2 files changed, 77 insertions, 61 deletions

diff --git a/crates/ide_db/src/helpers/insert_use/tests.rs b/crates/ide_db/src/helpers/insert_use/tests.rs
index 048c213e2..248227d29 100644
--- a/crates/ide_db/src/helpers/insert_use/tests.rs
+++ b/crates/ide_db/src/helpers/insert_use/tests.rs
@@ -44,7 +44,7 @@ fn insert_not_group_empty() {
 
 #[test]
 fn insert_existing() {
-    check_full("std::fs", "use std::fs;", "use std::fs;")
+    check_crate("std::fs", "use std::fs;", "use std::fs;")
 }
 
 #[test]
@@ -249,7 +249,7 @@ use self::fmt;",
 
 #[test]
 fn insert_no_imports() {
-    check_full(
+    check_crate(
         "foo::bar",
         "fn main() {}",
         r"use foo::bar;
@@ -263,7 +263,7 @@ fn insert_empty_file() {
     cov_mark::check!(insert_group_empty_file);
     // empty files will get two trailing newlines
     // this is due to the test case insert_no_imports above
-    check_full(
+    check_crate(
         "foo::bar",
         "",
         r"use foo::bar;
@@ -290,7 +290,7 @@ fn insert_empty_module() {
 #[test]
 fn insert_after_inner_attr() {
     cov_mark::check!(insert_group_empty_inner_attr);
-    check_full(
+    check_crate(
         "foo::bar",
         r"#![allow(unused_imports)]",
         r"#![allow(unused_imports)]
@@ -301,7 +301,7 @@ use foo::bar;",
 
 #[test]
 fn insert_after_inner_attr2() {
-    check_full(
+    check_crate(
         "foo::bar",
         r"#![allow(unused_imports)]
 
@@ -371,12 +371,12 @@ fn main() {}"#,
 
 #[test]
 fn merge_groups() {
-    check_last("std::io", r"use std::fmt;", r"use std::{fmt, io};")
+    check_module("std::io", r"use std::fmt;", r"use std::{fmt, io};")
 }
 
 #[test]
 fn merge_groups_last() {
-    check_last(
+    check_module(
         "std::io",
         r"use std::fmt::{Result, Display};",
         r"use std::fmt::{Result, Display};
@@ -386,12 +386,12 @@ use std::io;",
 
 #[test]
 fn merge_last_into_self() {
-    check_last("foo::bar::baz", r"use foo::bar;", r"use foo::bar::{self, baz};");
+    check_module("foo::bar::baz", r"use foo::bar;", r"use foo::bar::{self, baz};");
 }
 
 #[test]
 fn merge_groups_full() {
-    check_full(
+    check_crate(
         "std::io",
         r"use std::fmt::{Result, Display};",
         r"use std::{fmt::{Result, Display}, io};",
@@ -400,17 +400,21 @@ fn merge_groups_full() {
 
 #[test]
 fn merge_groups_long_full() {
-    check_full("std::foo::bar::Baz", r"use std::foo::bar::Qux;", r"use std::foo::bar::{Baz, Qux};")
+    check_crate("std::foo::bar::Baz", r"use std::foo::bar::Qux;", r"use std::foo::bar::{Baz, Qux};")
 }
 
 #[test]
 fn merge_groups_long_last() {
-    check_last("std::foo::bar::Baz", r"use std::foo::bar::Qux;", r"use std::foo::bar::{Baz, Qux};")
+    check_module(
+        "std::foo::bar::Baz",
+        r"use std::foo::bar::Qux;",
+        r"use std::foo::bar::{Baz, Qux};",
+    )
 }
 
 #[test]
 fn merge_groups_long_full_list() {
-    check_full(
+    check_crate(
         "std::foo::bar::Baz",
         r"use std::foo::bar::{Qux, Quux};",
         r"use std::foo::bar::{Baz, Quux, Qux};",
@@ -419,7 +423,7 @@ fn merge_groups_long_full_list() {
 
 #[test]
 fn merge_groups_long_last_list() {
-    check_last(
+    check_module(
         "std::foo::bar::Baz",
         r"use std::foo::bar::{Qux, Quux};",
         r"use std::foo::bar::{Baz, Quux, Qux};",
@@ -428,7 +432,7 @@ fn merge_groups_long_last_list() {
 
