From c42bbc5e37dee8b1de309a6dd5b892651de4b676 Mon Sep 17 00:00:00 2001
From: Edwin Cheng <edwin0cheng@gmail.com>
Date: Thu, 27 Feb 2020 23:03:18 +0800
Subject: Ignore hover on builtin macro

---
 crates/ra_ide/src/hover.rs | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/crates/ra_ide/src/hover.rs b/crates/ra_ide/src/hover.rs
index 177038e20..dfa0f1d97 100644
--- a/crates/ra_ide/src/hover.rs
+++ b/crates/ra_ide/src/hover.rs
@@ -174,6 +174,12 @@ pub(crate) fn hover(db: &RootDatabase, position: FilePosition) -> Option<RangeIn
         .ancestors()
         .find(|n| ast::Expr::cast(n.clone()).is_some() || ast::Pat::cast(n.clone()).is_some())?;
 
+    // if this node is a MACRO_CALL, it means that `descend_into_macros` is failed to resolve.
+    // (e.g expanding a builtin macro). So we give up here.
+    if node.kind() == MACRO_CALL {
+        return None;
+    }
+
     // FIXME: Currently `hover::typeof` do not work inside
     // macro expansion such that if the hover range is pointing to
     // a string literal, the following type_of will return None.
@@ -801,6 +807,25 @@ fn func(foo: i32) { if true { <|>foo; }; }
         );
     }
 
+    #[test]
+    fn test_hover_through_literal_string_in_builtin_macro() {
+        check_hover_no_result(
+            r#"
+            //- /lib.rs            
+            #[rustc_builtin_macro]
+            macro_rules! assert {
+                ($cond:expr) => {{ /* compiler built-in */ }};
+                ($cond:expr,) => {{ /* compiler built-in */ }};
+                ($cond:expr, $($arg:tt)+) => {{ /* compiler built-in */ }};
+            }        
+
+            fn foo() {
+                assert!("hel<|>lo");
+            }
+            "#,
+        );
+    }
+
     #[test]
     fn test_hover_non_ascii_space_doc() {
         check_hover_result(
-- 
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