9178bc059f3e932d94a52efba7a9e010f1bc6d37;p=rust.git

diff --git a/compiler/rustc_middle/src/ty/consts/kind.rs b/compiler/rustc_middle/src/ty/consts/kind.rs
index de63dae8a3d..d9721863a58 100644
--- a/compiler/rustc_middle/src/ty/consts/kind.rs
+++ b/compiler/rustc_middle/src/ty/consts/kind.rs
@@ -1,5 +1,3 @@
-use std::convert::TryInto;
-
 use super::Const;
 use crate::mir;
 use crate::mir::interpret::{AllocId, ConstValue, Scalar};
@@ -49,6 +47,7 @@ pub fn new(
 /// Represents a constant in Rust.
 #[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord, TyEncodable, TyDecodable)]
 #[derive(Hash, HashStable, TypeFoldable, TypeVisitable)]
+#[derive(derive_more::From)]
 pub enum ConstKind<'tcx> {
     /// A const generic parameter.
     Param(ty::ParamConst),
@@ -71,12 +70,19 @@ pub enum ConstKind<'tcx> {
 
     /// A placeholder for a const which could not be computed; this is
     /// propagated to avoid useless error messages.
+    #[from(ignore)]
     Error(ErrorGuaranteed),
 
     /// Expr which contains an expression which has partially evaluated items.
     Expr(Expr<'tcx>),
 }
 
+impl<'tcx> From<ty::ConstVid<'tcx>> for ConstKind<'tcx> {
+    fn from(const_vid: ty::ConstVid<'tcx>) -> Self {
+        InferConst::Var(const_vid).into()
+    }
+}
+
 #[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord, Hash)]
 #[derive(HashStable, TyEncodable, TyDecodable, TypeVisitable, TypeFoldable)]
 pub enum Expr<'tcx> {