Fix internal assertions renaming types using with (bytecodealliance#2215)

* Fix internal assertions renaming types using `with`

This commit fixes a fuzz bug that cropped up trying to rename a type
using `with`. The destination type that was created didn't have its new
name registered.

* Fix build on latest nightly

Some new warnings cropping up to handle.

Author: alexcrichton

crates/wit-parser/src/resolve.rs

@@ -3592,11 +3592,13 @@ impl Remap {
                 // reflect the change not only in the world key but additionally
                 // in the function itself.
                 let mut new_item = item.1.clone();
-                if let WorldItem::Function(f) = &mut new_item {
-                    f.name = n.clone();
-                }
                 let key = WorldKey::Name(n.clone());
                 cloner.world_item(&key, &mut new_item);
+                match &mut new_item {
+                    WorldItem::Function(f) => f.name = n.clone(),
+                    WorldItem::Type(id) => cloner.resolve.types[*id].name = Some(n.clone()),
+                    WorldItem::Interface { .. } => {}
+                }
 
                 let prev = get_items(cloner.resolve).insert(key, new_item);
                 if prev.is_some() {

tests/cli/merge-world-using-with.wit

@@ -0,0 +1,11 @@
+// RUN: component wit % -t | validate
+
+package a:b;
+
+world a {
+  resource foo;
+}
+
+world b {
+  include a with { foo as bar }
+}