Auto merge of rust-lang#117578 - compiler-errors:derive-encode-in-rustc_type_ir, r=davidtwco

Derive `TyEncodable`/`TyDecodable` in `rustc_type_ir`

when `derive(TyEncodable)` or `derive(TyDecodable)` sees an `I` type parameter on a struct that has no `'tcx`, then parameterize the `TyEncoder`/`TyDecoder`'s interner over that variable rather than `TyCtxt<'tcx>`.

Also, emit where clauses for fields rather than generics.

Author: bors

compiler/rustc_macros/src/serialize.rs

@@ -5,11 +5,16 @@ use syn::spanned::Spanned;
 
 pub fn type_decodable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::TokenStream {
     let decoder_ty = quote! { __D };
-    if !s.ast().generics.lifetimes().any(|lt| lt.lifetime.ident == "tcx") {
-        s.add_impl_generic(parse_quote! { 'tcx });
-    }
-    s.add_impl_generic(parse_quote! {#decoder_ty: ::rustc_type_ir::codec::TyDecoder<I = ::rustc_middle::ty::TyCtxt<'tcx>>});
-    s.add_bounds(synstructure::AddBounds::Generics);
+    let bound = if s.ast().generics.lifetimes().any(|lt| lt.lifetime.ident == "tcx") {
+        quote! { <I = ::rustc_middle::ty::TyCtxt<'tcx>> }
+    } else if s.ast().generics.type_params().any(|ty| ty.ident == "I") {
+        quote! { <I = I> }
+    } else {
+        quote! {}
+    };
+
+    s.add_impl_generic(parse_quote! {#decoder_ty: ::rustc_type_ir::codec::TyDecoder #bound });
+    s.add_bounds(synstructure::AddBounds::Fields);
 
     decodable_body(s, decoder_ty)
 }
@@ -97,12 +102,17 @@ fn decode_field(field: &syn::Field) -> proc_macro2::TokenStream {
 }
 
 pub fn type_encodable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::TokenStream {
-    if !s.ast().generics.lifetimes().any(|lt| lt.lifetime.ident == "tcx") {
-        s.add_impl_generic(parse_quote! {'tcx});
-    }
+    let bound = if s.ast().generics.lifetimes().any(|lt| lt.lifetime.ident == "tcx") {
+        quote! { <I = ::rustc_middle::ty::TyCtxt<'tcx>> }
+    } else if s.ast().generics.type_params().any(|ty| ty.ident == "I") {
+        quote! { <I = I> }
+    } else {
+        quote! {}
+    };
+
     let encoder_ty = quote! { __E };
-    s.add_impl_generic(parse_quote! {#encoder_ty: ::rustc_type_ir::codec::TyEncoder<I = ::rustc_middle::ty::TyCtxt<'tcx>>});
-    s.add_bounds(synstructure::AddBounds::Generics);
+    s.add_impl_generic(parse_quote! {#encoder_ty: ::rustc_type_ir::codec::TyEncoder #bound });
+    s.add_bounds(synstructure::AddBounds::Fields);
 
     encodable_body(s, encoder_ty, false)
 }

compiler/rustc_type_ir/src/canonical.rs

@@ -3,18 +3,17 @@ use std::hash::Hash;
 use std::ops::ControlFlow;
 
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
-use rustc_serialize::{Decodable, Encodable};
 
 use crate::fold::{FallibleTypeFolder, TypeFoldable};
 use crate::visit::{TypeVisitable, TypeVisitor};
-use crate::TyDecoder;
-use crate::{HashStableContext, Interner, TyEncoder, UniverseIndex};
+use crate::{HashStableContext, Interner, UniverseIndex};
 
 /// A "canonicalized" type `V` is one where all free inference
 /// variables have been rewritten to "canonical vars". These are
 /// numbered starting from 0 in order of first appearance.
 #[derive(derivative::Derivative)]
 #[derivative(Clone(bound = "V: Clone"), Hash(bound = "V: Hash"))]
+#[derive(TyEncodable, TyDecodable)]
 pub struct Canonical<I: Interner, V> {
     pub value: V,
     pub max_universe: UniverseIndex,
@@ -127,27 +126,3 @@ where
         self.variables.visit_with(folder)
     }
 }
-
-impl<I: Interner, E: TyEncoder<I = I>, V: Encodable<E>> Encodable<E> for Canonical<I, V>
-where
-    I::CanonicalVars: Encodable<E>,
-{
-    fn encode(&self, s: &mut E) {
-        self.value.encode(s);
-        self.max_universe.encode(s);
-        self.variables.encode(s);
-    }
-}
-
-impl<I: Interner, D: TyDecoder<I = I>, V: Decodable<D>> Decodable<D> for Canonical<I, V>
-where
-    I::CanonicalVars: Decodable<D>,
-{
-    fn decode(d: &mut D) -> Self {
-        Canonical {
-            value: Decodable::decode(d),
-            max_universe: Decodable::decode(d),
-            variables: Decodable::decode(d),
-        }
-    }
-}

compiler/rustc_type_ir/src/const_kind.rs

@@ -1,12 +1,8 @@
 use rustc_data_structures::stable_hasher::HashStable;
 use rustc_data_structures::stable_hasher::StableHasher;
-use rustc_serialize::{Decodable, Decoder, Encodable};
 use std::fmt;
 
