Add tests

compiler/rustc_parse/src/parser/ty.rs

@@ -348,7 +348,9 @@ impl<'a> Parser<'a> {
                     TyKind::Err(guar)
                 }
             }
-        } else if self.check_keyword(kw::Unsafe) {
+        } else if self.check_keyword(kw::Unsafe)
+            && self.look_ahead(1, |tok| matches!(tok.kind, token::Lt))
+        {
             self.parse_unsafe_binder_ty()?
         } else {
             let msg = format!("expected type, found {}", super::token_descr(&self.token));

tests/ui/feature-gates/feature-gate-unsafe-binders.rs

@@ -0,0 +1,7 @@
+#[cfg(any())]
+fn test() {
+    let x: unsafe<> ();
+    //~^ ERROR unsafe binder types are experimental
+}
+
+fn main() {}

tests/ui/feature-gates/feature-gate-unsafe-binders.stderr

@@ -0,0 +1,13 @@
+error[E0658]: unsafe binder types are experimental
+  --> $DIR/feature-gate-unsafe-binders.rs:3:12
+   |
+LL |     let x: unsafe<> ();
+   |            ^^^^^^^^^^^
+   |
+   = note: see issue #130516 <https://github.com/rust-lang/rust/issues/130516> for more information
+   = help: add `#![feature(unsafe_binders)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0658`.

tests/ui/unsafe-binders/expr.rs

@@ -0,0 +1,13 @@
+#![feature(unsafe_binders)]
+//~^ WARN the feature `unsafe_binders` is incomplete
+
+use std::unsafe_binder::{wrap_binder, unwrap_binder};
+
+fn main() {
+    let x = 1;
+    let binder: unsafe<'a> &'a i32 = wrap_binder!(x);
+    //~^ ERROR unsafe binders are not yet implemented
+    //~| ERROR unsafe binders are not yet implemented
+    let rx = *unwrap_binder!(binder);
+    //~^ ERROR unsafe binders are not yet implemented
+}

tests/ui/unsafe-binders/expr.stderr

@@ -0,0 +1,29 @@
+warning: the feature `unsafe_binders` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/expr.rs:1:12
+   |
+LL | #![feature(unsafe_binders)]
+   |            ^^^^^^^^^^^^^^
+   |
+   = note: see issue #130516 <https://github.com/rust-lang/rust/issues/130516> for more information
+   = note: `#[warn(incomplete_features)]` on by default
+
+error: unsafe binders are not yet implemented
+  --> $DIR/expr.rs:8:17
+   |
+LL |     let binder: unsafe<'a> &'a i32 = wrap_binder!(x);
+   |                 ^^^^^^^^^^^^^^^^^^
+
+error: unsafe binders are not yet implemented
+  --> $DIR/expr.rs:8:51
+   |
+LL |     let binder: unsafe<'a> &'a i32 = wrap_binder!(x);
+   |                                                   ^
+
+error: unsafe binders are not yet implemented
+  --> $DIR/expr.rs:11:30
+   |
+LL |     let rx = *unwrap_binder!(binder);
+   |                              ^^^^^^
+
+error: aborting due to 3 previous errors; 1 warning emitted
+

tests/ui/unsafe-binders/lifetime-resolution.rs

@@ -0,0 +1,19 @@
+#![feature(unsafe_binders)]
+//~^ WARN the feature `unsafe_binders` is incomplete
+
+fn foo<'a>() {
+    let good: unsafe<'b> &'a &'b ();
+    //~^ ERROR unsafe binders are not yet implemented
+
+    let missing: unsafe<> &'missing ();
+    //~^ ERROR unsafe binders are not yet implemented
+    //~| ERROR use of undeclared lifetime name `'missing`
+
+    fn inner<'b>() {
+        let outer: unsafe<> &'a &'b ();
+        //~^ ERROR unsafe binders are not yet implemented
+        //~| can't use generic parameters from outer item
+    }
+}
+
+fn main() {}

tests/ui/unsafe-binders/lifetime-resolution.stderr

@@ -0,0 +1,65 @@
+error[E0261]: use of undeclared lifetime name `'missing`
+  --> $DIR/lifetime-resolution.rs:8:28
+   |
+LL |     let missing: unsafe<> &'missing ();
+   |                            ^^^^^^^^ undeclared lifetime
+   |
+   = note: for more information on higher-ranked polymorphism, visit https://doc.rust-lang.org/nomicon/hrtb.html
+help: consider making the type lifetime-generic with a new `'missing` lifetime
+   |
+LL |     let missing: unsafe<'missing, > &'missing ();
+   |                         +++++++++
+help: consider introducing lifetime `'missing` here
+   |
+LL | fn foo<'missing, 'a>() {
+   |        +++++++++
+
+error[E0401]: can't use generic parameters from outer item
+  --> $DIR/lifetime-resolution.rs:13:30
+   |
+LL | fn foo<'a>() {
+   |        -- lifetime parameter from outer item
+...
+LL |         let outer: unsafe<> &'a &'b ();
+   |                              ^^ use of generic parameter from outer item
+   |
+help: consider making the type lifetime-generic with a new `'a` lifetime
+   |
+LL |         let outer: unsafe<'a, > &'a &'b ();
+   |                           +++
+help: consider introducing lifetime `'a` here
+   |
+LL |     fn inner<'a, 'b>() {
+   |              +++
+
+warning: the feature `unsafe_binders` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/lifetime-resolution.rs:1:12
+   |
+LL | #![feature(unsafe_binders)]
+   |            ^^^^^^^^^^^^^^
+   |
+   = note: see issue #130516 <https://github.com/rust-lang/rust/issues/130516> for more information
+   = note: `#[warn(incomplete_features)]` on by default
+
+error: unsafe binders are not yet implemented
+  --> $DIR/lifetime-resolution.rs:5:15
+   |
+LL |     let good: unsafe<'b> &'a &'b ();
+   |               ^^^^^^^^^^^^^^^^^^^^^
+
+error: unsafe binders are not yet implemented
+  --> $DIR/lifetime-resolution.rs:8:18
+   |
+LL |     let missing: unsafe<> &'missing ();
+   |                  ^^^^^^^^^^^^^^^^^^^^^
+
+error: unsafe binders are not yet implemented
+  --> $DIR/lifetime-resolution.rs:13:20
+   |
+LL |         let outer: unsafe<> &'a &'b ();
+   |                    ^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 5 previous errors; 1 warning emitted
+
+Some errors have detailed explanations: E0261, E0401.
+For more information about an error, try `rustc --explain E0261`.

tests/ui/unsafe-binders/simple.rs

@@ -0,0 +1,7 @@
+#![feature(unsafe_binders)]
+//~^ WARN the feature `unsafe_binders` is incomplete
+
+fn main() {
+    let x: unsafe<'a> &'a ();
+    //~^ ERROR unsafe binders are not yet implemented
+}

tests/ui/unsafe-binders/simple.stderr

@@ -0,0 +1,17 @@
+warning: the feature `unsafe_binders` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/simple.rs:1:12
+   |
+LL | #![feature(unsafe_binders)]
+   |            ^^^^^^^^^^^^^^
+   |
+   = note: see issue #130516 <https://github.com/rust-lang/rust/issues/130516> for more information
+   = note: `#[warn(incomplete_features)]` on by default
+
+error: unsafe binders are not yet implemented
+  --> $DIR/simple.rs:5:12
+   |
+LL |     let x: unsafe<'a> &'a ();
+   |            ^^^^^^^^^^^^^^^^^
+
+error: aborting due to 1 previous error; 1 warning emitted
+