Don't ICE on infinitely recursive types

`evaluate_obligation` can only be run on types that are already valid.
So rustdoc still has to run typeck even though it doesn't care about the
result.

2 files changed, 21 insertions, 0 deletions

diff --git a/src/test/rustdoc-ui/infinite-recursive-type.rs b/src/test/rustdoc-ui/infinite-recursive-type.rs
new file mode 100644
index 00000000000..32793fc4f76
--- /dev/null
+++ b/src/test/rustdoc-ui/infinite-recursive-type.rs
@@ -0,0 +1,4 @@
+enum E {
+//~^ ERROR recursive type `E` has infinite size
+    V(E),
+}
diff --git a/src/test/rustdoc-ui/infinite-recursive-type.stderr b/src/test/rustdoc-ui/infinite-recursive-type.stderr
new file mode 100644
index 00000000000..897445f200c
--- /dev/null
+++ b/src/test/rustdoc-ui/infinite-recursive-type.stderr
@@ -0,0 +1,17 @@
+error[E0072]: recursive type `E` has infinite size
+  --> $DIR/infinite-recursive-type.rs:1:1
+   |
+LL | enum E {
+   | ^^^^^^ recursive type has infinite size
+LL |
+LL |     V(E),
+   |       - recursive without indirection
+   |
+help: insert some indirection (e.g., a `Box`, `Rc`, or `&`) to make `E` representable
+   |
+LL |     V(Box<E>),
+   |       ^^^^ ^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0072`.