1 files changed, 222 insertions, 0 deletions
diff --git a/src/test/ui/typeck/typeck_type_placeholder_item.rs b/src/test/ui/typeck/typeck_type_placeholder_item.rs
new file mode 100644
index 000000000..22fedb22d
--- /dev/null
+++ b/src/test/ui/typeck/typeck_type_placeholder_item.rs
@@ -0,0 +1,222 @@
+// Needed for `type Y = impl Trait<_>` and `type B = _;`
+#![feature(associated_type_defaults)]
+#![feature(type_alias_impl_trait)]
+// This test checks that it is not possible to enable global type
+// inference by using the `_` type placeholder.
+
+fn test() -> _ { 5 }
+//~^ ERROR the placeholder `_` is not allowed within types on item signatures for return types
+
+fn test2() -> (_, _) { (5, 5) }
+//~^ ERROR the placeholder `_` is not allowed within types on item signatures for return types
+
+static TEST3: _ = "test";
+//~^ ERROR the placeholder `_` is not allowed within types on item signatures for static variables
+
+static TEST4: _ = 145;
+//~^ ERROR the placeholder `_` is not allowed within types on item signatures for static variables
+
+static TEST5: (_, _) = (1, 2);
+//~^ ERROR the placeholder `_` is not allowed within types on item signatures for static variables
+
+fn test6(_: _) { }
+//~^ ERROR the placeholder `_` is not allowed within types on item signatures for functions
+
+fn test6_b<T>(_: _, _: T) { }
+//~^ ERROR the placeholder `_` is not allowed within types on item signatures for functions
+
+fn test6_c<T, K, L, A, B>(_: _, _: (T, K, L, A, B)) { }
+//~^ ERROR the placeholder `_` is not allowed within types on item signatures for functions
+
+fn test7(x: _) { let _x: usize = x; }
+//~^ ERROR the placeholder `_` is not allowed within types on item signatures for functions
+
+fn test8(_f: fn() -> _) { }
+//~^ ERROR the placeholder `_` is not allowed within types on item signatures for functions
+//~^^ ERROR the placeholder `_` is not allowed within types on item signatures for functions
+
+struct Test9;
+
+impl Test9 {
+    fn test9(&self) -> _ { () }
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for return types
+
+    fn test10(&self, _x : _) { }
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for functions
+}
+
+fn test11(x: &usize) -> &_ {
+//~^ ERROR the placeholder `_` is not allowed within types on item signatures for return types
+    &x
+}
+
+unsafe fn test12(x: *const usize) -> *const *const _ {
+//~^ ERROR the placeholder `_` is not allowed within types on item signatures for return types
+    &x
+}
+
+impl Clone for Test9 {
+    fn clone(&self) -> _ { Test9 }
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for functions
+
+    fn clone_from(&mut self, other: _) { *self = Test9; }
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for functions
+}
+
+struct Test10 {
+    a: _,
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for structs
+    b: (_, _),
+}
+
+pub fn main() {
+    static A = 42;
+    //~^ ERROR missing type for `static` item
+    static B: _ = 42;
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for static variables
+    static C: Option<_> = Some(42);
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for static variables
+    fn fn_test() -> _ { 5 }
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for return types
+
+    fn fn_test2() -> (_, _) { (5, 5) }
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for return types
+
+    static FN_TEST3: _ = "test";
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for static variables
+
+    static FN_TEST4: _ = 145;
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for static variables
+
+    static FN_TEST5: (_, _) = (1, 2);
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for static variables
+
+    fn fn_test6(_: _) { }
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for functions
+
+    fn fn_test7(x: _) { let _x: usize = x; }
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for functions
+
+    fn fn_test8(_f: fn() -> _) { }
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for functions
+    //~^^ ERROR the placeholder `_` is not allowed within types on item signatures for functions
+
+    struct FnTest9;
+
+    impl FnTest9 {
+        fn fn_test9(&self) -> _ { () }
+        //~^ ERROR the placeholder `_` is not allowed within types on item signatures for return types
+
+        fn fn_test10(&self, _x : _) { }
