Fix edge case for ImportGranularity guessing

crates/ide_db/src/helpers/insert_use.rs

@@ -120,18 +120,22 @@ fn guess_granularity_from_scope(&self) -> ImportGranularityGuess {
             if eq_visibility(prev_vis, curr_vis.clone()) && eq_attrs(prev_attrs, curr_attrs.clone())
             {
                 if let Some((prev_path, curr_path)) = prev.path().zip(curr.path()) {
-                    if let Some(_) = common_prefix(&prev_path, &curr_path) {
+                    if let Some((prev_prefix, _)) = common_prefix(&prev_path, &curr_path) {
                         if prev.use_tree_list().is_none() && curr.use_tree_list().is_none() {
+                            let prefix_c = prev_prefix.qualifiers().count();
+                            let curr_c = curr_path.qualifiers().count() - prefix_c;
+                            let prev_c = prev_path.qualifiers().count() - prefix_c;
+                            if curr_c <= 1 || prev_c <= 1 {
                                 // Same prefix but no use tree lists so this has to be of item style.
                                 break ImportGranularityGuess::Item; // this overwrites CrateOrModule, technically the file doesn't adhere to anything here.
-                        } else {
+                            }
+                        }
                         // Same prefix with item tree lists, has to be module style as it
                         // can't be crate style since the trees wouldn't share a prefix then.
                         break ImportGranularityGuess::Module;
                     }
                 }
             }
-            }
             prev = curr;
             prev_vis = curr_vis;
             prev_attrs = curr_attrs;

crates/ide_db/src/helpers/insert_use/tests.rs

@@ -660,6 +660,13 @@ fn guess_item() {
         r"
 use foo::bar::baz;
 use foo::bar::qux;
+",
+        ImportGranularityGuess::Item,
+    );
+    check_guess(
+        r"
+use foo::bar::Bar;
+use foo::baz;
 ",
         ImportGranularityGuess::Item,
     );
@@ -679,6 +686,14 @@ fn guess_module() {
         r"
 use foo::bar::baz;
 use foo::{baz::{qux, quux}, bar};
+",
+        ImportGranularityGuess::Module,
+    );
+    check_guess(
+        r"
+use foo::bar::Bar;
+use foo::baz::Baz;
+use foo::{Foo, Qux};
 ",
         ImportGranularityGuess::Module,
     );

crates/syntax/src/ast/node_ext.rs

@@ -259,11 +259,14 @@ pub fn first_segment(&self) -> Option<ast::PathSegment> {
     }
 
     pub fn segments(&self) -> impl Iterator<Item = ast::PathSegment> + Clone {
-        // cant make use of SyntaxNode::siblings, because the returned Iterator is not clone
         successors(self.first_segment(), |p| {
             p.parent_path().parent_path().and_then(|p| p.segment())
         })
     }
+
+    pub fn qualifiers(&self) -> impl Iterator<Item = ast::Path> + Clone {
+        successors(self.qualifier(), |p| p.qualifier())
+    }
 }
 impl ast::UseTree {
     pub fn is_simple_path(&self) -> bool {