Auto merge of #4780 - flip1995:ice_4775, r=phansch

Fix ICE #4775

Fixes #4775

changelog: Fix ICE with const_generics

tests/ui/ice-4775.rs

@@ -0,0 +1,14 @@
+#![feature(const_generics)]
+#![allow(incomplete_features)]
+
+pub struct ArrayWrapper<const N: usize>([usize; N]);
+
+impl<const N: usize> ArrayWrapper<{ N }> {
+    pub fn ice(&self) {
+        for i in self.0.iter() {
+            println!("{}", i);
+        }
+    }
+}
+
+fn main() {}