Merge #7795

7795: Show docs on hover for keywords and primitives r=matklad a=Veykril

![lAWFadkziX](https://user-images.githubusercontent.com/3757771/109369534-eeb4f500-789c-11eb-8f2b-2f9c4e129de3.gif)

It's a bit annoying that this requires the `SyntaxNode` and `Semantics` to be pulled through `hover_for_definition` just so we can get the `std` crate but I couldn't think of a better way.

Co-authored-by: Lukas Wirth <[email protected]>

2 files changed, 12 insertions, 0 deletions

diff --git a/crates/ide_db/src/helpers.rs b/crates/ide_db/src/helpers.rs
index f9de8ce0e..3ff77400b 100644
--- a/crates/ide_db/src/helpers.rs
+++ b/crates/ide_db/src/helpers.rs
@@ -41,6 +41,10 @@ pub struct FamousDefs<'a, 'b>(pub &'a Semantics<'b, RootDatabase>, pub Option<Cr
 impl FamousDefs<'_, '_> {
     pub const FIXTURE: &'static str = include_str!("helpers/famous_defs_fixture.rs");
 
+    pub fn std(&self) -> Option<Crate> {
+        self.find_crate("std")
+    }
+
     pub fn core(&self) -> Option<Crate> {
         self.find_crate("core")
     }
diff --git a/crates/ide_db/src/helpers/famous_defs_fixture.rs b/crates/ide_db/src/helpers/famous_defs_fixture.rs
index bb4e9666b..d3464ae17 100644
--- a/crates/ide_db/src/helpers/famous_defs_fixture.rs
+++ b/crates/ide_db/src/helpers/famous_defs_fixture.rs
@@ -129,3 +129,11 @@ pub mod prelude {
 }
 #[prelude_import]
 pub use prelude::*;
+//- /libstd.rs crate:std deps:core
+//! Signatures of traits, types and functions from the std lib for use in tests.
+
+/// Docs for return_keyword
+mod return_keyword {}
+
+/// Docs for prim_str
+mod prim_str {}