AST/HIR: Merge ObjectSum and PolyTraitRef

Author: petrochenkov

src/librustc/hir/intravisit.rs

@@ -562,15 +562,11 @@ pub fn walk_ty<'v, V: Visitor<'v>>(visitor: &mut V, typ: &'v Ty) {
         TyPath(ref qpath) => {
             visitor.visit_qpath(qpath, typ.id, typ.span);
         }
-        TyObjectSum(ref ty, ref bounds) => {
-            visitor.visit_ty(ty);
-            walk_list!(visitor, visit_ty_param_bound, bounds);
-        }
         TyArray(ref ty, length) => {
             visitor.visit_ty(ty);
             visitor.visit_nested_body(length)
         }
-        TyPolyTraitRef(ref bounds) => {
+        TyObjectSum(ref bounds) => {
             walk_list!(visitor, visit_ty_param_bound, bounds);
         }
         TyImplTrait(ref bounds) => {

src/librustc/hir/lowering.rs

@@ -308,9 +308,6 @@ impl<'a> LoweringContext<'a> {
                         span: t.span,
                     })))
                 }
-                TyKind::ObjectSum(ref ty, ref bounds) => {
-                    hir::TyObjectSum(self.lower_ty(ty), self.lower_bounds(bounds))
-                }
                 TyKind::Array(ref ty, ref length) => {
                     let length = self.lower_expr(length);
                     hir::TyArray(self.lower_ty(ty),
@@ -320,8 +317,8 @@ impl<'a> LoweringContext<'a> {
                     let expr = self.lower_expr(expr);
                     hir::TyTypeof(self.record_body(expr, None))
                 }
-                TyKind::PolyTraitRef(ref bounds) => {
-                    hir::TyPolyTraitRef(self.lower_bounds(bounds))
+                TyKind::ObjectSum(ref bounds) => {
+                    hir::TyObjectSum(self.lower_bounds(bounds))
                 }
                 TyKind::ImplTrait(ref bounds) => {
                     hir::TyImplTrait(self.lower_bounds(bounds))

src/librustc/hir/mod.rs

@@ -1214,12 +1214,11 @@ pub enum Ty_ {
     ///
     /// Type parameters may be stored in each `PathSegment`.
     TyPath(QPath),
-
-    /// Something like `A+B`. Note that `B` must always be a path.
-    TyObjectSum(P<Ty>, TyParamBounds),
-    /// A type like `for<'a> Foo<&'a Bar>`
-    TyPolyTraitRef(TyParamBounds),
-    /// An `impl TraitA+TraitB` type.
+    /// A trait object type `Bound1 + Bound2 + Bound3`
+    /// where `Bound` is a trait or a lifetime.
+    TyObjectSum(TyParamBounds),
+    /// An `impl Bound1 + Bound2 + Bound3` type
+    /// where `Bound` is a trait or a lifetime.
     TyImplTrait(TyParamBounds),
     /// Unused for now
     TyTypeof(BodyId),

src/librustc/hir/print.rs

@@ -418,11 +418,7 @@ impl<'a> State<'a> {
             hir::TyPath(ref qpath) => {
                 self.print_qpath(qpath, false)?
             }
-            hir::TyObjectSum(ref ty, ref bounds) => {
-                self.print_type(&ty)?;
-                self.print_bounds("+", &bounds[..])?;
-            }
-            hir::TyPolyTraitRef(ref bounds) => {
+            hir::TyObjectSum(ref bounds) => {
                 self.print_bounds("", &bounds[..])?;
             }
             hir::TyImplTrait(ref bounds) => {

src/librustc_incremental/calculate_svh/svh_visitor.rs

@@ -441,7 +441,6 @@ enum SawTyComponent {
     SawTyTup,
     SawTyPath,
     SawTyObjectSum,
-    SawTyPolyTraitRef,
     SawTyImplTrait,
     SawTyTypeof,
     SawTyInfer
@@ -458,7 +457,6 @@ fn saw_ty(node: &Ty_) -> SawTyComponent {
       TyTup(..) => SawTyTup,
       TyPath(_) => SawTyPath,
       TyObjectSum(..) => SawTyObjectSum,
-      TyPolyTraitRef(..) => SawTyPolyTraitRef,
       TyImplTrait(..) => SawTyImplTrait,
       TyTypeof(..) => SawTyTypeof,
       TyInfer => SawTyInfer

src/librustc_passes/ast_validation.rs

@@ -143,8 +143,7 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                     err.emit();
                 });
             }
-            TyKind::ObjectSum(_, ref bounds) |
-            TyKind::PolyTraitRef(ref bounds) => {
+            TyKind::ObjectSum(ref bounds) => {
                 self.no_questions_in_bounds(bounds, "trait object types", false);
             }
             _ => {}

src/librustc_typeck/astconv.rs

@@ -73,7 +73,7 @@ use std::iter;
 use syntax::{abi, ast};
 use syntax::feature_gate::{GateIssue, emit_feature_err};
 use syntax::symbol::{Symbol, keywords};
-use syntax_pos::{Span, Pos};
+use syntax_pos::Span;
 use errors::DiagnosticBuilder;
 
 pub trait AstConv<'gcx, 'tcx> {
@@ -930,87 +930,6 @@ impl<'o, 'gcx: 'tcx, 'tcx> AstConv<'gcx, 'tcx>+'o {
         decl_ty.subst(self.tcx(), substs)
     }
 