-use crate::{
-    DebruijnIndex, DebugWithInfcx, HashStableContext, InferCtxtLike, Interner, TyDecoder,
-    TyEncoder, WithInfcx,
-};
+use crate::{DebruijnIndex, DebugWithInfcx, HashStableContext, InferCtxtLike, Interner, WithInfcx};
 
 use self::ConstKind::*;
 
@@ -20,6 +16,7 @@ use self::ConstKind::*;
     Ord = "feature_allow_slow_enum",
     Hash(bound = "")
 )]
+#[derive(TyEncodable, TyDecodable)]
 pub enum ConstKind<I: Interner> {
     /// A const generic parameter.
     Param(I::ParamConst),
@@ -92,67 +89,6 @@ where
     }
 }
 
-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> PartialEq for ConstKind<I> {
     fn eq(&self, other: &Self) -> bool {
         match (self, other) {

compiler/rustc_type_ir/src/lib.rs

@@ -10,6 +10,8 @@
 #![deny(rustc::diagnostic_outside_of_impl)]
 #![allow(internal_features)]
 
+extern crate self as rustc_type_ir;
+
 #[macro_use]
 extern crate bitflags;
 #[macro_use]

compiler/rustc_type_ir/src/predicate_kind.rs

@@ -1,18 +1,16 @@
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
-use rustc_serialize::Decoder;
-use rustc_serialize::{Decodable, Encodable};
 use std::fmt;
 use std::ops::ControlFlow;
 
 use crate::fold::{FallibleTypeFolder, TypeFoldable};
 use crate::visit::{TypeVisitable, TypeVisitor};
 use crate::{HashStableContext, Interner};
-use crate::{TyDecoder, TyEncoder};
 
 /// A clause is something that can appear in where bounds or be inferred
 /// by implied bounds.
 #[derive(derivative::Derivative)]
 #[derivative(Clone(bound = ""), Hash(bound = ""))]
+#[derive(TyEncodable, TyDecodable)]
 pub enum ClauseKind<I: Interner> {
     /// Corresponds to `where Foo: Bar<A, B, C>`. `Foo` here would be
     /// the `Self` type of the trait reference and `A`, `B`, and `C`
@@ -161,65 +159,9 @@ where
     }
 }
 
-impl<I: Interner, D: TyDecoder<I = I>> Decodable<D> for ClauseKind<I>
-where
-    I::Ty: Decodable<D>,
-    I::Const: Decodable<D>,
-    I::GenericArg: Decodable<D>,
-    I::TraitPredicate: Decodable<D>,
-    I::ProjectionPredicate: Decodable<D>,
-    I::TypeOutlivesPredicate: Decodable<D>,
-    I::RegionOutlivesPredicate: Decodable<D>,
-{
-    fn decode(d: &mut D) -> Self {
-        match Decoder::read_usize(d) {
-            0 => ClauseKind::Trait(Decodable::decode(d)),
-            1 => ClauseKind::RegionOutlives(Decodable::decode(d)),
-            2 => ClauseKind::TypeOutlives(Decodable::decode(d)),
-            3 => ClauseKind::Projection(Decodable::decode(d)),
-            4 => ClauseKind::ConstArgHasType(Decodable::decode(d), Decodable::decode(d)),
-            5 => ClauseKind::WellFormed(Decodable::decode(d)),
-            6 => ClauseKind::ConstEvaluatable(Decodable::decode(d)),
-            _ => panic!(
-                "{}",
-                format!(
-                    "invalid enum variant tag while decoding `{}`, expected 0..{}",
-                    "ClauseKind", 7,
-                )
-            ),
-        }
-    }
-}
-
-impl<I: Interner, E: TyEncoder> Encodable<E> for ClauseKind<I>
-where
-    I::Ty: Encodable<E>,
-    I::Const: Encodable<E>,
-    I::GenericArg: Encodable<E>,
-    I::TraitPredicate: Encodable<E>,
-    I::ProjectionPredicate: Encodable<E>,
-    I::TypeOutlivesPredicate: Encodable<E>,
-    I::RegionOutlivesPredicate: Encodable<E>,
-{
-    fn encode(&self, s: &mut E) {
-        let discriminant = clause_kind_discriminant(self);
-        match self {
-            ClauseKind::Trait(p) => s.emit_enum_variant(discriminant, |s| p.encode(s)),
-            ClauseKind::RegionOutlives(p) => s.emit_enum_variant(discriminant, |s| p.encode(s)),
-            ClauseKind::TypeOutlives(p) => s.emit_enum_variant(discriminant, |s| p.encode(s)),
-            ClauseKind::Projection(p) => s.emit_enum_variant(discriminant, |s| p.encode(s)),
-            ClauseKind::ConstArgHasType(c, t) => s.emit_enum_variant(discriminant, |s| {
-                c.encode(s);
-                t.encode(s);
-            }),
-            ClauseKind::WellFormed(p) => s.emit_enum_variant(discriminant, |s| p.encode(s)),
-            ClauseKind::ConstEvaluatable(p) => s.emit_enum_variant(discriminant, |s| p.encode(s)),
-        }
-    }
-}
-
 #[derive(derivative::Derivative)]
 #[derivative(Clone(bound = ""), Hash(bound = ""))]
+#[derive(TyEncodable, TyDecodable)]
 pub enum PredicateKind<I: Interner> {
     /// Prove a clause
     Clause(ClauseKind<I>),
@@ -418,83 +360,6 @@ where
     }
 }
 
