Add/Modify tests for argument position impl Trait

src/test/compile-fail/impl-trait/disallowed.rs

@@ -10,11 +10,6 @@
 
 #![feature(conservative_impl_trait)]
 
-fn arguments(_: impl Fn(),
-//~^ ERROR `impl Trait` not allowed outside of function and inherent method return types
-             _: Vec<impl Clone>) {}
-//~^ ERROR `impl Trait` not allowed outside of function and inherent method return types
-
 type Factory<R> = impl Fn() -> R;
 //~^ ERROR `impl Trait` not allowed outside of function and inherent method return types
 

src/test/compile-fail/impl-trait/impl-generic-mismatch.rs

@@ -0,0 +1,32 @@
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![feature(universal_impl_trait)]
+use std::fmt::Debug;
+
+trait Foo {
+    fn foo(&self, &impl Debug);
+}
+
+impl Foo for () {
+    fn foo<U: Debug>(&self, _: &U) { }
+    //~^ Error method `foo` has incompatible signature for trait
+}
+
+trait Bar {
+    fn bar<U: Debug>(&self, &U);
+}
+
+impl Bar for () {
+    fn bar(&self, _: &impl Debug) { }
+    //~^ Error method `bar` has incompatible signature for trait
+}
+
+fn main() {}

src/test/compile-fail/impl-trait/many-cases.rs

@@ -0,0 +1,71 @@
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! A simple test for testing many permutations of allowedness of
+//! impl Trait
+#![feature(conservative_impl_trait, universal_impl_trait, dyn_trait)]
+use std::fmt::Debug;
+
+// Allowed
+fn simple_universal(_: impl Debug) { panic!() }
+
+// Allowed
+fn simple_existential() -> impl Debug { panic!() }
+
+// Allowed
+fn collection_universal(_: Vec<impl Debug>) { panic!() }
+
+// Allowed
+fn collection_existential() -> Vec<impl Debug> { panic!() }
+
+// Disallowed
+fn fn_type_universal(_: fn(impl Debug)) { panic!() }
+//~^ ERROR `impl Trait` not allowed outside of function and inherent method return types
+
+// Disallowed
+fn fn_type_existential() -> fn(impl Debug) { panic!() }
+//~^ ERROR `impl Trait` not allowed outside of function and inherent method return types
+
+// Allowed
+fn dyn_universal(_: &dyn Iterator<Item = impl Debug>) { panic!() }
+
+// Disallowed
+fn dyn_fn_trait(_: &dyn Fn(impl Debug)) { panic!() }
+//~^ ERROR `impl Trait` not allowed outside of function and inherent method return types
+
+// Allowed
+fn nested_universal(_: impl Iterator<Item = impl Iterator>) { panic!() }
+
+// Allowed
+fn nested_existential() -> impl IntoIterator<Item = impl IntoIterator> {
+    vec![vec![0; 10], vec![12; 7], vec![8; 3]]
+}
+
+// Disallowed
+fn universal_fn_trait(_: impl Fn(impl Debug)) { panic!() }
+//~^ ERROR `impl Trait` not allowed outside of function and inherent method return types
+
+// Disallowed
+struct ImplMember { x: impl Debug }
+//~^ ERROR `impl Trait` not allowed outside of function and inherent method return types
+
+// Disallowed
+trait Universal {
+    // FIXME, should error?
+    fn universal(impl Debug);
+}
+
+// Disallowed
+trait Existential {
+    fn existential() -> impl Debug;
+    //~^ ERROR `impl Trait` not allowed outside of function and inherent method return types
+}
+
+fn main() {}