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| 1 | +use rustc_data_structures::stable_hasher::HashStable; |
| 2 | +use rustc_serialize::{Decodable, Decoder, Encodable}; |
| 3 | +use std::cmp::Ordering; |
| 4 | +use std::fmt; |
| 5 | +use std::hash; |
| 6 | + |
| 7 | +use crate::{ |
| 8 | + DebruijnIndex, DebugWithInfcx, HashStableContext, InferCtxtLike, Interner, OptWithInfcx, |
| 9 | + TyDecoder, TyEncoder, |
| 10 | +}; |
| 11 | + |
| 12 | +use self::ConstKind::*; |
| 13 | + |
| 14 | +/// Represents a constant in Rust. |
| 15 | +// #[derive(derive_more::From)] |
| 16 | +pub enum ConstKind<I: Interner> { |
| 17 | + /// A const generic parameter. |
| 18 | + Param(I::ParamConst), |
| 19 | + |
| 20 | + /// Infer the value of the const. |
| 21 | + Infer(I::InferConst), |
| 22 | + |
| 23 | + /// Bound const variable, used only when preparing a trait query. |
| 24 | + Bound(DebruijnIndex, I::BoundConst), |
| 25 | + |
| 26 | + /// A placeholder const - universally quantified higher-ranked const. |
| 27 | + Placeholder(I::PlaceholderConst), |
| 28 | + |
| 29 | + /// An unnormalized const item such as an anon const or assoc const or free const item. |
| 30 | + /// Right now anything other than anon consts does not actually work properly but this |
| 31 | + /// should |
| 32 | + Unevaluated(I::AliasConst), |
| 33 | + |
| 34 | + /// Used to hold computed value. |
| 35 | + Value(I::ValueConst), |
| 36 | + |
| 37 | + /// A placeholder for a const which could not be computed; this is |
| 38 | + /// propagated to avoid useless error messages. |
| 39 | + Error(I::ErrorGuaranteed), |
| 40 | + |
| 41 | + /// Unevaluated non-const-item, used by `feature(generic_const_exprs)` to represent |
| 42 | + /// const arguments such as `N + 1` or `foo(N)` |
| 43 | + Expr(I::ExprConst), |
| 44 | +} |
| 45 | + |
| 46 | +const fn const_kind_discriminant<I: Interner>(value: &ConstKind<I>) -> usize { |
| 47 | + match value { |
| 48 | + Param(_) => 0, |
| 49 | + Infer(_) => 1, |
| 50 | + Bound(_, _) => 2, |
| 51 | + Placeholder(_) => 3, |
| 52 | + Unevaluated(_) => 4, |
| 53 | + Value(_) => 5, |
| 54 | + Error(_) => 6, |
| 55 | + Expr(_) => 7, |
| 56 | + } |
| 57 | +} |
| 58 | + |
| 59 | +impl<I: Interner> hash::Hash for ConstKind<I> { |
| 60 | + fn hash<H: hash::Hasher>(&self, state: &mut H) { |
| 61 | + const_kind_discriminant(self).hash(state); |
| 62 | + match self { |
| 63 | + Param(p) => p.hash(state), |
| 64 | + Infer(i) => i.hash(state), |
| 65 | + Bound(d, b) => { |
| 66 | + d.hash(state); |
| 67 | + b.hash(state); |
| 68 | + } |
| 69 | + Placeholder(p) => p.hash(state), |
| 70 | + Unevaluated(u) => u.hash(state), |
| 71 | + Value(v) => v.hash(state), |
| 72 | + Error(e) => e.hash(state), |
| 73 | + Expr(e) => e.hash(state), |
| 74 | + } |
| 75 | + } |
| 76 | +} |
| 77 | + |
| 78 | +impl<CTX: HashStableContext, I: Interner> HashStable<CTX> for ConstKind<I> |
| 79 | +where |
| 80 | + I::ParamConst: HashStable<CTX>, |
| 81 | + I::InferConst: HashStable<CTX>, |
| 82 | + I::BoundConst: HashStable<CTX>, |
| 83 | + I::PlaceholderConst: HashStable<CTX>, |
| 84 | + I::AliasConst: HashStable<CTX>, |
| 85 | + I::ValueConst: HashStable<CTX>, |
| 86 | + I::ErrorGuaranteed: HashStable<CTX>, |
| 87 | + I::ExprConst: HashStable<CTX>, |
| 88 | +{ |
| 89 | + fn hash_stable( |
| 90 | + &self, |
| 91 | + hcx: &mut CTX, |
