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sinkuualexcrichton
sinkuu
authored and
alexcrichton
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Disallow impl Trait in unsupported position
1 parent 1860c05 commit 992e2f8

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+74
-17
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2 files changed

+74
-17
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Diff for: ‎src/librustc/hir/lowering.rs

+36-17
Original file line numberDiff line numberDiff line change
@@ -780,8 +780,9 @@ impl<'a> LoweringContext<'a> {
780780
_ => None,
781781
}),
782782
|this| {
783+
let itctx = ImplTraitContext::Universal(parent_id);
783784
this.collect_in_band_defs(parent_id, anonymous_lifetime_mode, |this| {
784-
(this.lower_generics(generics), f(this))
785+
(this.lower_generics(generics, itctx), f(this))
785786
})
786787
},
787788
);
@@ -1043,7 +1044,11 @@ impl<'a> LoweringContext<'a> {
10431044
}),
10441045
|this| {
10451046
hir::TyBareFn(P(hir::BareFnTy {
1046-
generic_params: this.lower_generic_params(&f.generic_params, &NodeMap()),
1047+
generic_params: this.lower_generic_params(
1048+
&f.generic_params,
1049+
&NodeMap(),
1050+
ImplTraitContext::Disallowed,
1051+
),
10471052
unsafety: this.lower_unsafety(f.unsafety),
10481053
abi: f.abi,
10491054
decl: this.lower_fn_decl(&f.decl, None, false),
@@ -1784,7 +1789,12 @@ impl<'a> LoweringContext<'a> {
17841789
}
17851790
}
17861791

1787-
fn lower_ty_param(&mut self, tp: &TyParam, add_bounds: &[TyParamBound]) -> hir::TyParam {
1792+
fn lower_ty_param(
1793+
&mut self,
1794+
tp: &TyParam,
1795+
add_bounds: &[TyParamBound],
1796+
itctx: ImplTraitContext,
1797+
) -> hir::TyParam {
17881798
let mut name = self.lower_ident(tp.ident);
17891799

17901800
// Don't expose `Self` (recovered "keyword used as ident" parse error).
@@ -1794,7 +1804,6 @@ impl<'a> LoweringContext<'a> {
17941804
name = Symbol::gensym("Self");
17951805
}
17961806

1797-
let itctx = ImplTraitContext::Universal(self.resolver.definitions().local_def_id(tp.id));
17981807
let mut bounds = self.lower_bounds(&tp.bounds, itctx);
17991808
if !add_bounds.is_empty() {
18001809
bounds = bounds
@@ -1878,6 +1887,7 @@ impl<'a> LoweringContext<'a> {
18781887
&mut self,
18791888
params: &Vec<GenericParam>,
18801889
add_bounds: &NodeMap<Vec<TyParamBound>>,
1890+
itctx: ImplTraitContext,
18811891
) -> hir::HirVec<hir::GenericParam> {
18821892
params
18831893
.iter()
@@ -1888,12 +1898,13 @@ impl<'a> LoweringContext<'a> {
18881898
GenericParam::Type(ref ty_param) => hir::GenericParam::Type(self.lower_ty_param(
18891899
ty_param,
18901900
add_bounds.get(&ty_param.id).map_or(&[][..], |x| &x),
1901+
itctx,
18911902
)),
18921903
})
18931904
.collect()
18941905
}
18951906

1896-
fn lower_generics(&mut self, g: &Generics) -> hir::Generics {
1907+
fn lower_generics(&mut self, g: &Generics, itctx: ImplTraitContext) -> hir::Generics {
18971908
// Collect `?Trait` bounds in where clause and move them to parameter definitions.
18981909
// FIXME: This could probably be done with less rightward drift. Also looks like two control
18991910
// paths where report_error is called are also the only paths that advance to after
@@ -1946,7 +1957,7 @@ impl<'a> LoweringContext<'a> {
19461957
}
19471958

