fix: splitting path of a glob import wrongly adds self

`ast::UseTree::split_prefix` handles globs now.
Removed an extra branch for globs in `ide_db::imports::merge_imports::recursive_merge` (superseeded by split_prefix).

crates/ide_assists/src/handlers/merge_imports.rs

@@ -330,7 +330,7 @@ fn test_merge_nested_list_self_and_glob() {
 use std::{fmt::{self, Display}};
 ",
             r"
-use std::{fmt::{self, *, Display}};
+use std::{fmt::{*, self, Display}};
 ",
         )
     }
@@ -440,4 +440,18 @@ fn test_empty_use() {
 fn main() {}",
         );
     }
+
+    #[test]
+    fn split_glob() {
+        check_assist(
+            merge_imports,
+            r"
+use foo::$0*;
+use foo::bar::Baz;
+",
+            r"
+use foo::{*, bar::Baz};
+",
+        );
+    }
 }

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

@@ -656,7 +656,7 @@ fn merge_mod_into_glob() {
     check_with_config(
         "token::TokenKind",
         r"use token::TokenKind::*;",
-        r"use token::TokenKind::{self, *};",
+        r"use token::TokenKind::{*, self};",
         &InsertUseConfig {
             granularity: ImportGranularity::Crate,
             enforce_granularity: true,
@@ -670,11 +670,10 @@ fn merge_mod_into_glob() {
 
 #[test]
 fn merge_self_glob() {
-    cov_mark::check!(merge_self_glob);
     check_with_config(
         "self",
         r"use self::*;",
-        r"use self::{self, *};",
+        r"use self::{*, self};",
         &InsertUseConfig {
             granularity: ImportGranularity::Crate,
             enforce_granularity: true,
@@ -693,7 +692,7 @@ fn merge_glob() {
         r"
 use syntax::{SyntaxKind::*};",
         r"
-use syntax::{SyntaxKind::{self, *}};",
+use syntax::{SyntaxKind::{*, self}};",
     )
 }
 
@@ -702,7 +701,7 @@ fn merge_glob_nested() {
     check_crate(
         "foo::bar::quux::Fez",
         r"use foo::bar::{Baz, quux::*};",
-        r"use foo::bar::{Baz, quux::{self::*, Fez}};",
+        r"use foo::bar::{Baz, quux::{*, Fez}};",
     )
 }
 

crates/ide_db/src/imports/merge_imports.rs

@@ -3,7 +3,7 @@
 
 use itertools::{EitherOrBoth, Itertools};
 use syntax::{
-    ast::{self, make, AstNode, HasAttrs, HasVisibility, PathSegmentKind},
+    ast::{self, AstNode, HasAttrs, HasVisibility, PathSegmentKind},
     ted,
 };
 
@@ -129,29 +129,7 @@ fn recursive_merge(lhs: &ast::UseTree, rhs: &ast::UseTree, merge: MergeBehavior)
                         _ => (),
                     }
 
-                    // Glob imports aren't part of the use-tree lists so we need
+                    if lhs_t.use_tree_list().is_none() && rhs_t.use_tree_list().is_none() {
-                    // to special handle them here as well this special handling
-                    // is only required for when we merge a module import into a
-                    // glob import of said module see the `merge_self_glob` or
-                    // `merge_mod_into_glob` tests.
-                    if lhs_t.star_token().is_some() || rhs_t.star_token().is_some() {
-                        if tree_is_self(lhs_t) || tree_is_self(&rhs_t) {
-                            cov_mark::hit!(merge_self_glob);
-                            let self_tree = make::use_tree(
-                                make::path_unqualified(make::path_segment_self()),
-                                None,
-                                None,
-                                false,
-                            )
-                            .clone_for_update();
-                            ted::replace(lhs_t.syntax(), self_tree.syntax());
-                            *lhs_t = self_tree;
-                            let glob = make::use_tree_glob().clone_for_update();
-                            use_trees.insert(idx, glob.clone());
-                            lhs.get_or_create_use_tree_list().add_use_tree(glob);
-                            continue;
-                        }
-                    } else if lhs_t.use_tree_list().is_none() && rhs_t.use_tree_list().is_none() {
                         continue;
                     }
                 }

crates/syntax/src/ast/edit_in_place.rs

@@ -302,16 +302,33 @@ pub fn get_or_create_use_tree_list(&self) -> ast::UseTreeList {
 
     /// Splits off the given prefix, making it the path component of the use tree,
     /// appending the rest of the path to all UseTreeList items.
+    ///
+    /// # Examples
+    ///
+    /// `prefix$0::suffix` -> `prefix::{suffix}`
+    ///
+    /// `prefix$0` -> `prefix::{self}`
+    ///
+    /// `prefix$0::*` -> `prefix::{*}`
     pub fn split_prefix(&self, prefix: &ast::Path) {
         debug_assert_eq!(self.path(), Some(prefix.top_path()));
         let path = self.path().unwrap();
         if &path == prefix && self.use_tree_list().is_none() {
-            let self_suffix = make::path_unqualified(make::path_segment_self()).clone_for_update();
+            if self.star_token().is_some() {
-            ted::replace(path.syntax(), self_suffix.syntax());
+                // path$0::* -> *
+                self.coloncolon_token().map(ted::remove);
+                ted::remove(prefix.syntax());
+            } else {
+                // path$0 -> self
+                let self_suffix =
+                    make::path_unqualified(make::path_segment_self()).clone_for_update();
+                ted::replace(path.syntax(), self_suffix.syntax());
+            }
         } else if split_path_prefix(prefix).is_none() {
             return;
         }
-
+        // At this point, prefix path is detached; _self_ use tree has suffix path.
+        // Next, transoform 'suffix' use tree into 'prefix::{suffix}'
         let subtree = self.clone_subtree().clone_for_update();
         ted::remove_all_iter(self.syntax().children_with_tokens());
         ted::insert(Position::first_child_of(self.syntax()), prefix.syntax());