1 //! FIXME: write short doc here
5 use hir::{db::HirDatabase, Adt, HasSource};
6 use ra_syntax::ast::{self, edit::IndentLevel, make, AstNode, NameOwner};
8 use crate::{Assist, AssistCtx, AssistId};
10 // Assist: fill_match_arms
12 // Adds missing clauses to a `match` expression.
15 // enum Action { Move { distance: u32 }, Stop }
17 // fn handle(action: Action) {
25 // enum Action { Move { distance: u32 }, Stop }
27 // fn handle(action: Action) {
29 // Action::Move { distance } => (),
30 // Action::Stop => (),
34 pub(crate) fn fill_match_arms(ctx: AssistCtx) -> Option<Assist> {
35 let match_expr = ctx.find_node_at_offset::<ast::MatchExpr>()?;
36 let match_arm_list = match_expr.match_arm_list()?;
38 // We already have some match arms, so we don't provide any assists.
39 // Unless if there is only one trivial match arm possibly created
40 // by match postfix complete. Trivial match arm is the catch all arm.
41 let mut existing_arms = match_arm_list.arms();
42 if let Some(arm) = existing_arms.next() {
43 if !is_trivial(&arm) || existing_arms.next().is_some() {
48 let expr = match_expr.expr()?;
49 let (enum_def, module) = {
50 let analyzer = ctx.source_analyzer(expr.syntax(), None);
51 (resolve_enum_def(ctx.db, &analyzer, &expr)?, analyzer.module()?)
53 let variants = enum_def.variants(ctx.db);
54 if variants.is_empty() {
60 ctx.add_assist(AssistId("fill_match_arms"), "Fill match arms", |edit| {
61 let indent_level = IndentLevel::from_node(match_arm_list.syntax());
66 .filter_map(|variant| build_pat(db, module, variant))
67 .map(|pat| make::match_arm(iter::once(pat), make::expr_unit()));
68 indent_level.increase_indent(make::match_arm_list(arms))
71 edit.target(match_expr.syntax().text_range());
72 edit.set_cursor(expr.syntax().text_range().start());
73 edit.replace_ast(match_arm_list, new_arm_list);
77 fn is_trivial(arm: &ast::MatchArm) -> bool {
79 Some(ast::Pat::PlaceholderPat(..)) => true,
85 db: &impl HirDatabase,
86 analyzer: &hir::SourceAnalyzer,
88 ) -> Option<hir::Enum> {
89 let expr_ty = analyzer.type_of(db, &expr)?;
91 let result = expr_ty.autoderef(db).find_map(|ty| match ty.as_adt() {
92 Some(Adt::Enum(e)) => Some(e),
99 db: &impl HirDatabase,
101 var: hir::EnumVariant,
102 ) -> Option<ast::Pat> {
103 let path = crate::ast_transform::path_to_ast(module.find_use_path(db, var.into())?);
105 // FIXME: use HIR for this; it doesn't currently expose struct vs. tuple vs. unit variants though
106 let pat: ast::Pat = match var.source(db).value.kind() {
107 ast::StructKind::Tuple(field_list) => {
109 iter::repeat(make::placeholder_pat().into()).take(field_list.fields().count());
110 make::tuple_struct_pat(path, pats).into()
112 ast::StructKind::Record(field_list) => {
113 let pats = field_list.fields().map(|f| make::bind_pat(f.name().unwrap()).into());
114 make::record_pat(path, pats).into()
116 ast::StructKind::Unit => make::path_pat(path),
124 use crate::helpers::{check_assist, check_assist_target};
126 use super::fill_match_arms;
129 fn fill_match_arms_empty_body() {
138 Es{ x: usize, y: usize }
152 Es{ x: usize, y: usize }
162 A::Es { x, y } => (),
170 fn test_fill_match_arm_refs() {
200 Es{ x: usize, y: usize }
210 Es{ x: usize, y: usize }
215 A::Es { x, y } => (),
223 fn fill_match_arms_target() {
238 fn fill_match_arms_trivial_arm() {
264 fn fill_match_arms_qualifies_path() {
268 mod foo { pub enum E { X, Y } }
278 mod foo { pub enum E { X, Y } }