| 92 | + hasher: &mut rustc_data_structures::stable_hasher::StableHasher, |
| 93 | + ) { |
| 94 | + const_kind_discriminant(self).hash_stable(hcx, hasher); |
| 95 | + match self { |
| 96 | + Param(p) => p.hash_stable(hcx, hasher), |
| 97 | + Infer(i) => i.hash_stable(hcx, hasher), |
| 98 | + Bound(d, b) => { |
| 99 | + d.hash_stable(hcx, hasher); |
| 100 | + b.hash_stable(hcx, hasher); |
| 101 | + } |
| 102 | + Placeholder(p) => p.hash_stable(hcx, hasher), |
| 103 | + Unevaluated(u) => u.hash_stable(hcx, hasher), |
| 104 | + Value(v) => v.hash_stable(hcx, hasher), |
| 105 | + Error(e) => e.hash_stable(hcx, hasher), |
| 106 | + Expr(e) => e.hash_stable(hcx, hasher), |
| 107 | + } |
| 108 | + } |
| 109 | +} |
| 110 | + |
| 111 | +impl<I: Interner, D: TyDecoder<I = I>> Decodable<D> for ConstKind<I> |
| 112 | +where |
| 113 | + I::ParamConst: Decodable<D>, |
| 114 | + I::InferConst: Decodable<D>, |
| 115 | + I::BoundConst: Decodable<D>, |
| 116 | + I::PlaceholderConst: Decodable<D>, |
| 117 | + I::AliasConst: Decodable<D>, |
| 118 | + I::ValueConst: Decodable<D>, |
| 119 | + I::ErrorGuaranteed: Decodable<D>, |
| 120 | + I::ExprConst: Decodable<D>, |
| 121 | +{ |
| 122 | + fn decode(d: &mut D) -> Self { |
| 123 | + match Decoder::read_usize(d) { |
| 124 | + 0 => Param(Decodable::decode(d)), |
| 125 | + 1 => Infer(Decodable::decode(d)), |
| 126 | + 2 => Bound(Decodable::decode(d), Decodable::decode(d)), |
| 127 | + 3 => Placeholder(Decodable::decode(d)), |
| 128 | + 4 => Unevaluated(Decodable::decode(d)), |
| 129 | + 5 => Value(Decodable::decode(d)), |
| 130 | + 6 => Error(Decodable::decode(d)), |
| 131 | + 7 => Expr(Decodable::decode(d)), |
| 132 | + _ => panic!( |
| 133 | + "{}", |
| 134 | + format!( |
| 135 | + "invalid enum variant tag while decoding `{}`, expected 0..{}", |
| 136 | + "ConstKind", 8, |
| 137 | + ) |
| 138 | + ), |
| 139 | + } |
| 140 | + } |
| 141 | +} |
| 142 | + |
| 143 | +impl<I: Interner, E: TyEncoder<I = I>> Encodable<E> for ConstKind<I> |
| 144 | +where |
| 145 | + I::ParamConst: Encodable<E>, |
| 146 | + I::InferConst: Encodable<E>, |
| 147 | + I::BoundConst: Encodable<E>, |
| 148 | + I::PlaceholderConst: Encodable<E>, |
| 149 | + I::AliasConst: Encodable<E>, |
| 150 | + I::ValueConst: Encodable<E>, |
| 151 | + I::ErrorGuaranteed: Encodable<E>, |
| 152 | + I::ExprConst: Encodable<E>, |
| 153 | +{ |
| 154 | + fn encode(&self, e: &mut E) { |
| 155 | + let disc = const_kind_discriminant(self); |
| 156 | + match self { |
| 157 | + Param(p) => e.emit_enum_variant(disc, |e| p.encode(e)), |
| 158 | + Infer(i) => e.emit_enum_variant(disc, |e| i.encode(e)), |
| 159 | + Bound(d, b) => e.emit_enum_variant(disc, |e| { |
| 160 | + d.encode(e); |
| 161 | + b.encode(e); |
| 162 | + }), |
| 163 | + Placeholder(p) => e.emit_enum_variant(disc, |e| p.encode(e)), |
| 164 | + Unevaluated(u) => e.emit_enum_variant(disc, |e| u.encode(e)), |
| 165 | + Value(v) => e.emit_enum_variant(disc, |e| v.encode(e)), |
| 166 | + Error(er) => e.emit_enum_variant(disc, |e| er.encode(e)), |
| 167 | + Expr(ex) => e.emit_enum_variant(disc, |e| ex.encode(e)), |
| 168 | + } |
| 169 | + } |
| 170 | +} |
| 171 | + |
| 172 | +impl<I: Interner> PartialOrd for ConstKind<I> { |
| 173 | + fn partial_cmp(&self, other: &Self) -> Option<Ordering> { |
| 174 | + Some(self.cmp(other)) |
| 175 | + } |
| 176 | +} |
| 177 | + |
| 178 | +impl<I: Interner> Ord for ConstKind<I> { |
