Move some files around

compiler/rustc_type_ir/src/const_kind.rs

@@ -0,0 +1,258 @@
+use rustc_data_structures::stable_hasher::HashStable;
+use rustc_serialize::{Decodable, Decoder, Encodable};
+use std::cmp::Ordering;
+use std::fmt;
+use std::hash;
+
+use crate::{
+    DebruijnIndex, DebugWithInfcx, HashStableContext, InferCtxtLike, Interner, OptWithInfcx,
+    TyDecoder, TyEncoder,
+};
+
+use self::ConstKind::*;
+
+/// Represents a constant in Rust.
+// #[derive(derive_more::From)]
+pub enum ConstKind<I: Interner> {
+    /// A const generic parameter.
+    Param(I::ParamConst),
+
+    /// Infer the value of the const.
+    Infer(I::InferConst),
+
+    /// Bound const variable, used only when preparing a trait query.
+    Bound(DebruijnIndex, I::BoundConst),
+
+    /// A placeholder const - universally quantified higher-ranked const.
+    Placeholder(I::PlaceholderConst),
+
+    /// An unnormalized const item such as an anon const or assoc const or free const item.
+    /// Right now anything other than anon consts does not actually work properly but this
+    /// should
+    Unevaluated(I::AliasConst),
+
+    /// Used to hold computed value.
+    Value(I::ValueConst),
+
+    /// A placeholder for a const which could not be computed; this is
+    /// propagated to avoid useless error messages.
+    Error(I::ErrorGuaranteed),
+
+    /// Unevaluated non-const-item, used by `feature(generic_const_exprs)` to represent
+    /// const arguments such as `N + 1` or `foo(N)`
+    Expr(I::ExprConst),
+}
+
+const fn const_kind_discriminant<I: Interner>(value: &ConstKind<I>) -> usize {
+    match value {
+        Param(_) => 0,
+        Infer(_) => 1,
+        Bound(_, _) => 2,
+        Placeholder(_) => 3,
+        Unevaluated(_) => 4,
+        Value(_) => 5,
+        Error(_) => 6,
+        Expr(_) => 7,
+    }
+}
+
+impl<I: Interner> hash::Hash for ConstKind<I> {
+    fn hash<H: hash::Hasher>(&self, state: &mut H) {
+        const_kind_discriminant(self).hash(state);
+        match self {
+            Param(p) => p.hash(state),
+            Infer(i) => i.hash(state),
+            Bound(d, b) => {
+                d.hash(state);
+                b.hash(state);
+            }
+            Placeholder(p) => p.hash(state),
+            Unevaluated(u) => u.hash(state),
+            Value(v) => v.hash(state),
+            Error(e) => e.hash(state),
+            Expr(e) => e.hash(state),
+        }
+    }
+}
+
+impl<CTX: HashStableContext, I: Interner> HashStable<CTX> for ConstKind<I>
+where
+    I::ParamConst: HashStable<CTX>,
+    I::InferConst: HashStable<CTX>,
+    I::BoundConst: HashStable<CTX>,
+    I::PlaceholderConst: HashStable<CTX>,
+    I::AliasConst: HashStable<CTX>,
+    I::ValueConst: HashStable<CTX>,
+    I::ErrorGuaranteed: HashStable<CTX>,
+    I::ExprConst: HashStable<CTX>,
+{
+    fn hash_stable(
+        &self,
+        hcx: &mut CTX,
+        hasher: &mut rustc_data_structures::stable_hasher::StableHasher,
+    ) {
+        const_kind_discriminant(self).hash_stable(hcx, hasher);
+        match self {
+            Param(p) => p.hash_stable(hcx, hasher),
+            Infer(i) => i.hash_stable(hcx, hasher),
+            Bound(d, b) => {
+                d.hash_stable(hcx, hasher);
+                b.hash_stable(hcx, hasher);
+            }
+            Placeholder(p) => p.hash_stable(hcx, hasher),
+            Unevaluated(u) => u.hash_stable(hcx, hasher),
+            Value(v) => v.hash_stable(hcx, hasher),
+            Error(e) => e.hash_stable(hcx, hasher),
+            Expr(e) => e.hash_stable(hcx, hasher),
+        }
+    }
+}
+
+impl<I: Interner, D: TyDecoder<I = I>> Decodable<D> for ConstKind<I>
+where
+    I::ParamConst: Decodable<D>,
+    I::InferConst: Decodable<D>,
+    I::BoundConst: Decodable<D>,
+    I::PlaceholderConst: Decodable<D>,
+    I::AliasConst: Decodable<D>,
+    I::ValueConst: Decodable<D>,
+    I::ErrorGuaranteed: Decodable<D>,
+    I::ExprConst: Decodable<D>,
+{
+    fn decode(d: &mut D) -> Self {
+        match Decoder::read_usize(d) {
+            0 => Param(Decodable::decode(d)),
+            1 => Infer(Decodable::decode(d)),
+            2 => Bound(Decodable::decode(d), Decodable::decode(d)),
+            3 => Placeholder(Decodable::decode(d)),
+            4 => Unevaluated(Decodable::decode(d)),
+            5 => Value(Decodable::decode(d)),
+            6 => Error(Decodable::decode(d)),
+            7 => Expr(Decodable::decode(d)),
+            _ => panic!(
+                "{}",
+                format!(
