Merge #10870

10870: ide: fix macro expansion for 'as _' r=Veykril a=jhgg

fixes: #10862

Co-authored-by: Jake Heinz <jh@discordapp.com>

crates/ide/src/expand_macro.rs

@@ -176,6 +176,10 @@ fn insert_whitespaces(syn: SyntaxNode) -> String {
                 res.push_str(token.text());
                 res.push(' ');
             }
+            AS_KW => {
+                res.push_str(token.text());
+                res.push(' ');
+            }
             T![;] => {
                 res.push_str(";\n");
                 res.extend(iter::repeat(" ").take(2 * indent));
@@ -210,6 +214,23 @@ mod tests {
         expect.assert_eq(&actual);
     }
 
+    #[test]
+    fn macro_expand_as_keyword() {
+        check(
+            r#"
+macro_rules! bar {
+    ($i:tt) => { $i as _ }
+}
+fn main() {
+    let x: u64 = ba$0r!(5i64);
+}
+"#,
+            expect![[r#"
+                bar
+                5i64 as _"#]],
+        );
+    }
+
     #[test]
     fn macro_expand_recursive_expansion() {
         check(