 #[test]
 fn merge_groups_long_full_nested() {
-    check_full(
+    check_crate(
         "std::foo::bar::Baz",
         r"use std::foo::bar::{Qux, quux::{Fez, Fizz}};",
         r"use std::foo::bar::{Baz, Qux, quux::{Fez, Fizz}};",
@@ -437,7 +441,7 @@ fn merge_groups_long_full_nested() {
 
 #[test]
 fn merge_groups_long_last_nested() {
-    check_last(
+    check_module(
         "std::foo::bar::Baz",
         r"use std::foo::bar::{Qux, quux::{Fez, Fizz}};",
         r"use std::foo::bar::Baz;
@@ -447,7 +451,7 @@ use std::foo::bar::{Qux, quux::{Fez, Fizz}};",
 
 #[test]
 fn merge_groups_full_nested_deep() {
-    check_full(
+    check_crate(
         "std::foo::bar::quux::Baz",
         r"use std::foo::bar::{Qux, quux::{Fez, Fizz}};",
         r"use std::foo::bar::{Qux, quux::{Baz, Fez, Fizz}};",
@@ -456,7 +460,7 @@ fn merge_groups_full_nested_deep() {
 
 #[test]
 fn merge_groups_full_nested_long() {
-    check_full(
+    check_crate(
         "std::foo::bar::Baz",
         r"use std::{foo::bar::Qux};",
         r"use std::{foo::bar::{Baz, Qux}};",
@@ -465,7 +469,7 @@ fn merge_groups_full_nested_long() {
 
 #[test]
 fn merge_groups_last_nested_long() {
-    check_full(
+    check_crate(
         "std::foo::bar::Baz",
         r"use std::{foo::bar::Qux};",
         r"use std::{foo::bar::{Baz, Qux}};",
@@ -474,7 +478,7 @@ fn merge_groups_last_nested_long() {
 
 #[test]
 fn merge_groups_skip_pub() {
-    check_full(
+    check_crate(
         "std::io",
         r"pub use std::fmt::{Result, Display};",
         r"pub use std::fmt::{Result, Display};
@@ -484,7 +488,7 @@ use std::io;",
 
 #[test]
 fn merge_groups_skip_pub_crate() {
-    check_full(
+    check_crate(
         "std::io",
         r"pub(crate) use std::fmt::{Result, Display};",
         r"pub(crate) use std::fmt::{Result, Display};
@@ -494,7 +498,7 @@ use std::io;",
 
 #[test]
 fn merge_groups_skip_attributed() {
-    check_full(
+    check_crate(
         "std::io",
         r#"
 #[cfg(feature = "gated")] use std::fmt::{Result, Display};
@@ -509,7 +513,7 @@ use std::io;
 #[test]
 #[ignore] // FIXME: Support this
 fn split_out_merge() {
-    check_last(
+    check_module(
         "std::fmt::Result",
         r"use std::{fmt, io};",
         r"use std::fmt::{self, Result};
@@ -519,29 +523,33 @@ use std::io;",
 
 #[test]
 fn merge_into_module_import() {
-    check_full("std::fmt::Result", r"use std::{fmt, io};", r"use std::{fmt::{self, Result}, io};")
+    check_crate("std::fmt::Result", r"use std::{fmt, io};", r"use std::{fmt::{self, Result}, io};")
 }
 
 #[test]
 fn merge_groups_self() {
-    check_full("std::fmt::Debug", r"use std::fmt;", r"use std::fmt::{self, Debug};")
+    check_crate("std::fmt::Debug", r"use std::fmt;", r"use std::fmt::{self, Debug};")
 }
 
 #[test]
 fn merge_mod_into_glob() {
-    check_full("token::TokenKind", r"use token::TokenKind::*;", r"use token::TokenKind::{*, self};")
+    check_crate(
+        "token::TokenKind",
+        r"use token::TokenKind::*;",
+        r"use token::TokenKind::{*, self};",
+    )
     // FIXME: have it emit `use token::TokenKind::{self, *}`?
 }
 
 #[test]
 fn merge_self_glob() {
-    check_full("self", r"use self::*;", r"use self::{*, self};")
+    check_crate("self", r"use self::*;", r"use self::{*, self};")
     // FIXME: have it emit `use {self, *}`?
 }
 
 #[test]
 fn merge_glob_nested() {
-    check_full(
+    check_crate(
         "foo::bar::quux::Fez",
         r"use foo::bar::{Baz, quux::*};",
         r"use foo::bar::{Baz, quux::{self::*, Fez}};",
@@ -550,7 +558,7 @@ fn merge_glob_nested() {
 
