2 files changed, 127 insertions, 47 deletions

diff --git a/crates/ide_assists/src/handlers/extract_struct_from_enum_variant.rs b/crates/ide_assists/src/handlers/extract_struct_from_enum_variant.rs
index 007aba23d..d3ff7b65c 100644
--- a/crates/ide_assists/src/handlers/extract_struct_from_enum_variant.rs
+++ b/crates/ide_assists/src/handlers/extract_struct_from_enum_variant.rs
@@ -11,14 +11,19 @@ use ide_db::{
     search::FileReference,
     RootDatabase,
 };
+use itertools::Itertools;
 use rustc_hash::FxHashSet;
 use syntax::{
-    algo::find_node_at_offset,
-    ast::{self, make, AstNode, NameOwner, VisibilityOwner},
-    ted, SyntaxNode, T,
+    ast::{
+        self, make, AstNode, AttrsOwner, GenericParamsOwner, NameOwner, TypeBoundsOwner,
+        VisibilityOwner,
+    },
+    match_ast,
+    ted::{self, Position},
+    SyntaxNode, T,
 };
 
-use crate::{AssistContext, AssistId, AssistKind, Assists};
+use crate::{assist_context::AssistBuilder, AssistContext, AssistId, AssistKind, Assists};
 
 // Assist: extract_struct_from_enum_variant
 //
@@ -70,11 +75,10 @@ pub(crate) fn extract_struct_from_enum_variant(
                     continue;
                 }
                 builder.edit_file(file_id);
-                let source_file = builder.make_mut(ctx.sema.parse(file_id));
                 let processed = process_references(
                     ctx,
+                    builder,
                     &mut visited_modules_set,
-                    source_file.syntax(),
                     &enum_module_def,
                     &variant_hir_name,
                     references,
@@ -84,13 +88,12 @@ pub(crate) fn extract_struct_from_enum_variant(
                 });
             }
             builder.edit_file(ctx.frange.file_id);
-            let source_file = builder.make_mut(ctx.sema.parse(ctx.frange.file_id));
             let variant = builder.make_mut(variant.clone());
             if let Some(references) = def_file_references {
                 let processed = process_references(
                     ctx,
+                    builder,
                     &mut visited_modules_set,
-                    source_file.syntax(),
                     &enum_module_def,
                     &variant_hir_name,
                     references,
@@ -100,12 +103,12 @@ pub(crate) fn extract_struct_from_enum_variant(
                 });
             }
 
-            let def = create_struct_def(variant_name.clone(), &field_list, enum_ast.visibility());
+            let def = create_struct_def(variant_name.clone(), &field_list, &enum_ast);
             let start_offset = &variant.parent_enum().syntax().clone();
             ted::insert_raw(ted::Position::before(start_offset), def.syntax());
             ted::insert_raw(ted::Position::before(start_offset), &make::tokens::blank_line());
 
-            update_variant(&variant);
+            update_variant(&variant, enum_ast.generic_param_list());
         },
     )
 }
@@ -149,7 +152,7 @@ fn existing_definition(db: &RootDatabase, variant_name: &ast::Name, variant: &Va
 fn create_struct_def(
     variant_name: ast::Name,
     field_list: &Either<ast::RecordFieldList, ast::TupleFieldList>,
-    visibility: Option<ast::Visibility>,
+    enum_: &ast::Enum,
 ) -> ast::Struct {
     let pub_vis = make::visibility_pub();
 
@@ -184,12 +187,38 @@ fn create_struct_def(
         }
     };
 
-    make::struct_(visibility, variant_name, None, field_list).clone_for_update()
+    // FIXME: This uses all the generic params of the enum, but the variant might not use all of them.
+    let strukt =
+        make::struct_(enum_.visibility(), variant_name, enum_.generic_param_list(), field_list)
+            .clone_for_update();
+
+    // copy attributes
+    ted::insert_all(
+        Position::first_child_of(strukt.syntax()),
+        enum_.attrs().map(|it| it.syntax().clone_for_update().into()).collect(),
+    );
+    strukt
 }
 
