Move imports_granularity=Item logic into sep fn.

src/formatting/imports.rs

@@ -179,19 +179,26 @@ pub(crate) fn merge_use_trees(use_trees: Vec<UseTree>, merge_by: SharedPrefix) -
             }
         }
     }
-    for merged in &mut result {
-        // If a path ends with `::self`, rewrite it to `::{self}`.
-        if let Some(UseSegment::Slf(..)) = merged.path.last() {
-            let slf_segment = merged.path.pop().unwrap();
-            merged.path.push(UseSegment::List(vec![UseTree::from_path(
-                vec![slf_segment],
-                DUMMY_SP,
-            )]));
-        }
-    }
     result
 }
 
+pub(crate) fn flatten_use_trees(use_trees: Vec<UseTree>) -> Vec<UseTree> {
+    use_trees
+        .into_iter()
+        .flat_map(UseTree::flatten)
+        .map(|mut tree| {
+            if let Some(UseSegment::Slf(..)) = tree.path.last() {
+                let self_segment = tree.path.pop().unwrap();
+                tree.path.push(UseSegment::List(vec![UseTree::from_path(
+                    vec![self_segment],
+                    DUMMY_SP,
+                )]));
+            }
+            tree
+        })
+        .collect()
+}
+
 impl fmt::Debug for UseTree {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt::Display::fmt(self, f)
@@ -552,25 +559,24 @@ impl UseTree {
                 SharedPrefix::Module => {
                     self.path[..self.path.len() - 1] == other.path[..other.path.len() - 1]
                 }
-                SharedPrefix::NoPrefix => false,
             }
         }
     }
 
     fn flatten(self) -> Vec<UseTree> {
         match self.path.last() {
             Some(UseSegment::List(list)) => {
+                if list.len() == 1 && list[0].path.len() == 1 {
+                    if let UseSegment::Slf(..) = list[0].path[0] {
+                        return vec![self];
+                    };
+                }
                 let prefix = &self.path[..self.path.len() - 1];
                 let mut result = vec![];
                 for nested_use_tree in list {
                     for flattened in &mut nested_use_tree.clone().flatten() {
                         let mut new_path = prefix.to_vec();
                         new_path.append(&mut flattened.path);
-                        if flattened.path.len() == 1 {
-                            if let UseSegment::Slf(..) = flattened.path[0] {
-                                new_path.pop();
-                            }
-                        }
                         result.push(UseTree {
                             path: new_path,
                             span: self.span,
@@ -865,7 +871,6 @@ impl Rewrite for UseTree {
 pub(crate) enum SharedPrefix {
     Crate,
     Module,
-    NoPrefix,
 }
 
 #[cfg(test)]
@@ -1081,24 +1086,22 @@ mod test {
     }
 
     #[test]
-    fn test_use_tree_merge_no_prefix() {
-        test_merge!(
-            NoPrefix,
-            ["foo::{a::{b, c}, d::e}"],
-            ["foo::a::b", "foo::a::c", "foo::d::e"]
+    fn test_flatten_use_trees() {
+        assert_eq!(
+            flatten_use_trees(parse_use_trees!["foo::{a::{b, c}, d::e}"]),
+            parse_use_trees!["foo::a::b", "foo::a::c", "foo::d::e"]
         );
 
-        test_merge!(
-            NoPrefix,
-            ["foo::{self, a, b::{c, d}, e::*}"],
-            [
+        assert_eq!(
+            flatten_use_trees(parse_use_trees!["foo::{self, a, b::{c, d}, e::*}"]),
+            parse_use_trees![
                 "foo::{self}",
                 "foo::a",
                 "foo::b::c",
                 "foo::b::d",
                 "foo::e::*"
             ]
-        )
+        );
     }
 
     #[test]

src/formatting/reorder.rs

@@ -12,7 +12,7 @@ use rustc_ast::ast;
 use rustc_span::{symbol::sym, Span};
 
 use crate::config::{Config, GroupImportsTactic, ImportGranularity};
-use crate::formatting::imports::UseSegment;
+use crate::formatting::imports::{flatten_use_trees, UseSegment};
 use crate::formatting::modules::{get_mod_inner_attrs, FileModMap};
 use crate::formatting::{
     imports::{merge_use_trees, UseTree},
@@ -233,9 +233,7 @@ fn rewrite_reorderable_or_regroupable_items(
                 ImportGranularity::Module => {
                     merge_use_trees(normalized_items, SharedPrefix::Module)
                 }
-                ImportGranularity::Item => {
-                    merge_use_trees(normalized_items, SharedPrefix::NoPrefix)
-                }
+                ImportGranularity::Item => flatten_use_trees(normalized_items),
                 ImportGranularity::Preserve => normalized_items,
             };