| 179 | + fn cmp(&self, other: &Self) -> Ordering { |
| 180 | + const_kind_discriminant(self) |
| 181 | + .cmp(&const_kind_discriminant(other)) |
| 182 | + .then_with(|| match (self, other) { |
| 183 | + (Param(p1), Param(p2)) => p1.cmp(p2), |
| 184 | + (Infer(i1), Infer(i2)) => i1.cmp(i2), |
| 185 | + (Bound(d1, b1), Bound(d2, b2)) => d1.cmp(d2).then_with(|| b1.cmp(b2)), |
| 186 | + (Placeholder(p1), Placeholder(p2)) => p1.cmp(p2), |
| 187 | + (Unevaluated(u1), Unevaluated(u2)) => u1.cmp(u2), |
| 188 | + (Value(v1), Value(v2)) => v1.cmp(v2), |
| 189 | + (Error(e1), Error(e2)) => e1.cmp(e2), |
| 190 | + (Expr(e1), Expr(e2)) => e1.cmp(e2), |
| 191 | + _ => { |
| 192 | + debug_assert!(false, "This branch must be unreachable, maybe the match is missing an arm? self = {self:?}, other = {other:?}"); |
| 193 | + Ordering::Equal |
| 194 | + } |
| 195 | + }) |
| 196 | + } |
| 197 | +} |
| 198 | + |
| 199 | +impl<I: Interner> PartialEq for ConstKind<I> { |
| 200 | + fn eq(&self, other: &Self) -> bool { |
| 201 | + match (self, other) { |
| 202 | + (Param(l0), Param(r0)) => l0 == r0, |
| 203 | + (Infer(l0), Infer(r0)) => l0 == r0, |
| 204 | + (Bound(l0, l1), Bound(r0, r1)) => l0 == r0 && l1 == r1, |
| 205 | + (Placeholder(l0), Placeholder(r0)) => l0 == r0, |
| 206 | + (Unevaluated(l0), Unevaluated(r0)) => l0 == r0, |
| 207 | + (Value(l0), Value(r0)) => l0 == r0, |
| 208 | + (Error(l0), Error(r0)) => l0 == r0, |
| 209 | + (Expr(l0), Expr(r0)) => l0 == r0, |
| 210 | + _ => false, |
| 211 | + } |
| 212 | + } |
| 213 | +} |
| 214 | + |
| 215 | +impl<I: Interner> Eq for ConstKind<I> {} |
| 216 | + |
| 217 | +impl<I: Interner> Clone for ConstKind<I> { |
| 218 | + fn clone(&self) -> Self { |
| 219 | + match self { |
| 220 | + Param(arg0) => Param(arg0.clone()), |
| 221 | + Infer(arg0) => Infer(arg0.clone()), |
| 222 | + Bound(arg0, arg1) => Bound(arg0.clone(), arg1.clone()), |
| 223 | + Placeholder(arg0) => Placeholder(arg0.clone()), |
| 224 | + Unevaluated(arg0) => Unevaluated(arg0.clone()), |
| 225 | + Value(arg0) => Value(arg0.clone()), |
| 226 | + Error(arg0) => Error(arg0.clone()), |
| 227 | + Expr(arg0) => Expr(arg0.clone()), |
| 228 | + } |
| 229 | + } |
| 230 | +} |
| 231 | + |
| 232 | +impl<I: Interner> fmt::Debug for ConstKind<I> { |
| 233 | + fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { |
| 234 | + OptWithInfcx::new_no_ctx(self).fmt(f) |
| 235 | + } |
| 236 | +} |
| 237 | + |
| 238 | +impl<I: Interner> DebugWithInfcx<I> for ConstKind<I> { |
| 239 | + fn fmt<InfCtx: InferCtxtLike<I>>( |
| 240 | + this: OptWithInfcx<'_, I, InfCtx, &Self>, |
| 241 | + f: &mut core::fmt::Formatter<'_>, |
| 242 | + ) -> core::fmt::Result { |
| 243 | + use ConstKind::*; |
| 244 | + |
| 245 | + match this.data { |
| 246 | + Param(param) => write!(f, "{param:?}"), |
| 247 | + Infer(var) => write!(f, "{:?}", &this.wrap(var)), |
| 248 | + Bound(debruijn, var) => crate::debug_bound_var(f, *debruijn, var.clone()), |
| 249 | + Placeholder(placeholder) => write!(f, "{placeholder:?}"), |
| 250 | + Unevaluated(uv) => { |
| 251 | + write!(f, "{:?}", &this.wrap(uv)) |
| 252 | + } |
| 253 | + Value(valtree) => write!(f, "{valtree:?}"), |
| 254 | + Error(_) => write!(f, "{{const error}}"), |
| 255 | + Expr(expr) => write!(f, "{:?}", &this.wrap(expr)), |
| 256 | + } |
| 257 | + } |
| 258 | +} |
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