Merge #2786

2786: Proper handling local in hover r=flodiebold a=edwin0cheng

This PR implement back the `Local` hover information generation, which is fall back to a general case catch previously :

https://github.com/rust-analyzer/rust-analyzer/blob/9a44f627be0b3c49184e3ad594849f9b5ed78daa/crates/ra_ide/src/hover.rs#L173-L182



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

Author: bors[bot]

crates/ra_ide/src/hover.rs

@@ -128,7 +128,7 @@ fn hover_text_from_name_kind(db: &RootDatabase, name_kind: NameKind) -> Option<S
             hir::ModuleDef::TypeAlias(it) => from_def_source(db, it),
             hir::ModuleDef::BuiltinType(it) => Some(it.to_string()),
         },
-        Local(_) => None,
+        Local(it) => Some(rust_code_markup(it.ty(db).display_truncated(db, None).to_string())),
         TypeParam(_) | SelfType(_) => {
             // FIXME: Hover for generic param
             None
@@ -174,6 +174,8 @@ pub(crate) fn hover(db: &RootDatabase, position: FilePosition) -> Option<RangeIn
         .value
         .ancestors()
         .find(|n| ast::Expr::cast(n.clone()).is_some() || ast::Pat::cast(n.clone()).is_some())?;
+
+    // The following logic will not work if token is coming from a macro
     let frange = FileRange { file_id: position.file_id, range: node.text_range() };
     res.extend(type_of(db, frange).map(rust_code_markup));
     if res.is_empty() {
@@ -729,4 +731,20 @@ fn func(foo: i32) { if true { <|>foo; }; }
             &["fn foo()"],
         );
     }
+
+    #[test]
+    fn test_hover_through_expr_in_macro() {
+        check_hover_result(
+            "
+            //- /lib.rs
+            macro_rules! id {
+                ($($tt:tt)*) => { $($tt)* }
+            }
+            fn foo(bar:u32) {
+                let a = id!(ba<|>r);
+            }            
+            ",
+            &["u32"],
+        );
+    }
 }