src/test/ui/typeck/typeck_type_placeholder_item.rs

   1 // Needed for `type Y = impl Trait<_>` and `type B = _;`
   2 #![feature(type_alias_impl_trait, associated_type_defaults)]
   3 // This test checks that it is not possible to enable global type
   4 // inference by using the `_` type placeholder.
   5
   6 fn test() -> _ { 5 }
   7 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
   8
   9 fn test2() -> (_, _) { (5, 5) }
  10 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
  11
  12 static TEST3: _ = "test";
  13 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
  14
  15 static TEST4: _ = 145;
  16 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
  17
  18 static TEST5: (_, _) = (1, 2);
  19 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
  20
  21 fn test6(_: _) { }
  22 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
  23
  24 fn test6_b<T>(_: _, _: T) { }
  25 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
  26
  27 fn test6_c<T, K, L, A, B>(_: _, _: (T, K, L, A, B)) { }
  28 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
  29
  30 fn test7(x: _) { let _x: usize = x; }
  31 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
  32
  33 fn test8(_f: fn() -> _) { }
  34 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
  35
  36 struct Test9;
  37
  38 impl Test9 {
  39     fn test9(&self) -> _ { () }
  40     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
  41
  42     fn test10(&self, _x : _) { }
  43     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
  44 }
  45
  46 fn test11(x: &usize) -> &_ {
  47 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
  48     &x
  49 }
  50
  51 unsafe fn test12(x: *const usize) -> *const *const _ {
  52 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
  53     &x
  54 }
  55
  56 impl Clone for Test9 {
  57     fn clone(&self) -> _ { Test9 }
  58     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
  59
  60     fn clone_from(&mut self, other: _) { *self = Test9; }
  61     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
  62 }
  63
  64 struct Test10 {
  65     a: _,
  66     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
  67     b: (_, _),
  68 }
  69
  70 pub fn main() {
  71     static A = 42;
  72     //~^ ERROR missing type for `static` item
  73     static B: _ = 42;
  74     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
  75     static C: Option<_> = Some(42);
  76     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
  77
  78     fn fn_test() -> _ { 5 }
  79     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
  80
  81     fn fn_test2() -> (_, _) { (5, 5) }
  82     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
  83
  84     static FN_TEST3: _ = "test";
  85     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
  86
  87     static FN_TEST4: _ = 145;
  88     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
  89
  90     static FN_TEST5: (_, _) = (1, 2);
  91     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
  92
  93     fn fn_test6(_: _) { }
  94     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
  95
  96     fn fn_test7(x: _) { let _x: usize = x; }
  97     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
  98
  99     fn fn_test8(_f: fn() -> _) { }
 100     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
 101
 102     struct FnTest9;
 103
 104     impl FnTest9 {
 105         fn fn_test9(&self) -> _ { () }
 106         //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
 107
 108         fn fn_test10(&self, _x : _) { }
 109         //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
 110     }
 111
 112     impl Clone for FnTest9 {
 113         fn clone(&self) -> _ { FnTest9 }
 114         //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
 115
 116         fn clone_from(&mut self, other: _) { *self = FnTest9; }
 117         //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
 118     }
 119
 120     struct FnTest10 {
 121         a: _,
 122         //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
 123         b: (_, _),
 124     }
 125
 126     fn fn_test11(_: _) -> (_, _) { panic!() }
 127     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
 128     //~| ERROR type annotations needed
 129
 130     fn fn_test12(x: i32) -> (_, _) { (x, x) }
 131     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
 132
 133     fn fn_test13(x: _) -> (i32, _) { (x, x) }
 134     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
 135 }
 136
 137 trait T {
 138     fn method_test1(&self, x: _);
 139     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
 140     fn method_test2(&self, x: _) -> _;
 141     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
 142     fn method_test3(&self) -> _;
 143     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
 144     fn assoc_fn_test1(x: _);
 145     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
 146     fn assoc_fn_test2(x: _) -> _;
 147     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
 148     fn assoc_fn_test3() -> _;
 149     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
 150 }
 151
 152 struct BadStruct<_>(_);
 153 //~^ ERROR expected identifier, found reserved identifier `_`
 154 //~| ERROR the type placeholder `_` is not allowed within types on item signatures
 155 trait BadTrait<_> {}
 156 //~^ ERROR expected identifier, found reserved identifier `_`
 157 impl BadTrait<_> for BadStruct<_> {}
 158 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
 159
 160 fn impl_trait() -> impl BadTrait<_> {
 161 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
 162     unimplemented!()
 163 }
 164
 165 struct BadStruct1<_, _>(_);
 166 //~^ ERROR expected identifier, found reserved identifier `_`
 167 //~| ERROR expected identifier, found reserved identifier `_`
 168 //~| ERROR the name `_` is already used
 169 //~| ERROR the type placeholder `_` is not allowed within types on item signatures
 170 struct BadStruct2<_, T>(_, T);
 171 //~^ ERROR expected identifier, found reserved identifier `_`
 172 //~| ERROR the type placeholder `_` is not allowed within types on item signatures
 173
 174 type X = Box<_>;
 175 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
 176
 177 struct Struct;
 178 trait Trait<T> {}
 179 impl Trait<usize> for Struct {}
 180 type Y = impl Trait<_>;
 181 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
 182 fn foo() -> Y {
 183     Struct
 184 }
 185
 186 trait Qux {
 187     type A;
 188     type B = _;
 189     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
 190     const C: _;
 191     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
 192     const D: _ = 42;
 193     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
 194     // type E: _; // FIXME: make the parser propagate the existence of `B`
 195 }
 196 impl Qux for Struct {
 197     type A = _;
 198     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
 199     type B = _;
 200     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
 201     const C: _;
 202     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
 203     //~| ERROR associated constant in `impl` without body
 204     const D: _ = 42;
 205     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures
 206 }