-    fn ast_ty_to_object_trait_ref(&self,
-                                  rscope: &RegionScope,
-                                  span: Span,
-                                  ty: &hir::Ty,
-                                  bounds: &[hir::TyParamBound])
-                                  -> Ty<'tcx>
-    {
-        /*!
-         * In a type like `Foo + Send`, we want to wait to collect the
-         * full set of bounds before we make the object type, because we
-         * need them to infer a region bound.  (For example, if we tried
-         * made a type from just `Foo`, then it wouldn't be enough to
-         * infer a 'static bound, and hence the user would get an error.)
-         * So this function is used when we're dealing with a sum type to
-         * convert the LHS. It only accepts a type that refers to a trait
-         * name, and reports an error otherwise.
-         */
-
-        let tcx = self.tcx();
-        match ty.node {
-            hir::TyPath(hir::QPath::Resolved(None, ref path)) => {
-                if let Def::Trait(trait_def_id) = path.def {
-                    self.trait_path_to_object_type(rscope,
-                                                   path.span,
-                                                   trait_def_id,
-                                                   ty.id,
-                                                   path.segments.last().unwrap(),
-                                                   span,
-                                                   partition_bounds(bounds))
-                } else {
-                    struct_span_err!(tcx.sess, ty.span, E0172,
-                                     "expected a reference to a trait")
-                        .span_label(ty.span, &format!("expected a trait"))
-                        .emit();
-                    tcx.types.err
-                }
-            }
-            _ => {
-                let mut err = struct_span_err!(tcx.sess, ty.span, E0178,
-                                               "expected a path on the left-hand side \
-                                                of `+`, not `{}`",
-                                               tcx.map.node_to_pretty_string(ty.id));
-                err.span_label(ty.span, &format!("expected a path"));
-                let hi = bounds.iter().map(|x| match *x {
-                    hir::TraitTyParamBound(ref tr, _) => tr.span.hi,
-                    hir::RegionTyParamBound(ref r) => r.span.hi,
-                }).max_by_key(|x| x.to_usize());
-                let full_span = hi.map(|hi| Span {
-                    lo: ty.span.lo,
-                    hi: hi,
-                    expn_id: ty.span.expn_id,
-                });
-                match (&ty.node, full_span) {
-                    (&hir::TyRptr(ref lifetime, ref mut_ty), Some(full_span)) => {
-                        let ty_str = hir::print::to_string(&tcx.map, |s| {
-                            use syntax::print::pp::word;
-                            use syntax::print::pprust::PrintState;
-
-                            word(&mut s.s, "&")?;
-                            s.print_opt_lifetime(lifetime)?;
-                            s.print_mutability(mut_ty.mutbl)?;
-                            s.popen()?;
-                            s.print_type(&mut_ty.ty)?;
-                            s.print_bounds(" +", bounds)?;
-                            s.pclose()
-                        });
-                        err.span_suggestion(full_span, "try adding parentheses (per RFC 438):",
-                                            ty_str);
-                    }
-
-                    _ => {
-                        help!(&mut err,
-                                   "perhaps you forgot parentheses? (per RFC 438)");
-                    }
-                }
-                err.emit();
-                tcx.types.err
-            }
-        }
-    }
-
     /// Transform a PolyTraitRef into a PolyExistentialTraitRef by
     /// removing the dummy Self type (TRAIT_OBJECT_DUMMY_SELF).
     fn trait_ref_to_existential(&self, trait_ref: ty::TraitRef<'tcx>)
@@ -1534,9 +1453,6 @@ impl<'o, 'gcx: 'tcx, 'tcx> AstConv<'gcx, 'tcx>+'o {
             hir::TySlice(ref ty) => {
                 tcx.mk_slice(self.ast_ty_to_ty(rscope, &ty))
             }
-            hir::TyObjectSum(ref ty, ref bounds) => {
-                self.ast_ty_to_object_trait_ref(rscope, ast_ty.span, ty, bounds)
-            }
             hir::TyPtr(ref mt) => {
                 tcx.mk_ptr(ty::TypeAndMut {
                     ty: self.ast_ty_to_ty(rscope, &mt.ty),
@@ -1609,7 +1525,7 @@ impl<'o, 'gcx: 'tcx, 'tcx> AstConv<'gcx, 'tcx>+'o {
                 }
                 tcx.mk_fn_ptr(bare_fn_ty)
             }
-            hir::TyPolyTraitRef(ref bounds) => {
+            hir::TyObjectSum(ref bounds) => {
                 self.conv_object_ty_poly_trait_ref(rscope, ast_ty.span, bounds)
             }
             hir::TyImplTrait(ref bounds) => {