-impl<I: Interner, D: TyDecoder<I = I>> Decodable<D> for PredicateKind<I>
-where
-    I::DefId: Decodable<D>,
-    I::Const: Decodable<D>,
-    I::GenericArgs: Decodable<D>,
-    I::Term: Decodable<D>,
-    I::CoercePredicate: Decodable<D>,
-    I::SubtypePredicate: Decodable<D>,
-    I::ClosureKind: Decodable<D>,
-    ClauseKind<I>: Decodable<D>,
-{
-    fn decode(d: &mut D) -> Self {
-        match Decoder::read_usize(d) {
-            0 => PredicateKind::Clause(Decodable::decode(d)),
-            1 => PredicateKind::ObjectSafe(Decodable::decode(d)),
-            2 => PredicateKind::ClosureKind(
-                Decodable::decode(d),
-                Decodable::decode(d),
-                Decodable::decode(d),
-            ),
-            3 => PredicateKind::Subtype(Decodable::decode(d)),
-            4 => PredicateKind::Coerce(Decodable::decode(d)),
-            5 => PredicateKind::ConstEquate(Decodable::decode(d), Decodable::decode(d)),
-            6 => PredicateKind::Ambiguous,
-            7 => PredicateKind::AliasRelate(
-                Decodable::decode(d),
-                Decodable::decode(d),
-                Decodable::decode(d),
-            ),
-            _ => panic!(
-                "{}",
-                format!(
-                    "invalid enum variant tag while decoding `{}`, expected 0..{}",
-                    "PredicateKind", 8,
-                )
-            ),
-        }
-    }
-}
-
-impl<I: Interner, E: TyEncoder> Encodable<E> for PredicateKind<I>
-where
-    I::DefId: Encodable<E>,
-    I::Const: Encodable<E>,
-    I::GenericArgs: Encodable<E>,
-    I::Term: Encodable<E>,
-    I::CoercePredicate: Encodable<E>,
-    I::SubtypePredicate: Encodable<E>,
-    I::ClosureKind: Encodable<E>,
-    ClauseKind<I>: Encodable<E>,
-{
-    fn encode(&self, s: &mut E) {
-        let discriminant = predicate_kind_discriminant(self);
-        match self {
-            PredicateKind::Clause(c) => s.emit_enum_variant(discriminant, |s| c.encode(s)),
-            PredicateKind::ObjectSafe(d) => s.emit_enum_variant(discriminant, |s| d.encode(s)),
-            PredicateKind::ClosureKind(d, g, k) => s.emit_enum_variant(discriminant, |s| {
-                d.encode(s);
-                g.encode(s);
-                k.encode(s);
-            }),
-            PredicateKind::Subtype(c) => s.emit_enum_variant(discriminant, |s| c.encode(s)),
-            PredicateKind::Coerce(c) => s.emit_enum_variant(discriminant, |s| c.encode(s)),
-            PredicateKind::ConstEquate(a, b) => s.emit_enum_variant(discriminant, |s| {
-                a.encode(s);
-                b.encode(s);
-            }),
-            PredicateKind::Ambiguous => s.emit_enum_variant(discriminant, |_s| {}),
-            PredicateKind::AliasRelate(a, b, d) => s.emit_enum_variant(discriminant, |s| {
-                a.encode(s);
-                b.encode(s);
-                d.encode(s);
-            }),
-        }
-    }
-}
-
 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, Copy)]
 #[derive(HashStable_Generic, Encodable, Decodable)]
 pub enum AliasRelationDirection {