3 files changed, 101 insertions, 49 deletions

diff --git a/crates/assists/src/handlers/extract_struct_from_enum_variant.rs b/crates/assists/src/handlers/extract_struct_from_enum_variant.rs
index 1bf5a4214..14209b771 100644
--- a/crates/assists/src/handlers/extract_struct_from_enum_variant.rs
+++ b/crates/assists/src/handlers/extract_struct_from_enum_variant.rs
@@ -1,3 +1,6 @@
+use std::iter;
+
+use either::Either;
 use hir::{AsName, EnumVariant, Module, ModuleDef, Name};
 use ide_db::{defs::Definition, search::Reference, RootDatabase};
 use rustc_hash::{FxHashMap, FxHashSet};
@@ -31,48 +34,32 @@ pub(crate) fn extract_struct_from_enum_variant(
     ctx: &AssistContext,
 ) -> Option<()> {
     let variant = ctx.find_node_at_offset::<ast::Variant>()?;
-
-    fn is_applicable_variant(variant: &ast::Variant) -> bool {
-        1 < match variant.kind() {
-            ast::StructKind::Record(field_list) => field_list.fields().count(),
-            ast::StructKind::Tuple(field_list) => field_list.fields().count(),
-            ast::StructKind::Unit => 0,
-        }
-    }
-
-    if !is_applicable_variant(&variant) {
-        return None;
-    }
-
-    let field_list = match variant.kind() {
-        ast::StructKind::Tuple(field_list) => field_list,
-        _ => return None,
-    };
+    let field_list = extract_field_list_if_applicable(&variant)?;
 
     let variant_name = variant.name()?;
     let variant_hir = ctx.sema.to_def(&variant)?;
     if existing_definition(ctx.db(), &variant_name, &variant_hir) {
         return None;
     }
+
     let enum_ast = variant.parent_enum();
-    let visibility = enum_ast.visibility();
     let enum_hir = ctx.sema.to_def(&enum_ast)?;
-    let variant_hir_name = variant_hir.name(ctx.db());
-    let enum_module_def = ModuleDef::from(enum_hir);
-    let current_module = enum_hir.module(ctx.db());
     let target = variant.syntax().text_range();
     acc.add(
         AssistId("extract_struct_from_enum_variant", AssistKind::RefactorRewrite),
         "Extract struct from enum variant",
         target,
         |builder| {
-            let definition = Definition::ModuleDef(ModuleDef::EnumVariant(variant_hir));
-            let res = definition.usages(&ctx.sema).all();
+            let variant_hir_name = variant_hir.name(ctx.db());
+            let enum_module_def = ModuleDef::from(enum_hir);
+            let usages =
+                Definition::ModuleDef(ModuleDef::EnumVariant(variant_hir)).usages(&ctx.sema).all();
 
             let mut visited_modules_set = FxHashSet::default();
+            let current_module = enum_hir.module(ctx.db());
             visited_modules_set.insert(current_module);
             let mut rewriters = FxHashMap::default();
-            for reference in res {
+            for reference in usages {
                 let rewriter = rewriters
                     .entry(reference.file_range.file_id)
                     .or_insert_with(SyntaxRewriter::default);
@@ -94,20 +81,34 @@ pub(crate) fn extract_struct_from_enum_variant(
                 builder.rewrite(rewriter);
             }
             builder.edit_file(ctx.frange.file_id);
-            update_variant(&mut rewriter, &variant_name, &field_list);
+            update_variant(&mut rewriter, &variant);
             extract_struct_def(
                 &mut rewriter,
                 &enum_ast,
                 variant_name.clone(),
                 &field_list,
                 &variant.parent_enum().syntax().clone().into(),
-                visibility,
+                enum_ast.visibility(),
             );
             builder.rewrite(rewriter);
         },
     )
 }
 
+fn extract_field_list_if_applicable(
+    variant: &ast::Variant,
+) -> Option<Either<ast::RecordFieldList, ast::TupleFieldList>> {
+    match variant.kind() {
+        ast::StructKind::Record(field_list) if field_list.fields().next().is_some() => {
+            Some(Either::Left(field_list))
+        }
+        ast::StructKind::Tuple(field_list) if field_list.fields().count() > 1 => {
+            Some(Either::Right(field_list))
+        }
+        _ => None,
+    }
+}
+
 fn existing_definition(db: &RootDatabase, variant_name: &ast::Name, variant: &EnumVariant) -> bool {
     variant
         .parent_enum(db)
@@ -150,19 +151,29 @@ fn extract_struct_def(
     rewriter: &mut SyntaxRewriter,
     enum_: &ast::Enum,
     variant_name: ast::Name,
-    variant_list: &ast::TupleFieldList,
+    field_list: &Either<ast::RecordFieldList, ast::TupleFieldList>,
     start_offset: &SyntaxElement,
     visibility: Option<ast::Visibility>,
 ) -> Option<()> {
-    let variant_list = make::tuple_field_list(
-        variant_list
-            .fields()
-            .flat_map(|field| Some(make::tuple_field(Some(make::visibility_pub()), field.ty()?))),
-    );
+    let pub_vis = Some(make::visibility_pub());
+    let field_list = match field_list {
+        Either::Left(field_list) => {
+            make::record_field_list(field_list.fields().flat_map(|field| {
+                Some(make::record_field(pub_vis.clone(), field.name()?, field.ty()?))
+            }))
+            .into()
+        }
+        Either::Right(field_list) => make::tuple_field_list(
+            field_list
+                .fields()
+                .flat_map(|field| Some(make::tuple_field(pub_vis.clone(), field.ty()?))),
+        )
+        .into(),
+    };
 
     rewriter.insert_before(
         start_offset,
-        make::struct_(visibility, variant_name, None, variant_list.into()).syntax(),
+        make::struct_(visibility, variant_name, None, field_list).syntax(),
     );
     rewriter.insert_before(start_offset, &make::tokens::blank_line());
 