 #[test]
 fn merge_nested_considers_first_segments() {
-    check_full(
+    check_crate(
         "hir_ty::display::write_bounds_like_dyn_trait",
         r"use hir_ty::{autoderef, display::{HirDisplayError, HirFormatter}, method_resolution};",
         r"use hir_ty::{autoderef, display::{HirDisplayError, HirFormatter, write_bounds_like_dyn_trait}, method_resolution};",
@@ -559,7 +567,7 @@ fn merge_nested_considers_first_segments() {
 
 #[test]
 fn skip_merge_last_too_long() {
-    check_last(
+    check_module(
         "foo::bar",
         r"use foo::bar::baz::Qux;",
         r"use foo::bar;
@@ -569,7 +577,7 @@ use foo::bar::baz::Qux;",
 
 #[test]
 fn skip_merge_last_too_long2() {
-    check_last(
+    check_module(
         "foo::bar::baz::Qux",
         r"use foo::bar;",
         r"use foo::bar;
@@ -592,7 +600,7 @@ fn merge_last_fail() {
     check_merge_only_fail(
         r"use foo::bar::{baz::{Qux, Fez}};",
         r"use foo::bar::{baaz::{Quux, Feez}};",
-        MergeBehavior::Last,
+        MergeBehavior::Module,
     );
 }
 
@@ -601,7 +609,7 @@ fn merge_last_fail1() {
     check_merge_only_fail(
         r"use foo::bar::{baz::{Qux, Fez}};",
         r"use foo::bar::baaz::{Quux, Feez};",
-        MergeBehavior::Last,
+        MergeBehavior::Module,
     );
 }
 
@@ -610,7 +618,7 @@ fn merge_last_fail2() {
     check_merge_only_fail(
         r"use foo::bar::baz::{Qux, Fez};",
         r"use foo::bar::{baaz::{Quux, Feez}};",
-        MergeBehavior::Last,
+        MergeBehavior::Module,
     );
 }
 
@@ -619,7 +627,7 @@ fn merge_last_fail3() {
     check_merge_only_fail(
         r"use foo::bar::baz::{Qux, Fez};",
         r"use foo::bar::baaz::{Quux, Feez};",
-        MergeBehavior::Last,
+        MergeBehavior::Module,
     );
 }
 
@@ -648,12 +656,12 @@ fn check(
     assert_eq_text!(ra_fixture_after, &result);
 }
 
-fn check_full(path: &str, ra_fixture_before: &str, ra_fixture_after: &str) {
-    check(path, ra_fixture_before, ra_fixture_after, Some(MergeBehavior::Full), false, true)
+fn check_crate(path: &str, ra_fixture_before: &str, ra_fixture_after: &str) {
+    check(path, ra_fixture_before, ra_fixture_after, Some(MergeBehavior::Crate), false, true)
 }
 
-fn check_last(path: &str, ra_fixture_before: &str, ra_fixture_after: &str) {
-    check(path, ra_fixture_before, ra_fixture_after, Some(MergeBehavior::Last), false, true)
+fn check_module(path: &str, ra_fixture_before: &str, ra_fixture_after: &str) {
+    check(path, ra_fixture_before, ra_fixture_after, Some(MergeBehavior::Module), false, true)
 }
 
 fn check_none(path: &str, ra_fixture_before: &str, ra_fixture_after: &str) {
diff --git a/crates/ide_db/src/helpers/merge_imports.rs b/crates/ide_db/src/helpers/merge_imports.rs
index 3f5bbef7f..8fb40e837 100644
--- a/crates/ide_db/src/helpers/merge_imports.rs
+++ b/crates/ide_db/src/helpers/merge_imports.rs
@@ -2,26 +2,27 @@
 use std::cmp::Ordering;
 
 use itertools::{EitherOrBoth, Itertools};
-use syntax::ast::{
-    self, edit::AstNodeEdit, make, AstNode, AttrsOwner, PathSegmentKind, VisibilityOwner,
+use syntax::{
+    ast::{self, make, AstNode, AttrsOwner, PathSegmentKind, VisibilityOwner},
+    ted,
 };
 
