test E0133 when calling free/impl async unsafe fn in safe code

Author: delan

src/test/ui/async-await/async-unsafe-fn-call-in-safe.rs

@@ -0,0 +1,16 @@
+// edition:2018
+
+#![feature(async_await, async_closure)]
+
+struct S;
+
+impl S {
+    async unsafe fn f() {}
+}
+
+async unsafe fn f() {}
+
+fn main() {
+    S::f(); //~ ERROR call to unsafe function is unsafe
+    f(); //~ ERROR call to unsafe function is unsafe
+}

src/test/ui/async-await/async-unsafe-fn-call-in-safe.stderr

@@ -0,0 +1,19 @@
+error[E0133]: call to unsafe function is unsafe and requires unsafe function or block
+  --> $DIR/async-unsafe-fn-call-in-safe.rs:14:5
+   |
+LL |     S::f();
+   |     ^^^^^^ call to unsafe function
+   |
+   = note: consult the function's documentation for information on how to avoid undefined behavior
+
+error[E0133]: call to unsafe function is unsafe and requires unsafe function or block
+  --> $DIR/async-unsafe-fn-call-in-safe.rs:15:5
+   |
+LL |     f();
+   |     ^^^ call to unsafe function
+   |
+   = note: consult the function's documentation for information on how to avoid undefined behavior
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0133`.