Fix auto-import namespace collision merges

crates/ide-assists/src/handlers/auto_import.rs

@@ -127,6 +127,7 @@ pub(crate) fn auto_import(acc: &mut Assists, ctx: &AssistContext<'_, '_>) -> Opt
             acc.add_group(&group_label, assist_id, label, range, |builder| {
                 let editor = builder.make_editor(scope.as_syntax_node());
                 insert_use_with_editor(
+                    &ctx.sema,
                     &scope,
                     mod_path_to_ast(&import_path, edition),
                     &ctx.config.insert_use,
@@ -147,6 +148,7 @@ pub(crate) fn auto_import(acc: &mut Assists, ctx: &AssistContext<'_, '_>) -> Opt
             acc.add_group(&group_label, assist_id, label, range, |builder| {
                 let editor = builder.make_editor(scope.as_syntax_node());
                 insert_use_as_alias_with_editor(
+                    &ctx.sema,
                     &scope,
                     mod_path_to_ast(&import_path, edition),
                     &ctx.config.insert_use,
@@ -352,8 +354,8 @@ mod tests {
     use test_fixture::WithFixture;
 
     use crate::tests::{
-        TEST_CONFIG, check_assist, check_assist_by_label, check_assist_not_applicable,
-        check_assist_target,
+        TEST_CONFIG, check_assist, check_assist_by_label, check_assist_import_one,
+        check_assist_not_applicable, check_assist_target,
     };
 
     fn check_auto_import_order(before: &str, order: &[&str]) {
@@ -553,6 +555,80 @@ mod baz {
         );
     }
 
+    #[test]
+    fn preserves_value_namespace_when_merging() {
+        check_assist(
+            auto_import,
+            r#"
+use foo::bar;
+
+mod foo {
+    pub mod bar {
+        pub struct Baz;
+    }
+    pub fn bar() {}
+}
+
+fn main() {
+    let _: Baz$0;
+    bar();
+}
+"#,
+            r#"
+use foo::{bar, bar::Baz};
+
+mod foo {
+    pub mod bar {
+        pub struct Baz;
+    }
+    pub fn bar() {}
+}
+
+fn main() {
+    let _: Baz;
+    bar();
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn preserves_value_namespace_when_merging_all_imports() {
+        check_assist_import_one(
+            auto_import,
+            r#"
+use foo::bar;
+
+mod foo {
+    pub mod bar {
+        pub struct Baz;
+    }
+    pub fn bar() {}
+}
+
+fn main() {
+    let _: Baz$0;
+    bar();
+}
+"#,
+            r#"
+use {foo::bar, foo::bar::Baz};
+
+mod foo {
+    pub mod bar {
+        pub struct Baz;
+    }
+    pub fn bar() {}
+}
+
+fn main() {
+    let _: Baz;
+    bar();
+}
+"#,
+        );
+    }
+
     #[test]
     fn applicable_when_found_an_import() {
         check_assist(

crates/ide-assists/src/handlers/convert_bool_to_enum.rs

@@ -88,7 +88,7 @@ pub(crate) fn convert_bool_to_enum(acc: &mut Assists, ctx: &AssistContext<'_, '_
             );
             for (file_id, scope, path) in delayed_mutations {
                 let editor = edit.make_editor(scope.as_syntax_node());
-                insert_use_with_editor(&scope, path, &ctx.config.insert_use, &editor);
+                insert_use_with_editor(&ctx.sema, &scope, path, &ctx.config.insert_use, &editor);
                 edit.add_file_edits(file_id, editor);
             }
         },

crates/ide-assists/src/handlers/convert_tuple_return_type_to_struct.rs

@@ -155,7 +155,13 @@ fn replace_usages(
                 }
             }
             if let Some((import_scope, path)) = import_data {
-                insert_use_with_editor(&import_scope, path, &ctx.config.insert_use, &editor);
+                insert_use_with_editor(
+                    &ctx.sema,
+                    &import_scope,
+                    path,
+                    &ctx.config.insert_use,
+                    &editor,
+                );
             }
         });
         edit.add_file_edits(file_id.file_id(ctx.db()), editor);

crates/ide-assists/src/handlers/extract_function.rs

@@ -204,6 +204,7 @@ pub(crate) fn extract_function(acc: &mut Assists, ctx: &AssistContext<'_, '_>) -
 
                     if let Some(mod_path) = mod_path {
                         insert_use_with_editor(
+                            &ctx.sema,
                             &scope,
                             mod_path_to_ast_with_factory(make, &mod_path, edition),
                             &ctx.config.insert_use,

crates/ide-assists/src/handlers/extract_struct_from_enum_variant.rs

@@ -1,7 +1,7 @@
 use std::iter;
 
 use either::Either;
-use hir::{EnumVariant, HasCrate, Module, ModuleDef, Name};
+use hir::{EnumVariant, HasCrate, Module, ModuleDef, Name, Semantics};
 use ide_db::{
     FxHashSet, RootDatabase,
     defs::Definition,
@@ -90,6 +90,7 @@ pub(crate) fn extract_struct_from_enum_variant(
                 let file_editor = builder.make_editor(processed[0].0.syntax());
                 processed.into_iter().for_each(|(path, node, import)| {
                     apply_references(
+                        &ctx.sema,
                         ctx.config.insert_use,
                         path,
                         node,
@@ -110,7 +111,15 @@ pub(crate) fn extract_struct_from_enum_variant(
                     references,
                 );
                 processed.into_iter().for_each(|(path, node, import)| {
-                    apply_references(ctx.config.insert_use, path, node, import, edition, &editor)
+                    apply_references(
+                        &ctx.sema,
+                        ctx.config.insert_use,
+                        path,
+                        node,
+                        import,
+                        edition,
+                        &editor,
+                    )
                 });
             }
 
