[rustc.git] / src / test / ui / traits / alias / no-duplicates.rs

// The purpose of this test is to demonstrate that duplicating object safe traits
// that are not auto traits is rejected with trait aliases even though one could
// reasonably accept this.

#![feature(trait_alias)]

use std::marker::Unpin;

// Some arbitrary object-safe trait:
trait Obj {}

// Nest a few levels deep:
trait _0 = Obj;
trait _1 = _0;

type _T00 = dyn _0 + _0;
//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]

type _T01 = dyn _1 + _0;
//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]

type _T02 = dyn _1 + _1;
//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]

type _T03 = dyn Obj + _1;
//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]

type _T04 = dyn _1 + Obj;
//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]

// Nest some more and in weird ways:

trait _2 = _0 + _1;
trait _3 = Obj;
trait _4 = _3;

type _T10 = dyn _2 + _3;
//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]

type _T11 = dyn _3 + _2;
//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]

type _T12 = dyn Obj + _2;
//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]

type _T13 = dyn _2 + Obj;
//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]

type _T14 = dyn _1 + _3;
//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]

type _T15 = dyn _3 + _1;
//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]

type _T16 = dyn _1 + _4;
//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]

type _T17 = dyn _4 + _1;
//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]

// Include auto traits:

trait _5 = Obj + Send;

type _T20 = dyn _5 + _5;
//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]

type _T21 = dyn Obj + _5;
//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]

type _T22 = dyn _5 + Obj;
//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]

type _T23 = dyn _5 + Send + Sync + Obj;
//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]

// Also nest:

trait _6 = _5 + _5; // ==> Obj + Send + Obj + Send

type _T30 = dyn _6;
//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]

type _T31 = dyn _6 + Send;
//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]

type _T32 = dyn Send + _6;
//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]

// Nest some more:

trait _7 = _5 + Sync;
trait _8 = Unpin + _7;

type _T40 = dyn _8 + Obj;
//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]

type _T41 = dyn Obj + _8;
//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]

type _T42 = dyn _8 + _4;
//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]

type _T43 = dyn _4 + _8;
//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]

type _T44 = dyn _4 + Send + Sync + _8;
//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]

// Take higher ranked types into account.

// Note that `'a` and `'b` are intentionally different to make sure we consider
// them semantically the same.
trait ObjL<'l> {}
trait _9 = for<'a> ObjL<'a>;
trait _10 = for<'b> ObjL<'b>;
type _T50 = dyn _9 + _10;
//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]

trait ObjT<T> {}
trait _11 = ObjT<for<'a> fn(&'a u8)>;
trait _12 = ObjT<for<'b> fn(&'b u8)>;
type _T60 = dyn _11 + _12;
//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]

fn main() {}
Commit	Line	Data
dc9dc135 XL	1	// The purpose of this test is to demonstrate that duplicating object safe traits
	2	// that are not auto traits is rejected with trait aliases even though one could
	3	// reasonably accept this.
	4
	5	#![feature(trait_alias)]
	6
	7	use std::marker::Unpin;
	8
	9	// Some arbitrary object-safe trait:
	10	trait Obj {}
	11
	12	// Nest a few levels deep:
	13	trait _0 = Obj;
	14	trait _1 = _0;
	15
	16	type _T00 = dyn _0 + _0;
	17	//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
	18
	19	type _T01 = dyn _1 + _0;
	20	//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
	21
	22	type _T02 = dyn _1 + _1;
	23	//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
	24
	25	type _T03 = dyn Obj + _1;
	26	//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
	27
	28	type _T04 = dyn _1 + Obj;
	29	//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
	30
	31	// Nest some more and in weird ways:
	32
	33	trait _2 = _0 + _1;
	34	trait _3 = Obj;
	35	trait _4 = _3;
	36
	37	type _T10 = dyn _2 + _3;
	38	//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
	39
	40	type _T11 = dyn _3 + _2;
	41	//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
	42
	43	type _T12 = dyn Obj + _2;
	44	//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
	45
	46	type _T13 = dyn _2 + Obj;
	47	//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
	48
	49	type _T14 = dyn _1 + _3;
	50	//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
	51
	52	type _T15 = dyn _3 + _1;
	53	//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
	54
	55	type _T16 = dyn _1 + _4;
	56	//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
	57
	58	type _T17 = dyn _4 + _1;
	59	//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
	60
	61	// Include auto traits:
	62
	63	trait _5 = Obj + Send;
	64
65	type _T20 = dyn _5 + _5;
66	//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
67
68	type _T21 = dyn Obj + _5;
69	//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
70
71	type _T22 = dyn _5 + Obj;
72	//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
73
74	type _T23 = dyn _5 + Send + Sync + Obj;
75	//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
76
77	// Also nest:
78
79	trait _6 = _5 + _5; // ==> Obj + Send + Obj + Send
80
81	type _T30 = dyn _6;
82	//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
83
84	type _T31 = dyn _6 + Send;
85	//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
86
87	type _T32 = dyn Send + _6;
88	//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
89
90	// Nest some more:
91
92	trait _7 = _5 + Sync;
93	trait _8 = Unpin + _7;
94
95	type _T40 = dyn _8 + Obj;
96	//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
97
98	type _T41 = dyn Obj + _8;
99	//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
100
101	type _T42 = dyn _8 + _4;
102	//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
103
104	type _T43 = dyn _4 + _8;
105	//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
106
107	type _T44 = dyn _4 + Send + Sync + _8;
108	//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
109
110	// Take higher ranked types into account.
111
112	// Note that `'a` and `'b` are intentionally different to make sure we consider
113	// them semantically the same.
114	trait ObjL<'l> {}
115	trait _9 = for<'a> ObjL<'a>;
116	trait _10 = for<'b> ObjL<'b>;
117	type _T50 = dyn _9 + _10;
118	//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
119
120	trait ObjT<T> {}
121	trait _11 = ObjT<for<'a> fn(&'a u8)>;
122	trait _12 = ObjT<for<'b> fn(&'b u8)>;
123	type _T60 = dyn _11 + _12;
124	//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
125
126	fn main() {}