+                    "invalid enum variant tag while decoding `{}`, expected 0..{}",
+                    "ConstKind", 8,
+                )
+            ),
+        }
+    }
+}
+
+impl<I: Interner, E: TyEncoder<I = I>> Encodable<E> for ConstKind<I>
+where
+    I::ParamConst: Encodable<E>,
+    I::InferConst: Encodable<E>,
+    I::BoundConst: Encodable<E>,
+    I::PlaceholderConst: Encodable<E>,
+    I::AliasConst: Encodable<E>,
+    I::ValueConst: Encodable<E>,
+    I::ErrorGuaranteed: Encodable<E>,
+    I::ExprConst: Encodable<E>,
+{
+    fn encode(&self, e: &mut E) {
+        let disc = const_kind_discriminant(self);
+        match self {
+            Param(p) => e.emit_enum_variant(disc, |e| p.encode(e)),
+            Infer(i) => e.emit_enum_variant(disc, |e| i.encode(e)),
+            Bound(d, b) => e.emit_enum_variant(disc, |e| {
+                d.encode(e);
+                b.encode(e);
+            }),
+            Placeholder(p) => e.emit_enum_variant(disc, |e| p.encode(e)),
+            Unevaluated(u) => e.emit_enum_variant(disc, |e| u.encode(e)),
+            Value(v) => e.emit_enum_variant(disc, |e| v.encode(e)),
+            Error(er) => e.emit_enum_variant(disc, |e| er.encode(e)),
+            Expr(ex) => e.emit_enum_variant(disc, |e| ex.encode(e)),
+        }
+    }
+}
+
+impl<I: Interner> PartialOrd for ConstKind<I> {
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+impl<I: Interner> Ord for ConstKind<I> {
+    fn cmp(&self, other: &Self) -> Ordering {
+        const_kind_discriminant(self)
+            .cmp(&const_kind_discriminant(other))
+            .then_with(|| match (self, other) {
+                (Param(p1), Param(p2)) => p1.cmp(p2),
+                (Infer(i1), Infer(i2)) => i1.cmp(i2),
+                (Bound(d1, b1), Bound(d2, b2)) => d1.cmp(d2).then_with(|| b1.cmp(b2)),
+                (Placeholder(p1), Placeholder(p2)) => p1.cmp(p2),
+                (Unevaluated(u1), Unevaluated(u2)) => u1.cmp(u2),
+                (Value(v1), Value(v2)) => v1.cmp(v2),
+                (Error(e1), Error(e2)) => e1.cmp(e2),
+                (Expr(e1), Expr(e2)) => e1.cmp(e2),
+                _ => {
+                    debug_assert!(false, "This branch must be unreachable, maybe the match is missing an arm? self = {self:?}, other = {other:?}");
+                    Ordering::Equal
+                }
+            })
+    }
+}
+
+impl<I: Interner> PartialEq for ConstKind<I> {
+    fn eq(&self, other: &Self) -> bool {
+        match (self, other) {
+            (Param(l0), Param(r0)) => l0 == r0,
+            (Infer(l0), Infer(r0)) => l0 == r0,
+            (Bound(l0, l1), Bound(r0, r1)) => l0 == r0 && l1 == r1,
+            (Placeholder(l0), Placeholder(r0)) => l0 == r0,
+            (Unevaluated(l0), Unevaluated(r0)) => l0 == r0,
+            (Value(l0), Value(r0)) => l0 == r0,
+            (Error(l0), Error(r0)) => l0 == r0,
+            (Expr(l0), Expr(r0)) => l0 == r0,
+            _ => false,
+        }
+    }
+}
+
+impl<I: Interner> Eq for ConstKind<I> {}
+
+impl<I: Interner> Clone for ConstKind<I> {
+    fn clone(&self) -> Self {
+        match self {
+            Param(arg0) => Param(arg0.clone()),
+            Infer(arg0) => Infer(arg0.clone()),
+            Bound(arg0, arg1) => Bound(arg0.clone(), arg1.clone()),
+            Placeholder(arg0) => Placeholder(arg0.clone()),
+            Unevaluated(arg0) => Unevaluated(arg0.clone()),
+            Value(arg0) => Value(arg0.clone()),
+            Error(arg0) => Error(arg0.clone()),
+            Expr(arg0) => Expr(arg0.clone()),
+        }
+    }
+}
+
+impl<I: Interner> fmt::Debug for ConstKind<I> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        OptWithInfcx::new_no_ctx(self).fmt(f)
+    }
+}
+
+impl<I: Interner> DebugWithInfcx<I> for ConstKind<I> {
+    fn fmt<InfCtx: InferCtxtLike<I>>(
+        this: OptWithInfcx<'_, I, InfCtx, &Self>,
+        f: &mut core::fmt::Formatter<'_>,
+    ) -> core::fmt::Result {
+        use ConstKind::*;
+
+        match this.data {
+            Param(param) => write!(f, "{param:?}"),
+            Infer(var) => write!(f, "{:?}", &this.wrap(var)),
+            Bound(debruijn, var) => crate::debug_bound_var(f, *debruijn, var.clone()),
+            Placeholder(placeholder) => write!(f, "{placeholder:?}"),
+            Unevaluated(uv) => {
+                write!(f, "{:?}", &this.wrap(uv))
+            }
+            Value(valtree) => write!(f, "{valtree:?}"),
+            Error(_) => write!(f, "{{const error}}"),
+            Expr(expr) => write!(f, "{:?}", &this.wrap(expr)),
+        }
+    }
+}