Don't render () in calls to assoc functions

crates/ra_ide_api/src/completion/completion_context.rs

@@ -137,6 +137,13 @@ impl<'a> CompletionContext<'a> {
         };
         if let Some(segment) = ast::PathSegment::cast(parent) {
             let path = segment.parent_path();
+            self.is_call = path
+                .syntax()
+                .parent()
+                .and_then(ast::PathExpr::cast)
+                .and_then(|it| it.syntax().parent().and_then(ast::CallExpr::cast))
+                .is_some();
+
             if let Some(mut path) = hir::Path::from_ast(path) {
                 if !path.is_ident() {
                     path.segments.pop().unwrap();
@@ -176,12 +183,6 @@ impl<'a> CompletionContext<'a> {
                     }
                 }
             }
-            self.is_call = path
-                .syntax()
-                .parent()
-                .and_then(ast::PathExpr::cast)
-                .and_then(|it| it.syntax().parent().and_then(ast::CallExpr::cast))
-                .is_some()
         }
         if let Some(field_expr) = ast::FieldExpr::cast(parent) {
             // The receiver comes before the point of insertion of the fake

crates/ra_ide_api/src/completion/completion_item.rs

@@ -427,6 +427,17 @@ mod tests {
                 frob<|>();
             }
             ",
+        );
+        check_reference_completion(
+            "dont_render_function_parens_if_already_call_assoc_fn",
+            "
+            //- /lib.rs
+            struct Foo {}
+            impl Foo { fn new() -> Foo {} }
+            fn main() {
+                Foo::ne<|>();
+            }
+            ",
         )
     }
 

crates/ra_ide_api/src/completion/snapshots/completion_item__dont_render_function_parens_if_already_call_assoc_fn.snap

@@ -0,0 +1,24 @@
+---
+created: "2019-02-17T18:29:14.513213526Z"
+creator: insta@0.6.2
+source: crates/ra_ide_api/src/completion/completion_item.rs
+expression: kind_completions
+---
+[
+    CompletionItem {
+        completion_kind: Reference,
+        label: "new",
+        kind: Some(
+            Method
+        ),
+        detail: Some(
+            "fn new() -> Foo"
+        ),
+        documentation: None,
+        lookup: None,
+        insert_text: None,
+        insert_text_format: PlainText,
+        source_range: [67; 69),
+        text_edit: None
+    }
+]