Make def_key and HIR parenting consistent.

src/test/ui/impl-trait/impl-trait-in-macro.rs

@@ -0,0 +1,20 @@
+use std::fmt::Debug;
+
+macro_rules! i {
+    ($($tr:tt)*) => { impl $($tr)* };
+}
+
+fn foo(x: i!(Debug), y: i!(Debug)) -> String {
+    let mut a = x;
+    a = y; //~ ERROR mismatched
+    format!("{:?}", a)
+}
+
+trait S<T> {}
+
+fn much_universe<T: S<i!(Debug)>, U: IntoIterator<Item = i!(Iterator<Item = i!(Clone)>)>>(
+    _: i!(Debug + Clone),
+) {
+}
+
+fn main() {}

src/test/ui/impl-trait/impl-trait-in-macro.stderr

@@ -0,0 +1,20 @@
+error[E0308]: mismatched types
+  --> $DIR/impl-trait-in-macro.rs:9:9
+   |
+LL |     ($($tr:tt)*) => { impl $($tr)* };
+   |                       ----
+   |                       |
+   |                       expected type parameter
+   |                       found type parameter
+...
+LL |     a = y;
+   |         ^ expected type parameter `impl Debug`, found a different type parameter `impl Debug`
+   |
+   = note: expected type parameter `impl Debug` (type parameter `impl Debug`)
+              found type parameter `impl Debug` (type parameter `impl Debug`)
+   = note: a type parameter was expected, but a different one was found; you might be missing a type parameter or trait bound
+   = note: for more information, visit https://doc.rust-lang.org/book/ch10-02-traits.html#traits-as-parameters
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.

src/test/ui/impl-trait/universal-two-impl-traits.rs

@@ -6,4 +6,11 @@ fn foo(x: impl Debug, y: impl Debug) -> String {
     format!("{:?}", a)
 }
 
-fn main() { }
+trait S<T> {}
+
+fn much_universe<T: S<impl Debug>, U: IntoIterator<Item = impl Iterator<Item = impl Clone>>>(
+    _: impl Debug + Clone,
+) {
+}
+
+fn main() {}