-fn update_variant(variant: &ast::Variant) -> Option<()> {
+fn update_variant(variant: &ast::Variant, generic: Option<ast::GenericParamList>) -> Option<()> {
     let name = variant.name()?;
-    let tuple_field = make::tuple_field(None, make::ty(&name.text()));
+    let ty = match generic {
+        // FIXME: This uses all the generic params of the enum, but the variant might not use all of them.
+        Some(gpl) => {
+            let gpl = gpl.clone_for_update();
+            gpl.generic_params().for_each(|gp| {
+                match gp {
+                    ast::GenericParam::LifetimeParam(it) => it.type_bound_list(),
+                    ast::GenericParam::TypeParam(it) => it.type_bound_list(),
+                    ast::GenericParam::ConstParam(_) => return,
+                }
+                .map(|it| it.remove());
+            });
+            make::ty(&format!("{}<{}>", name.text(), gpl.generic_params().join(", ")))
+        }
+        None => make::ty(&name.text()),
+    };
+    let tuple_field = make::tuple_field(None, ty);
     let replacement = make::variant(
         name,
         Some(ast::FieldList::TupleFieldList(make::tuple_field_list(iter::once(tuple_field)))),
@@ -208,18 +237,17 @@ fn apply_references(
     if let Some((scope, path)) = import {
         insert_use(&scope, mod_path_to_ast(&path), insert_use_cfg);
     }
-    ted::insert_raw(
-        ted::Position::before(segment.syntax()),
-        make::path_from_text(&format!("{}", segment)).clone_for_update().syntax(),
-    );
+    // deep clone to prevent cycle
+    let path = make::path_from_segments(iter::once(segment.clone_subtree()), false);
+    ted::insert_raw(ted::Position::before(segment.syntax()), path.clone_for_update().syntax());
     ted::insert_raw(ted::Position::before(segment.syntax()), make::token(T!['(']));
     ted::insert_raw(ted::Position::after(&node), make::token(T![')']));
 }
 
 fn process_references(
     ctx: &AssistContext,
+    builder: &mut AssistBuilder,
     visited_modules: &mut FxHashSet<Module>,
-    source_file: &SyntaxNode,
     enum_module_def: &ModuleDef,
     variant_hir_name: &Name,
     refs: Vec<FileReference>,
@@ -228,8 +256,9 @@ fn process_references(
     // and corresponding nodes up front
     refs.into_iter()
         .flat_map(|reference| {
-            let (segment, scope_node, module) =
-                reference_to_node(&ctx.sema, source_file, reference)?;
+            let (segment, scope_node, module) = reference_to_node(&ctx.sema, reference)?;
+            let segment = builder.make_mut(segment);
+            let scope_node = builder.make_syntax_mut(scope_node);
             if !visited_modules.contains(&module) {
                 let mod_path = module.find_use_path_prefixed(
                     ctx.sema.db,
@@ -251,23 +280,22 @@ fn process_references(
 
 fn reference_to_node(
     sema: &hir::Semantics<RootDatabase>,
-    source_file: &SyntaxNode,
     reference: FileReference,
 ) -> Option<(ast::PathSegment, SyntaxNode, hir::Module)> {
-    let offset = reference.range.start();
-    if let Some(path_expr) = find_node_at_offset::<ast::PathExpr>(source_file, offset) {
-        // tuple variant
-        Some((path_expr.path()?.segment()?, path_expr.syntax().parent()?))
-    } else if let Some(record_expr) = find_node_at_offset::<ast::RecordExpr>(source_file, offset) {
-        // record variant
-        Some((record_expr.path()?.segment()?, record_expr.syntax().clone()))
-    } else {
-        None
-    }
-    .and_then(|(segment, expr)| {
-        let module = sema.scope(&expr).module()?;
-        Some((segment, expr, module))
-    })
+    let segment =
+        reference.name.as_name_ref()?.syntax().parent().and_then(ast::PathSegment::cast)?;
+    let parent = segment.parent_path().syntax().parent()?;
+    let expr_or_pat = match_ast! {
+        match parent {
+            ast::PathExpr(_it) => parent.parent()?,
+            ast::RecordExpr(_it) => parent,
+            ast::TupleStructPat(_it) => parent,
+            ast::RecordPat(_it) => parent,
+            _ => return None,
+        }
+    };
+    let module = sema.scope(&expr_or_pat).module()?;
+    Some((segment, expr_or_pat, module))
 }
 
