Add ide-assist: extract_impl_items

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

@@ -0,0 +1,264 @@
+use crate::assist_context::{AssistContext, Assists};
+use ide_db::assists::AssistId;
+use syntax::{
+    AstNode, SyntaxKind, TextRange,
+    ast::{self, edit_in_place::Indent, make},
+    syntax_editor::Position,
+    ted,
+};
+
+// Assist: extract_impl_items
+//
+// Extract selected impl items into new impl.
+//
+// ```
+// struct Foo;
+// impl Foo {
+//     fn foo() {}
+//     $0fn bar() {}
+//     fn baz() {}$0
+// }
+// ```
+// ->
+// ```
+// struct Foo;
+// impl Foo {
+//     fn foo() {}
+// }
+//
+// impl Foo {
+//     fn bar() {}
+//
+//     fn baz() {}
+// }
+// ```
+pub(crate) fn extract_impl_items(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option<()> {
+    if ctx.has_empty_selection() {
+        return None;
+    }
+    let item = ctx.find_node_at_trimmed_offset::<ast::AssocItem>()?;
+    let impl_ = ast::Impl::cast(item.syntax().parent()?.parent()?)?;
+    let indent = impl_.indent_level();
+    let selection = ctx.selection_trimmed();
+    let items = selection_items(&impl_, selection)?;
+
+    let target = TextRange::new(
+        items.first()?.syntax().text_range().start(),
+        items.last()?.syntax().text_range().end(),
+    );
+    acc.add(
+        AssistId::refactor_extract("extract_impl_items"),
+        "Extract items into new impl block",
+        target,
+        |builder| {
+            let mut edit = builder.make_editor(impl_.syntax());
+            let new_impl = impl_.clone_for_update();
+
+            for origin_item in &items {
+                if let Some(token) = origin_item.syntax().prev_sibling_or_token()
+                    && token.kind() == SyntaxKind::WHITESPACE
+                {
+                    edit.delete(token);
+                }
+                edit.delete(origin_item.syntax());
+            }
+
+            if let Some(assoc_item_list) = new_impl.assoc_item_list() {
+                let new_item_list = make::assoc_item_list(None);
+                ted::replace(assoc_item_list.syntax(), new_item_list.clone_for_update().syntax());
+            }
+
+            let assoc_item_list = new_impl.get_or_create_assoc_item_list();
+
+            for item in items {
+                assoc_item_list.add_item(item.clone_for_update());
+            }
+
+            edit.insert_all(
+                Position::after(impl_.syntax()),
+                vec![
+                    make::tokens::whitespace(&format!("\n\n{indent}")).into(),
+                    new_impl.syntax().clone().into(),
+                ],
+            );
+
+            builder.add_file_edits(ctx.vfs_file_id(), edit);
+        },
+    )
+}
+
+fn selection_items(impl_: &ast::Impl, selection: TextRange) -> Option<Vec<ast::AssocItem>> {
+    let items = impl_
+        .assoc_item_list()?
+        .assoc_items()
+        .filter(|item| {
+            let item_range = item.syntax().text_range();
+            selection == item_range
+                || selection.intersect(item_range).is_some_and(|range| !range.is_empty())
+                    && !item_range.contains_range(selection)
+        })
+        .collect::<Vec<_>>();
+    Some(items)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    #[test]
+    fn test_extract_impl_items() {
+        check_assist(
+            extract_impl_items,
+            r#"
+struct Foo;
+impl Foo {
+    fn other_1() {}
+
+    /// some docs
+
+    /// some docs
+    fn $0extract_1() {}
+
+    // some comment
+
+    fn extract_2() {}
+
+    const EXTRACT_3: u32 = 2;$0
+
+    fn other_2() {}
+}
+            "#,
+            r#"
+struct Foo;
+impl Foo {
+    fn other_1() {}
+
+    // some comment
+
+    fn other_2() {}
+}
+
+impl Foo {
+    /// some docs
+
+    /// some docs
+    fn extract_1() {}
+
+    fn extract_2() {}
+
+    const EXTRACT_3: u32 = 2;
+}
+            "#,
+        );
+    }
+
+    #[test]
+    fn test_extract_impl_items_with_generics() {
+        check_assist(
+            extract_impl_items,
+            r#"
+struct Foo<T>(T);
+impl<T> Foo<T>
+where
+    T: Clone,
+{
+    fn other_1() {}
+
+    /// some docs
+    fn $0extract_1() {}
+
+    // some comment
+    fn extract_2() {}
+
+    const EXTRACT_3: u32 = 2;$0
+
+    fn other_2() {}
+}
+            "#,
+            r#"
+struct Foo<T>(T);
+impl<T> Foo<T>
+where
+    T: Clone,
+{
+    fn other_1() {}
+
+    fn other_2() {}
+}
+
+impl<T> Foo<T>
+where
+    T: Clone,
+{
+    /// some docs
+    fn extract_1() {}
+
+    // some comment
+    fn extract_2() {}
+
+    const EXTRACT_3: u32 = 2;
+}
+            "#,
+        );
+    }
+
+    #[test]
+    fn test_extract_impl_items_with_indent() {
+        check_assist(
+            extract_impl_items,
+            r#"
+mod foo {
+    mod bar {
+        struct Foo;
+        impl Foo {
+            fn other_1() {
+                todo!()
+            }
+
+            $0fn extract_1() {
+                todo!()
+            }$0
+        }
+    }
+}
+            "#,
+            r#"
+mod foo {
+    mod bar {
+        struct Foo;
+        impl Foo {
+            fn other_1() {
+                todo!()
+            }
+        }
+
+        impl Foo {
+            fn extract_1() {
+                todo!()
+            }
+        }
+    }
+}
+            "#,
+        );
+    }
+    #[test]
+    fn test_extract_impl_items_in_body_not_application() {
+        check_assist_not_applicable(
+            extract_impl_items,
+            r#"
+struct Foo;
+impl Foo {
+    fn other_1() {
+        todo!()
+    }
+
+    fn other_1() {
+        $0()$0
+    }
+}
+            "#,
+        );
+    }
+}

crates/ide-assists/src/lib.rs

@@ -144,6 +144,7 @@ mod handlers {
     mod expand_rest_pattern;
     mod extract_expressions_from_format_string;
     mod extract_function;
+    mod extract_impl_items;
     mod extract_module;
     mod extract_struct_from_enum_variant;
     mod extract_type_alias;
@@ -278,6 +279,7 @@ mod handlers {
             expand_glob_import::expand_glob_import,
             expand_glob_import::expand_glob_reexport,
             expand_rest_pattern::expand_rest_pattern,
+            extract_impl_items::extract_impl_items,
             extract_expressions_from_format_string::extract_expressions_from_format_string,
             extract_struct_from_enum_variant::extract_struct_from_enum_variant,
             extract_type_alias::extract_type_alias,

crates/ide-assists/src/tests/generated.rs

@@ -1127,6 +1127,33 @@ fn $0fun_name(n: i32) {
     )
 }
 
+#[test]
+fn doctest_extract_impl_items() {
+    check_doc_test(
+        "extract_impl_items",
+        r#####"
+struct Foo;
+impl Foo {
+    fn foo() {}
+    $0fn bar() {}
+    fn baz() {}$0
+}
+"#####,
+        r#####"
+struct Foo;
+impl Foo {
+    fn foo() {}
+}
+
+impl Foo {
+    fn bar() {}
+
+    fn baz() {}
+}
+"#####,
+    )
+}
+
 #[test]
 fn doctest_extract_module() {
     check_doc_test(