@@ -173,15 +184,14 @@ fn extract_struct_def(
     Some(())
 }
 
-fn update_variant(
-    rewriter: &mut SyntaxRewriter,
-    variant_name: &ast::Name,
-    field_list: &ast::TupleFieldList,
-) -> Option<()> {
-    let (l, r): (SyntaxElement, SyntaxElement) =
-        (field_list.l_paren_token()?.into(), field_list.r_paren_token()?.into());
-    let replacement = vec![l, variant_name.syntax().clone().into(), r];
-    rewriter.replace_with_many(field_list.syntax(), replacement);
+fn update_variant(rewriter: &mut SyntaxRewriter, variant: &ast::Variant) -> Option<()> {
+    let name = variant.name()?;
+    let tuple_field = make::tuple_field(None, make::ty(name.text()));
+    let replacement = make::variant(
+        name,
+        Some(ast::FieldList::TupleFieldList(make::tuple_field_list(iter::once(tuple_field)))),
+    );
+    rewriter.replace(variant.syntax(), replacement.syntax());
     Some(())
 }
 
@@ -243,10 +253,18 @@ enum A { One(One) }"#,
         check_assist(
             extract_struct_from_enum_variant,
             "enum A { <|>One { foo: u32, bar: u32 } }",
-            r#"struct One {
-    pub foo: u32,
-    pub bar: u32
-}
+            r#"struct One{ pub foo: u32, pub bar: u32 }
+
+enum A { One(One) }"#,
+        );
+    }
+
+    #[test]
+    fn test_extract_struct_one_field_named() {
+        check_assist(
+            extract_struct_from_enum_variant,
+            "enum A { <|>One { foo: u32 } }",
+            r#"struct One{ pub foo: u32 }
 
 enum A { One(One) }"#,
         );
@@ -350,4 +368,14 @@ fn another_fn() {
     fn test_extract_not_applicable_one_field() {
         check_not_applicable(r"enum A { <|>One(u32) }");
     }
+
+    #[test]
+    fn test_extract_not_applicable_no_field_tuple() {
+        check_not_applicable(r"enum A { <|>None() }");
+    }
+
+    #[test]
+    fn test_extract_not_applicable_no_field_named() {
+        check_not_applicable(r"enum A { <|>None {} }");
+    }
 }
diff --git a/crates/ide/src/diagnostics/fixes.rs b/crates/ide/src/diagnostics/fixes.rs
index 02e17ba43..d275dd75b 100644
--- a/crates/ide/src/diagnostics/fixes.rs
+++ b/crates/ide/src/diagnostics/fixes.rs
@@ -157,7 +157,8 @@ fn missing_record_expr_field_fix(
         return None;
     }
     let new_field = make::record_field(
-        record_expr_field.field_name()?,
+        None,
+        make::name(record_expr_field.field_name()?.text()),
         make::ty(&new_field_type.display_source_code(sema.db, module.into()).ok()?),
     );
 
diff --git a/crates/syntax/src/ast/make.rs b/crates/syntax/src/ast/make.rs
index 2cf436e7a..b1578820f 100644
--- a/crates/syntax/src/ast/make.rs
+++ b/crates/syntax/src/ast/make.rs
@@ -110,8 +110,16 @@ pub fn record_expr_field(name: ast::NameRef, expr: Option<ast::Expr>) -> ast::Re
     }
 }
 
-pub fn record_field(name: ast::NameRef, ty: ast::Type) -> ast::RecordField {
-    ast_from_text(&format!("struct S {{ {}: {}, }}", name, ty))
+pub fn record_field(
+    visibility: Option<ast::Visibility>,
+    name: ast::Name,
+    ty: ast::Type,
+) -> ast::RecordField {
+    let visibility = match visibility {
+        None => String::new(),
+        Some(it) => format!("{} ", it),
+    };
+    ast_from_text(&format!("struct S {{ {}{}: {}, }}", visibility, name, ty))
 }
 
 pub fn block_expr(
@@ -360,6 +368,13 @@ pub fn tuple_field_list(fields: impl IntoIterator<Item = ast::TupleField>) -> as
     ast_from_text(&format!("struct f({});", fields))
 }
 
+pub fn record_field_list(
+    fields: impl IntoIterator<Item = ast::RecordField>,
+) -> ast::RecordFieldList {
+    let fields = fields.into_iter().join(", ");
+    ast_from_text(&format!("struct f {{ {} }}", fields))
+}
+
 pub fn tuple_field(visibility: Option<ast::Visibility>, ty: ast::Type) -> ast::TupleField {
     let visibility = match visibility {
         None => String::new(),
@@ -368,6 +383,14 @@ pub fn tuple_field(visibility: Option<ast::Visibility>, ty: ast::Type) -> ast::T
     ast_from_text(&format!("struct f({}{});", visibility, ty))
 }
 
+pub fn variant(name: ast::Name, field_list: Option<ast::FieldList>) -> ast::Variant {
+    let field_list = match field_list {
+        None => String::new(),
+        Some(it) => format!("{}", it),
+    };
+    ast_from_text(&format!("enum f {{ {}{} }}", name, field_list))
+}
+
 pub fn fn_(
     visibility: Option<ast::Visibility>,
     fn_name: ast::Name,