 #[cfg(test)]
@@ -278,6 +306,12 @@ mod tests {
 
     use super::*;
 
+    fn check_not_applicable(ra_fixture: &str) {
+        let fixture =
+            format!("//- /main.rs crate:main deps:core\n{}\n{}", ra_fixture, FamousDefs::FIXTURE);
+        check_assist_not_applicable(extract_struct_from_enum_variant, &fixture)
+    }
+
     #[test]
     fn test_extract_struct_several_fields_tuple() {
         check_assist(
@@ -312,6 +346,32 @@ enum A { One(One) }"#,
     }
 
     #[test]
+    fn test_extract_struct_carries_over_generics() {
+        check_assist(
+            extract_struct_from_enum_variant,
+            r"enum En<T> { Var { a: T$0 } }",
+            r#"struct Var<T>{ pub a: T }
+
+enum En<T> { Var(Var<T>) }"#,
+        );
+    }
+
+    #[test]
+    fn test_extract_struct_carries_over_attributes() {
+        check_assist(
+            extract_struct_from_enum_variant,
+            r#"#[derive(Debug)]
+#[derive(Clone)]
+enum Enum { Variant{ field: u32$0 } }"#,
+            r#"#[derive(Debug)]#[derive(Clone)] struct Variant{ pub field: u32 }
+
+#[derive(Debug)]
+#[derive(Clone)]
+enum Enum { Variant(Variant) }"#,
+        );
+    }
+
+    #[test]
     fn test_extract_struct_keep_comments_and_attrs_one_field_named() {
         check_assist(
             extract_struct_from_enum_variant,
@@ -496,7 +556,7 @@ enum E {
 }
 
 fn f() {
-    let e = E::V { i: 9, j: 2 };
+    let E::V { i, j } = E::V { i: 9, j: 2 };
 }
 "#,
             r#"
@@ -507,7 +567,34 @@ enum E {
 }
 
 fn f() {
-    let e = E::V(V { i: 9, j: 2 });
+    let E::V(V { i, j }) = E::V(V { i: 9, j: 2 });
+}
+"#,
+        )
+    }
+
+    #[test]
+    fn extract_record_fix_references2() {
+        check_assist(
+            extract_struct_from_enum_variant,
+            r#"
+enum E {
+    $0V(i32, i32)
+}
+
+fn f() {
+    let E::V(i, j) = E::V(9, 2);
+}
+"#,
+            r#"
+struct V(pub i32, pub i32);
+
+enum E {
+    V(V)
+}
+
+fn f() {
+    let E::V(V(i, j)) = E::V(V(9, 2));
 }
 "#,
         )
@@ -610,12 +697,6 @@ fn foo() {
         );
     }
 
-    fn check_not_applicable(ra_fixture: &str) {
-        let fixture =
-            format!("//- /main.rs crate:main deps:core\n{}\n{}", ra_fixture, FamousDefs::FIXTURE);
-        check_assist_not_applicable(extract_struct_from_enum_variant, &fixture)
-    }
-
     #[test]
     fn test_extract_enum_not_applicable_for_element_with_no_fields() {
         check_not_applicable("enum A { $0One }");
diff --git a/crates/syntax/src/ast/make.rs b/crates/syntax/src/ast/make.rs
index 0cf170626..4c3c9661d 100644
--- a/crates/syntax/src/ast/make.rs
+++ b/crates/syntax/src/ast/make.rs
@@ -580,12 +580,11 @@ pub fn fn_(
 pub fn struct_(
     visibility: Option<ast::Visibility>,
     strukt_name: ast::Name,
-    type_params: Option<ast::GenericParamList>,
+    generic_param_list: Option<ast::GenericParamList>,
     field_list: ast::FieldList,
 ) -> ast::Struct {
     let semicolon = if matches!(field_list, ast::FieldList::TupleFieldList(_)) { ";" } else { "" };
-    let type_params =
-        if let Some(type_params) = type_params { format!("<{}>", type_params) } else { "".into() };
+    let type_params = generic_param_list.map_or_else(String::new, |it| it.to_string());
     let visibility = match visibility {
         None => String::new(),
         Some(it) => format!("{} ", it),