src/test/ui/typeck/typeck_type_placeholder_item.rs

   1 // Needed for `type Y = impl Trait<_>` and `type B = _;`
   2 #![feature(associated_type_defaults)]
   3 // revisions: min_tait full_tait
   4 #![feature(min_type_alias_impl_trait)]
   5 #![cfg_attr(full_tait, feature(type_alias_impl_trait))]
   6 //[full_tait]~^ WARN incomplete
   7 // This test checks that it is not possible to enable global type
   8 // inference by using the `_` type placeholder.
   9
  10 fn test() -> _ { 5 }
  11 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for return types
  12
  13 fn test2() -> (_, _) { (5, 5) }
  14 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for return types
  15
  16 static TEST3: _ = "test";
  17 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for static variables
  18
  19 static TEST4: _ = 145;
  20 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for static variables
  21
  22 static TEST5: (_, _) = (1, 2);
  23 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for static variables
  24
  25 fn test6(_: _) { }
  26 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for functions
  27
  28 fn test6_b<T>(_: _, _: T) { }
  29 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for functions
  30
  31 fn test6_c<T, K, L, A, B>(_: _, _: (T, K, L, A, B)) { }
  32 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for functions
  33
  34 fn test7(x: _) { let _x: usize = x; }
  35 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for functions
  36
  37 fn test8(_f: fn() -> _) { }
  38 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for functions
  39 //~^^ ERROR the type placeholder `_` is not allowed within types on item signatures for functions
  40
  41 struct Test9;
  42
  43 impl Test9 {
  44     fn test9(&self) -> _ { () }
  45     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for return types
  46
  47     fn test10(&self, _x : _) { }
  48     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for functions
  49 }
  50
  51 fn test11(x: &usize) -> &_ {
  52 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for return types
  53     &x
  54 }
  55
  56 unsafe fn test12(x: *const usize) -> *const *const _ {
  57 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for return types
  58     &x
  59 }
  60
  61 impl Clone for Test9 {
  62     fn clone(&self) -> _ { Test9 }
  63     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for return types
  64
  65     fn clone_from(&mut self, other: _) { *self = Test9; }
  66     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for functions
  67 }
  68
  69 struct Test10 {
  70     a: _,
  71     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for structs
  72     b: (_, _),
  73 }
  74
  75 pub fn main() {
  76     static A = 42;
  77     //~^ ERROR missing type for `static` item
  78     static B: _ = 42;
  79     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for static variables
  80     static C: Option<_> = Some(42);
  81     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for static variables
  82     fn fn_test() -> _ { 5 }
  83     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for return types
  84
  85     fn fn_test2() -> (_, _) { (5, 5) }
  86     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for return types
  87
  88     static FN_TEST3: _ = "test";
  89     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for static variables
  90
  91     static FN_TEST4: _ = 145;
  92     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for static variables
  93
  94     static FN_TEST5: (_, _) = (1, 2);
  95     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for static variables
  96
  97     fn fn_test6(_: _) { }
  98     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for functions
  99
 100     fn fn_test7(x: _) { let _x: usize = x; }
 101     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for functions
 102
 103     fn fn_test8(_f: fn() -> _) { }
 104     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for functions
 105     //~^^ ERROR the type placeholder `_` is not allowed within types on item signatures for functions
 106
 107     struct FnTest9;
 108
 109     impl FnTest9 {
 110         fn fn_test9(&self) -> _ { () }
 111         //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for return types
 112
 113         fn fn_test10(&self, _x : _) { }
 114         //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for functions
 115     }
 116
 117     impl Clone for FnTest9 {
 118         fn clone(&self) -> _ { FnTest9 }
 119         //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for return types
 120
 121         fn clone_from(&mut self, other: _) { *self = FnTest9; }
 122         //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for functions
 123     }
 124
 125     struct FnTest10 {
 126         a: _,
 127         //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for structs
 128         b: (_, _),
 129     }
 130
 131     fn fn_test11(_: _) -> (_, _) { panic!() }
 132     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for return types
 133     //~| ERROR type annotations needed
 134
 135     fn fn_test12(x: i32) -> (_, _) { (x, x) }
 136     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for return types
 137
 138     fn fn_test13(x: _) -> (i32, _) { (x, x) }
 139     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for return types
 140 }
 141
 142 trait T {
 143     fn method_test1(&self, x: _);
 144     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for functions
 145     fn method_test2(&self, x: _) -> _;
 146     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for functions
 147     fn method_test3(&self) -> _;
 148     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for functions
 149     fn assoc_fn_test1(x: _);
 150     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for functions
 151     fn assoc_fn_test2(x: _) -> _;
 152     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for functions
 153     fn assoc_fn_test3() -> _;
 154     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for functions
 155 }
 156
 157 struct BadStruct<_>(_);
 158 //~^ ERROR expected identifier, found reserved identifier `_`
 159 //~| ERROR the type placeholder `_` is not allowed within types on item signatures for structs
 160 trait BadTrait<_> {}
 161 //~^ ERROR expected identifier, found reserved identifier `_`
 162 impl BadTrait<_> for BadStruct<_> {}
 163 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for implementations
 164
 165 fn impl_trait() -> impl BadTrait<_> {
 166 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for opaque types
 167     unimplemented!()
 168 }
 169
 170 struct BadStruct1<_, _>(_);
 171 //~^ ERROR expected identifier, found reserved identifier `_`
 172 //~| ERROR expected identifier, found reserved identifier `_`
 173 //~| ERROR the name `_` is already used
 174 //~| ERROR the type placeholder `_` is not allowed within types on item signatures for structs
 175 struct BadStruct2<_, T>(_, T);
 176 //~^ ERROR expected identifier, found reserved identifier `_`
 177 //~| ERROR the type placeholder `_` is not allowed within types on item signatures for structs
 178
 179 type X = Box<_>;
 180 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for type aliases
 181
 182 struct Struct;
 183 trait Trait<T> {}
 184 impl Trait<usize> for Struct {}
 185 type Y = impl Trait<_>;
 186 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for opaque types
 187 fn foo() -> Y {
 188     Struct
 189 }
 190
 191 trait Qux {
 192     type A;
 193     type B = _;
 194     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for associated types
 195     const C: _;
 196     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for constants
 197     const D: _ = 42;
 198     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for constants
 199     // type E: _; // FIXME: make the parser propagate the existence of `B`
 200     type F: std::ops::Fn(_);
 201     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for associated types
 202 }
 203 impl Qux for Struct {
 204     type A = _;
 205     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for associated types
 206     type B = _;
 207     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for associated types
 208     const C: _;
 209     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for constants
 210     //~| ERROR associated constant in `impl` without body
 211     const D: _ = 42;
 212     //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for constants
 213 }
 214
 215 fn map<T>(_: fn() -> Option<&'static T>) -> Option<T> {
 216     None
 217 }
 218
 219 fn value() -> Option<&'static _> {
 220 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for return types
 221     Option::<&'static u8>::None
 222 }
 223
 224 const _: Option<_> = map(value);
 225 //~^ ERROR the type placeholder `_` is not allowed within types on item signatures for constants