Merge #3494

3494: Implement include macro r=matklad a=edwin0cheng

This PR implement builtin `include` macro.

* It does not support include as expression yet.
* It doesn't consider `env!("OUT_DIR")` yet.


Co-authored-by: Edwin Cheng <edwin0cheng@gmail.com>

crates/ra_hir_ty/src/tests/macros.rs

@@ -438,6 +438,51 @@ fn main() {
     );
 }
 
+#[test]
+fn infer_builtin_macros_include() {
+    let (db, pos) = TestDB::with_position(
+        r#"
+//- /main.rs 
+#[rustc_builtin_macro]
+macro_rules! include {() => {}}
+
+include!("foo.rs");
+
+fn main() {
+    bar()<|>;
+}
+
+//- /foo.rs
+fn bar() -> u32 {0}
+"#,
+    );
+    assert_eq!("u32", type_at_pos(&db, pos));
+}
+
+#[test]
+fn infer_builtin_macros_include_concat() {
+    let (db, pos) = TestDB::with_position(
+        r#"
+//- /main.rs 
+#[rustc_builtin_macro]
+macro_rules! include {() => {}}
+
+#[rustc_builtin_macro]
+macro_rules! concat {() => {}}
+
+include!(concat!("f", "oo.rs"));
+
+fn main() {
+    bar()<|>;
+}
+
+//- /foo.rs
+fn bar() -> u32 {0}
+"#,
+    );
+    assert_eq!("u32", type_at_pos(&db, pos));
+}
+
 #[test]
 fn infer_builtin_macros_concat_with_lazy() {
     assert_snapshot!(