19481959
hir::Generics {
1949-
params: self.lower_generic_params(&g.params, &add_bounds),
1960+
params: self.lower_generic_params(&g.params, &add_bounds, itctx),
19501961
where_clause: self.lower_where_clause(&g.where_clause),
19511962
span: g.span,
19521963
}
@@ -1980,6 +1991,7 @@ impl<'a> LoweringContext<'a> {
19801991
bound_generic_params: this.lower_generic_params(
19811992
bound_generic_params,
19821993
&NodeMap(),
1994+
ImplTraitContext::Disallowed,
19831995
),
19841996
bounded_ty: this.lower_ty(bounded_ty, ImplTraitContext::Disallowed),
19851997
bounds: bounds
@@ -2063,7 +2075,8 @@ impl<'a> LoweringContext<'a> {
20632075
p: &PolyTraitRef,
20642076
itctx: ImplTraitContext,
20652077
) -> hir::PolyTraitRef {
2066-
let bound_generic_params = self.lower_generic_params(&p.bound_generic_params, &NodeMap());
2078+
let bound_generic_params =
2079+
self.lower_generic_params(&p.bound_generic_params, &NodeMap(), itctx);
20672080
let trait_ref = self.with_parent_impl_lifetime_defs(
20682081
&bound_generic_params
20692082
.iter()
@@ -2218,7 +2231,7 @@ impl<'a> LoweringContext<'a> {
22182231
ItemKind::GlobalAsm(ref ga) => hir::ItemGlobalAsm(self.lower_global_asm(ga)),
22192232
ItemKind::Ty(ref t, ref generics) => hir::ItemTy(
22202233
self.lower_ty(t, ImplTraitContext::Disallowed),
2221-
self.lower_generics(generics),
2234+
self.lower_generics(generics, ImplTraitContext::Disallowed),
22222235
),
22232236
ItemKind::Enum(ref enum_definition, ref generics) => hir::ItemEnum(
22242237
hir::EnumDef {
@@ -2228,15 +2241,21 @@ impl<'a> LoweringContext<'a> {
22282241
.map(|x| self.lower_variant(x))
22292242
.collect(),
22302243
},
2231-
self.lower_generics(generics),
2244+
self.lower_generics(generics, ImplTraitContext::Disallowed),
22322245
),
22332246
ItemKind::Struct(ref struct_def, ref generics) => {
22342247
let struct_def = self.lower_variant_data(struct_def);
2235-
hir::ItemStruct(struct_def, self.lower_generics(generics))
2248+
hir::ItemStruct(
2249+
struct_def,
2250+
self.lower_generics(generics, ImplTraitContext::Disallowed),
2251+
)
22362252
}
22372253
ItemKind::Union(ref vdata, ref generics) => {
22382254
let vdata = self.lower_variant_data(vdata);
2239-
hir::ItemUnion(vdata, self.lower_generics(generics))
2255+
hir::ItemUnion(
2256+
vdata,
2257+
self.lower_generics(generics, ImplTraitContext::Disallowed),
2258+
)
22402259
}
22412260
ItemKind::Impl(
22422261
unsafety,
@@ -2315,13 +2334,13 @@ impl<'a> LoweringContext<'a> {
23152334
hir::ItemTrait(
23162335
self.lower_is_auto(is_auto),
23172336
self.lower_unsafety(unsafety),
2318-
self.lower_generics(generics),
2337+
self.lower_generics(generics, ImplTraitContext::Disallowed),
23192338
bounds,
23202339
items,
23212340
)
23222341
}
23232342
ItemKind::TraitAlias(ref generics, ref bounds) => hir::ItemTraitAlias(
2324-
self.lower_generics(generics),
2343+
self.lower_generics(generics, ImplTraitContext::Disallowed),
23252344
self.lower_bounds(bounds, ImplTraitContext::Disallowed),
23262345
),
23272346
ItemKind::MacroDef(..) | ItemKind::Mac(..) => panic!("Shouldn't still be around"),
@@ -2456,7 +2475,7 @@ impl<'a> LoweringContext<'a> {
24562475

24572476
let (generics, node) = match i.node {
24582477
TraitItemKind::Const(ref ty, ref default) => (
2459-
this.lower_generics(&i.generics),
2478+
this.lower_generics(&i.generics, ImplTraitContext::Disallowed),
24602479
hir::TraitItemKind::Const(
24612480
this.lower_ty(ty, ImplTraitContext::Disallowed),
24622481
default
@@ -2497,7 +2516,7 @@ impl<'a> LoweringContext<'a> {
24972516
)
24982517
}
24992518
TraitItemKind::Type(ref bounds, ref default) => (
2500-
this.lower_generics(&i.generics),
2519+
this.lower_generics(&i.generics, ImplTraitContext::Disallowed),
25012520
hir::TraitItemKind::Type(
25022521
this.lower_bounds(bounds, ImplTraitContext::Disallowed),
25032522
default
@@ -2554,7 +2573,7 @@ impl<'a> LoweringContext<'a> {
25542573
ImplItemKind::Const(ref ty, ref expr) => {
25552574
let body_id = this.lower_body(None, |this| this.lower_expr(expr));
25562575
(
2557-
this.lower_generics(&i.generics),
2576+
this.lower_generics(&i.generics, ImplTraitContext::Disallowed),
25582577
hir::ImplItemKind::Const(
25592578
this.lower_ty(ty, ImplTraitContext::Disallowed),
25602579
body_id,
@@ -2585,7 +2604,7 @@ impl<'a> LoweringContext<'a> {
25852604
)
25862605
}
25872606
ImplItemKind::Type(ref ty) => (
2588-
this.lower_generics(&i.generics),
2607+
this.lower_generics(&i.generics, ImplTraitContext::Disallowed),
25892608
hir::ImplItemKind::Type(this.lower_ty(ty, ImplTraitContext::Disallowed)),
25902609
),
25912610
ImplItemKind::Macro(..) => panic!("Shouldn't exist any more"),

Diff for: ‎src/test/compile-fail/issue-47715.rs

+38
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,38 @@
1+
// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
2+
// file at the top-level directory of this distribution and at
3+
// http://rust-lang.org/COPYRIGHT.
4+
//
5+
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6+
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7+
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8+
// option. This file may not be copied, modified, or distributed
9+
// except according to those terms.
10+
11+
trait Foo {}
12+
13+
trait Bar<T> {}
14+
15+
trait Iterable {
16+
type Item;
17+
}
18+
19+
struct Container<T: Iterable<Item = impl Foo>> {
20+
//~^ ERROR `impl Trait` not allowed
21+
field: T
22+
}
23+
24+
enum Enum<T: Iterable<Item = impl Foo>> {
25+
//~^ ERROR `impl Trait` not allowed
26+
A(T),
27+
}
28+
29+
union Union<T: Iterable<Item = impl Foo> + Copy> {
30+
//~^ ERROR `impl Trait` not allowed
31+
x: T,
32+
}
33+
34+
type Type<T: Iterable<Item = impl Foo>> = T;
35+
//~^ ERROR `impl Trait` not allowed
36+
37+
fn main() {
38+
}

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