Fix use crate as <name>; imports

crates/hir_def/src/nameres/collector.rs

@@ -656,13 +656,18 @@ impl DefCollector<'_> {
                 }
             }
         } else {
-            match import.path.segments().last() {
-                Some(last_segment) => {
             let name = match &import.alias {
                 Some(ImportAlias::Alias(name)) => Some(name.clone()),
                 Some(ImportAlias::Underscore) => None,
-                        None => Some(last_segment.clone()),
+                None => match import.path.segments().last() {
+                    Some(last_segment) => Some(last_segment.clone()),
+                    None => {
+                        cov_mark::hit!(bogus_paths);
+                        return;
+                    }
+                },
             };
+
             log::debug!("resolved import {:?} ({:?}) to {:?}", name, import, def);
 
             // extern crates in the crate root are special-cased to insert entries into the extern prelude: rust-lang/rust#54658
@@ -674,9 +679,6 @@ impl DefCollector<'_> {
 
             self.update(module_id, &[(name, def)], vis, ImportType::Named);
         }
-                None => cov_mark::hit!(bogus_paths),
-            }
-        }
     }
 
     fn update(

crates/hir_def/src/nameres/tests.rs

@@ -713,3 +713,22 @@ pub fn f() {}
         "#]],
     );
 }
+
+#[test]
+fn use_crate_as() {
+    check(
+        r#"
+use crate as foo;
+
+use foo::bar as baz;
+
+fn bar() {}
+        "#,
+        expect![[r#"
+            crate
+            bar: v
+            baz: v
+            foo: t
+        "#]],
+    );
+}