@@ -385,6 +394,7 @@ fn collect_variant_comments(
 }
 
 fn apply_references(
+    sema: &Semantics<'_, RootDatabase>,
     insert_use_cfg: InsertUseConfig,
     segment: ast::PathSegment,
     node: SyntaxNode,
@@ -395,6 +405,7 @@ fn apply_references(
     let make = editor.make();
     if let Some((scope, path)) = import {
         insert_use_with_editor(
+            sema,
             &scope,
             mod_path_to_ast_with_factory(make, &path, edition),
             &insert_use_cfg,

crates/ide-assists/src/handlers/merge_imports.rs

@@ -98,7 +98,7 @@ fn merge_uses(
     };
     let mut merged = first.clone();
     for item in &rest {
-        merged = try_merge_imports(editor.make(), &merged, item, mb)?;
+        merged = try_merge_imports(editor.make(), &merged, item, mb, None)?;
     }
     for item in rest {
         item.remove(editor);

crates/ide-assists/src/handlers/replace_qualified_name_with_use.rs

@@ -95,7 +95,7 @@ pub(crate) fn replace_qualified_name_with_use(
                 Some(qualifier) => make.path_concat(qualifier, path),
                 None => path,
             };
-            insert_use_with_editor(&scope, path, &ctx.config.insert_use, &editor);
+            insert_use_with_editor(&ctx.sema, &scope, path, &ctx.config.insert_use, &editor);
             builder.add_file_edits(ctx.vfs_file_id(), editor);
         },
     )

crates/ide-assists/src/handlers/unqualify_method_call.rs

@@ -106,6 +106,7 @@ fn add_import(
 
         if let Some(scope) = scope {
             ide_db::imports::insert_use::insert_use_with_editor(
+                &ctx.sema,
                 &scope,
                 import,
                 &ctx.config.insert_use,

crates/ide-completion/src/lib.rs

@@ -304,14 +304,21 @@ pub fn resolve_completion_edits(
         let full_path = make.path_from_text_with_edition(&import.path, current_edition);
         if import.as_underscore {
             insert_use::insert_use_as_alias_with_editor(
+                &sema,
                 &scope,
                 full_path,
                 &config.insert_use,
                 current_edition,
                 &editor,
             );
         } else {
-            insert_use::insert_use_with_editor(&scope, full_path, &config.insert_use, &editor);
+            insert_use::insert_use_with_editor(
+                &sema,
+                &scope,
+                full_path,
+                &config.insert_use,
+                &editor,
+            );
         }
     });
 

crates/ide-completion/src/tests/flyimport.rs

@@ -100,6 +100,98 @@ fn main() {
     );
 }
 
+#[test]
+fn flyimport_preserves_value_namespace_when_merging() {
+    check_edit(
+        "Baz",
+        r#"
+//- /lib.rs crate:dep
+pub mod bar {
+    pub struct Baz;
+}
+pub fn bar() {}
+
+//- /main.rs crate:main deps:dep
+use dep::bar;
+
+fn main() {
+    Ba$0;
+    bar();
+}
+"#,
+        r#"
+use dep::{bar, bar::Baz};
+
+fn main() {
+    Baz;
+    bar();
+}
+"#,
+    );
+}
+
+#[test]
+fn flyimport_preserves_macro_namespace_when_merging() {
+    check_edit(
+        "vec!",
+        r#"
+//- /lib.rs crate:dep
+pub mod vec {
+    pub struct Vec;
+}
+#[macro_export]
+macro_rules! vec {
+    () => {};
+}
+
+//- /main.rs crate:main deps:dep
+use dep::vec::Vec;
+
+fn main() {
+    ve$0
+}
+"#,
+        r#"
+use dep::{vec, vec::Vec};
+
+fn main() {
+    vec!($0)
+}
+"#,
+    );
+}
+
+#[test]
+fn flyimport_preserves_macro_namespace_with_existing_self() {
+    check_edit(
+        "vec!",
+        r#"
+//- /lib.rs crate:dep
+pub mod vec {
+    pub struct Vec;
+}
+#[macro_export]
+macro_rules! vec {
+    () => {};
+}
+
+//- /main.rs crate:main deps:dep
+use dep::vec::{self, Vec};
+
+fn main() {
+    ve$0
+}
+"#,
+        r#"
+use dep::{vec, vec::Vec};
+
+fn main() {
+    vec!($0)
+}
+"#,
+    );
+}
+
 #[test]
 fn struct_fuzzy_completion() {
     check_edit(