src/librustc_typeck/diagnostics.rs

@@ -1864,55 +1864,6 @@ fn bar(foo: Foo) -> u32 {
 ```
 "##,
 
-E0172: r##"
-This error means that an attempt was made to specify the type of a variable with
-a combination of a concrete type and a trait. Consider the following example:
-
-```compile_fail,E0172
-fn foo(bar: i32+std::fmt::Display) {}
-```
-
-The code is trying to specify that we want to receive a signed 32-bit integer
-which also implements `Display`. This doesn't make sense: when we pass `i32`, a
-concrete type, it implicitly includes all of the traits that it implements.
-This includes `Display`, `Debug`, `Clone`, and a host of others.
-
-If `i32` implements the trait we desire, there's no need to specify the trait
-separately. If it does not, then we need to `impl` the trait for `i32` before
-passing it into `foo`. Either way, a fixed definition for `foo` will look like
-the following:
-
-```
-fn foo(bar: i32) {}
-```
-
-To learn more about traits, take a look at the Book:
-
-https://doc.rust-lang.org/book/traits.html
-"##,
-
-E0178: r##"
-In types, the `+` type operator has low precedence, so it is often necessary
-to use parentheses.
-
-For example:
-
-```compile_fail,E0178
-trait Foo {}
-
-struct Bar<'a> {
-    w: &'a Foo + Copy,   // error, use &'a (Foo + Copy)
-    x: &'a Foo + 'a,     // error, use &'a (Foo + 'a)
-    y: &'a mut Foo + 'a, // error, use &'a mut (Foo + 'a)
-    z: fn() -> Foo + 'a, // error, use fn() -> (Foo + 'a)
-}
-```
-
-More details can be found in [RFC 438].
-
-[RFC 438]: https://github.com/rust-lang/rfcs/pull/438
-"##,
-
 E0182: r##"
 You bound an associated type in an expression path which is not
 allowed.
@@ -4152,6 +4103,7 @@ register_diagnostics! {
 //  E0163, // merged into E0071
 //  E0167,
 //  E0168,
+//  E0172, // non-trait found in a type sum, moved to resolve
 //  E0173, // manual implementations of unboxed closure traits are experimental
 //  E0174,
     E0183,

src/librustdoc/clean/mod.rs

@@ -1504,9 +1504,6 @@ pub enum Type {
     // _
     Infer,
 
-    // for<'a> Foo(&'a)
-    PolyTraitRef(Vec<TyParamBound>),
-
     // impl TraitA+TraitB
     ImplTrait(Vec<TyParamBound>),
 }
@@ -1768,24 +1765,26 @@ impl Clean<Type> for hir::Ty {
                     trait_: box resolve_type(cx, trait_path.clean(cx), self.id)
                 }
             }
-            TyObjectSum(ref lhs, ref bounds) => {
-                let lhs_ty = lhs.clean(cx);
+            TyObjectSum(ref bounds) => {
+                let lhs_ty = bounds[0].clean(cx);
                 match lhs_ty {
-                    ResolvedPath { path, typarams: None, did, is_generic } => {
-                        ResolvedPath {
-                            path: path,
-                            typarams: Some(bounds.clean(cx)),
-                            did: did,
-                            is_generic: is_generic,
+                    TraitBound(poly_trait, ..) => {
+                        match poly_trait.trait_ {
+                            ResolvedPath { path, typarams: None, did, is_generic } => {
+                                ResolvedPath {
+                                    path: path,
+                                    typarams: Some(bounds[1..].clean(cx)),
+                                    did: did,
+                                    is_generic: is_generic,
+                                }
+                            }
+                            _ => Infer // shouldn't happen
                         }
                     }
-                    _ => {
-                        lhs_ty // shouldn't happen
-                    }
+                    _ => Infer // shouldn't happen
                 }
             }
             TyBareFn(ref barefn) => BareFunction(box barefn.clean(cx)),
-            TyPolyTraitRef(ref bounds) => PolyTraitRef(bounds.clean(cx)),
             TyImplTrait(ref bounds) => ImplTrait(bounds.clean(cx)),
             TyInfer => Infer,
             TyTypeof(..) => panic!("Unimplemented type {:?}", self.node),

src/librustdoc/html/format.rs

@@ -679,19 +679,6 @@ fn fmt_type(t: &clean::Type, f: &mut fmt::Formatter, use_absolute: bool) -> fmt:
                 }
             }
         }
-        clean::PolyTraitRef(ref bounds) => {
-            for (i, bound) in bounds.iter().enumerate() {
-                if i != 0 {
-                    write!(f, " + ")?;
-                }
-                if f.alternate() {
-                    write!(f, "{:#}", *bound)?;
-                } else {
-                    write!(f, "{}", *bound)?;
-                }
-            }
-            Ok(())
-        }
         clean::ImplTrait(ref bounds) => {
             write!(f, "impl ")?;
             for (i, bound) in bounds.iter().enumerate() {