+        //~^ ERROR the placeholder `_` is not allowed within types on item signatures for functions
+    }
+
+    impl Clone for FnTest9 {
+        fn clone(&self) -> _ { FnTest9 }
+        //~^ ERROR the placeholder `_` is not allowed within types on item signatures for functions
+
+        fn clone_from(&mut self, other: _) { *self = FnTest9; }
+        //~^ ERROR the placeholder `_` is not allowed within types on item signatures for functions
+    }
+
+    struct FnTest10 {
+        a: _,
+        //~^ ERROR the placeholder `_` is not allowed within types on item signatures for structs
+        b: (_, _),
+    }
+
+    fn fn_test11(_: _) -> (_, _) { panic!() }
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for return types
+    //~| ERROR type annotations needed
+
+    fn fn_test12(x: i32) -> (_, _) { (x, x) }
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for return types
+
+    fn fn_test13(x: _) -> (i32, _) { (x, x) }
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for return types
+}
+
+trait T {
+    fn method_test1(&self, x: _);
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for functions
+    fn method_test2(&self, x: _) -> _;
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for functions
+    fn method_test3(&self) -> _;
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for functions
+    fn assoc_fn_test1(x: _);
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for functions
+    fn assoc_fn_test2(x: _) -> _;
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for functions
+    fn assoc_fn_test3() -> _;
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for functions
+}
+
+struct BadStruct<_>(_);
+//~^ ERROR expected identifier, found reserved identifier `_`
+//~| ERROR the placeholder `_` is not allowed within types on item signatures for structs
+trait BadTrait<_> {}
+//~^ ERROR expected identifier, found reserved identifier `_`
+impl BadTrait<_> for BadStruct<_> {}
+//~^ ERROR the placeholder `_` is not allowed within types on item signatures for implementations
+
+fn impl_trait() -> impl BadTrait<_> {
+//~^ ERROR the placeholder `_` is not allowed within types on item signatures for opaque types
+    unimplemented!()
+}
+
+struct BadStruct1<_, _>(_);
+//~^ ERROR expected identifier, found reserved identifier `_`
+//~| ERROR expected identifier, found reserved identifier `_`
+//~| ERROR the name `_` is already used
+//~| ERROR the placeholder `_` is not allowed within types on item signatures for structs
+struct BadStruct2<_, T>(_, T);
+//~^ ERROR expected identifier, found reserved identifier `_`
+//~| ERROR the placeholder `_` is not allowed within types on item signatures for structs
+
+type X = Box<_>;
+//~^ ERROR the placeholder `_` is not allowed within types on item signatures for type aliases
+
+struct Struct;
+trait Trait<T> {}
+impl Trait<usize> for Struct {}
+type Y = impl Trait<_>;
+//~^ ERROR the placeholder `_` is not allowed within types on item signatures for opaque types
+fn foo() -> Y {
+    Struct
+}
+
+trait Qux {
+    type A;
+    type B = _;
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for associated types
+    const C: _;
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for constants
+    const D: _ = 42;
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for constants
+    // type E: _; // FIXME: make the parser propagate the existence of `B`
+    type F: std::ops::Fn(_);
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for associated types
+}
+impl Qux for Struct {
+    type A = _;
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for associated types
+    type B = _;
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for associated types
+    const C: _;
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for constants
+    //~| ERROR associated constant in `impl` without body
+    const D: _ = 42;
+    //~^ ERROR the placeholder `_` is not allowed within types on item signatures for constants
+}
+
+fn map<T>(_: fn() -> Option<&'static T>) -> Option<T> {
+    None
+}
+
+fn value() -> Option<&'static _> {
+//~^ ERROR the placeholder `_` is not allowed within types on item signatures for return types
+    Option::<&'static u8>::None
+}
+
+const _: Option<_> = map(value);
+//~^ ERROR the placeholder `_` is not allowed within types on item signatures for constants