 /// What type of merges are allowed.
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
 pub enum MergeBehavior {
-    /// Merge everything together creating deeply nested imports.
-    Full,
-    /// Only merge the last import level, doesn't allow import nesting.
-    Last,
+    /// Merge imports from the same crate into a single use statement.
+    Crate,
+    /// Merge imports from the same module into a single use statement.
+    Module,
 }
 
 impl MergeBehavior {
     #[inline]
     fn is_tree_allowed(&self, tree: &ast::UseTree) -> bool {
         match self {
-            MergeBehavior::Full => true,
+            MergeBehavior::Crate => true,
             // only simple single segment paths are allowed
-            MergeBehavior::Last => {
+            MergeBehavior::Module => {
                 tree.use_tree_list().is_none() && tree.path().map(path_len) <= Some(1)
             }
         }
@@ -41,10 +42,12 @@ pub fn try_merge_imports(
         return None;
     }
 
+    let lhs = lhs.clone_subtree().clone_for_update();
     let lhs_tree = lhs.use_tree()?;
     let rhs_tree = rhs.use_tree()?;
     let merged = try_merge_trees(&lhs_tree, &rhs_tree, merge_behavior)?;
-    Some(lhs.with_use_tree(merged).clone_for_update())
+    ted::replace(lhs_tree.syntax(), merged.syntax());
+    Some(lhs)
 }
 
 pub fn try_merge_trees(
@@ -65,7 +68,7 @@ pub fn try_merge_trees(
     } else {
         (lhs.split_prefix(&lhs_prefix), rhs.split_prefix(&rhs_prefix))
     };
-    recursive_merge(&lhs, &rhs, merge)
+    recursive_merge(&lhs, &rhs, merge).map(|it| it.clone_for_update())
 }
 
 /// Recursively "zips" together lhs and rhs.
@@ -78,7 +81,8 @@ fn recursive_merge(
         .use_tree_list()
         .into_iter()
         .flat_map(|list| list.use_trees())
-        // we use Option here to early return from this function(this is not the same as a `filter` op)
+        // We use Option here to early return from this function(this is not the
+        // same as a `filter` op).
         .map(|tree| match merge.is_tree_allowed(&tree) {
             true => Some(tree),
             false => None,
@@ -111,8 +115,10 @@ fn recursive_merge(
                     let tree_is_self = |tree: ast::UseTree| {
                         tree.path().as_ref().map(path_is_self).unwrap_or(false)
                     };
-                    // check if only one of the two trees has a tree list, and whether that then contains `self` or not.
-                    // If this is the case we can skip this iteration since the path without the list is already included in the other one via `self`
+                    // Check if only one of the two trees has a tree list, and
+                    // whether that then contains `self` or not. If this is the
+                    // case we can skip this iteration since the path without
+                    // the list is already included in the other one via `self`.
                     let tree_contains_self = |tree: &ast::UseTree| {
                         tree.use_tree_list()
                             .map(|tree_list| tree_list.use_trees().any(tree_is_self))
@@ -127,9 +133,11 @@ fn recursive_merge(
                         _ => (),
                     }
 
-                    // glob imports arent part of the use-tree lists so we need 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
+                    // Glob imports aren't part of the use-tree lists so we need
+                    // 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() {
                         *lhs_t = make::use_tree(
                             make::path_unqualified(make::path_segment_self()),
@@ -137,7 +145,7 @@ fn recursive_merge(
                             None,
                             false,
                         );
-                        use_trees.insert(idx, make::glob_use_tree());
+                        use_trees.insert(idx, make::use_tree_glob());
                         continue;
                     }
 
@@ -153,7 +161,7 @@ fn recursive_merge(
                 }
             }
             Err(_)
-                if merge == MergeBehavior::Last
+                if merge == MergeBehavior::Module
                     && use_trees.len() > 0
                     && rhs_t.use_tree_list().is_some() =>
             {
@@ -165,11 +173,11 @@ fn recursive_merge(
         }
     }
 
-    Some(if let Some(old) = lhs.use_tree_list() {
-        lhs.replace_descendant(old, make::use_tree_list(use_trees)).clone_for_update()
-    } else {
-        lhs.clone()
-    })
+    let lhs = lhs.clone_subtree().clone_for_update();
+    if let Some(old) = lhs.use_tree_list() {
+        ted::replace(old.syntax(), make::use_tree_list(use_trees).syntax().clone_for_update());
+    }
+    ast::UseTree::cast(lhs.syntax().clone_subtree())
 }
 
 /// Traverses both paths until they differ, returning the common prefix of both.