move hover implementation to ra_analysis

1 files changed, 57 insertions, 0 deletions

diff --git a/crates/ra_analysis/src/hover.rs b/crates/ra_analysis/src/hover.rs
new file mode 100644
index 000000000..c3825f6ea
--- /dev/null
+++ b/crates/ra_analysis/src/hover.rs
@@ -0,0 +1,57 @@
+use ra_db::{Cancelable, SyntaxDatabase};
+use ra_syntax::{ast, AstNode};
+
+use crate::{db::RootDatabase, RangeInfo, FilePosition, FileRange};
+
+pub(crate) fn hover(
+    db: &RootDatabase,
+    position: FilePosition,
+) -> Cancelable<Option<RangeInfo<String>>> {
+    let mut res = Vec::new();
+    let range = if let Some(rr) = db.approximately_resolve_symbol(position)? {
+        for nav in rr.resolves_to {
+            res.extend(db.doc_text_for(nav)?)
+        }
+        rr.reference_range
+    } else {
+        let file = db.source_file(position.file_id);
+        let expr: ast::Expr = ctry!(ra_editor::find_node_at_offset(
+            file.syntax(),
+            position.offset
+        ));
+        let frange = FileRange {
+            file_id: position.file_id,
+            range: expr.syntax().range(),
+        };
+        res.extend(db.type_of(frange)?);
+        expr.syntax().range()
+    };
+    if res.is_empty() {
+        return Ok(None);
+    }
+    let res = RangeInfo::new(range, res.join("\n\n---\n"));
+    Ok(Some(res))
+}
+
+#[cfg(test)]
+mod tests {
+    use ra_syntax::TextRange;
+
+    use crate::mock_analysis::single_file_with_position;
+
+    #[test]
+    fn hover_shows_type_of_an_expression() {
+        let (analysis, position) = single_file_with_position(
+            "
+            pub fn foo() -> u32 { 1 }
+
+            fn main() {
+                let foo_test = foo()<|>;
+            }
+        ",
+        );
+        let hover = analysis.hover(position).unwrap().unwrap();
+        assert_eq!(hover.range, TextRange::from_to(95.into(), 100.into()));
+        assert_eq!(hover.info, "u32");
+    }
+}